Improved multi-cylinder hydraulic machine

Abstract

Hydraulic machine in which each pair formed by a piston (50) and a housing (40) defines, between the piston (50) and the housing (40), a first chamber (60) and a second chamber (70) which are separate, the cylinder block (30) and the distributor (165) each having a plurality of inner ducts defining a first set of ducts and a second set of ducts, said sets of ducts opening at the interface between the distributor (165) and the cylinder block (30) in two distinct radii relative to the main axis (Z-Z) and being suitable for supplying the first chambers (60) and the second chambers (70), respectively.

Description

Description Title of the invention: Improved multi-cylinder hydraulic machine Technical Field

[0001] The present invention relates to a multi-cylinder hydraulic machine having an improved distribution structure. Prior art

[0002] Multi-displacement hydraulic machines are known and commonly used. Such hydraulic machines have several displacement values ​​that can be engaged, in order to offer several operating modes. For example, hydraulic machines offer a first mode delivering high torque at low speed, and a second mode delivering reduced torque at high speed.

[0003] Such hydraulic machines offer advantageous flexibility while maintaining a small footprint.

[0004] A recurring difficulty in the production of such hydraulic machines concerns fluid distribution. The production of such multiple displacements generally involves complex structures for the associated distributor. We can notably cite document FR2836960 which presents a structure of a multi-displacement hydraulic motor with a specific distributor.

[0005] The present invention aims to respond at least partially to this problem. Statement of the invention

[0006] The present invention thus relates to a hydraulic machine comprising: a first assembly and a second assembly, movable in rotation relative to each other along a main axis, the first assembly comprising a casing and a multi-lobe cam, the second assembly comprising a shaft, a cylinder block, the cylinder block having a plurality of housings in which pistons slide, each piston being positioned in a housing, the hydraulic machine further comprising a distributor adapted to supply and discharge fluid, the distributor bearing against the cylinder block along an interface extending radially relative to the main axis, characterized in that each pair formed by a piston and a housing defines between the piston and the housing a first chamber and a second separate chamber, the cylinder block and the distributor each have a plurality of internal conduits defining a first set of conduits and a second set of conduits,said sets of conduits opening at the interface between the distributor and the cylinder block along two distinct radii relative to the main axis and being adapted to supply the first chambers and the second chambers respectively.

[0007] In one example, the shaft extends out of the housing, and is adapted to transmit or receive rotational motion and / or torque.

[0008] In one example, the cam extends around the cylinder block relative to the main axis, and the cylinder block is configured such that the pistons slide radially relative to the main axis upon relative rotation between the first set and the second set.

[0009] In one example, the distributor is a groove distributor.

[0010] According to one example, the distributor is a stud distributor, having at least one distribution plate at the interface between the distributor and the cylinder block.

[0011] According to one example, the distributor comprises two concentric distribution plates; a first distribution plate adapted to connect the conduits of the first set of conduits, and a second distribution plate adapted to connect the conduits of the second set of conduits.

[0012] According to an example, for each pair formed by a piston and a housing, the first chamber has a cylinder capacity strictly greater than the second chamber.

[0013] According to one example, for each pair formed by a housing and a piston, the first chamber and the second chamber have different effective sections.

[0014] According to an example, for each pair formed by a housing and a piston, the first chamber has an effective section strictly greater than the second chamber.

[0015] According to one example, for each pair formed by a housing and a piston, the first chamber has an effective section strictly lower than the second chamber.

[0016] According to one example, each housing has a first portion having a first section SI, and a second portion having a second section S2, the first section SI being strictly greater than the second section S2, the first portion extending from an external surface of the cylinder block, and the second portion extending from the first portion. The pistons are typically configured so as to define an effective section during operation, such that the effective section of the first chambers is strictly greater than the effective section of the second chambers.

[0017] According to one example, for each pair formed by a piston and a housing, the first chamber and the second chamber are superimposed according to a sliding direction of the piston in the housing.

[0018] In one example, the set of first chambers defines a constant velocity motor or pump, and the set of second chambers defines a constant velocity motor or pump.

[0019] For a hydraulic motor, the homokinetic characteristic means that, when the fluid supply flow rate is constant, the rotational speed of the rotating part of the motor, typically the cylinder block or the cam, is substantially constant. In other words, the rotation occurs smoothly. In a homokinetic motor, the fluid balance is substantially zero, that is, at any given moment, the quantity of fluid entering the cylinders is substantially equal to the quantity of fluid leaving the cylinders.

[0020] For a hydraulic pump, the homokinetic characteristic means that when the rotation speed of the rotating part is constant, the flow rate of fluid delivered by the pump is constant. In other words, the flow rate delivered does not present any jolts.

[0021] Since a constant flow rate circulates in the different conduits for a constant rotation speed of the hydraulic machine, there is no acceleration or deceleration of the fluid in the conduits, which in particular makes it possible to reduce pressure losses and therefore increase the efficiency of the machine.

[0022] According to one example, the set of first chambers defines a first hydraulic sub-machine which operates by the collaboration of the pistons sliding in these first chambers with a multi-lobe cam and which is configured in such a way that said first hydraulic sub-machine is homogeneous. The term homogeneous means that at constant rotation (of the cylinder block) for each cam lobe, the flow circulating in the first chambers whose pistons travel through the cam lobe in question is constant. An example of a hydraulic machine with homogeneous flow is presented in patent application WO2023 / 242502A1 to which a person skilled in the art may refer.

[0023] When the hydraulic machine (or sub-machine) associates a particular distribution means for a lobe or a group of lobes of the multi-lobe cam, the fact that the hydraulic machine (or sub-machine) is homogeneous allows a constant flow to circulate in the conduits of this distribution means. assigned to this lobe or group of lobes for a constant rotational speed of the hydraulic machine (or sub-machine).

[0024] To the extent that a constant flow circulates in the various conduits of the distribution system dedicated to a lobe or a group of lobes for a constant rotation speed of the hydraulic machine, there is no acceleration or deceleration of the fluid in the conduits of the distribution system dedicated to this lobe or this group of lobes, which in particular makes it possible to reduce pressure losses and therefore to increase the efficiency of the hydraulic machine or sub-machine.

[0025] According to one example, the set of second chambers defines a second hydraulic sub-machine which operates by the collaboration of the pistons sliding in these second chambers with a multi-lobe cam configured such that said second hydraulic sub-machine is homogeneous.

[0026] In one example, the cam profile is non-sinusoidal. The non-sinusoidal cam allows profiles that allow homokinetic or homogeneity of the hydraulic machine (or sub-machine).

[0027] According to one example, the cam profile has cam flats. What the person skilled in the art calls a cam flat is a part of the cam for which, for a given angular sector of the cam, the radius of the cam profile does not change. Consequently, a piston traveling along a cam flat does not move in its housing and does not generate flow. This makes it possible, for example, to prevent pressure peaks in the chamber from being created when passing from one distribution orifice to another. This makes it possible, in particular, to space the distribution orifices apart from each other to improve sealing by preventing leaks from high-pressure conduits to low-pressure conduits at the distribution face.

[0028] The present invention also relates to an assembly comprising a hydraulic machine as defined above, and a displacement change valve adapted to selectively supply pressure to the first set of conduits and / or the second set of conduits.

[0029] According to one example, said assembly further comprises a displacement selector, said displacement selector defines at least two configurations in which the first chambers and / or the second chambers are supplied for distinct sets of angular sectors of the cam.

[0030] According to one example, the displacement selector comprises a first selection valve, which defines at least two distinct configurations in which the first chambers are energized when positioned opposite distinct sets of angular sectors of the cam, and a second selection valve, which defines at least two distinct configurations in which the second chambers are energized when positioned opposite distinct sets of angular sectors of the cam.

[0031] The fact of pooling the change of displacement by piston stages (first and second chambers) and the cam lobes (angular sectors) has the advantage of ensuring an exchange between the bypass sub-circuit and the main circuit when the machine operates in reduced displacement, which improves the thermal behavior of a machine which would operate for a long time in reduced displacement by the piston stages. Indeed, if we only reduce the displacement of the hydraulic machine for example by supplying only the first chambers, the oil in the second chambers (not efficient) would not necessarily be renewed and would tend to heat up due to the back and forth of the pistons in their housings and its circulation in the conduits. Brief description of the drawings

[0032] The invention and its advantages will be better understood upon reading the detailed description given below of different embodiments of the invention given as non-limiting examples.

[0033] [Fig. 1] Figure 1 shows schematically a multiple displacement hydraulic machine.

[0034] [Fig. 2] Figure 2 shows a cylinder block structure of a multiple displacement hydraulic machine according to one aspect of the invention.

[0035] [Fig. 3] Figure 3 shows an example of a multiple displacement hydraulic machine structure according to one aspect of the invention.

[0036] [Fig. 4] Figure 4 shows another example of a multiple displacement hydraulic machine structure according to one aspect of the invention.

[0037] [Fig. 5] Figure 5 shows an example of a structure of a multi-displacement hydraulic machine according to one aspect of the invention.

[0038] [Fig. 6] Figure 6 shows an example of a distributor structure for a hydraulic machine according to one aspect of the invention.

[0039] [Fig. 7] Figure 7 shows another example of a multi-displacement hydraulic machine structure according to one aspect of the invention.

[0040] Throughout the figures, common elements are identified by identical numerical references. Description of the embodiments

[0041] Figure 1 is a schematic representation of a multiple displacement hydraulic machine. In the example illustrated, a hydraulic motor M is schematized as being composed of two hydraulic sub-motors M1 and M2 coupled in rotation. One and / or the other of the two hydraulic sub-motors M1 and M2 can be selectively engaged, typically by controlling the intake and discharge of each of the two hydraulic sub-motors M1 and M2. It is understood that this figure can also be transposed for a hydraulic pump composed of two hydraulic sub-pumps.

[0042] Figures 2, 3 and 5 illustrate an embodiment of a multi-displacement hydraulic machine according to one aspect of the invention. The hydraulic machine may have a hydraulic motor or pump operation.

[0043] Figure 2 shows a partial view of a cylinder block 30 defining a housing 40 in which a piston 50 slides, typically adapted to be held in contact with a cam, for example a cam multi-lobe. In operation, the pistons follow the cam. Thus, the pistons move back and forth in their respective housings according to the geometry of the cam, while remaining in contact with the cam.

[0044] A multi-lobe cam is a cam formed to have undulations or lobes, so that a piston in a cylinder block housing shown centered with respect to the cam and remaining in contact with the cam reciprocates in its housing during rotation.

[0045] The cam is typically non-sinusoidal. A non-sinusoidal cam profile makes it possible to create a cam profile that allows the creation of a homokinetic or homogeneous hydraulic machine (or sub-machine) as we will see later.

[0046] Figure 3 shows a more complete view, including a cam 20 and a casing 10. The cam 20 is positioned so as to surround the cylinder block 30 relative to the main axis ZZ. The casing 10 and the cam 20 define an internal volume in which the cylinder block 30 is housed. The cylinder block 30 is integral with a shaft 32 mounted to rotate relative to the casing 10 by means of bearings 12. The cylinder block 30 and the shaft 32 form an assembly that is rotatable relative to the assembly formed by the cam 20 and the casing 10 by means of an axis 32 defining the main axis ZZ. The shaft 32 typically extends outside the casing 10, and is adapted to receive or transmit a movement and / or a rotational torque depending on whether the hydraulic machine has a hydraulic pump or hydraulic motor operation. In the example shown, the cam surrounds the cylinder block.Alternatively, the adapter 100 may have a radial architecture with an internal cam mounted to rotate relative to the cylinder block 30 and to a casing 10, the cylinder block 30 then typically being integral in rotation with the casing 10.

[0047] Figure 5 shows an example of a radial machine structure. This figure shows a cylinder block 30 surrounded by a multi-lobe cam 20. In this example, the cylinder block 30 comprises 9 housings and the cam defines 6 lobes.

[0048] In the illustrated example, the hydraulic machine has a radial structure. By radial structure, it is meant that the pistons 50 and the housings 40 are arranged so as to define a movement of the pistons 50 in a radial direction relative to the main axis ZZ. In the remainder of the description, the radial direction refers to a radial direction relative to the main axis ZZ.

[0049] In the structure proposed by the present invention, each pair formed by a piston 50 and a housing 40 defines a first chamber 60 and a second chamber 70 which are distinct, isolated from each other by means of sealing elements.

[0050] The first chamber 60 and the second chamber 70 are typically superimposed according to the sliding direction of the piston 50 in the housing 40, here the radial direction relative to the main axis ZZ.

[0051] In the example illustrated, the housing 40 has two distinct portions; a first portion 41 having a first section S1, and a second portion 42 having a second section S2, the first section S1 being strictly greater than the second section S2, the first portion extending from an external surface of the cylinder block 30 and opening opposite the cam, and the second portion 42 extending from the first portion 41 so as to form the bottom of the housing 40. The second portion 42 is thus typically blind in the sliding direction of the pistons 50.

[0052] The piston 50 also has a first portion 51 and a second portion 52 adapted to slide respectively in the first portion 41 and the second portion 42 of the housing 40 while ensuring the sealing of the first chamber 60 and the second chamber 70.

[0053] Such a structure makes it possible to define in a single cylinder block and on a single row of pistons coming into contact with the same cam, two distinct hydraulic machines via the first chambers 60 and the second chambers 70. The two hydraulic machines thus formed can have identical or distinct cylinder capacities, which are designated respectively by C1 and C2. The displacement is defined as the product of the effective section of a chamber considered by the stroke of the piston, the effective section of a piston being the total surface area of ​​the piston which participates in creating a force tending to move the piston in the desired direction. We distinguish the displacement for a given piston and the displacement for a motor or a pump, which is equal to the sum of the displacement of the pistons for the motor or the pump considered. The displacement Cl of the first chambers 60 is thus defined by the stroke of the piston multiplied by the effective section of the first chambers 60. The displacement C2 of the second chambers 70 is thus defined by the stroke of the piston multiplied by the effective section of the second chambers 70.The proposed structure thus makes it possible to produce a structure allowing multi-cylinder operation with a limited number of pistons and lobes and with the same row of pistons, which is advantageous in terms of compactness and therefore integration.

[0054] For each pair formed by a housing and a piston, the first chamber 60 and the second chamber 70 thus typically have distinct effective sections. The first chamber 60 can thus have an effective section strictly greater than the second chamber 70, or conversely, the first chamber 60 can thus have an effective section strictly less than the second chamber 70.

[0055] The displacement of the hydraulic machine can thus be modulated by supplying or not the first chambers 60 and / or the second chambers 70. The hydraulic machine can thus have a displacement equal to C1, to C2, or to C1+C2.

[0056] Each of the two hydraulic machines thus formed typically defines a homokinetic hydraulic machine; for a constant rotational speed of the cylinder block 30 relative to the cam 20, the first chambers 60 and / or the second chambers 70 deliver a constant or substantially constant flow rate, in contrast in particular to an oscillating linear actuator which delivers pressure by pulsations.

[0057] The set of first chambers 60 typically defines a first hydraulic sub-machine which operates by the collaboration of the pistons 50 sliding in these first chambers 60 with the multi-lobe cam 20 configured in such a way that said first hydraulic sub-machine is homogeneous. The term homogeneous means that at constant rotation (of the cylinder block) for each cam lobe 20, the flow circulating in the first chambers 60 whose pistons 50 travel through the cam lobe 20 in question is constant. An example of a hydraulic machine with homogeneous flow is presented in patent application WO2023 / 242502A1 to which those skilled in the art may refer.

[0058] When the hydraulic machine (or sub-machine) associates a particular distribution means for a lobe or a group of lobes of the multi-lobe cam 20, the fact that the hydraulic machine (or sub-machine) is homogeneous allows a constant flow rate to circulate in the conduits of this distribution means assigned to this lobe or group of lobes for a constant rotation speed of the hydraulic machine (or sub-machine).

[0059] To the extent that a constant flow circulates in the various conduits of the distribution system dedicated to a lobe or a group of lobes for a constant rotation speed of the hydraulic machine, there is no acceleration or deceleration of the fluid in the conduits of the distribution system dedicated to this lobe or this group of lobes, which in particular makes it possible to reduce pressure losses and therefore to increase the efficiency of the hydraulic machine or sub-machine.

[0060] According to one example, the set of second chambers 70 defines a second hydraulic sub-machine which operates by the collaboration of the pistons 50 sliding in these second chambers 70 with a multi-lobe cam configured such that said second hydraulic sub-machine is homogeneous.

[0061] Conduits 62 and 72 are arranged in the cylinder block 30, these conduits extending respectively from the first chambers 60 and from the second chambers 70 and emerging from a lateral surface of the cylinder block 30. The conduits 62 and 72 are then supplied by a distributor 165.

[0062] The cylinder block 30 thus comprises conduits 62 and 72 opening opposite the distributor 165, making it possible to connect the first chambers 60 and the second chambers 70 to the distributor 165. The conduits 62 and 72 typically open at an interface between the cylinder block 30 and the distributor 165, the interface typically being between two surfaces extending radially relative to the main axis ZZ.

[0063] the ducts 62 and 72 formed in the cylinder block 30 open at distinct positions relative to the main axis ZZ; for example the ducts connected to the first chambers 60 are centered on a circle of radius RI relative to the main axis ZZ, and the ducts connected to the second chambers 70 are centered on a circle of radius R2 relative to the main axis ZZ with RI different from R2. In the example illustrated, RI is strictly greater than R2, the first chambers 60 being located radially to the outside relative to the second chambers 70. The distributor 165 has internal ducts adapted to open at the interface between the distributor 165 and the cylinder block, opposite the ducts 62 and 72, and thus allow supply and discharge of the first chambers 60 and second chambers 70.It is thus possible to define a first set of conduits for supplying the first chambers 60, comprising conduits internal to the distributor 165 and the conduit 62 internal to the cylinder block. It is also possible to define a second set of conduits for supplying the second chambers 70, comprising conduits internal to the distributor 165 and the conduit 72 internal to the cylinder block.

[0064] Figure 6 illustrates an example of such a distributor 165. This figure presents a view of the face of the distributor 165 coming to the interface with the cylinder block 30. Reference 160 designates the internal ducts of the distributor 165 adapted to come opposite the ducts 62 and 64 of the cylinder block 30 extending from the first chambers 60, and reference 170 designates the internal ducts of the distributor 165 adapted to come opposite the ducts 72 and 74 of the cylinder block 30 extending from the second chambers 70. It can be seen that the internal ducts 160 are arranged along a circle of radius DI relative to the main axis ZZ, and that the internal ducts 170 are arranged along a circle of radius D2 relative to the main axis ZZ, such that D1 > D2.

[0065] Such a structure makes it possible to simplify the connection of the chambers to the distributor, and thus to simplify the general structure of the distributor 165 compared to known structures.

[0066] In this figure 6, the internal conduits 160 and 170 of the distributor 165 which supply the same piston open onto the distribution face of the distributor 165 on the same radius (they are angularly aligned) however, they could be angularly offset to open onto the staggered distribution face (this makes it possible to put more material between the orifices of the distributor 165 and therefore to increase the mechanical strength of this material in the face of forces - in particular those due to the pressure of the fluid).

[0067] In the same way, the orifices of the conduits 62 of the cylinder block 30 opening at the distribution interface which supply / discharge the chambers 60 can be angularly offset (relative to the axis of rotation of the hydraulic machine) from the orifices of the conduits 72 of the cylinder block which supply the chambers 70. Thus, the orifices of the supply / discharge conduits 62 of the first chambers 60 can be offset in a staggered manner from the orifices of the supply / discharge conduits 72 of the second chambers on the cylinder block.

[0068] In the example illustrated in Figure 6, we see that the distribution orifices of the conduits 160 on the distributor 165 extend over the same angle as the distribution orifices of the conduits 170 (for an equivalent radial extent, the surface area of ​​the orifices of the conduits 160 is greater than the surface area of ​​the orifices of the conduits 170). It could be otherwise and in particular, the distribution orifices of the conduits 160 could have an angular extent strictly less than or greater than the angular extent of the distribution orifices of the conduits 170. The same applies to the radial extent. Thus, the hydraulic machine can, for example, adjust in its design the surface area of ​​the distribution orifices according to the flow rate that it wants to pass into the first chambers 60 or into the second chambers 70... In the example illustrated in Figure 3, the distributor 165 is a grooved distributor.It includes in particular a distribution cover 167 equipped with a valve. displacement change 169, adapted to selectively connect the different conduits 62 and 72 to an inlet or a discharge of fluid formed in the casing or in the distribution cover 167.

[0069] For example, considering engine operation, the displacement change valve 169 may in particular make it possible to connect the first 60 and / or the second chambers 70 to the intake in order to obtain operation with a displacement equal to C1, C2 or C1+C2. For example, in the case where only the second chambers 70 are supplied, the first chambers 60 may be connected to a reservoir R, or be connected to each other and isolated from the intake and the discharge. The operation of a displacement selector is well known and will therefore not be detailed here.

[0070] The displacement change valve 169 can be integrated into the distribution cover 167 or into the casing 10 or into the distributor 165, or even be attached to the casing 10.

[0071] Alternatively, the distributor 165 may be a stud distributor.

[0072] Figure 4 schematically illustrates such a variant. Only the elements that differ from Figure 3 described previously are indicated here. A stud distributor typically comprises a distribution part or plate interposed between the cylinder block 30 and the casing 10, comprising distribution orifices adapted to connect supply and delivery ducts formed in the casing 10, and ducts formed in the cylinder block 30. The interposed distribution plate may, for example, take the form of a ring or a disc centered relative to the main axis ZZ. In the example illustrated, two distribution plates 162 and 172 of annular shape are interposed between the distributor and the cylinder block 30, respectively opposite the ducts 62 and 72.

[0073] Alternatively, the distributor may have a single distribution plate, typically annular in shape, having holes formed opposite the conduits 62 and 72.

[0074] Optionally, the distributor 165 can be adapted to provide a supply and discharge of fluid into the first chambers 60 and / or into the second chambers 70 for a first angular sector and for a second angular sector.

[0075] By angular sector is meant an angular subdivision of the multi-lobe cam 20 or a group of joined or disjointed angular subdivisions of the cam 20. For example, an angular sector as defined here may group together several lobes or several half-lobes of the multi-lobe cam 20, possibly disjoint. As indicated previously, the distributor 165 is typically configured so as to allow a variation in the displacement of the hydraulic machine by engaging or not engaging the first chambers 60 and / or the second chambers 70. Such functionality makes it possible to obtain different displacement values, namely a zero displacement, a displacement equal to C1, a displacement equal to C2, or a displacement equal to C1+C2.

[0076] Optionally, the distributor 165 may be configured to modify the angular sector for which the first chambers 60 and / or the second chambers 70 are engaged.

[0077] The cam 20 is typically a multi-lobe cam comprising a plurality of lobe portions. The distributor 165 may be configured so as to have several operating modes, for example an operating mode in which it makes it possible to supply fluid to the first chambers 60 over all of the lobe portions of the cam 20, and one or more other operating modes in which, for certain lobe portions, the first chambers 60 are not supplied.

[0078] In the same way, depending on the structure of the assembly, the distributor 165 can be configured so as to have several operating modes, for example an operating mode in which it makes it possible to supply fluid to the second chambers 70 over all of the lobe portions of the cam 20, and one or more other operating modes in which, for certain lobe portions, the second chambers 70 are not supplied.

[0079] Such disengagement of the first chambers 60 and / or the second chambers 70 on a part of the angular sectors can in particular be achieved by connecting the conduits corresponding to the same orifice (intake or discharge), or by closing the fluid intake for the conduits corresponding to the disengaged angular sectors.

[0080] The control of the distributor 165 to define the portions of lobes supplied can for example be carried out by means of a valve or several valves which can for example be integrated into the distributor 165 or be upstream or downstream of the distributor 165, typically upstream or downstream of the cylinder capacity change valve 169. Figure 7 schematically shows a variant of Figure 3 in which such valves are designated respectively by the references 86 and 87 for the valves associated respectively with the first chambers 60 and with the second chambers 70. These two valves 86 and 87 are connected to a cylinder capacity selection valve 80 making it possible to supply one and / or the other of the valves 86 and 87.The cylinder capacity selection valve 80 thus makes it possible to define which chambers among the first and / or second chambers 60 and 70 are supplied, while the valves 86 and 87 respectively define for the first chambers 60 and for the second chambers 70 the angular sectors for which they are supplied.

[0081] The system may thus, for example, comprise a first selection valve making it possible to define several distinct sets of angular sectors, and making it possible to control the supply of the first chambers 60 according to these different sets of angular sectors. In the same way, the system may, for example, comprise a second selection valve making it possible to define several distinct sets of angular sectors, and making it possible to control the supply of the second chambers 70 according to these different sets of angular sectors.

[0082] Such a structure makes it possible to control the displacement on two levels, by supplying chambers 60 and 70, and by supplying the lobe portions, and thus makes it possible to multiply the possible displacements for the hydraulic machine.

[0083] Thus, in addition to the cylinder capacities Cl, C2 and C1+C2 mentioned previously, it is possible, for example, to obtain additional cylinder capacities of the type 0.5 * Cl by considering that the distributor 160 makes it possible to disengage the lobe portions corresponding to half of the cylinder capacity, or more generally additional cylinder capacities of the type X * Cl, X*C2 or X*(C1+C2), X corresponding to the ratio of lobe portions which are then active.

[0084] It is also possible to have additional cylinder capacities of the type X * Cl, Y*C2 or X*C1 + Y*C2, X corresponding to the ratio of lobe portions which are then made active to supply / discharge the first chambers 60, and Y corresponding to the ratio of lobe portions which are then made active to supply / discharge the second chambers 70.

[0085] Depending on the structure of the distributor and the means employed, it is typically possible to define several sets of lobe portions which can be selectively engaged or not, thus defining several ratios of lobe portions to multiply the number of possible combinations and displacements, which thus offers additional functionalities and operating modes.

[0086] In particular, in the example illustrated in Figure 7, the distribution and displacement selection system does not allow symmetrical operation. However, the invention could be implemented with a symmetrical distribution and displacement selection system. In a hydraulic machine with symmetrical distribution operating as a motor, an inversion of the pressure levels at its terminals changes the direction of rotation while maintaining equivalent operation. In a hydraulic machine with symmetrical distribution operating as a pump, an inversion of the direction of rotation of the input shaft generates an inversion of the pressure levels at its terminals while maintaining equivalent operation.

[0087] Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0088] It is also obvious that all the characteristics described with reference to a method are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims

Claims

1. Hydraulic machine comprising: a first assembly and a second assembly, movable in rotation relative to each other along a main axis (ZZ), the first assembly comprising a casing (10) and a multi-lobe cam (20), the second assembly comprising a shaft (32), a cylinder block (30), the cylinder block (30) having a plurality of housings (40) in which pistons (50) slide, each piston (50) being positioned in a housing (40), the hydraulic machine further comprising a distributor (165) adapted to supply and discharge fluid, the distributor (165) bearing against the cylinder block (30) along an interface extending radially relative to the main axis (ZZ), characterized in that each pair formed by a piston (50) and a housing (40) defines between the piston (50) and the housing (40) a first chamber (60) and a second chamber (70) which are distinct,the cylinder block (30) and the distributor (165) each have a plurality of internal conduits defining a first set of conduits and a second set of conduits, said sets of conduits opening at the interface between the distributor (165) and the cylinder block (30) along two distinct radii relative to the main axis (ZZ) and being adapted to supply the first chambers (60) and the second chambers (70) respectively.,

2. A hydraulic machine according to claim 1, wherein the shaft (32) extends out of the housing (10), and is adapted to transmit or receive rotational movement and / or torque.

3. A hydraulic machine according to claim 1 or 2, wherein the cam (20) extends around the cylinder block (30) relative to the main axis (ZZ), and wherein the cylinder block (30) is configured such that the pistons (50) slide radially relative to the main axis (ZZ) during relative rotation between the first assembly and the second assembly.

4. Hydraulic machine according to one of claims 1 to 3, in which the distributor (165) is a groove distributor, or in which the distributor (165) is a stud distributor having at least one distribution plate (162, 172) at the interface between the distributor (165) and the cylinder block (30).

5. Hydraulic machine according to one of claims 1 to 4, in which for each pair formed by a piston (50) and a housing (40), the first chamber (60) has a cylinder capacity strictly greater than the second chamber (70).

6. Hydraulic machine according to one of claims 1 to 5, in which each housing (40) has a first portion (41) having a first section SI, and a second portion (42) having a second section S2, the first section SI being strictly greater than the second section S2, the first portion (41) extending from an external surface of the cylinder block (30), and the second portion (42) extending from the first portion (41).

7. Hydraulic machine according to one of claims 1 to 6, in which for each pair formed by piston (50) and a housing (40), the first chamber (60) and the second chamber (70) are superimposed in a sliding direction of the piston (50) in the housing (40).

8. An assembly comprising a hydraulic machine according to one of the preceding claims and a displacement change valve (169) adapted to selectively supply pressure to the first set of conduits and / or the second set of conduits.

9. An assembly according to claim 8, further comprising a displacement selector, said displacement selector defines at least two configurations in which the first chambers (60) and / or the second chambers (70) are supplied for distinct sets of angular sectors of the cam (20).

10. An assembly according to claim 9, wherein the displacement selector comprises a first selection valve, which defines at least two distinct configurations in which the first chambers (60) are supplied when positioned opposite sets of distinct angular sectors of the cam (20), and a second selection valve, which defines at least two distinct configurations in which the second chambers (70) are supplied when positioned opposite sets of distinct angular sectors of the cam (20).

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