FR2975731A1 - HYDRAULIC TRANSMISSION DEVICE WHICH CAN CONSTITUTE A COMPACT HYDRAULIC STARTER - Google Patents

Abstract

Device (40) for hydraulic transmission for a machine comprising: - a hydraulic motor (42) which can be decoupled with radial pistons (58), comprising a cam (46B) integral with a housing (46), a cylinder block (48) and an internal fluid distributor (50) disposed in the housing (46); and - a hydraulic pump (44) having a drive member (90); wherein the housing and the distributor are mounted relative rotation relative to a fixed support (54) about an axis of rotation (A), while the cylinder block is fixed on said support. The device is characterized in that the drive member (90) of the pump is integral in rotation with the motor housing.

Description

The present invention relates to a hydraulic transmission device for a machine comprising: a hydraulic motor that can be disengaged with radial pistons, comprising a cam integral with a housing, a cylinder block and an internal fluid distributor arranged in the housing; - A hydraulic pump comprising a drive member in which the housing and the distributor are mounted relative rotation relative to a fixed support about an axis of rotation, while the cylinder block is fixed on said support. By "fixed" support is meant here a support which is a non-rotating part of the device. This support is therefore intended to be fixed relative to the machine. It ensures the mechanical maintenance of the cylinder block, and more generally, the hydraulic motor, on the machine. Preferably, the cylinder block is rigidly fixed on the support. The crankcase is the crankcase of the hydraulic motor; it houses in particular the cylinder block and the fluid distributor. The invention more particularly relates to a hydraulic transmission device of the aforementioned type, which can be used to rapidly rotate a machine member or a tool whose drive is then relayed by another motor above a threshold of speed. It is in particular a machine or a tool having a high inertia. Such devices are used in particular to serve as a starter for internal combustion engines, for example diesel engines. A known solution for making a starter is to use an electric motor powered by a battery. However, electric starters and batteries are not suitable for a very large number of startup operations. However, today, in order to save fuel, it is desired to be able to stop a heat engine as soon as it is no longer needed, even if it is restarted almost immediately afterwards. With such use, the number of starts that the engine undergoes is very important: Also, the number of starts that must ensure the starter greatly exceeds the number of starts that can ensure an electric starter. A known alternative is to use a hydraulic motor as a starter. Such an engine can indeed constitute a starter.

effective for an internal combustion engine, particularly when the internal combustion engine is used to drive a load having a large inertia: Indeed, the hydrostatic starter has a density (volumetric) of very high power, which allows it to be less bulky than an electric starter. The use of a hydrostatic engine to make a starter is also interesting because it is robust, and has a long life, allowing it to ensure a very large number of starts. A hydraulic motor can in particular be used as a starter for an internal combustion engine such as that of a vehicle, in particular of the type of urban transport vehicle, having a large mass. The internal combustion engine is then used, when the torque it must provide to ensure the displacement of the vehicle is zero or low, to ensure the filling of pressurized fluid of a battery by means of a pump. When stopped or idling, the internal combustion engine is shut down; thanks to the accumulator, the restart of the internal combustion engine is ensured by the hydraulic motor, actuated by the fluid from the accumulator. One known embodiment for a diesel engine hydraulic starter is illustrated in FIG. 1. In this figure, valves, control, control, safety, etc., unless otherwise indicated, are not shown. Figure 1 shows a diesel engine 10, provided with a hydraulic transmission device 12 as a starter.

The device 12 comprises an accumulator 14 of fluid under pressure, a pump 16, a hydraulic motor 18, and a tank 20 of fluid under atmospheric pressure. The accumulator 14 is connected via a duct 22 to the hydraulic motor 18 so that, in order to start the engine 10, the motor 18 is supplied with fluid under pressure. When the engine 18 is thus powered, the fluid after having passed through the engine 18 is directed towards the tank 20 via an exhaust pipe 24. The casing 26 of the engine 18 is mounted in the end of the crankshaft of the heat engine 10. casing 26 is a rotating casing which is the output member of the motor 18. Thus, when the motor 18 is supplied with fluid under pressure, the casing 26 begins to rotate and in turn rotates the crankshaft of the motor 10, which causes the engine 10 to start. In addition, a belt 28 which passes into external grooves respectively formed on the casing 30 of the pump 16 and on the casing 26 of the motor 18, links in rotation the pump 16 and the motor 18. For this reason, when the crankshaft of the engine 10 rotates, the housing 26 of the engine 18 and the housing 30 of the pump 16 also rotate. Furthermore, the pump 16 is connected by a suction duct 32 to the tank 20, and by a filling duct 34 to the accumulator 14.

As indicated, during all the operating phases of the motor 10, the pump 16 is actuated (that is to say that its housing 30 is rotated). Also, when the motor 10 rotates, the pump 16 pumps the fluid into the reservoir 20 so as to fill the accumulator 14, via the conduits 32 and 34. The stopping of the filling of the accumulator is controlled by a valve 36 interposed between the accumulator 14 and the conduits 22 and 34. The operation of the device 12 is as follows: When the motor 10 is stopped, the accumulator 14 is in principle filled.

To start the engine 10, it causes the emptying of the accumulator 14 in the tank 20 via the engine 18. The passage of the pressurized fluid from the accumulator actuates the motor 18 the housing 26 of the engine 18 starts to rotate, which in turn rotates the crankshaft of the engine 10 and causes the engine 10 to start. The engine 10 is then in operation. During the operation phase of the engine 10, via the belt 28, the casing 26 of the motor 18 drives the casing 30 of the pump 16. The pump 16 thus actuated then charges the accumulator 14 with pressurized fluid.

In general, the hydraulic starting system 12 complements an electric starting system. Although the operation of the hydraulic device 12 is satisfactory, the device 12 is relatively bulky, which makes its implementation difficult on many equipment, including many engines such as the engine 10.

More generally, the known hydraulic motors as well as the components of the circuit necessary to supply them are not optimized for use as starters for combustion engines of vehicles or other machines. Hydraulic motors require many hoses, the installation of a booster pump, and the drive of it by an output shaft of the engine or via an additional electric drive. As a result, the implementation of a hydraulic motor, and the circuit that accompanies it, as a starter of a heat engine, turns out to be a complicated operation.

However, an example of a hydraulic starter which has a certain compactness is provided by GB1395901. This document discloses a hydraulic starter associating a hydraulic motor with radial pistons, associated with a pump for charging an accumulator. The motor is of the fixed housing type, with a rotating shaft on which is fixed the cylinder block. The output member of the motor is a coupling piece fixed at the end of the motor shaft. The presence of this part induces additional length and additional complexity for the hydraulic starter. When the pressure inside the accumulator becomes low, a valve device activates a hydraulic clutch interposed between the motor shaft and the drive member of the pump. The motor shaft then drives the pump, the rotation of which then makes it possible to recharge the accumulator. Also, although the motor is placed in the vicinity of the pump, this starter has the disadvantage of a large size and complexity, particularly because of the clutch interposed between the motor and the pump, the objective of the invention is therefore to provide an improved hydraulic transmission device, of the type presented in introduction, which can constitute a relatively simple hydraulic starter and having a small footprint. This object is achieved in a device presented in the introduction, thanks to the fact that the drive member of the pump is integral in rotation with the motor housing. The pump is thus rotated by the casing (directly or indirectly); it can therefore be arranged in the immediate vicinity of the motet ir Pt tntOgree with it.

Moreover, as the housing is rotating, it is - directly or indirectly - the output member of the starter, which makes unnecessary the use of a coupling part fixed at the end of the motor output shaft, as in the previous embodiment presented previously. Advantageously, the invention provides a device that is not only compact, but also economical to produce, because of the reduced length of the connection ducts between the pump and the hydraulic motor, the reduction in the number of connection components, and a reduction in the number of connecting components. reduced number of operations for its assembly on the engines, including a reduction in the number of hydraulic connections to be made. In the above definition, the expression 'integral in rotation' means permanently connected. Therefore, no clutch is interposed between the pump and the motor, and the pump is driven continuously when the engine is running. The absence of clutch provides a considerable simplification over the previous embodiment mentioned above. In the device according to the invention, the fixing of the motor on the support can be done in different ways.

The support first ensures the maintenance of the cylinder block. In addition, the housing and the distributor must be arranged so as to be rotatable relative to the cylinder block. Finally, the distributor must also be located opposite the cylinder block to ensure the distribution of fluid to the cylinders of the cylinder block.

Given these technical constraints, the support can in particular be carried out in the following two embodiments In a first embodiment, the support comprises a preferably substantially cylindrical portion around which the dispenser is arranged. This substantially cylindrical portion may advantageously extend inside the cylinder block to allow the maintenance thereof. The support can then be in the form of a support shaft (essentially arranged in the form of a tree), which configuration has the advantage of a very great compactness. The substantially cylindrical portion may adopt any shape, generally of revolution, sufficiently elongated to allow the distributor and if necessary the cylinder block to be arranged around the

substantially cylindrical portion. This portion can thus for example be of generally conical shape. In this embodiment, the cylinder block is held by the interior (in the case where the support forms a shaft passing inside the cylinder block) or at least in the vicinity of its axis of rotation. The dispenser is arranged around the support. This embodiment is extremely compact while ensuring an effective mechanical maintenance of the cylinder block. In a second embodiment, the support and / or the cylinder block comprises an axial bore formed along the axis of rotation of the motor, in which the distributor is disposed. The vicinity of the axis of rotation of the engine, where the distributor is located, is then used for the exchange of fluid of the engine. Conversely, the volume located radially around the distributor is occupied by the support and / or the cylinder block to ensure the fixing of the cylinder block on the support. The cylinder block is thus fixed to the support by its outer periphery. This embodiment is advantageous if the motor undergoes significant bending forces, tending to misalign the cylinder block relative to the support.

The hydraulic motor generates a motor torque (or braking) which must be transmitted to the machine on which the device is attached. To allow the transmission of this torque, advantageously the support may comprise an arm-shaped part in which passes at least one duct and which extends in a direction substantially perpendicular to the axis of rotation. Due to its shape, the arm-shaped portion of the support is attached to a fixed part of the machine and thus serves as a link arm, preventing unwanted rotation of the device relative to the machine. Finally, the device according to the invention can be integrated into a starting system for a rotary drive machine. In this case, the starting system comprises a device as defined above and said drive member, the housing being rotatably connected therewith. Preferably, the housing may be disposed in a portion of the rotary drive member. The driving machine may for example be an internal combustion engine, including a diesel engine.

In the device according to the invention, the pump can be arranged relative to the support in different ways. In one embodiment, an axis of rotation of the drive member of the pump coincides with the axis of rotation of the hydraulic motor. The transmission of motion between the hydraulic motor and the pump can thus be achieved by simple mechanical members, these two components having drive members aligned along the same axis. In one embodiment, the drive member of the pump 10 is rotated directly by the housing. The motor housing can then be the only output member (rotational drive) of the hydraulic motor, with the pump on the one hand, and with other components of the machine in which the device is integrated, on the other hand part (for example, the crankshaft of the diesel engine of a vehicle). In one embodiment, the driving member of the pump is rotated by a drive shaft fixed to the housing and disposed at least partly inside the support. This arrangement can in particular allow the drive member of the pump to be coaxial with the axis of rotation of the motor. In one embodiment, the pump is at least partially, and possibly entirely, disposed within the support. The device is then particularly compact. The arrangement of the pump - at least partially - in the support promotes integration within the support itself of some of the conduits connected to the pump and / or the motor. In one embodiment, at least one intake or discharge pipe of the pump and / or at least one supply or exhaust duct of the motor passes through the support. For example, a feed pipe of the pump may be formed in the support and connect an inlet chamber of the pump to a fitting arranged on an outer surface of the support: Thus, the supply of the fluid pump is realized in a particularly simple and compact way. In one embodiment, an engine exhaust duct 35 and a pump supply duct meet in a semi-inclipment located in the support. So, advantageously these

conduits are compactly arranged, and the device may comprise only three external ports or connections. In one embodiment, a conduit for supplying the pump and / or exhaust of the motor is formed in the support shaft and connects a connector arranged on an outer surface of the support shaft with an internal space of the casing. Preferably, this conduit serves both the pump supply and the engine exhaust, when the fluid escaping from the engine is rejected in the internal space of the housing. The integration of the pump in the support can be carried out so as to allow the lubrication of the support thanks to the fluid present inside the housing of the hydraulic motor. For this purpose, in the embodiment mentioned above and comprising a drive shaft for driving the pump and disposed at least partly inside the support, a feed passage of the pump through which passes a fluid supplying the pump may be formed between the drive shaft and the support. The passage of the fluid in this passage cools and lubricates the support. To conduct the fluid in the supply passage, a pump supply duct may be formed in the holder and connect an internal space of the casing to the supply passage.

In one embodiment, the device may then comprise a fluid supply conduit for injecting a pump supply fluid into said internal space; said inner space being further connected to said supply passage via a supply conduit for supplying the fluid supply passage; an orifice of the supply duct in the internal space of the casing and an orifice of the supply duct in the internal space being arranged axially on either side of the cylinder block. The fluid supply duct may for example connect a fitting arranged on an outer surface of the support to the internal space of the casing.

This supply conduit serves in particular to introduce into the internal space the fluid supplying the pump (or a part thereof). By arranging the orifice of the supply duct in the internal space of the casing and the orifice of the supply duct in the internal space axially on either side of the cylinder block, the supply fluid of the pump, from the fluid supply duct, is led to sweep the cylinder block (or at least pass from one side to the other of the latter) to come to feed the pump. This sweep thus allows efficient cooling of the cylinder block. Furthermore, when the motor is rotated in only one direction, in one embodiment the fluid escapement of the cylinder block is in an internal space of the housing. This allows a particularly simple motor arrangement. The power supply of the motor can also be carried out very simply: a single annular groove can ensure the supply of fluid to the engine. This single groove can be formed on an outer surface of the support. 10 To integrate the pump in the holder, it is best to choose the most compact pump possible. Preferably, a pump is chosen in which a larger transverse dimension perpendicular to the axis of rotation is smaller than the diameter of the cylinder block, for example a gear pump. The pump can then generally be placed completely inside the support. As indicated above, the transmission device according to the invention can in particular be used to drive in rotation a rotary drive member of a machine. For this purpose, in one embodiment, the casing has, for its coupling with the member to be driven, a flange, an outer groove adapted to receive a pulley belt, or a toothing for a chain or a gear . In a particularly advantageous arrangement, the housing can thus be directly attached to one end of the crankshaft of an internal combustion engine. The invention will be well understood and its advantages will appear better on reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which - Figure 1 already described is a schematic view of a diesel engine 30 equipped with a known hydraulic device, serving as a starter - Figure 2 is a schematic view of an engine equipped with a hydraulic device according to the invention, serving as a starter - Figure 3 is an axial section of a hydraulic device according to the invention, in a first embodiment; FIG. 4 is a section perpendicular to its axis of the hydraulic device FIG.

- Figure 5 is an axial section of a hydraulic device according to the invention, in a second embodiment; - Figure 6 is a section perpendicular to its axis of the hydraulic device of Figure 5; - Figure 7 is an axial section of a hydraulic device according to the invention, in a third embodiment; and FIG. 8 is a section perpendicular to its axis of the hydraulic device of FIG. 7. FIG. 2 represents a motor 110 equipped with a hydraulic device 40 according to the invention. The motor 110 and the device 40, unless otherwise indicated, are identical to the motor 10 and the device 12 presented above. The identical elements or having the same function therefore have the same reference numerals in both cases, and will not be described again.

The implementation of the invention in the hydraulic device 40 allows a much more compact arrangement, as shown in Figure 2, than in the embodiment illustrated by Figure 1. Indeed, in the embodiment of the figure 2, the device 40 comprises a pump 44 having the same role as the pump 16; however, the pump 44 instead of being an external pump pulley connected to the motor 18, is an internal pump, integrated with the hydraulic motor 42 (see Figures 3 and 4). In addition, the connection of the hydraulic device 40 is simplified, and advantageously comprises only three ducts: a duct 124 connecting an external connection 70 of the motor 42 to the tank 20; a conduit 22 connecting the accumulator 14 to a first connector 72 of the motor 42; and a duct 23 connecting the accumulator 14 to a second connection 74 of the motor 42. The ducts 22 and 23 are connected to the accumulator 14 by a valve 136. FIGS. 3 and 4 show in more detail the device 40, which constitutes a first embodiment of the invention. The device 40 comprises a hydraulic motor 42 in which is integrated a hydraulic pump 44. The motor 42 is a decrabotabie engine with radial pistons. It includes: 2975731 He

a casing 46 composed of three parts, namely a cover 46A, a corrugated cam 46B, and a distribution casing 46C - a cylinder block 48 and a fluid distributor 50, disposed in an inner space 52 of the casing 46; 5 .. a support in the form of a support shaft 54, on which is fixed rigidly the cylinder block 48. The cylinder block 48 has cylinders 56 in which pistons 58 slide. These pistons 58 are arranged so to be able to transmit a pressure on the inner surface of the cam 46B. In known manner, the pressures exerted by the pistons 58 allow the motor 42 to develop a driving torque. This driving torque is transmitted by the housing 46, which acts as an output member of the motor 42, to the equipment to which the motor 42 is coupled: This equipment is here the crankshaft of the internal combustion engine 110. To transmit the transmission of the torque generated by the hydraulic motor 42 to the diesel engine 110, the motor 42 has a flange 60 formed on an outer circumference of the timing case 46C. The flange 60 is screwed onto the crankshaft of the engine 110. The interior components of the engine 42 are arranged in the following manner: The distributor 50 is rigidly connected to the timing case 46C by means not shown. The pistons 58 are retractable pistons. They are returned to the cylinders 56 by springs 62, when the pressure inside the cylinders 56 is less than that prevailing in the inner space 52 and the difference between the two pressures exceeds a predetermined value, which depends on the springs 62. The housing 46 is held in position on the support shaft 54 by ball bearings 64 and 66 disposed on either side of the cylinder block 48.

The bearings 64 and 66 hold the housing 46 and the distributor 50 so that they can rotate about the axis A of the support shaft 54. The pump 44 is a compact gear pump. In a manner known per se, it has (fig.4) two toothed wheels 68A, 68B which mesh with each other and ensure the pumping of the fluid passing through the pump 44.

The largest transverse dimension D of the pump 44, measured perpendicularly to the axis of rotation A, is smaller than the diameter of the cylinder block and even the radius of the cylinder block, which makes it possible to integrate the pump 44 without particular difficulties in the support shaft 54. The pump 44 is mounted in a bore (a chamber) formed in the support shaft 54. It is held in position by its cover 45, which is screwed onto the end surface of the support shaft 54 by a screw 47.

The cover 45 is actually integrated in the volume of the support shaft 54, so that the pump 44 is completely integrated in the support shaft 54. It is disposed inside a first end 54A of the support shaft, the cylinder block 48 being arranged around the opposite end 54B of the support shaft, and the distributor 50 being placed between the cylinder block 48 and the pump 44. This arrangement makes it possible to place the pump 44 as close as possible to the dispenser 50 and thus to optimize the circulation of fluid in the device 40. The circulation of fluid in the device 40 will now be detailed. Two subsets mainly exchange fluid: the motor 42 and the pump 44. The entire exchange of fluid of the device 40 is via three connections 70, 72 and 74, formed in the first end 54A of the shaft 25. 54. For the admission and discharge of fluid pump 44, two ducts 76 and 78 are formed in the end 54A of the support shaft. The pump admission conduit 76 connects the connector 70 to the inlet chamber 441 of the pump 44. The pump discharge conduit 78 connects the delivery chamber 440 of the pump 44 to the connector 74. For the supply of motor fluid 42, an angled supply duct 80 is formed in the support shaft 54. This duct 80 connects the connector 72 to an annular groove 75, formed on an outer circumference of the support shaft 54, to the inside of the distributor 50. The operation of the motor 42 is as follows:

The fluid supplying the motor 42, coming from the accumulator 14 via the conduit 22, is injected into the device 40 via the connector 72. Via the conduit 80, it is injected into the groove 75. The distributor 50 comprises first distribution 82. These convey the fluid from the groove 75 to cylinder ducts 84 formed in the cylinder block 48, by which the fluid is injected into the cylinders 56. In a manner known per se, the distributor 50, which is rotated by the casing 46, successively supplies the different cylinders 56. The pistons 58 are in turn urged by the pressure in the cylinders 56 to exit the cylinders the pressure they exert on the cam 468 generates a driving torque . Thus, the injection of pressurized fluid from the accumulator 14 makes it possible to drive the casing 46 in rotation, which consequently ensures, via the flange 60, the starting of the motor 110.

Upon retraction of the pistons 58, the fluid is removed from the cylinders 56 by the cylinder ducts 84; it is thus driven via second distribution ducts 86 into the internal space 52 of the casing 46. A duct 88 passing through the support shaft 54 connects the internal space of the casing with the duct 76. This duct 88 joins the conduit 76, which serves to supply the pump, in a branch T in the support shaft. This branch therefore divides the conduit 76 into two portions, namely an outer portion 76 ', connecting the connector 70 to the branch T, and an inner portion 76', connecting the branch T to the inlet chamber of the pump 441 (fig.4).

The conduit 88 thus allows the escape of the fluid discharged by the motor, from the internal space 52 to the outside of the support shaft, via the conduit portion 76 'and the coupling 70, the fluid is directed from the connection 70 via the conduit 124 into the reservoir 20. The operation of the pump 44 is as follows: The pump has a part or drive member 90 which allows its drive. This part 90 forms a shaft on which is fixed the toothed wheel 68A. The pump is disposed in the support shaft 54 so that the axis of the part 90 coincides with the axis of rotation A of the engine. Furthermore, a drive shaft 92 is fixed (screwed) in the cover 46A of the motor 42. Of course, any other method of fixing the drive shaft 92 to the cover 46A can be used,

as for example a flat drive finger having the shape of a screwdriver blade, etc. The axis of the shaft 92 is also coincident with the axis of rotation A of the motor. An axial cylindrical bore 94 is made along the axis A in the support shaft 54 to allow the passage of the drive shaft 92 and the drive part 90. The drive part 90 is secured in rotation with the drive shaft 92 by means of a drive finger 96. The drive part 90 of the pump is thus rotated by the housing 46, via the drive shaft 92 and the drive finger. The drive finger 96 allows in particular a limited axial displacement, along the axis A, between the drive shaft 92 and the drive part 90. Such displacement may be necessary depending on the relative expansions. The pump 44 is supported by two bearings 98A and 98B disposed axially on either side of the gears 68A, 68B. When the pump is actuated, under the effect of the rotation of the gear formed by the wheels 68A and 68B, the fluid is sucked from the reservoir 20 via the conduit 124 and the conduit 76. It is pumped by the gears 68A and 68B and transferred from the suction chamber 441 to the discharge chamber 440. It is thus forced under pressure into the conduit 78, and thence to the accumulator 14 via the conduit 23. The pump thus ensures the filling of 14. Figures 5 and 6 show a device 140 illustrating a second embodiment of the invention, very close to the first embodiment illustrated in FIGS. 3 and 4. The difference between the first and second modes of embodiment is the path of the feed fluid of the pump. The hydraulic device 140 may be used as a hydraulic starter for an internal combustion engine, as in the first embodiment. Its integration into a motor is exactly the same as that of the device 40 presented in FIGS. 2 to 4. The second embodiment, unless otherwise stated, may be considered as identical to the first embodiment. Identical elements or elements having the same function carry the same numerical references in both embodiments.

In the second embodiment, the support shaft 154 has the following differences with the support shaft of the first embodiment: First, with respect to the duct 76, only the outer portion 76 'thereof is formed. This portion 76 ', in combination with the conduit 88, forms a connection between the connector 70 and the inner space 52 of the casing 46. Conversely, in this second embodiment, the internal portion 76 "of the duct 76 is not formed. There is thus no direct communication between the connection 70 and the inlet chamber 441 of the pump 44.

It is in fact via the internal space 52 that the fluid supplying the pump will pass. For this purpose, for supplying the pump, a supply duct 100 is pierced between the internal space 52 and the bore 94. This supply duct 100 is formed in the vicinity of the cover 46A, and preferably the most close to this one. The conduit 100 allows the passage of fluid from the internal space 52 to the bore 94. Inside the bore 94, an annular feed passage 102 is provided by means of a clearance provided between the support shaft 154 on the one hand, and the drive shaft 92 and the drive part 90 on the other hand. This clearance is calculated so that the section of the feed passage 102 is sufficient for feeding the pump. In addition, a second feed passage 104 is provided at the end 154A of the support shaft which is on the side of the pump 44. This second passage 104 connects the annular space 102 to the suction chamber 441 of the pump 44, and allows the fluid to pass from the annular space 102 to the chamber 441, bypassing the outside (radially) the bearing 98B. In this embodiment, the operation of the pump is as follows: The fluid is sucked by the pump from its suction chamber 441. The aspirated fluid enters the support shaft 154 through the connector 70, passes through the conduits 76 'and 88, the inner space 52 of the housing, the conduit 100, the feed passage 102, the second feed passage 104, to finally reach the suction chamber 441. The advantage of this path is that the fluid sweeps the inner space 52 of the housing, as well as the annular space 102 between the passages 100 and 104. In so doing, it cools lubricates these various elements, including all the outer faces of the block 48, the drive shaft 92 and the training part 90. In this case

purpose, the passage 100 is formed at the end 154E of the support shaft opposite the end 154A which contains the pump 44; also, the pump feed fluid travels the annular passage 102 over almost the entire length thereof, thus allowing optimized lubrication and cooling of the bore 94. Other aspects of the operation of the device 140 of Figs. and 6 are identical to those of the device 40 shown in the first embodiment. In the second embodiment, it is therefore noted that the ducts 88 and 76 'therefore carry both the exhaust fluid of the engine, and the supply fluid of the pump. These two fluid flows of opposite direction partially compensate in the ducts 88 and 76 '. FIGS. 7 and 8 show a device 240 illustrating a third embodiment of the invention, very close to the first two embodiments illustrated by FIGS. 3 to 6. The specificity of the third embodiment with respect to the first two modes of embodiment is the arrangement of the support (254) and consequently the fluid exchange conduits of the device. Despite these differences, the operation of the device 240 is substantially identical to that of the devices 40 and 140. The third embodiment, unless otherwise stated, may be considered identical to the first embodiment. The elements that are identical or have the same function carry the same numerical references in the first, second and third embodiments.

However, some elements of the third embodiment which are specifically described carry an increased numeral reference of 200 relative to the element having the same function in the first embodiment. The device 240 comprises a hydraulic motor 242 which is integrated with a hydraulic pump 244. The motor 242 is a decibatable radial piston engine which comprises. a rotating casing 246 composed of three parts 246A, 2468, and 246C fastened together by screws 243, the housing having an axis of rotation A - a cylinder block 248 and a fluid distributor 250; and

a support 254. The support 254 is formed in two parts, namely with a head 256 which closes the motor 242 on a first side with respect to the axis A (on the right in FIG. 7), and a part 258 in the form of a linking arm, which extends in a direction substantially perpendicular to the axis A. The end of the arm 258 may be fixed on a machine by means not shown, to allow the support 254 to provide mechanical support of the device 240. In addition, in the arm 258 pass two hydraulic fluid conduits 276 and 280, whereby the support 254 also provides part of the fluid exchange of the engine 242. The cylinder block 248 of the engine 242 is fixed on the 254. For this, it has a cylindrical tubular projection 249, which extends concentrically about the axis A on the first side of the cylinder block. The end of this projection 249 is fixed on the support 254 by means not shown; the projection 249 thus ensures the fixing of the cylinder block on the support 254. The portion 246A of the casing forms a cover which closes the motor 242 on the second side of the cylinder block 248 (that is to say on the left side on Figure 7). This portion 246A comprises a central shaft 247 which extends along the axis A passing through a bore 221 of axis A formed in the cylinder block. The end of the shaft 247 is inside the projection 249 and provides support for the distributor 250. The latter is disposed inside a bore 275 of axis A formed inside the tubular projection 249. This bore 275 forms a fluid exchange groove whose role will be specified later. The housing 246 is held relative to the cylinder block 248 by bearings 264 and 266, which hold the housing 246 so that they can rotate about the axis A. The bearing 264 is disposed in the bore 221 between the cylinder block 248 and the shaft 247, and the bearing 266 is disposed between the outer surface of the projection 249 and the inner surface of the housing portion 246C. The pump 244 is arranged inside the head 256 of the support 254. It is identical to the pump 44 shown above, except for the shape of its drive part 290. The end of the drive part 290 is arranged so as to be integral in rotation of

the shaft 247, and thus the housing 246. The junction between the shaft 247 and the part 290 is provided by a connecting piece 291. The fluid exchange of the device 240 is as follows: The device 240 comprises three fluid exchange conduits 276, 278 and 280. The first conduit 278 is formed in part in the head 256 of the carrier 254 and partly in a pump cover 279. This cover 279 is attached to the first side of the head 256, that is to say on the opposite side of the cylinder block 248. When the pump 244 is in place in the head 256, the cover 279 serves to block it inside the head 256. The conduit 278 connects the delivery chamber 2440 of the pump 244 to an external connection 274 formed on an outer surface of the cover 279. The conduits 276 and 280 (FIG. 8), formed in the support 254, allow the connection of the device 240 respectively to the conduits 124 and 22 shown in FIG. 2 via connections of the support 254 not shown. Only the conduit 280 (and not the conduit 276) appears on the section of Figure 7. The end of the conduit 280 which is on the side of the device 240 opens into the groove 275 mentioned above.

On the other hand, the end of the conduit 276 which is on the side of the device 240 is divided into two branches. The first branch is connected to the inlet chamber 2441 of the pump 244. The second branch opens (not shown) in an internal space 252 arranged between the distributor 250 and the head 256, this internal space having a shape of revolution around the axis A. The groove 275 and the internal space 252 play the same role in the device 240 as the groove 75 and the internal space 52 in the device 40. In particular, the distributor 250 comprises first and second distribution ducts 282 and 286 providing the distribution of fluid in the cylinders of the cylinder block, similarly to the ducts 82 and 86 respectively. As a result, the operation of the motor 242 and the pump 244 is identical to that of the motor 42 and Finally, the output torque of the motor 242 is not delivered, as in the previous embodiments, via a flange formed on one of the parts of the housing. In the device 240, a pulley piece 223 is attached to the cover housing 246A. The outer surface of this part has a grooved groove 225 adapted to drive a belt. Advantageously, various parts similar to the piece 223 can be mounted interchangeably on the motor 242, to easily adapt the motor 242 and in particular the drive groove thereof to the type of belt (or possibly chain or other body d). drive) that the motor must drive.

Claims (15)

REVENDICATIONS1. Device (40,140) for hydraulic transmission for a machine comprising: - a hydraulic motor (42) which can be tilted with radial pistons (58), comprising a cam (46B) integral with a casing (46), a cylinder block (48) and an internal fluid distributor (50) disposed in the housing (46); and - a hydraulic pump (44) comprising a drive member (90), in which the housing and the distributor are mounted relative to a fixed support (54,154) about an axis of rotation (A), while the cylinder block is fixed on said support the device characterized in that the drive member (90) of the pump is integral in rotation with the motor housing. 2. Device according to claim 1, wherein the pump is at least partially disposed within said support. 3. Device according to claim 1 or 2, wherein the drive member of the pump is rotated by a drive shaft (92) fixed to the housing (46) and disposed at least partly inside. of the support (54,154). 4. Device according to claim 3, wherein a supply passage (102) of the pump (44) through which a fluid supplying the pump passes is formed between the drive shaft (92) and the support (54). . 5. Device according to claim 4, wherein a supply duct (100) of the pump is formed in the support and connects an internal space of the casing to said feed passage (102). 6. Device according to claim 5, comprising a fluid supply duct (76 ', 88) for injecting a pump feed fluid into said internal space, said internal space being further connected to said feed passage via a supply duct for supplying the fluid supply passageway in which an orifice of the supply duct (100) in the internal space of the casing and an orifice of the supply duct (88) in the internal space (52) are arranged axially on both sides of the cylinder block. 7. Device according to any one of claims 1 to 6, wherein at least one duct (76) for admission or discharge of the pump and / or at least one duct (76,88) supply or 10 d Engine exhaust passes through the bracket. The device of claim 7, wherein a supply duct (76) of the pump formed in the holder connects an inlet chamber (441) of the pump to a connector (70) arranged on an outer surface of the pump. support. 9. Device according to claim 7 or 8, wherein an exhaust duct of the motor (88) and a conduit (76) for supplying the pump meet in a branch (T) located in the support (54). 10. Device according to any one of claims 1 to 9, wherein the support comprises an axial bore formed along the axis of rotation of the motor, wherein the distributor is disposed. 25 11. Device according to any one of claims 1 to 9, wherein the support comprises a portion, preferably substantially cylindrical, around which the dispenser is arranged. Apparatus according to any one of claims 1 to 11, wherein the fluid outlet of the cylinder block is in an internal space (52) of the housing (46). 13. Device according to any one of claims 1 to 12, wherein the support comprises an arm-shaped portion in which 35 passes at least one duct and which extends in a direction substantially PeMendiei flair to the axis of rotation . 20 14. Device according to any one of claims 1 to 13, characterized in that the housing has, for coupling with a member to be driven, a flange, an outer groove adapted to receive a belt, or a toothing for a chain or gear. 15. Starting system for a rotary drive machine, in particular an internal combustion engine (110), comprising a device according to any one of claims 1 to 14 and said rotary drive member, the housing being connected. in rotation to said drive member.