Hydraulic machine provided with turning drawer

Abstract

The invention relates to a hydraulic machine (100) comprising:-a distribution cover (2.3); -a dispenser (16); -a displacement selection drawer (35) mounted to slide between a first position, in which the machine is configured to operate at a first displacement, and a second position, in which the machine is configured to operate at a second displacement different from the first displacement; and-a turning drawer (26) mounted to slide between a first position, in which the machine is configured to apply torque in a first direction about the axis of rotation (10), and a second position, in which the machine is configured to apply torque in a second direction, in which the machine is configured to apply torque in a first direction about the axis of rotation (10). The diverting drawer (26) is mounted so as to slide along an axis (42) at a distance from the axis of rotation (10), the diverting drawer extending:-in the wall of the dispenser (16), or-in the wall of the dispensing closure and outside the displacement selection drawer (35).

Description

Technical Field

[0001] The present invention relates to hydraulic machines. Background Art

[0002] From document FR-3 024 503 a hydraulic machine is known which comprises a housing, radial pistons, a multi-lobed cam and a distributor. The machine comprises several sub-motors. A displacement selection slide valve is mounted to slide between a first position associated with a first displacement and a second position associated with a second displacement. The slide valve position control thus allows the displacement of the machine to be selected. The slide valve is coaxial with the machine and is located in the distributor.

[0003] A reversing sliding valve is also provided, which is mounted to slide between a first position and a second position associated with two pressure configurations. The sliding valve is controlled by the pressure difference at the machine terminals. When the configuration of the motor is changed (i.e. when the low pressure and the high pressure are reversed), it can be ensured that the bypassed or bypassed sub-motor does not have a groove supplied with high pressure. This reversing sliding valve actually forms a sliding valve for selecting the lowest pressure. The second sliding valve extends inside the first sliding valve, coaxial with the first sliding valve. It should be remembered that in the term "reversing sliding valve", it is not always the direction of rotation of the hydraulic machine that is changed, but in fact the direction of the torque applied by the hydraulic machine on the shaft. In fact, different configurations of the sliding valve can be envisaged, in which the machine can operate as a pump or as a motor when the shaft of the machine rotates in the same direction (for example, this is the case when the hydraulic motor is used to perform hydrostatic braking in pump mode).

[0004] However, this arrangement makes the manufacture of the machine more complicated. An attempt to remedy this can be made by miniaturizing the reversing slide valve, but this reduction in size makes the manufacture more expensive and has its limitations. In fact, the two slide valves must occupy a certain volume to avoid internal leakage between the lines of the high-pressure and low-pressure circuits. Therefore, a certain amount of matter must be associated with them, or a certain amount of material and high precision in producing the parts must be taken into account.

[0005] An object of the invention is to facilitate the production of a hydraulic machine comprising such a sliding valve. Summary of the invention

[0006] To this end, a hydraulic machine is provided according to the present invention, the hydraulic machine comprising:

[0007] - dispensing caps,

[0008] - a distributor,

[0009] a displacement selector slide valve mounted to slide between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and

[0010] a reversing slide valve mounted to slide between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation and a second position in which the machine is configured to apply a torque in a second direction,

[0011] The direction-changing sliding valve is installed to slide along an axis away from the rotation axis.

[0012] The reversing slide valve:

[0013] - extends in the wall of the distributor, or

[0014] - Extends in the wall of the dispensing closure and outside the displacement selection slide valve.

[0015] Thus, by means of these positions of the reversing slide valve, the constraints associated with large volumes are reduced, which facilitates manufacturing. Then, high-performance dual-displacement machines can be easily produced. The positions provided for the reversing slide valve do not affect performance.

[0016] The displacement selector slide valve experiences a large flow rate through it, especially when the machine is at low displacement, because fluid recirculates from the bypassed or by-passed portion of the machine. On the other hand, the reversing slide valve experiences no flow through it (except for leakage flow which is minimized by expanding the slide valve) once it is locked in one of the two operating positions.

[0017] If necessary, the invention allows the displacement selector slide valve to be kept in the center of the distributor, so that the fluid circulation takes place as close as possible to the grooves of the high-pressure and low-pressure lines. However, it leads to keeping the direction-changing slide valve away from the axis of rotation. In the case where the direction-changing slide valve extends outside the displacement selector slide valve, this simplifies the manufacture of the direction-changing slide valve, because the direction-changing slide valve does not experience a large flow rate of fluid passing through it.

[0018] The fact of having two separate slide valves allows the slide valve to be less restricted in compactness compared to the prior art.

[0019] This technology is applicable to all hydraulic machines, regardless of whether they are used in motor or pump mode.

[0020] Likewise, in the term "reversing slide valve", it is not always the direction of rotation of the hydraulic machine that is changed, but actually the direction of the torque exerted by the machine on the shaft. In fact, there are different configurations of slide valves in which the machine can be operated as a pump or as a motor when the shaft turns in the same direction (this is the case, for example, when the motor is used in pump mode to perform hydrostatic braking).

[0021] In one embodiment, the displacement selector slide valve extends within the distributor.

[0022] Assuming that the slide valve experiences a large flow rate through it when the machine is at low displacement (recirculation of the fluid from the sub-motor is bypassed); this configuration shortens the trajectory of the oil so as to limit the head losses.

[0023] Provision can be made for the displacement selection slide valve to be coaxial with the axis of rotation.

[0024] Also, given that the displacement selector slide valve experiences a large flow rate when the machine is at low displacement (ie when one of the slaves is bypassed), this axial configuration shortens the oil path as much as possible and limits head losses to a minimum.

[0025] It may be provided that the direction-changing slide valve extends outside the displacement selection slide valve.

[0026] Provision may be made for the direction-changing sliding valve to be mounted so as to slide in a direction parallel to the axis of rotation.

[0027] Provision can also be made for the direction-changing sliding valve to be mounted so as to slide in a direction which is not parallel to the axis of rotation.

[0028] It may be provided that the machine comprises a high-pressure line and a low-pressure line and is configured so that the reversing slide valve moves under the influence of the pressure in the high-pressure line. The hydraulic machine can only work when a pressure difference is established at its terminals. Depending on the "terminal" where the high pressure occurs, the slide valve places itself in one configuration or the other. The reversing slide valve places itself in a recess comprising a chamber at each end, each chamber being connected to one or the other of the high-pressure and low-pressure lines, respectively.

[0029] Provision may be made for the second displacement to be smaller than the first displacement, the second displacement being achieved by a set of pistons or cam lobes forming a regular polygon centred on the axis of rotation.

[0030] It can also be provided that the group forms a pattern having axial symmetry and / or central symmetry.

[0031] Therefore, the occurrence of parasitic forces and parasitic moments is avoided.

[0032] According to the present invention, there is also provided a subassembly for a hydraulic machine,

[0033] This subcomponent includes:

[0034] - a distributor,

[0035] a displacement selector slide valve mounted to slide in the distributor between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and

[0036] a reversing slide valve mounted to slide in the dispenser between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation and a second position in which the machine is configured to apply a torque in a second direction,

[0037] The direction-changing sliding valve is mounted to slide along an axis away from the rotation axis.

[0038] For example, the displacement selection slide valve is coaxial with the main axis.

[0039] Provision may be made for the fluid path from the inlet of the machine to the displacement changing slide valve to be shorter than the fluid path from the inlet to the reversing slide valve.

[0040] It can also be stipulated that

[0041] The cover forms an annular groove.

[0042] The distributor forms a groove,

[0043] The groove of the cover and the groove of the dispenser form a volume with a center of gravity,

[0044] The displacement select slide valve is positioned closer to the center of gravity than the direction changing slide valve.

[0045] According to the invention there is also provided an arrangement comprising at least one machine according to the invention.

[0046] According to the present invention there is also provided a method for controlling a hydraulic machine, wherein:

[0047] - the displacement selector slide valve slides between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and

[0048] the direction-changing slide valve slides between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation and a second position in which the machine is configured to apply a torque in a second direction about the axis and the direction-changing slide valve slides along an axis away from the axis of rotation,

[0049] The reversing slide valve:

[0050] - extends in the wall of the distributor, or

[0051] - Extends in the wall of the dispensing closure and outside the displacement selection slide valve.

[0052] According to the present invention there is also provided a method for controlling a hydraulic machine, wherein:

[0053] - the displacement selection slide valve slides between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement, the displacement selection slide valve being controlled by the pressure in the control duct, exerting thrust on the spring; and

[0054] the direction-changing slide valve slides between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation and a second position in which the machine is configured to apply a torque in a second direction about the axis and the direction-changing slide valve slides along an axis away from the axis of rotation,

[0055] The reversing slide valve is moved depending on whether the high pressure is established in the machine in the supply or discharge duct.

[0056] The reversing slide valve:

[0057] - extends in the wall of the distributor, or

[0058] - Extends in the wall of the dispensing closure and outside the displacement selection slide valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] We will now present embodiments of the invention by way of non-limiting examples, with the support of the accompanying drawings, in which:

[0060] Figure 1 is an axial cross-sectional view of a hydraulic machine according to a first embodiment of the present invention;

[0061] Figures 2 to 5 It is shown Figure 1 Axial cross-sectional views of the machine in four operating configurations;

[0062] Figure 6 It is a transverse section view of the machine;

[0063] Figures 7 to 10 is similar to Figures 2 to 5 , showing a machine according to a second embodiment;

[0064] Fig.11 is an axial cross-sectional view of a dispenser of a machine according to a second embodiment;

[0065] Fig.12 is a view of a reversing slide valve of the machine; and

[0066] Fig.13 and Fig.14 A modified embodiment of the end portion of the reversing sliding valve is shown. DETAILED DESCRIPTION

[0067] Ⅰ. First embodiment

[0068] We will refer to Figures 1 to 6 A first embodiment of the hydraulic machine of the present invention is described.

[0069] 1. Yes Introduction of the machine

[0070] We mainly describe the aspects of the machine 100 that are relevant to the invention. Additional details of the machine itself, known per se, can be taken from document FR-3 024 503 already mentioned.

[0071] Reference Figure 1 The machine 100 comprises a fixed housing, in this case in three parts 2.1, 2.2 and 2.3, which are attached one after another along the axis of rotation 10 and are assembled, for example, by screws (not shown in the cross-sectional plane). The fixed housing comprises a corrugated or multi-lobed reaction cam 4, which is rigidly coupled to the central part 2.2 of the housing and is, for example, manufactured therein. The lobes of the cam are Figure 6 Visible in.

[0072] The machine comprises a cylinder block 6 mounted to rotate relative to the housing and relative to the cam 4 about a main axis 10 and having a plurality of cylindrical recesses 12, radial in this example, capable of being supplied with a pressurized fluid and inside which pistons 14 are mounted to slide. In this case, the cylinder block 6 drives in rotation a shaft 5 which, for this purpose, cooperates with a spline (not shown) of the cylinder block 6. In this example, the shaft carries an output flange 9. Each piston 14 carries a follower 7 by means of which the piston is supported on the cam and rolls on it.

[0073] The machine 100 is of the fixed housing type and has a rotating cylinder block. However, the invention is also applicable to machines having a rotating housing and a fixed cylinder block. The machine 100 can be operated as a motor or a pump.

[0074] like Figure 2 As shown, the machine 100 comprises an internal dispenser 16 which is coupled to the housing 2.1, 2.2, 2.3 with respect to rotation about the axis 10. In other words, the dispenser 16 and the cam 4 do not rotate relative to each other. The dispenser 16 is housed inside a rear portion 2.3 of the housing, which is also indicated here by the term "dispensing closure". This portion 2.3 is provided by a plurality of cams 4, each of which has ... Figure 2The bell shown may be a single block or closed by an applied plate at its axial end opposite the cylinder block. This end is considered here as the rear part of the machine and the flange 9 is considered as the front part of the machine.

[0075] When the machine is operated in motor mode, the distributor 16 has the function of supplying pressurized fluid to the piston recesses. Given the multi-lobe shape of the cam, the pressure exerted by the piston on the cam drives the shaft 5 to rotate relative to the housing and thus drives the load through the flange 9. In pump mode, the rotation of the shaft drives the rolling of the follower 7 on the cam 4 and the reciprocating movement of the piston in its recess. This causes the fluid to be discharged from these recesses and pressurize the high-pressure line via the distributor.

[0076] The distributor 16 has a planar outer front face 18 which extends in a plane perpendicular to the axis 10 and into which the distributor ducts 34 open. These ducts extend in particular in a direction parallel to the axis 10.

[0077] The distributor also has an outer peripheral lateral face 19 with four annular circular grooves 16eA, 16eB, 16eC and 16eD. The grooves are sequentially connected to each other in the direction of the axis 10 between the cylinder block (groove 16eA is closest to the cylinder block) and the rear end (groove 16eD is closest to the rear end).

[0078] The dispensing cover 2.3 has an inner lateral face 20 which forms a cavity for accommodating the dispenser 16, so that the two faces 19 and 20 face each other and are in contact with each other in the male-female assembly. The face 20 of the dispensing cover has annular circular main grooves 2A, 2B, 2C and 2D facing the grooves 16eA, 16eB, 16eC and 16eD of the dispenser 16, respectively.

[0079] Grooves 2B and 2D communicate with main supply and discharge ducts (R and L respectively) drilled into the wall of the dispensing closure 2.3. Ducts R and L are connected to the hydraulic circuit and thus the high-pressure and low-pressure lines are connected to the hydraulic circuit. In the preferred direction arbitrarily chosen for the description, the fluid supply in forward movement is accomplished through duct L and groove 2D, while the discharge occurs through duct R and groove 2B. Conversely, in the case of backward movement, the supply is accomplished through duct R and groove 2B, while the discharge occurs through duct L and groove 2D.

[0080] Reference Figures 2 to 5 , the distributor 16 has a cylindrical central recess 33 with axis 10. Here, the recess is of the through-type and is open at both ends of the distributor. Nevertheless, there is a plate for retaining the spring on the cylinder block side.

[0081] Annular grooves 16iB, 16iA, 16iC and 16iD are provided in the inner face of the recess, successive to one another along the front axis and the rear axis.

[0082] These grooves are open in the region of their axis and lead to the central recess 33. They are spaced apart from each other along the axis so that they are not adjacent. These grooves together with the conduit 34 form four corresponding fluid compartments (enclosures), which we here represent with the same reference numerals 16iB, 16iA, 16iC and 16iD as the grooves.

[0083] Here, the machine has two active operating displacements. For this purpose, the conduits 34 form two corresponding assemblies, each of which comprises a first set of conduits and a second set of conduits. All conduits 34 allow the piston recesses 12 to be supplied and are arranged in the distributor.

[0084] In the first assembly, a first set of conduits 34 is connected to the first chamber 16iB. Here, these conduits 34 are four in number and form the diagonal lines of a rectangle, such as Figure 6 As shown. A second set of ducts is connected to the second compartment 16iD. Here, these ducts are also four in number and form a rectangular diagonal identical to the aforementioned rectangular diagonal, but offset angularly relative to it around the axis. These two groups form the main submachine.

[0085] In the second assembly, a first group of ducts is connected to the third compartment 16iA. Here, the number of ducts is two and they are diametrically opposite on either side of the axis 10. A second group of ducts is connected to the fourth compartment 16iC. Here, the number of ducts is also two and they are diametrically opposite on either side of the axis 10, the diameter being angularly offset around the axis relative to the previous diameter. These two groups form a secondary daughter machine, which is sometimes bypassed or by-passed in order to operate the machine at minimum displacement, that is, only with the main daughter machine.

[0086] For example, each sub-motor or sub-machine corresponds to a row of pistons or a distribution of a certain number of cams in a cylinder block.

[0087] The details of the configuration of all these ducts 34 are not disclosed here, as it is within the scope of a person skilled in the art to determine this configuration according to the specifications of the machine, in particular the number of cylinders.

[0088] refer to Figure 2 The machine 100 comprises a displacement selector formed by a slide valve 35 and capable of being controlled to provide the machine with a high displacement configuration and a low displacement configuration as desired.

[0089] In the large displacement configuration, the first chamber 16iB and the third chamber 16iA are connected to one of the main ducts R, L, and the second chamber 16iD and the fourth chamber 16iC are connected to the other of the main ducts R, L. For example, in the case of the forward movement embodiment described later, the second chamber 16iD and the fourth chamber 16iC are connected together and connected to the main high-pressure duct, while the first chamber 16iB and the third chamber 16iA are connected together and connected to the other main low-pressure duct.

[0090] In small displacement configuration:

[0091] - Any of the first chamber 16iB, the third chamber 16iA and the fourth chamber 16iC is connected to one of the main ducts (low pressure), while the second chamber 16iD is connected to the other main duct (high pressure). This corresponds to forward movement;

[0092] - Alternatively, the second chamber 16iD, the third chamber 16iA and the fourth chamber 16iC are connected to one of the main ducts (low pressure), while the first chamber 16iB is connected to the other main duct (high pressure). This corresponds to a backward movement.

[0093] Thus, the first and second groups of distribution ducts 34 define a first and second sub-machine, respectively. In large displacements, both sub-machines are active, since their corresponding two groups of distribution ducts 34 are connected to the supply and exhaust, respectively. In small displacements, only the first sub-machine is active, and the two groups of distribution ducts 34 of the second assembly (i.e., the second sub-machine) are connected to the same main duct at low pressure.

[0094] In order to change the displacement of the motor, the displacement selection slide valve 35 is controlled to switch the machine from one configuration to another. To this end, the slide valve 35 is coaxially received in the central recess 33 of the distributor 16. The slide valve is installed to slide in the axial direction relative to the distributor.

[0095] Thus, the sliding valve 35 can be moved between a first position and a second position, wherein the first position corresponds to a large displacement configuration, in which the sliding valve connects the first chamber 16iB and the third chamber 16iA together by isolating the second chamber 16iD and the fourth chamber 16i C ​​(the second chamber and the fourth chamber themselves are also connected together via the sliding valve 35), and the second position corresponds to a small displacement configuration, in which the sliding valve is combined with the sliding valve 26 to allow the selection of a minimum pressure, connecting the three chambers together while isolating them from the last chamber.

[0096] Specific reference Figure 2, the machine 100 also includes a reversing slide valve 26. In this embodiment, the slide valve extends in the wall of the dispensing closure 2.3 and extends outside the displacement selection slide valve 35. To this end, the dispensing closure includes a cylindrical housing 39 having an axis 42 parallel to the axis 10 and away from the axis. The recess 39 is completely away from the recess 33 of the displacement selection slide valve 35 and the axis 10 and away from the displacement selection slide valve. In this example, the recess 39 is open to the outside of the machine at the rear side. The recess is blocked by a threaded plug 46. The reversing slide valve 26 is coaxially received in the recess 39 of the dispensing closure. The reversing slide valve is mounted to slide relative to the dispensing closure along the axis 42 between a first position and a second position, in which the machine is configured to apply a torque in a first direction and in which the machine is configured to apply a torque in a second direction opposite to the first direction. The machine is configured so that the reversing slide valve 26 moves under the influence of pressure from a high-pressure pipeline, as will be seen below.

[0097] The two sliding valves 35, 26 have grooves on their lateral surfaces, and the direction-changing sliding valve 26 has an internal conduit, which is as shown in FIG. Figure 2 and are arranged to allow the operations described below. Figure 1 In the figure, the sliding valve is not shown.

[0098] We will now describe the machine's operating modes according to displacement.

[0099] 2. In large displacement

[0100] Figure 2 Corresponds to the forward movement of the machine operating as a motor. Therefore, the duct L corresponds to the supply and reception of high pressure, which duct is in communication with the groove 2D of the dispensing cap. The groove 2D is axisymmetric (it completely surrounds the dispenser 16), and high pressure is also established in the duct 22, which extends from the groove 2D to the groove 50 of the recess 39. The pressurized fluid then flows through the internal duct 27 of the sliding valve 26, which connects the lateral wall of the sliding valve facing the groove 50 and the right axial end face of the sliding valve directed backwards. Therefore, regardless of the initial position of the sliding valve 26, the pressurized fluid passing in the duct 27 exerts a thrust in the chamber 28 (extending in the recess 39 between the said face and the plug 46) so as to place the sliding valve. Figure 2 The forward motion configuration of , i.e. its front-most position, here the left-most position.

[0101] Figure 3Corresponds to the backward movement of the motor. This means that the duct R corresponds to the supply and reception of high pressure, which duct is in communication with the groove 2B. This groove is axisymmetric and also establishes high pressure in the duct 24, which extends in the distribution cover from the groove 2B to the groove 54 of the sliding valve 26. The pressurized fluid then flows through the internal duct 29 of the sliding valve 26, which connects the groove 54 of the sliding valve and the left axial end face of the sliding valve oriented towards the cylinder body 6. From then on, regardless of the initial position of the sliding valve 26, the pressurized fluid flowing through the duct 29 exerts a thrust in the chamber 31 (extending in the recess 39 between said face and the bottom of the recess) so as to place the sliding valve in the Figure 3 The rearwardly moved configuration, ie its rearwardly rearward position, abuts against the plug 46.

[0102] like Figure 2 As shown, it should be noted that in the distributor 16:

[0103] - the outer groove 16eA is permanently connected to the inner groove 16iA via the conduit 64,

[0104] - the outer groove 16eB is permanently connected to the inner groove 16iB through the conduit 63,

[0105] - the outer groove 16eC is in permanent communication with the inner groove 16iC via the conduit 65, and

[0106] The outer groove 16eD is in permanent communication with the inner groove 16iD via a conduit 66 .

[0107] These inner tubes are Figure 2 , but may actually be located in different planes from each other.

[0108] The displacement selection slide valve 35 is controlled by a hydraulic control duct P leading to a chamber 21, which is located at the end of the recess 33. The control duct P is connected to a pilot line where a control pressure is applied or not, depending on the desired displacement. By default, the slide valve is in Figure 2 and Figure 3 , in which the control conduit P exerts no pressure in the chamber 21. The spring 30 exerts a restoring force on the sliding valve, which is then biased in the direction of the pilot line. This configuration allows the groove 16iB to be connected to the groove 16iA via the first annular lateral groove 56 of the sliding valve 35, and allows the groove 16iC to be connected to the groove 16iD through the second annular lateral groove 58 of the sliding valve.

[0109] Therefore, in forward movement or backward movement, there are two inner grooves connected to high pressure and two inner grooves connected to low pressure.

[0110] a) In forward motion

[0111] refer to Figure 2 , in the forward movement, high pressure arrives through the supply conduit L, which arrives in the groove 2D, which is connected to the inner groove 16iD through the conduit 66. The inner groove 16iD is in fluid communication with the inner groove 16iC through the displacement selection slide valve 35. The two grooves are therefore at high pressure. They correspond to the supply to the two sub-motors.

[0112] The discharge conduit R is connected to the channel 2B which is connected to the channel 16iB through the conduit 63. The inner channel 16iB is in fluid communication with the inner channel 16iA through the displacement selection slide valve 35. These two channels are at low pressure and correspond to the discharge of the two active sub-motors.

[0113] Thus, the motor formed by the machine operates at full displacement, each of the two sub-motors being supplied with high pressure and exhausting with low pressure.

[0114] b) In backward motion

[0115] Reference Figure 3 In the backward movement, high pressure arrives through the supply duct R, which arrives in the groove 2B, which is connected to the inner groove 16iB through the duct 63. Through the displacement selection slide valve 35, the inner groove 16iB is in fluid communication with the inner groove 16iA: these two grooves are therefore at high pressure.

[0116] The exhaust duct L is connected to the channel 2D which is connected to the channel 16iD by means of the duct 66. Through the sliding valve 35, the inner channel 16iD is in fluid communication with the inner channel 16iC: these two channels are at low pressure and correspond to the exhaust of the sub-motor.

[0117] Therefore, the motor is also operated at full displacement, each of the two sub-motors being supplied with high pressure and discharged with low pressure.

[0118] 3. In small displacement

[0119] When pressure is applied in chamber 21 by control duct P, displacement selector slide valve 35 is pressed against the force applied by spring 30. The displacement selector slide valve then places itself in a low displacement configuration, to the left, in which the sub-motor is deactivated, as Figure 4 and Figure 5 As shown. Therefore, the position of the slide valve 35 isolates each of the inner grooves 16iB and 16iD from the other grooves. The inner grooves 16iA and 16iC are placed to communicate with each other.

[0120] a) In forward motion

[0121] In forward motion, reference Figure 4, the pressurized fluid arrives through the conduit L, which corresponds to the supply. Then, a high pressure is established in the groove 2D, and also in the inner groove 16iD through the fluid communication achieved by the conduit 66. The displacement selection slide valve 35 is arranged in this configuration to isolate the inner groove 16iD from the other inner grooves. A high pressure is also established in the conduit 22 through the groove 2D, and as previously described, a high pressure is also established in the conduit 27, so that the chamber 28 is placed under high pressure, so as to place the change-of-direction slide valve 26 Figure 4 , placed on the left. In this configuration, the sliding valve does not allow the high pressure of conduit 22 to be in fluid communication with another compartment (in particular, not in fluid communication with conduit 23). Therefore, only one compartment is subjected to high pressure. This corresponds to the supply of a single sub-motor.

[0122] The discharge that takes place through the conduit R is at low pressure. The groove 2B is therefore at low pressure and, due to the presence of the conduit 63, the inner groove 16iB is also at low pressure. In view of the configuration of the displacement selection slide valve 35, the inner groove 16iB appears to be isolated from the other compartments. Nevertheless, through the groove 2B, the conduit 24 itself is connected to the low pressure and, in view of the position of the reversing slide valve 26, the conduits 24 and 25 are in communication through the groove 54. The conduit 25 itself is in communication with the conduit 64, which allows the inner groove 16iA to be set at low pressure. However, the inner groove 16iA is placed so as to communicate with the inner groove 16iC through the position of the displacement selection slide valve 35.

[0123] In short, Figure 4 In the configuration of , the chamber connected to groove 2D is at high pressure, and all other chambers connected to grooves 2B, 2A and 2C are at low pressure. One of the sub-motors is bypassed or by-passed: it is not subjected to pressure. Its intake and discharge are at low pressure.

[0124] b) In backward motion

[0125] In the backward movement, refer to Figure 5 , the pressurized fluid arrives through the conduit R, which corresponds to the supply. Then, a high pressure is established in the groove 2B. Through the fluid communication achieved by the conduit 63, a high pressure is also established in the inner groove 16iB. The displacement selection slide valve 35 is arranged in this configuration to isolate the inner groove 16iB from the other grooves. A high pressure is also established in the conduit 24 through the groove 2B. As previously described, this high pressure is also established in the conduit 29 of the slide valve 26, so that the left chamber 31 is placed under high pressure, so that the slide valve is placed on the right side, Figure 5 The slide valve does not allow the high pressure of the conduit 24 to be in fluid communication with another compartment (in particular, not in communication with the conduit 25). Likewise, only one compartment is therefore subjected to high pressure. This corresponds to the supply of a single sub-motor.

[0126] The discharge that takes place through the duct L is at low pressure. The groove 2D is therefore at low pressure and, thanks to the presence of the conduit 66, the inner groove 16iD is also at low pressure. In view of the configuration of the sliding valve 35, the inner groove 16iD appears to be isolated from the other compartments. Nevertheless, through the groove 2D, the conduit 22 itself is connected to the low pressure and, in view of the position of the reversing sliding valve 26, the conduits 22 and 23 are in communication through the groove 50. The conduit 23 itself is in communication with the conduit 65, which allows the inner groove 16iC to be set at low pressure. However, the inner groove 16iC is placed in communication with the inner groove 16iA by the position of the displacement selection sliding valve 35.

[0127] In short, Figure 5 In the configuration of , the chamber connected to groove 2B is at high pressure, and all other chambers connected to grooves 2D, 2C and 2A are at low pressure. Likewise, one of the sub-motors is bypassed or by-passed: it is not pressurized. Its intake and discharge are at low pressure.

[0128] The sub-motors that are sometimes deactivated correspond to the grooves 2A and 2C. The sub-motors that are never deactivated correspond to the compartments connected to the grooves 2B and 2D.

[0129] When the motor is bypassed, the piston 14 associated therewith continues to follow the profile of the cam 4 (except in the case where the piston is retracted by a freewheel spring or a freewheel). This continues to generate a recirculation of the fluid in the bypassed sub-motor. In our case, this recirculation is carried out between the compartments 2A and 2C by means of the displacement selection slide valve 35.

[0130] In the machine of this embodiment, it is observed that the fluid path from the inlet of the machine to the displacement change slide valve 35 is shorter than the fluid path from the inlet to the change-direction slide valve 26. In this example, this is achieved by the fact that the displacement selection slide valve 35 extends in the dispenser while being coaxial with the axis of rotation, while the change-direction slide valve 26 is located in the wall of the dispensing closure and outside the displacement selection slide valve 35.

[0131] However, considering that the grooves 2A, 2B, 2C and 2D of the cover and the grooves of the distributors 16eA, 16eB, 16eC and 16eD form a volume having a center of gravity, this arrangement can also be obtained because the displacement selection slide valve 35 is located closer to the center of gravity than the change-direction slide valve 26. Figures 1 to 5 and Fig.11 In the embodiment described in , the center of gravity is merged with the axis 10 .

[0132] Ⅱ. Second embodiment

[0133] We will now refer to Figures 7 to 12 A second embodiment is described. Certain features common to the first embodiment will not be described again.

[0134] The main difference between this machine 200 and the machine of the first embodiment is that this time the reversing slide valve 26 and its recess 39 extend in the wall of the dispenser 16. This occurs Figure 7 and Fig.11 middle, Fig.11 Only the distributor is shown. However, as in the first embodiment, the recess and the slide valve 26 are located completely outside the displacement selection slide valve 35 and at a distance therefrom.

[0135] The structure of the machine is generally the same and its operation is also the same, with the configuration of some of the conduits being modified with regard to the position of the sliding valve 26 in the distributor 16 .

[0136] This embodiment in particular allows saving space in the cover.

[0137] Figure 7 Corresponds to the forward movement of the motor. This means that the conduit L corresponds to the supply and receives the high pressure, which conduit communicates with the groove 2D. The groove 2D is axisymmetric and also builds up a high pressure in the conduit 222, which communicates with said groove. Regardless of the initial position of the reversing sliding valve 26, the pressurized fluid reaches the chamber 28 due to the end section of the sliding valve 26, which has a reduced diameter relative to the adjacent section facing the conduit 222. The fluid exerts an axial thrust on this section and places the sliding valve Figure 7 The configuration is placed on the left side, closest to the cylinder block, which is also the position of the sliding valve. Fig. 9 The position in the forward motion configuration.

[0138] Figure 8 Corresponds to the backward movement of the motor. This means that the conduit R corresponds to the supply and reception of high pressure, which conduit communicates with the groove 2B. The groove is axisymmetric and also builds up high pressure in the conduit 224, which communicates with the groove 2B. Likewise, whatever the initial position of the reversing sliding valve 26, the pressurized fluid reaches the chamber 37 via the conduit 225 facing the left axial end section of the sliding valve 26, which has a reduced diameter relative to the adjacent sections. The fluid exerts an axial thrust on this section and places the sliding valve Figure 8 This is also the configuration of Fig.10 configuration, and therefore on the right.

[0139] refer to Figure 7 , it should be noted that:

[0140] - the groove 2A is in permanent communication with the inner groove 16iA (via the conduit 64),

[0141] - groove 2B is in permanent communication with groove 16iB (via conduit 63),

[0142] - groove 2C is in permanent communication with groove 16iC (via conduit 65), and

[0143] - Groove 2D is in permanent communication (via conduit 66) with groove 16iD.

[0144] The inner conduits are shown in a cross-sectional plane, but may lie in respective different planes.

[0145] The displacement selector slide valve 35 is controlled by the hydraulic control conduit P. By default, the slide valve is in Figure 7 and Figure 8 A configuration in which the control duct P exerts no pressure in the chamber 21. The spring 30 exerts a restoring force on the sliding valve 35, which is then pressed in the direction of the control duct. This configuration allows the connection of the groove 16iB with the groove 16iA and the connection of the groove 16iC with the groove 16iD. Thus, in forward or backward movement, there are two inner grooves connected to high pressure and two inner grooves connected to low pressure.

[0146] 4. In large displacement

[0147] a) In forward motion

[0148] refer to Figure 7 , in the forward movement, high pressure reaches the groove 2D through the supply conduit L, which is connected to the inner groove 16iD through the conduit 66. The inner groove 16iD is in fluid communication with the inner groove 16iC through the groove 58 of the sliding valve 35. They are therefore at high pressure and correspond to the supply to the two sub-motors.

[0149] The discharge duct R is connected to the groove 2B which is connected to the groove 16iB by the duct 63. The inner groove 16iB is in fluid communication with the inner groove 16iA through the groove 56 of the displacement selection slide valve: these two grooves are at low pressure and correspond to the discharge of the two sub-motors.

[0150] Thus, the motor operates at full displacement, each of the two sub-motors being supplied with high pressure and discharged with low pressure.

[0151] b) In backward motion

[0152] Reference Figure 8 In the backward movement, high pressure reaches the groove 2B through the supply conduit R, which is connected to the inner groove 16iB through the conduit 63. Through the groove 56; the inner groove 16iB is in fluid communication with the inner groove 16iA: these two grooves are therefore at high pressure.

[0153] The exhaust duct L is connected to the channel 2D which is connected to the channel 16iD by means of the duct 66. Through the channel 58, the inner channel 16iD is in fluid communication with the inner channel 16iC: these two channels are at low pressure and correspond to the exhaust of the two sub-motors.

[0154] Therefore, the motor is also operated at full displacement, the two sub-motors being supplied with high pressure and discharged with low pressure.

[0155] 5. In low displacement

[0156] In low displacement, when pressure is applied in chamber 21 through control conduit P, displacement selection slide valve 35 is biased against the force applied by spring 30. Fig. 9 and Fig.10 As shown, when one sub-motor is deactivated, the displacement selection slide valve places itself on the left side of the low displacement configuration. The displacement rotary slide valve moves in the direction of the cylinder block and compresses the spring. Therefore, the position of the slide valve 35 isolates the inner groove 16iB from the other grooves, and also isolates the inner groove 16iD from the other grooves, while the inner grooves 16iA and 16iC are placed in communication with each other.

[0157] a) In forward motion

[0158] Fig. 9 Corresponds to forward movement. This means that conduit L corresponds to supplying and receiving high pressure, which conduit is in communication with groove 2D. High pressure is also established in conduits 222 and 223, which are in communication with groove 2D. And regardless of the initial position of the reversing sliding valve 26, since the end section 31 of the sliding valve has a reduced diameter, the pressurized fluid reaches the right chamber 28 through the conduit 222 of reduced diameter. The fluid exerts an axial thrust on this section 31 and places the sliding valve 26 in the Fig. 9 Then, the sliding valve does not allow the high pressure of conduit 222 (or 223) to communicate with the fluid of another chamber.

[0159] The high pressure in the groove 2D is also established in the inner groove 16iD by the fluid communication achieved by the conduit 66. The displacement selection slide valve 35 is arranged in this configuration to isolate the inner groove 16iD from the other inner grooves. Therefore, a single chamber associated with the groove (i.e. the chamber of the groove 2D) is subjected to high pressure. This corresponds to the supply of a single sub-motor.

[0160] The discharge through the pipe R is at low pressure. Therefore, the groove 2B is at low pressure, and, due to the presence of the conduit 63, the inner groove 16iB is also at low pressure (see Figure 7). In view of the configuration of the displacement selection slide valve 35, the inner groove 16iB appears to be isolated from the other compartments. Nevertheless, through the groove 2B, the conduit 224 is at a low pressure. In view of the position of the reversing slide valve 26 and its groove 54, the conduits 224 and 27 are connected. Since the conduit 27 is connected to the inner groove 16iA, it also puts itself at a low pressure. However, the inner groove 16iA is placed so as to communicate with the inner groove 16iC through the position of the displacement selection slide valve 35.

[0161] In short, Fig. 9 In the configuration of , the compartment connected to the channel D is at high pressure, and all other compartments B, A and C are at low pressure. One sub-motor is bypassed and not pressurized: its intake and its discharge are at low pressure.

[0162] b) In backward motion

[0163] Fig.10 This means that the conduit R corresponds to the supply and receives high pressure, which conduit is in communication with the groove 2B. High pressure is also established in the conduit 225, which is in communication with the groove B. Likewise, regardless of the initial position of the sliding valve 26, the pressurized fluid reaches the left chamber 37 through the conduit 224 of reduced diameter, since the end section 32 of the sliding valve has a reduced diameter. The fluid exerts an axial thrust on this section and places the sliding valve 26 in a Fig.10 configuration, abutting to the right at the end of travel in the rearward direction.

[0164] The high pressure in groove 2B is also established in the inner groove 16iB by the fluid communication achieved by the conduit 63. The displacement selection slide valve 35 is arranged in this configuration to isolate the inner groove 16iB from the other inner grooves. The high pressure is also established in the conduit 224 through the groove B and, as previously described, in the chamber 37 via the reduced diameter 32, so as to place the change-direction slide valve 26 in the Fig.10 The sliding valve in this configuration does not allow the high pressure of conduit 224 or 225 to communicate with the other fluid.

[0165] Therefore, the single chamber is subjected to high pressure. This corresponds to the supply of the sub-motor.

[0166] The discharge that occurs through the conduit L is at low pressure. The groove 2D is therefore at low pressure, and, due to the presence of the conduit 66, the inner groove 16iD is also at low pressure (see Figure 7). In view of the configuration of the displacement selection slide valve 35, the inner groove 16iD appears to be isolated from all other compartments. Nevertheless, through the groove 2D, the conduit 222 itself is also connected to the low pressure. In view of the position of the reversing slide valve 26, the conduits 223 and 36 are connected through the reduced diameter section 55 of the slide valve 26. The conduit 36 ​​allows the inner groove 16iC to be set to a low pressure. However, the inner groove 16iC is placed in communication with the inner groove 16iA through the position of the displacement selection slide valve 35.

[0167] In short, Fig.10 In the configuration of , the chamber connected to groove 2B is at high pressure, and all other chambers associated with grooves 2D, 2C and 2A, respectively, are at low pressure. Likewise, one sub-motor is bypassed: its intake and its discharge are at low pressure.

[0168] In this embodiment, a subassembly for a hydraulic machine is therefore determined, which includes the distributor 16 , the displacement selection slide valve 35 and the change-direction slide valve 26 .

[0169] The reduced diameter of the conduits 222, 225 serves to inhibit the movement of the reversing slide valve 26 or shuttle valve. In fact, they form a jet or restriction which has the effect of limiting the flow rate and preventing the slide valve from changing too quickly from one position to another. In the figure, it can be seen that the jet is achieved by reducing the diameter of the holes 222, 224. Alternatively, it is conceivable that this is done, for example, by a perforated stop which can be introduced by force into a conduit of constant cross section.

[0170] Various modifications may be made to the present invention without departing from the scope of the invention.

[0171] In the second embodiment, the reduced diameter section of the direction-changing sliding valve 26 is completed by an annular groove. Fig.13 In a variation of , the same functionality can be provided by slot 60. Fig.14 In the variant of , this function is provided by the flat portion 62. In the first embodiment, this function is provided by the internal conduit of the change-of-direction sliding valve 26.

[0172] like Fig.12 As shown, the direction-changing slide valve is axisymmetric. This facilitates production and avoids problems in the assembly of hydraulic machines.

Claims

1. A hydraulic machine (100; 200), comprising: - a dispensing cover (2.3), - a distributor (16), a displacement selector slide valve (35) mounted to slide between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and a reversing slide valve (26) mounted to slide between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation (10) and a second position in which the machine is configured to apply a torque in a second direction, The direction-changing sliding valve (26) is mounted to slide along an axis (42) away from the rotation axis (10), The direction-changing sliding valve: - extends in the wall of the distributor (16), or - Extends in the wall of the dispensing closure and outside the displacement selection slide valve (35).

2. The machine (100; 200) according to the preceding claim, wherein: The displacement selection slide valve (35) extends within the distributor (16).

3. The machine (100; 200) according to any one of the preceding claims, wherein: The displacement selection sliding valve (35) is coaxial with the rotation axis (10).

4. The machine (100; 200) according to any one of the preceding claims, wherein: The direction-changing sliding valve (26) extends outside the displacement selecting sliding valve (35).

5. The machine (100; 200) according to any one of the preceding claims, wherein: The direction-changing sliding valve (26) is installed to slide in a direction parallel to the rotation axis (10).

6. A machine according to any one of claims 1 to 4, wherein: The direction-changing sliding valve (26) is installed to slide in a direction that is not parallel to the rotation axis (10).

7. A machine (100; 200) according to any one of the preceding claims, comprising a high pressure line and a low pressure line and being configured such that the change-of-direction sliding valve (26) moves under the influence of the pressure in the high pressure line.

8. The machine (100; 200) according to any one of the preceding claims, wherein: The second displacement is smaller than the first displacement, and the second displacement is achieved by a group of pistons (14) or cam lobes (4), the group forming a regular polygon centered on the rotation axis (10).

9. A machine according to any one of the preceding claims, wherein: The fluid path from the inlet of the machine to the displacement changing slide valve (35) is shorter than the fluid path from the inlet to the direction changing slide valve (26).

10. The machine (100; 200) according to any one of the preceding claims, wherein: The cover forms annular grooves (2A, 2B, 2C and 2D), The distributor forms grooves (16eA, 16eB, 16eC and 16eD), The groove of the cover and the groove of the dispenser form a volume having a center of gravity, The displacement selection slide valve (35) is positioned closer to the center of gravity than the direction changing slide valve (26).

11. An arrangement comprising at least one machine (100; 200) according to any one of the preceding claims.

12. A subassembly for a hydraulic machine, The subcomponents include: - a distributor (16), a displacement selection slide valve (35) mounted to slide in the distributor between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and a reversing slide valve (26) mounted to slide in the dispenser between a first position in which the machine is configured to apply a torque in a first direction about the axis of rotation (10) and a second position in which the machine is configured to apply a torque in a different direction, The direction-changing sliding valve (26) is installed to slide along an axis away from the rotation axis.

13. A method for controlling a hydraulic machine (100; 200), wherein: a displacement selector slide valve (35) sliding between a first position in which the machine is configured to operate at a first displacement and a second position in which the machine is configured to operate at a second displacement different from the first displacement; and a change-direction sliding valve (26) sliding between a first position, in which the machine is configured to apply a torque in a first direction about the axis of rotation, and a second position, in which the machine is configured to apply a torque in a second direction about the axis, the change-direction sliding valve (26) sliding along an axis away from the axis of rotation, The direction-changing sliding valve (26): - extends in the wall of the distributor (16), or - Extends in the wall of the dispensing closure and outside of said displacement selecting slide valve.

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