Patent Application
20240247635
The present disclosure relates to a hydraulic machine comprising an improved sweep system.
The hydraulic machine 100 as schematized has a shaft 102 extending along a main axis X-X. Schematically, several portions can be defined for the hydraulic machine 100: a proximal portion 110, a middle portion 120 and a distal portion 130, the designations proximal and distal being defined arbitrarily with respect to the main axis X-X, and being used in the text to locate the position of different elements.
The proximal portion 110 has a distribution supply function. It comprises a distributor 112, and more generally the means ensuring a supply and a discharge of fluid, typically two ducts defining a duct qualified as high-pressure (HP) duct and a duct qualified as low-pressure (LP) duct.
The middle portion 120 defines the hydro-torque of the hydraulic machine 100. It comprises a cylinder block 122 comprising a plurality of housings in which pistons 124 are slidably mounted, said pistons 124 coming into contact with a multi-lobe cam 126.
The distal portion 130 typically comprises the bearing of the hydraulic machine 100. In the example represented, the distal portion comprises two tapered roller bearings 132 forming a rolling bearing ensuring the relative rotational movement of the hydraulic machine. The distal portion 130 can also comprise other elements, for example a braking device.
Thus in the hydraulic machine 100, the closed-loop circuit corresponds to the circuit in which the working fluid of the hydraulic machine 100 circulates, typically oil, linked to the rotational movement of the hydraulic machine 100. The closed-loop circuit also comprises a booster pump 12, which can be coupled to this same primary motor M or driven by another element. The booster pump 12 is connected to the ducts of the hydraulic circuit via check valves 14 so as to ensure a boosting the hydraulic circuit.
In such a hydraulic machine 100, the closed-loop circuit of the hydraulic machine 100 is distinguished with respect to its internal volume.
The internal volume of the hydraulic machine 100 is here defined as being the space inside the hydraulic machine which is not part of the closed loop, and which is typically at an internal pressure very much lower than the pressure of the working fluid of the hydraulic machine, for example at a pressure close to atmospheric or ambient pressure. The closed-loop circuit is typically sealed and isolated from the internal volume by means of suitable sealing elements.
The working fluid circulating in the closed-loop circuit and which travels through the different components of a hydraulic circuit such as pumps, motors, ducts and various regulation components tends to heat up, in particular due to friction between the different inner elements of the hydraulic machine 100 and to the pressure drops.
To cool the fluid circulating in the closed-loop circuit, it is known to provide for an exchange function; oil which is qualified as “hot” is taken from the closed loop on the line of lowest pressure thanks to an exchange valve 16 to replace it with the same volume of oil that comes from a tank R thanks to the booster pump 12 and to the circuit elements associated with the boosting, this oil being at a lower temperature and having been typically filtered. Such a function thus makes it possible to lower the temperature of the oil circulating in the closed loop.
However, as indicated above, the internal volume of the hydraulic machine 100 is dissociated from the closed loop in a sealed manner, as a result, the exchange does not cool the oil contained in the internal volume of the hydraulic machine 100.
To cool the internal volume, it is therefore known to carry out a sweep of the internal volume of the hydraulic machine 100 by means of a fluid which is introduced into the internal volume (for example taken from a low-pressure branch of the hydraulic circuit thanks to the exchange valve or directly coming from the booster pump) then to make this same amount of fluid exit through a drain.
However, the solutions currently proposed do not allow carrying out a sweep of the entire internal volume, or require defining dedicated sweep streams having intake and discharge ducts distributed in the different portions of the hydraulic machine 100, for example in the proximal portion 110 and the distal portion 130 which is restrictive in terms of implantation and maintenance. The addition of additional ducts indeed poses additional problems in terms of access and increases the risk of tearing of the ducts.
Another known solution consists in using the leaks from the closed loop towards the internal volume of the hydraulic machine 100 in association with a drain added to the casing of the hydraulic machine 100 to carry out a sweep of the internal volume. Nevertheless, it turns out that such a solution leads to insufficient sweep that does not allow cooling the entire internal volume and in particular the parts farthest from the areas in which the leaks occur and from the drain.
Whatever the structure proposed, when the internal volume of the motor is not sufficiently swept, the oil present in the internal volume can heat up, in particular due to the friction of the different movable parts or pressure drops, and become hotter than the exchanged oil, particularly in areas of the internal volume remote from the inlet or the outlet of the sweep fluid.
The present disclosure aims to respond at least partially to these problems.
In order to respond at least partially to these problems, the present invention relates to an assembly comprising a hydraulic machine comprising a first assembly and a second assembly that are movable in rotation relative to each other along a main axis, the first assembly comprising a shaft (102) and the second assembly comprising a casing,
According to an example, the sweep circuit defines two streams in the internal volume of the hydraulic machine:
According to an example, the secondary stream defines a circulation of fluid within the proximal portion, between the fluid inlet orifice and the fluid outlet orifice.
According to an example, the primary stream and the secondary stream are calibrated by means of restrictions defining the maximum fluid flow rate for each of said streams.
According to an example, the distal portion of the hydraulic machine comprises a braking device.
According to an example, said assembly comprises an exchange valve, adapted to take hydraulic fluid from the duct having the lowest pressure among the intake duct and the discharge duct of the hydraulic machine; and inject it into the fluid inlet orifice of the sweep circuit.
According to an example, said exchange valve is integrated into a distribution cover of the hydraulic machine.
According to an example, said assembly comprises a sweep valve, adapted to take hydraulic fluid from a booster circuit associated with the hydraulic machine or from a control circuit associated with the hydraulic machine.
According to an example, the sweep circuit comprises ducts formed in the distributor and/or the shaft and/or the cylinder block of the hydraulic machine, so as to convey the sweep fluid from the inlet orifice to the distal portion of the hydraulic machine, and inject the sweep fluid into an internal volume of the distal portion of the hydraulic machine.
The distal portion then typically comprises a sleeve positioned around the shaft, bearing against the cylinder block, said bearing of the sleeve against the cylinder block being provided with a sealing element, said sleeve being configured so as to define a fluid passage along the shaft, up to a distal end of the internal volume of the distal portion of the hydraulic machine.
The invention and its advantages will be better understood upon reading the detailed description given below of different embodiments of the invention given by way of non-limiting examples.
In all of the figures, common elements are identified by identical numerical references.
The proximal portion 110 has a distribution supply function. It comprises a distributor 112 surrounded by a distribution cover 113, and more generally the means ensuring a fluid supply and discharge, typically two ducts 114 defining a duct qualified as high-pressure duct and a duct qualified as low-pressure duct, which are here formed in the distribution cover 113.
The middle portion 120 defines a portion generally qualified as being the hydro-torque of the hydraulic machine 100. It comprises a cylinder block 122 comprising a plurality of housings in which pistons 124 are slidably mounted, said pistons 124 coming into contact with a multilobe cam 126.
The distal portion 130 typically comprises the bearing of the hydraulic machine 100. In the example represented, the distal portion comprises two tapered roller bearings 132 forming a rolling bearing ensuring the relative rotational movement of the hydraulic machine 100, as well as a braking device 134 adapted to selectively apply a friction force opposing to the rotational movement of the hydraulic machine 100, and dynamic seals. The braking device 134 as represented comprises stacks of disks 135 and an actuator 137, adapted to selectively engage or disengage said stacks of disks 135 and thus apply or not a resistive force opposing the rotational movement of the hydraulic machine 100.
As indicated in the preamble, considering that the hydraulic connectors are located in the proximal portion 110, a problem concerns the fluid sweep of the internal volume of the middle portion 120 and of the distal portion 130. By internal volume of the hydraulic machine 100, it is meant a volume internal to the casing of the hydraulic machine 100, but distinct from the ducts in which the hydraulic working fluid of the hydraulic machine 100 circulates.
A first assembly and a second assembly are defined for the hydraulic machine 100 which are movably mounted in rotation relative to each other about the main axis X-X via the bearings 132. One of the first assembly and of the second assembly is typically fixed and forms a stator of the hydraulic machine 100, while the other of the first assembly and of the second assembly is movable and forms a rotor of the hydraulic machine 100.
In the example illustrated, the shaft 102 and the cylinder block 122 form a first assembly, while the cam 126, the distribution cover 113 and more generally the casing of the hydraulic machine 100 form a second assembly, the first assembly being movable in rotation relative to the second assembly along the main axis X-X.
Advantageously, but optionally, the hydraulic machine 100 according to the invention can comprise one of the following characteristics, taken alone or in any combination: the hydraulic machine 100 is a hydraulic motor; the hydraulic machine 100 is a hydraulic machine with radial pistons; the hydraulic machine 100 comprises a cam provided with several lobes; the hydraulic machine 100 comprises a casing formed of two lateral casing elements framing a central annular casing element, a cam comprising a lobed cam formed on a radially inner surface of the central casing element, a cylinder block mounted in relative rotation in the casing about an axis X-X, facing the cam, a shaft connected in rotation with the cylinder block, pistons guided in radial sliding in respective cylinders of the cylinder block and bearing on the lobes of the cam via of rollers, a planar distributor adapted to ensure a fluid connection with the cylinders of the cylinder block, so that the successive bearing of the pistons on the lobes of the cam causes the relative rotation of the cylinder block and of the elements linked thereto relative to the casing.
The hydraulic machine 100 as proposed here comprises means defining a sweep circuit generally designated by the numerical reference 200, adapted to ensure a sweep of the internal volume of the proximal portion 110, of the middle portion 120 and of the distal portion 130 while having fluid inlet and outlet orifices only in the proximal portion 110.
More specifically, the hydraulic machine 100 comprises an inlet orifice 210 and an outlet orifice 220 between which a sweep circuit 200 is formed. In the example illustrated, the inlet orifice 210 and the orifice outlet 220 are formed in the distribution cover 113.
According to an example, the inlet orifice 210 is connected to an exchange valve 240, adapted to take a fluid flow rate from the hydraulic circuit associated with the hydraulic machine, and to convey this flow rate thus taken towards the inlet orifice 210. Said exchange valve 240 may or may not be integrated into the hydraulic machine 100. It may be added onto the hydraulic machine 100, for example positioned in a flange fixed on the hydraulic machine 100. The figures schematically represent the exchange valve 240 connected to hydraulic ducts ensuring the circulation of hydraulic working fluid of the hydraulic machine 100.
The exchange valve 240 is thus typically configured so as to take fluid from the low-pressure duct connected to the hydraulic machine 100, typically the discharge in the case of a hydraulic motor, or the intake in the case of a hydraulic pump.
As a variant, the sweep can be done in parallel with the exchange circuit.
As a variant, the sweep fluid arriving at the inlet orifice 210 can come from the booster pump 12. As a variant, the sweep fluid may come from a control circuit associated with the hydraulic machine 100. As a variant, the sweep fluid may come from a high-pressure duct connected to the hydraulic machine 100; it can then be brought into the sweep circuit via a pressure reducer. As a variant, the sweep fluid can come from a high-pressure duct internal to the hydraulic machine 100. It is understood that these embodiments are not limiting, and that the sweep fluid can be taken from any suitable fluid source. The fluid is typically oil.
The outlet orifice 220 is typically connected to a tank R typically at ambient pressure of the hydraulic circuit associated with the hydraulic machine 100, typically via a filter and/or a heat exchanger.
The fluid used to carry out the sweep within the internal volume of the hydraulic machine 100 is thus typically the same fluid as the one used for the actuation of the hydraulic machine 100. It is however understood that the fluid carrying out the sweep in the internal volume of the hydraulic machine is at a pressure significantly lower than the pressure of the fluid in the intake and discharge ducts of the hydraulic machine 100; the fluid carrying out the sweep being at the internal pressure within the internal volume of the casing of the hydraulic machine 100, as opposed to the fluid circulating in the hydraulic ducts of the hydraulic machine in connection with the movement of the pistons and qualified as working fluid.
The sweep circuit 200 as presented defines a primary stream F1 and a secondary stream F2 circulating in the internal volume of the hydraulic machine 100.
The distribution of the fluid between the primary stream F1 and the secondary stream F2 is for example carried out by calibration of sections, typically downstream of the inlet orifice 210, or by any other suitable means making it possible to divide a stream of fluid into two streams. It is thus defined, for example, a maximum flow rate that can be conveyed to the secondary stream F2, the remaining flow rate then being conveyed to the primary stream F1, or vice versa. It is also possible to define a maximum flow rate that can be conveyed to the primary stream F1 and a maximum flow rate that can be conveyed to the secondary stream F2.
The example illustrated defines a primary sweep stream F1 and a secondary sweep stream F2 schematized by arrows F1 and F2 respectively. The primary stream F1 and the secondary stream F2 are here schematized as being separated from the inlet orifice 210. It is however understood that this embodiment is not limiting, and that the separation into two streams can be carried out in any point downstream of the inlet orifice 210.
In the example illustrated in
The secondary stream F2 takes the following route:
The association of the primary stream F1 and of the secondary stream F2 thus makes it possible to ensure fluid sweep in the internal volume of the different portions of the hydraulic machine 100, and thus to ensure cooling and lubrication of the different portions of the hydraulic machine 100 while retaining fluid supply ducts grouped together in the proximal portion 110 of the hydraulic machine 100.
It is however understood that the embodiment represented in
The following figures show different other embodiments. Only the differences with respect to the embodiment already described with reference to
In the example represented in
In this embodiment, the primary stream F1 takes the following route, from the inlet orifice 210 to the outlet orifice 220:
There is therefore in this embodiment a sweep circuit making it possible to ensure fluid sweep in the internal volume of the different portions of the hydraulic machine 100, and thus to ensure cooling and lubrication of the different portions of the hydraulic machine 100 while retaining fluid supply ducts grouped together in the proximal portion 110 of the hydraulic machine 100.
In this example, the primary stream F1 is conveyed from the inlet orifice 210 to the distal portion 130 via ducts arranged in the distributor cover 113, in the multilobe cam 126 and in a distal cover 138, that is to say generally in the casing of the hydraulic machine 100.
The primary stream F1 is thus re-injected at the distal end of the internal volume of the distal portion 130. The primary stream F1 then passes through the internal volume of the distal portion 130 then the middle portion 120 for example by bypassing the cylinder block 122 via a passage radially outward from the main axis X-X, and joins the proximal portion 110 to reach the outlet orifice 220.
This embodiment is a variant of
The primary stream F1 thus opens out into the distal portion 130, between the two bearings 132, then joins the middle portion by passing through one of the bearings 132, passes through the middle portion 120 and joins the proximal portion 110 to reach the outlet orifice 220.
In view of the different embodiments, it is thus understood that in general, the invention proposes to define a primary sweep stream F1 in the internal volume of the hydraulic machine 100, which enters and exits the hydraulic machine by the proximal portion of the hydraulic machine 100, and which ensures a circulation of fluid in the different portions of the hydraulic machine 100, namely a circulation of the sweep fluid successively passing through the proximal portion 110, the middle portion 120 and the distal portion 130, then which passes back through the middle portion 120 and the proximal portion 110 before exiting the hydraulic machine 100.
This primary stream F1 of sweep fluid thus ensures lubrication and cooling of the different portions of the hydraulic machine 100. A secondary stream F2 of sweep fluid typically ensures in parallel a stream of sweep fluid in the proximal portion 110 and the middle portion 120 of the hydraulic machine 100, to ensure lubrication and cooling of the distribution components and the elements associated with the cylinder block 122 of the hydraulic machine 100.
The primary stream F1 and the secondary stream F2 are thus calibrated for example via sections defining a maximum flow rate for either or both of these streams. The primary stream F1 and the secondary stream F2 typically join in the middle portion 120 or in the proximal portion 110 of the hydraulic machine 100 before reaching the outlet orifice 220.
Thus, at least part of the sweep fluid circulates throughout the internal volume of the hydraulic machine 100, and reaches the components positioned in the portions of the hydraulic machine 100 furthest from the inlet orifice 210 and the outlet orifice 220 without requiring that one of these orifices be in a middle or distal portion and/or without requiring an addition of other inlet or outlet orifices of the sweep fluid.
The invention as proposed thus makes it possible to propose a hydraulic machine 100 having fluid intake and discharge ducts only in a proximal portion of the hydraulic machine 100, which thus makes it possible to keep a minimized space requirement and a simplified integration for the hydraulic machine 100 with respect to a hydraulic machine structure in which additional hydraulic ducts are added in order to define additional sweep streams within the hydraulic machine 100.
Ensuring a fluid sweep makes it possible to avoid a temperature rise and/or premature wear in the different portions of the hydraulic machine 100.
The assembly according to the invention can be applied to a hydraulic machine 100 associated with a closed-loop hydraulic circuit or an open-loop hydraulic circuit.
Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Particularly, individual characteristics of the different illustrated/mentioned embodiments can be combined in additional embodiments. Consequently, the description and drawings should be considered in an illustrative rather than a restrictive sense.
It is also obvious that all the characteristics described with reference to one method can be transposed, alone or in combination, to one device, and conversely, all the characteristics described with reference to one device can be transposed, alone or in combination, to one method.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2105228 | Mar 2021 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2022/050885 | 5/9/2022 | WO |
