EP0284460B1 - Pressurised fluid mechanism, pump or engine, with several displacement volumes - Google Patents

Description

Hydraulic mechanisms, motor or pump, are already known which allow several (at least two) separate displacement to be obtained.

Thus, FR-A-2 481 755 describes and represents a pressurized fluid mechanism, motor or pump, such as a hydraulic motor, with at least two separate displacements, non-zero, capable of being selected, consisting of: at least a first external connection to a source of pressurized fluid and at least a second external connection to a fluid exhaust, at least one cam, the profile of which comprises several successive undulations, said undulations being distributed in at least first and second distinct groups of undulations and each undulation comprising a first ramp and a second ramp; a cylinder block, which is rotatably mounted with respect to said cam about an axis of rotation and which has a plurality of cylinders disposed substantially radially with respect to said axis of rotation; at least one piston being slidably mounted inside each cylinder, being capable of bearing on the cam and delimiting inside said cylinder a working chamber which is connected to a communication face of the cylinder block; a plurality of connecting cylinder conduits. each a working chamber at said communication face of the cylinder block; a fluid distribution face, which is integral in rotation with the cam, which is held in abutment on the communication face of the cylinder block and into which open first and second fluid distribution conduits corresponding to said first and second ramps each corrugation and capable (the distribution conduits) of being placed in communication, during the relative rotation of the cylinder block with respect to the cam, with said cylinder conduits of the various cylinders; and a displacement selection device comprising at least a first displacement selection drawer disposed between said first and second external connections and the first and / or second distribution conduits corresponding to the corrugations of the second group of corrugations; this first displacement selection drawer having a first position capable of corresponding a) to the communication of the first distribution conduits corresponding to the corrugations of the two groups of corrugations with the first external connection, and b) to the communication second distribution conduits corresponding to the corrugations of the two groups of corrugations with the second external connector, and having a second position capable of corresponding to a) the communication of the first distribution conduits corresponding to the corrugations of the first group of corrugations with the first external connection, b) connecting the second distribution conduits corresponding to the undulations of said first group of undulations with the second external connection, and c) permanently isolating the first distribution conduits corresponding to the undulations of the second corrugation group with the first external connection and / or to the permanent isolation of the second distribution conduits corresponding to the undulations of said second group of undulations from the second external connection.

It is also known, in such mechanisms whose cubic capacity is selected by choosing to connect to the normal supply system the cylinders which are at each instant arranged opposite the cams, either of the two groups, or of only one of these two groups of cams, to provide separate strokes of the pistons located opposite the cams of one or the other of these groups. FR-A-2 127 268 represents a mechanism of this type.

All of these mechanisms work well, but their very design generally makes them complex and expensive to manufacture.

The invention intends to remedy these drawbacks of known mechanisms by providing for a simpler constitution and capable, without costly machining, of ensuring the cubic capacity selections desired by the user, in particular from three distinct non-zero cubic capacities and one zero cubic capacity.

To this end, in a mechanism similar to that previously defined, according to the invention, the displacement selection device comprises a second displacement selection drawer, which also has two positions and is arranged between the first and second external fittings. and the first and / or second distribution conduits corresponding to the corrugations of the first group of corrugations, this second displacement selection drawer having a first position which corresponds to a) the communication of the first distribution conduits corresponding to the corrugations of the first group of corrugations with the first external connection, b) the communication of the second distribution conduits corresponding to the corrugations of said first group of corrugations with the second external connection, and having a second position which corresponds to the insulation of the first distribution conduits corresponding to the undulations of the first group of undulations with the first external connection and / or with the permanent isolation of the second distribution conduits corresponding to the undulations of said first group of undulations with the second external connection.

Another definition of the invention, overall, equivalent to that which has just been given, consists in clarifying that the invention relates to a pressurized fluid mechanism, motor or pump, such as a hydraulic motor, to at at least two separate cubic capacities, non-zero, capable of being selected, consisting of: at least a first external connection to a source of pressurized fluid and at least a second external connection to a fluid exhaust; at least one cam, the profile of which comprises several successive undulations, said undulations being distributed in at least a first and a second distinct group of undulations and each undulation comprising a first ramp and a second ramp; a cylinder block, which is rotatably mounted relative to said cam around a axis of rotation and which comprises a plurality of cylinders arranged substantially radially with respect to said axis of rotation; at least one piston being slidably mounted inside each cylinder, being capable of bearing on the cam and delimiting inside said cylinder a working chamber which is connected to a communication face of the cylinder block; a plurality of cylinder conduits each connecting a working chamber to said communication face of the cylinder block; a fluid distribution face, which is integral in rotation with the cam, which is held in abutment on the communication face of the cylinder block and into which open first and second fluid distribution conduits corresponding to said first and second ramps each corrugation and capable (the distribution conduits) of being placed in communication, during the relative rotation of the cylinder block with respect to the cam, with said cylinder conduits of the various cylinders; a first displacement selection drawer disposed between said first and second external connections and the first and / or second distribution conduits corresponding to the corrugations of the second group of corrugations; and a second displacement selection drawer disposed between said first and second external connections and the first and / or second distribution conduits corresponding to the corrugations of the first group of corrugations; each of said first and second displacement selection drawers having two particular positions which, when combined, correspond to A) the first position of the first displacement selection drawer and the first position of the second displacement selection drawer, a) to the communication of the first distribution conduits corresponding to the corrugations of the two groups of corrugations with the first external connection, and b) communication of the second distribution conduits corresponding to the corrugations of the two groups of corrugations with the second external connection , B) the second position of the first displacement selection drawer and the first position of the second displacement selection drawer, a) when the first distribution conduits correspond to the corrugations of the first group of corrugations with the first external connection, b) when the second d pipes are put into communication distribution corresponding to the undulations of said first group of undulations with the second external connection, and c) to the permanent isolation of the first distribution conduits corresponding to the undulations of the second group of undulations with the first external connection and / or to the permanent isolation of the second distribution conduits corresponding to the corrugations of said second group of corrugations from the second external connection, C) the first position of the first displacement selection drawer and the second position of the second displacement selection drawer , a) when the first distribution conduits corresponding to the corrugations of the second group of corrugations are put into communication with the first external connection, b) when the second distribution conduits corresponding to the corrugations of the second group of corrugations are brought into communication with the second external connection, and c) to the permanent isolation of the first distribution conduits tribution corresponding to the undulations of the first group of undulations with the first external connection and / or to the permanent isolation of the second distribution conduits corresponding to the undulations of said first group of undulations with the second external connection, and D) the second position of the first displacement selection drawer and the second position of the second displacement selection drawer, at the permanent isolation of the first distribution conduits corresponding to the corrugations of the first group of corrugations from the first external connection and to the permanent isolation of the second distribution conduits corresponding to the corrugations of the second group of corrugations from the second external connection, and / or to the permanent isolation of the second distribution conduits corresponding to the corrugations of the first group of corrugations with the second external connection and with the permanent isolation of the first corr distribution pipes responding to the undulations of the second group of undulations with the first external connection, and / or to the permanent isolation of the first distribution conduits corresponding to the undulations of the two groups of undulations with the first external connection, and / or permanent isolation of the second distribution conduits corresponding to the corrugations of the two groups of corrugations from the second external connection.

• - dans ce mécanisme, a) trois enceintes de distribution distinctes sont prévues, liées à la came, cependant que les premiers conduits de distribution correspondant aux ondulations du premier groupe d'ondulations débouchent dans une première desdites enceintes de distribution, que les premiers conduits de distribution correspondant aux ondulations du deuxième groupe d'ondulations débouchent dans une deuxième enceinte desdites trois enceintes de distribution, et que les deuxièmes conduits de distribution correspondant aux ondulations des premier et deuxième groupes d'ondulations débouchent dans la troisième de ces trois enceintes de distribution ; b) chacun des premier et deuxième tiroirs de sélection de la cylindrée est monté mobile dans un alésage ménagé dans un corps de tiroir, cependant que, pour chaque alésage, des première, deuxième et troisème chambres de transit sont ménagées dans ledit corps et débouchent dans ledit alésage ; c) une chambre de communication est ménagée dans chaque tiroir et débouche à sa périphérie ; d) les liaisons permanentes suivantes sont réalisées: de la première chambre de transit correspondant à chaque tiroir avec le premier raccord externe, de la deuxième chambre de transit correspondant au premier tiroir avec la deuxième enceinte de distribution, de la deuxième chambre de transit correspondant au deuxième tiroir avec la première enceinte de distribution, et des troisièmes chambres de transit correspondant aux deux tiroirs avec la troisième enceinte de distribution et avec le deuxième raccord externe; et e) les liaisons suivantes sont réalisées dans les premières et/ou deuxièmes positions de chacun des deux tiroirs de sélection de la cylindrée : dans la première position du premier tiroir, liaison des première et deuxième chambres de transit correspondant à ce premier tiroir, au moyen de la chambre de commu nication dudit premier tiroir, dans la deuxième position du premier tiroir, liaison des deuxième et troisième chambres de transit correspondant à ce premier tiroir, au moyen de la chambre de communication dudit premier tiroir, dans la première position du deuxième tiroir, liaison des première et deuxième chambres de transit correspondant à ce deuxième tiroir, au moyen de la chambre de communication dudit deuxième tiroir, et dans la deuxième position du deuxième tiroir, liaison des deuxième et troisième chambres de transit correspondant à ce deuxième tiroir, au moyen de la chambre de communication dudit deuxième tiroir ;
• - le deuxième tiroir de sélection de la cylindrée est identique au premier tiroir de sélection de la cylindrée ;
• - la came est partie constituante d'un carter, qui constitue lui-même le corps de tiroir dans lequel sont ménagés les alésages des premier et deuxième tiroirs de sélection de la cylindrée ;
• - chaque tiroir est monté coulissant en translation à l'intérieur de l'alésage correspondant ;
• - chaque alésage de tiroir comprend au moins un fond, cependant qu'à l'intérieur de cet alésage, entre une extrémité du tiroir correspondant de sélection de la cylindrée et ledit fond, est ménagée une chambre de réglage par fluide sous pression de la position dudit tiroir de sélection de la cylindrée ;
• - la came a un nombre pair d'ondulations, les ondulations du premier groupe d'ondulations ayant chacune une première amplitude à laquelle correspond une première course d'un piston prenant appui sur ladite ondulation, et les ondulations du deuxième groupe d'ondulations ayant chacune une deuxième amplitude à laquelle correspond une deuxième course d'un piston prenant appui sur ladite ondulation, pendant la rotation relative du bloc-cylindres par rapport à la came, la deuxième course ayant une valeur différente de la première course, et les diverses ondulations se succédant de manière qu'une quelconque ondulation du deuxième groupe d'ondulations soit comprise entre deux ondulations du premier groupe d'ondulations.

In addition, the following advantageous arrangements are preferably adopted:

• - in this mechanism, a) three separate distribution enclosures are provided, linked to the cam, while the first distribution conduits corresponding to the corrugations of the first group of corrugations open into a first of said distribution enclosures, that the first distribution conduits distribution corresponding to the corrugations of the second group of corrugations open into a second enclosure of said three distribution enclosures, and that the second distribution conduits corresponding to the corrugations of the first and second groups of corrugations open into the third of these three distribution enclosures; b) each of the first and second displacement selection drawers is movably mounted in a bore formed in a drawer body, while, for each bore, first, second and third transit chambers are formed in said body and open into said bore; c) a communication chamber is provided in each drawer and opens at its periphery; d) the following permanent connections are made: from the first transit chamber corresponding to each drawer with the first external connection, from the second transit chamber corresponding to the first drawer with the second distribution enclosure, from the second transit chamber corresponding to the second drawer with the first distribution enclosure, and third transit chambers corresponding to the two drawers with the third distribution enclosure and with the second connector external; and e) the following connections are made in the first and / or second positions of each of the two displacement selection drawers: in the first position of the first drawer, connection of the first and second transit chambers corresponding to this first drawer, to the means of the communication chamber of said first drawer, in the second position of the first drawer, connection of the second and third transit chambers corresponding to this first drawer, by means of the communication chamber of said first drawer, in the first position of the second drawer, connection of the first and second transit chambers corresponding to this second drawer, by means of the communication chamber of said second drawer, and in the second position of the second drawer, connection of the second and third transit chambers corresponding to this second drawer, by means of the communication chamber of said second drawer;
• - The second displacement selection drawer is identical to the first displacement selection drawer;
• - The cam is a constituent part of a housing, which itself constitutes the drawer body in which the bores of the first and second displacement selection drawers are formed;
• - Each drawer is slidably mounted in translation inside the corresponding bore;
• each drawer bore comprises at least one bottom, however inside this bore, between one end of the corresponding drawer for selecting the displacement and said bottom, is provided a chamber for adjusting the position of the fluid under pressure said displacement selection drawer;
• the cam has an even number of undulations, the undulations of the first group of undulations each having a first amplitude to which corresponds a first stroke of a piston resting on said undulation, and the undulations of the second group of undulations having each a second amplitude to which a second stroke of a piston corresponding to said undulation corresponds, during the relative rotation of the cylinder block with respect to the cam, the second stroke having a value different from the first stroke, and the various undulations succeeding each other so that any undulation of the second group of undulations is between two undulations of the first group of undulations.

The advantages of the new proposed arrangements actually reside in the great facility obtained for producing mechanisms with several displacements, with the smallest number of machining operations necessary, and consequently with a low cost price, of course while retaining the desired functional characteristics. .

The invention will be better understood, and secondary characteristics and their advantages will appear during the description of an embodiment given below by way of example.

It is understood that the description and the drawings are given for information only and are not limiting.

• - la figure 1 est une coupe axiale, suivant 1-1 de la figure 3, d'un moteur hydraulique conforme à l'invention, dans une première configuration de ses tiroirs de la cylindrée de ce moteur ;
• - la figure 2 est une coupe transversale suivant II-II de la figure 1 ;
• - les figures 3, 4 et 5 sont des coupes transversales, respectivement, suivant III-III, IV-IV et V-V de la figure 1 ;
• - les figures 6, 7 et 8 sont des coupes axiales analogues à celle de la figure 1, mais correspondant, respectivement, à des deuxième, troisième et quatrième configurations des tiroirs de sélection de la cylindrée du moteur ; et,
• - la figure 9 représente un circuit de commande du moteur des figures 1 à 8.

Reference will be made to the accompanying drawings, in which:

• - Figure 1 is an axial section, along 1-1 of Figure 3, of a hydraulic motor according to the invention, in a first configuration of its drawers of the displacement of this motor;
• - Figure 2 is a cross section along II-II of Figure 1;
• - Figures 3, 4 and 5 are cross sections, respectively, along III-III, IV-IV and VV of Figure 1;
• - Figures 6, 7 and 8 are axial sections similar to that of Figure 1, but corresponding, respectively, to second, third and fourth configurations of the engine displacement selection drawers; and,
• FIG. 9 represents a motor control circuit of FIGS. 1 to 8.

• - un carter en trois parties 1a, 1b, 1 assemblées par des vis 2 ;
• - un arbre de sortie 4, monté rotatif par rapport au carter autour d'un axe géométrique 9, au moyen de deux paliers à rouleaux 5 ;
• - un bloc-cylindres 6, qui est monté sur une extrémité de l'arbre de sortie 4, intérieure au carter et munie de cannelures 7, qui est rendu solidaire en rotation dudit arbre de sortie au moyen de cannelures complémentaires 8 dudit arbre de sortie et qui est ainsi monté à rotation autour de l'axe géométrique 9 ;
• - une glace de distribution 10, qui est susceptible d'osciller très légèrement parallèlement à l'axe 9, et qui est rendue solidaire en rotation de la partie 1 du carter au moyen d'encoches et d'ergots 11 associés, dont sont munies ces deux piéces ;
• - une came 12 présentant, en l'espèce, six ondulations qui se succèdent continûment, en étant réparties en deux groupes d'ondulations 12a - 12d et 12c - 12b, chaque ondulation à 12d du premier groupe étant constituée par une première rampe 12a et par une deuxième rampe 12d, et étant intercalée entre deux ondulations du deuxième groupe, dont chaque ondulation est elle-même constituée par une première rampe 12c et par une deuxième rampe 12b;
• - une pluralité de cylindres 13, qui sont ménagés dans le bloc-cylindres 6 et qui sont disposés radialement par rapport à l'axe 9, et angulairement régulièrement espacés les uns des autres ;
• - une pluralité de pistons 14, qui sont montés coulissants dans les cylindres, un par cylindre, et qui portent, chacun, un rouleau 15, d'axe 16 parallèle à l'axe 9, susceptible d'être en appui sur les diverses ondulations de la came 12 ;
• - deux tiroirs de sélection de la cylindrée, un premier tiroir 17 et un deuxième tiroir 18, cylindriques, identiques et montés coulissants à l'intérieur d'alésages 19 et 20, respectivement, ménagés dans la partie 1 du carter.

The engine shown in Figures 1 to 5 includes:

• - a casing in three parts 1a, 1b, 1 assembled by screws 2;
• - An output shaft 4, rotatably mounted relative to the housing about a geometric axis 9, by means of two roller bearings 5;
• - A cylinder block 6, which is mounted on one end of the output shaft 4, inside the casing and provided with splines 7, which is made to rotate with said output shaft by means of complementary splines 8 of said output shaft and which is thus mounted for rotation about the geometric axis 9;
• - A distribution window 10, which is capable of oscillating very slightly parallel to the axis 9, and which is made integral in rotation with part 1 of the casing by means of notches and associated lugs 11, which are provided these two pieces;
• a cam 12 having, in this case, six undulations which follow one another continuously, being distributed in two groups of undulations 12a - 12d and 12c - 12b, each undulation at 12d of the first group consisting of a first ramp 12a and by a second ramp 12d, and being interposed between two undulations of the second group, each undulation of which is itself constituted by a first ramp 12c and by a second ramp 12b;
• - A plurality of cylinders 13, which are formed in the cylinder block 6 and which are arranged radially relative to the axis 9, and angularly regularly spaced from each other;
• - A plurality of pistons 14, which are slidably mounted in the cylinders, one per cylinder, and which each carry a roller 15, of axis 16 parallel to axis 9, capable of being supported on the various undulations cam 12;
• - Two displacement selection drawers, a first drawer 17 and a second drawer 18, cylindrical, identical and mounted sliding inside bores 19 and 20, respectively, formed in part 1 of the housing.

• - entre la glace de distribution 10 et la partie 1c du carter, trois enceintes de distibution - les première 21, deuxième 22 et troisième enceintes 23 - sont ménagées, conformées en des gorges ;
• - dans la partie 1 du carter, trois chambres de transit correspondant au premier tiroir 17 de sélection de la cylindrée - les première 24, deuxième 25 et troisième chambres de transit 26 - sont conformées en des gorges qui débouchent dans l'alésage 19, en étant séparées les unes des autres ;
• - toujours dans la partie 1c, trois autres chambres de transit correspondent au deuxième tiroir 18 de sélection de la cylindrée - les première 27, deuxième 28 et troisième chambres de transit 29 - sont conformées en des gorges qui débouchent dans l'alésage 20, en étant séparées les unes des autres ;
• - chaque tiroir de sélection de la cylindrée comporte une chambre de communication, formée par une gorge intermédiaire, susceptible, en fonction de la position du tiroir correspondant, de mettre en communication soit les première et deuxième chambres de transit correspondantes, soit les deuxième et troisième chambres de transit : ce sont les chambres de communication 30 du premier tiroir 17 de sélection de la cylindrée, et 31 du deuxième tiroir 18 de sélection de la cylindrée ;
• - chaque tiroir de sélection de la cylindrée 17, 18 est susceptible d'être placé dans une première position (mise en communication des première et deuxième chambres de transit 24 - 25, ou, 27 - 28) sous l'effet d'un ressort 32, 33, ou dans une deuxième position (mise en communication des deuxième et troisième chambres de transit 25 - 26, ou 28 - 29) sous l'effet prédominant, et antagoniste de celui du ressort, de la pression d'un fluide de pilotage contenu dans une chambre de pilotage 34, 35 délimitée par une extrémité dudit tiroir ;
• - ces chambres de pilotage 34, 35 sont par ailleurs reliées à des conduits 36, 37 au moyen de raccords 38, 39, respectivement ;
• - la glace de distribution 10 comporte une face transversale plane 40, qui est sensiblement perpendiculaire à l'axe géométrique 9 et qui est en appui de glissement sur une face transversale plane 3, dont est muni le bloc-cylindres 6 ;
• - les chambres de travail 41 délimitées par les pistons 14 à l'intérieur des cylindres 13 communiquent avec la face plane 3 du bloc-cylindres au moyen de conduits de cylindres 42 et débouchent dans cette face plane 3 par des orifices 43 régulièrement répartis sur un cercle centré sur l'axe géométrique 9 ;
• - aux rampes de la came correspondent, ménagés dans la glace de distribution 10, des conduits de distribution de fluide qui débouchent dans la face plane 40 par des orifices 44 susceptibles, chacun, de communiquer successivement avec chaque orifice 43 des conduits de cylindres 42 au cours de la rotation relative du bloc-cylindres 6 par rapport à l'ensemble de la glace de distribution 10, du carter ta - 1 b - 1 et de la came 12 : il s'agit des premiers conduits de distribution 45a correspondant aux premières rampes 12a du premier groupe d'ondulations, des deuxièmes conduits de distribution 45d correspondant aux deuxièmes rampes 12d du premier groupe d'ondulations, des premiers conduits de distribution 45c correspondant aux premières rampes 12c du deuxième groupe d'ondulations et des deuxièmes conduits de distribution 45b correspondant aux deuxièmes rampes 12b du deuxième groupe d'ondulations ;
• - les conduits de distribution communiquent en permanence, les premiers conduits de distribution 45a correspondant au premier groupe d'ondulations avec la première enceinte de distribution (gorge) 21, les deuxièmes conduits de distribution 45d correspondant au premier groupe d'ondulations avec la troisième enceinte de distribution 23, les premiers conduits de distribution 45c correspondant au deuxième groupe d'ondulations avec la deuxième enceinte de distribution 22 et les deuxièmes conduits de distribution 45b correspondant au deuxième groupe d'ondulations avec, également, la troisième enceinte de distribution 23 ;
• - les premières chambres de transit, 24 relative au premier tiroir de sélection de la cylindrée 17 et 27 relative au deuxième tiroir de sélection de la cylindrée 18, sont en communication permanente avec un conduit 46 au moyen d'un premier raccord externe 47;
• - les troisièmes chambres de transit, 26 relative au premier tiroir de sélection de la cylindrée 17 et 29 relative au deuxième tiroir de sélection de la cylindrée 18, sont en communication permanente avec un conduit 48 au moyen d'un deuxième raccord externe 49 ;
• - la deuxième chambre de transit 25 relative au premier tiroir de sélection de la cylindrée 17 et la deuxième enceinte de distribution 22 sont en communication permanente au moyen d'un passage 50 ménagé dans la partie 1q du carter ;
• - la deuxième chambre de transit 28 correspondant au deuxième tiroir de sélection de la cylindrée 18 et la première enceinte de distribution 21 sont en communication permanente au moyen d'un passage 51 ménagé dans la partie 1 du carter ;
• - les tiroirs de sélection de la cylindrée réalisent en outre les liaisons suivantes :
• . le premier tiroir de sélection de la cylindrée 17, placé dans sa première position (figures 1 et 7, action prédominante du ressort 32), met en communication les première 24 et deuxième chambres de transit 25 qui lui correspondent, ceci au moyen de sa chambre de communication 30 ;
• . le premier tiroir de sélection de la cylindrée 17, placé dans sa deuxième position (figures 6 et 8, action prédominante du fluide de pilotage contenu dans la chambre de pilotage 34), met en communication les deuxième 25 et troisième chambres de transit 26 qui lui correspondent, ceci au moyen de sa chambre de communication 30 ;
• . le deuxième tiroir de sélection de la cylindrée 18, placé dans sa première position (figures 1 et 6, action prédominante du ressort 33), met en communication les première 27 et deuxième chambres de transit 28 qui lui correspondent, ceci au moyen de sa chambre de communication 31,
• . le deuxième tiroir de sélection de la cylindrée 18, placé dans sa deuxième position (figures 7 et 8, action prédominante du fluide de pilotage contenu dans la chambre de pilotage 35), met en communication les deuxième 28 et troisième chambres de transit 29 qui lui correspondent, ceci au moyen de sa chambre de communication 31.

The following features can be noted:

• - Between the distribution glass 10 and the part 1c of the casing, three distribution chambers - the first 21, second 22 and third chambers 23 - are formed, shaped into grooves;
• - in part 1 of the housing, three transit chambers corresponding to the first selection drawer 17 of the displacement - the first 24, second 25 and third transit chambers 26 - are shaped as grooves which open into the bore 19, being separated from each other;
• - still in part 1c, three other transit chambers correspond to the second displacement selection slide 18 - the first 27, second 28 and third transit chambers 29 - are formed into grooves which open into the bore 20, in being separated from each other;
• - each displacement selection drawer has a communication chamber, formed by an intermediate groove, capable, depending on the position of the corresponding drawer, to connect either the first and second corresponding transit chambers, or the second and third transit chambers: these are the communication chambers 30 of the first displacement selection drawer 17, and 31 of the second displacement selection drawer 18;
• each displacement selection drawer 17, 18 can be placed in a first position (communication between the first and second transit chambers 24 - 25, or, 27 - 28) under the effect of a spring 32, 33, or in a second position (connecting the second and third transit chambers 25 - 26, or 28 - 29) under the predominant effect, and antagonistic of that of the spring, of the pressure of a piloting contained in a piloting chamber 34, 35 delimited by one end of said drawer;
• - These pilot chambers 34, 35 are also connected to conduits 36, 37 by means of fittings 38, 39, respectively;
• - The dispensing glass 10 has a flat transverse face 40, which is substantially perpendicular to the geometric axis 9 and which is in sliding support on a flat transverse face 3, which is provided with the cylinder block 6;
• the working chambers 41 delimited by the pistons 14 inside the cylinders 13 communicate with the flat face 3 of the cylinder block by means of cylinder ducts 42 and open into this flat face 3 through orifices 43 regularly distributed over a circle centered on the geometric axis 9;
• - The ramps of the cam correspond, formed in the distribution glass 10, fluid distribution conduits which open into the flat face 40 through orifices 44 capable, each, of communicating successively with each orifice 43 of the cylinder conduits 42 at during the relative rotation of the cylinder block 6 with respect to the assembly of the distribution glass 10, of the casing ta - 1 b - 1 and of the cam 12: these are the first distribution conduits 45a corresponding to the first ramps 12a of the first group of undulations, second distribution conduits 45d corresponding to the second ramps 12d of the first group of undulations, first distribution conduits 45c corresponding to the first ramps 12c of the second group of undulations and second distribution conduits 45b corresponding to the second ramps 12b of the second group of undulations;
• the distribution conduits communicate permanently, the first distribution conduits 45a corresponding to the first group of corrugations with the first distribution enclosure (groove) 21, the second distribution conduits 45d corresponding to the first group of corrugations with the third enclosure distribution 23, the first distribution conduits 45c corresponding to the second group of corrugations with the second distribution enclosure 22 and the second distribution conduits 45b corresponding to the second group of corrugations with, also, the third distribution enclosure 23;
• - The first transit chambers, 24 relating to the first displacement selection drawer 17 and 27 relating to the second selection selection cylinder 18, are in permanent communication with a conduit 46 by means of a first external connection 47;
• - The third transit chambers, 26 relating to the first displacement selection drawer 17 and 29 relating to the second selection selection cylinder 18, are in permanent communication with a conduit 48 by means of a second external connection 49;
• - The second transit chamber 25 relating to the first displacement selection drawer 17 and the second distribution enclosure 22 are in permanent communication by means of a passage 50 formed in the part 1q of the casing;
• - The second transit chamber 28 corresponding to the second displacement selection drawer 18 and the first distribution enclosure 21 are in permanent communication by means of a passage 51 formed in part 1 of the casing;
• - the displacement selection drawers also carry out the following connections:
• . the first displacement selection drawer 17, placed in its first position (FIGS. 1 and 7, predominantly action of the spring 32), connects the first 24 and second transit chambers 25 which correspond to it, this by means of its chamber communication 30;
• . the first displacement selection drawer 17, placed in its second position (FIGS. 6 and 8, predominant action of the piloting fluid contained in the piloting chamber 34), connects the second 25 and third transit chambers 26 which correspond, this by means of its communication chamber 30;
• . the second displacement selection drawer 18, placed in its first position (FIGS. 1 and 6, predominantly action of the spring 33), connects the first 27 and second transit chambers 28 which correspond to it, this by means of its chamber communication 31,
• . the second displacement selection drawer 18, placed in its second position (FIGS. 7 and 8, predominant action of the pilot fluid contained in the pilot chamber 35), connects the second 28 and third transit chambers 29 which correspond, this by means of its communication chamber 31.

• - une pompe principale 52 ;
• - un distributeur principal de fluide 53 à trois positions ;
• - une première pompe de pilotage 54 ;
• - un premier distributeur de pilotage 55 à deux positions ;
• - une deuxième pompe de pilotage 56 ; - un deuxième distributeur de pilotage 57 deux positions ;
• - un réservoir de fluide hydraulique 58.

FIG. 9 represents a circuit for controlling and supplying fluid to the engine which has just been described. This circuit includes:

• - a main pump 52;
• - a main fluid distributor 53 with three positions;
• - a first pilot pump 54;
• - a first pilot valve 55 with two positions;
• - a second pilot pump 56; - A second control valve 57 two positions;
• - a hydraulic fluid reservoir 58.

• - le conduit d'aspiration 59 de la pompe principale 52 relie celle-ci au réservoir 58 ;
• - le conduit de refoulement 60 de la pompe principale 52 relie celle-ci au distributeur principal 53 ;
• - le conduit d'aspiration 61 de la première pompe de pilotage 54 relie celle-ci au réservoir 58 ;
• - le conduit de refoulement 62 de la première pompe de pilotage 54 relie celle-ci au premier distributeur de pilotage 55 ;
• - le conduit d'aspiration 63 de la deuxième pompe de pilotage 56 relie celle-ci au réservoir 58 ;
• - le conduit de refoulement 64 de la deuxième pompe de pilotage 56 relie celle-ci au deuxième distributeur de pilotage 57 ;
• - des conduits 65, 66 et 67 relient le distributeur principal 53, les premier 55 et deuxième distributeurs de pilotage 57 au réservoir 58, respectivement ;
• - les conduits 46 et 48 sont raccordés au distributeur principal 53 ;
• - les conduits 36 et 37 sont raccordés aux premier 55 et deuxième distributeurs de pilotage 57, respectivement.

The following conduits connect these various constituents:

• - The suction pipe 59 of the main pump 52 connects the latter to the reservoir 58;
• - the discharge pipe 60 of the main pump 52 connects the latter to the main distributor 53;
• - The suction duct 61 of the first pilot pump 54 connects the latter to the reservoir 58;
• - The discharge conduit 62 of the first pilot pump 54 connects the latter to the first pilot distributor 55;
• - The suction pipe 63 of the second pilot pump 56 connects the latter to the reservoir 58;
• - The discharge conduit 64 of the second pilot pump 56 connects the latter to the second pilot distributor 57;
• - conduits 65, 66 and 67 connect the main distributor 53, the first 55 and second pilot distributors 57 to the reservoir 58, respectively;
• - conduits 46 and 48 are connected to the main distributor 53;
• - The conduits 36 and 37 are connected to the first 55 and second pilot distributors 57, respectively.

• - la première position, aux mises en communication des conduits 60 et 46, et, des conduits 48 et 65 ;
• - la deuxième position, à l'obturation des conduits 46 et 48, et, à la mise en communication des conduits 60 et 65 ; et
• - la troisième position, aux mises en communication des conduits 60 et 48, et, des conduits 46 et 65.

The three positions of the main distributor 53 correspond:

• - The first position, when the conduits 60 and 46 are put into communication, and, conduits 48 and 65;
• - The second position, to close conduits 46 and 48, and, to connect conduits 60 and 65; and
• - the third position, when the conduits 60 and 48 are put into communication, and, conduits 46 and 65.

• - la première position, à la mise en communication des conduits 36, 62 et 66 ; et,
• - la deuxième position, à la mise en communication des conduits 62 et 36, et, à l'obturation du conduit 66.

The two positions of the first control valve 55 correspond:

• - The first position, when the conduits 36, 62 and 66 are put into communication; and,
• - the second position, when the conduits 62 and 36 are placed in communication, and when the conduit 66 is closed.

• - la première position, à la mise en communication des conduits 37, 64 et 67 ; et,
• - la deuxième position, à la mise en communication des conduits 64 et 37, et, à l'obturation du conduit 67.

The two positions of the second pilot control valve 57 correspond:

• - The first position, when the conduits 37, 64 and 67 are put into communication; and,
• - the second position, when the conduits 64 and 37 are placed in communication, and when the conduit 67 is closed.

In the embodiment shown, all the pistons 14 have the same diameter, so that the volume of fluid displaced by a piston is proportional to the stroke of this piston along a ripple, with the same coefficient of proportionality (equal to the piston section) for all corrugations. In addition, any ripple 12a - 12d gives a piston, which travels it, a stroke C1 (return), while some ripple 12c - 12b gives a piston, which travels it, a stroke C2 (go -return) different from C1.

It has also been seen that there are the same number of corrugations 12a - 12d (three) as of corrugations 12c - 12b (three), so that the engine displacements likely to be active, which correspond to a complete rotation of the output shaft 4, are simply proportional, with the same coefficient of proportionality, to the races C1 and C2, ie kC1 and kC2.

• - les premier 17 et deuxième tiroirs 18 de sélection de la cylindrée étant placés dans leur première position respective (figure 1), les conduits 45a et 45c contiennent le fluide sous pression refoulé par la pompe principale 52, les conduits 45b et 45d communiquent avec le réservoir 58 au moyen des conduits 48 et 65, et les rampes 12a et 12c correspondent à des courses motrices des pistons, la cylindrée apparente étant : CY1 = k (C1 + C2) ;
• - le premier tiroir 17 de sélection de la cylindrée étant placé dans sa deuxième position et le deuxième tiroir 18 de sélection de la cylindrée étant placé dans sa première position (figure 6), seuls les conduits 45a contiennent le fluide sous pression refoulé par la pompe principale 52, alors que les conduits 45c (ainsi que les conduits 45b et 45d) communiquent avec le réservoir 58, et seules les rampes 12a correspondent à des courses motrices des pistons, et la cylindrée apparente étant : CY2 = k C1 ;
• - le premier tiroir 17 de sélection de la cylindrée étant placé dans sa première position et le deuxième tiroir 18 de sélection de la cylindrée étant placé dans sa deuxième position (figure 7), seuls les conduits 45c contiennent le fluide sous pression refoulé par la pompe principale 52, alors que les conduits 45a (et les conduits 4ELb et 45d)communiquent avec le réservoir 58, et seules les rampes 12c correspondent à des courses motrices des pistons, la cylindrée apparente étant alors CY3 = kC2 ;
• - enfin, les deux tiroirs 17 et 18 de sélection de la cylindrée étant placés dans leurs deuxièmes positions respectives (figure 8), il n'y a plus aucune course motrice, la cylindrée apparente étant CY4 = 0.

The following effective displacements are then obtained, the main distributor 53 being in its first position:

• the first 17 and second drawers 18 for selecting the displacement being placed in their respective first position (FIG. 1), the conduits 45a and 45c contain the pressurized fluid discharged by the main pump 52, the conduits 45b and 45d communicate with the reservoir 58 by means of the conduits 48 and 65, and the ramps 12a and 12c correspond to motor strokes of the pistons, the apparent displacement being: CY1 = k (C1 + C2);
• - the first displacement selection drawer 17 being placed in its second position and the second displacement selection drawer 18 being placed in its first position (FIG. 6), only the conduits 45a contain the pressurized fluid discharged by the pump main 52, while the conduits 45c (as well as the conduits 45b and 45d) communicate with the reservoir 58, and only the ramps 12a correspond to motor strokes of the pistons, and the apparent cubic capacity being: CY2 = k C1;
• - the first displacement selection drawer 17 being placed in its first position and the second displacement selection drawer 18 being placed in its second position (FIG. 7), only the conduits 45c contain the pressurized fluid discharged by the pump main 52, while the conduits 45a (and the conduits 4ELb and 45d) communicate with the reservoir 58, and only the ramps 12c correspond to motor strokes of the pistons, the apparent displacement then being CY3 = kC2;
• - Finally, the two drawers 17 and 18 for selecting the displacement being placed in their second respective positions (FIG. 8), there is no longer any driving stroke, the apparent displacement being CY4 = 0.

Obtaining three apparent cubic capacities distinct from each other CY1, CY2 and CY3 and distinct from 0, to which correspond three speeds V1, V2 and V3, respectively, also distinct from rotation of the output shaft 4 of the engine, is thus achieved.

This was obtained very simply by means of two drawers 17 and 18, simple (cylindrical, with only one groove each), identical in addition, and therefore by means of inexpensive manufacture.

It should be noted that the drawers 17, 18 having only one communication chamber (or groove) 30, 31, and the bores 19, 20 each having only three transit chambers 24-25- 26, 27-28-29, the overall length of each set of a drawer and the bore, in which it is housed, is not very significant and is in particular not greater than the length necessary for placing place of the distribution ice 10. There is therefore no increase tation of the overall length of the motor.

It should be noted that if, in the embodiment shown, it was considered optimum and preferable to have recourse to only one distribution enclosure 23 allowing the return to the reservoir 58 of the fluid escaping from the working chambers 41 of the cylinders by the distribution conduits 45b and 45d, it would also have been possible to split this enclosure 23 and to connect the distribution conduits 45b to a first enclosure, called the exhaust, and the distribution conduits 45d to a second enclosure, called the exhaust, separate from the first. Such a variant is expressly envisaged in the present patent application.

Furthermore, the choice was made, in the embodiment shown, to selectively put the first distribution conduits 45a and / or 45c into communication with the pressureless exhaust 58. If the strokes of a piston must be neutralized opposite certain undulations 12a - 12d, or 12c - 12b, it is actually necessary to ensure that the pressure in the first conduits is equal to that in the corresponding second conduits. In the event that these pressures are different, the above-mentioned neutralization of certain strokes of a piston would only be partial, which remains possible, although, a priori, complicated. It would also have been possible, still within the framework of the invention and to neutralize certain piston strokes, not to selectively isolate the first distribution conduits 45a and / or 45c from the supply of pressurized fluid (main pump 52 ), but to selectively isolate the second distribution conduits 45d and / or 45b from the pressureless exhaust (reservoir 58), for example by placing these second distribution conduits in communication with the supply of pressurized fluid. All these alternative embodiments are included in the present invention.

It is also in accordance with the invention that, as a variant, the drawers 17 and 18 are designed as rotary fluid distribution drawers, similar to that shown in FR-A-1 572 390.

Claims (8)

1. A pressurized fluid, engine or pump, mechanism, e.g. a hydraulic motor having at least two selectable distinct non-zero cylinder capacities, constituted by:

- at least one first external connector (46-47) for connection to a source (52) of fluid under pressure, and at least one second external connector (49-48) for connection to a fluid exhaust (58);

- at least one cam (12) whose profile corresponds to a plurality of successive undulations (12a 12d; 12c-12b), said undulations being divided at least into first and second distinct groups of undulations with each undulation comprising a first slope and a second slope;

- a cylinder block (6) mounted to rotate relative to said cam about an axis of rotation (9) and which includes a plurality of cylinders (13) disposed substantially radially relative to said axis of rotation;

- each cylinder having at least one piston (14) slidably mounted therein and suitable for bearing against the cam and delimiting, within said cylinder, a working chamber (41) which is connected (42) to a communication face (3) of the cylinder block;

- a plurality of cylinder ducts (42) each connecting one (41) of the working chambers to said communication face (3) of the cylinder block;

- a fluid distribution face (40) constrained to rotate (11) with the cam (12), said face permanently bearing against the communication face of the cylinder block and having first (45a-45c) and second (45d-45b) fluid distribution orifices opening out therein and corresponding to said first (12a-12q) and second (12d-12b) slopes of each of the undulations, said distribution ducts being suitable for being put into communication, during relative rotation of the cylinder block and the cam, with the cylinder ducts (42) of the various cylinders;

- a first cylinder-capacity selection slide valve (17) disposed between said first and second external connectors and the first and/or second distribution ducts corresponding to the undulations of the second group of undulations;

- a second cylinder-capacity selection slide valve (18) disposed between said second external connectors and the first and/or second distribution ducts corresponding to the undulations of the first group of undulations;

- each of said first (17) and second (18) cylinder-capacity selection slide valves having two particular positions, which together correspond: A) with the first cylinder-capacity selection slide valve (17) and the second cylinder-capacity selection slide valve (18) both being in their respective first positions, a) to the first distribution ducts (45^g _-45cj corresponding to the undulations of both groups of undulations being put into communication with the first external connector, (46-47) and b) to the second distribution ducts (45d-45b) corresponding to the undulations in both groups of undulations being put into communication with the second external connector (48-49), B) with the first cylinder-capacity selection slide valve (17) being in its second position and the second cylinder-capacity selection slide valve (18) being in its first position, a) to the first distribution ducts (45a) corresponding to the undulations of the first group of undulations being put into communication with the first external connector (46-47), b) to the second distribution ducts (45M corresponding to the undulations of said first group of undulations being put into communication with the second esternal connector (48-49), and c) to the first distribution ducts (45c) corresponding to the undulations of the second group of undulations being permanently isolated from the first external connector (46-47) and/or to the second distribution ducts corresponding to the undulations of said second group of undulations being permanently isolated from the second external connector (48-49); C) with the first cylinder-capacity selection slide valve (17) in its first position and the second cylinder-capacity selection slide valve (18) being in its second position, a) to the first distribution ducts (45_Q) corresponding to the undulations of the second group of undulations being put into communication with the first external connector (46-47), b) to the second distribution ducts (45b) corresponding to the undulations of the second group of undulations being put into communication with the second external connector (48-49), and c) to the first distribution ducts (45a) corresponding to the undulations of the first group of undulations being permanently isolated from the first external connector (46-47) and/or to the second distribution ducts corresponding to undulations of the first group of undulations being permanently isolated from the second external connector (48-49); and D) with the first cylinder-capacity selection slide valve (17) in its second position and the second cylinder-capacity selection slide valve (18) in its second position, to the first distribution ducts corresponding to undulations of the first group of undulations being permanently isolated from the first external connector and to the second distribution ducts corresponding to the undulations of the second group of undulations being permanently isolated from the second external connector and/or to the second distribution ducts corresponding to the undulations of the first group of undulations being permanently isolated from the second external connector and to the first distribution ducts corresponding to the undulations to the second group of undulations being permanently isolated from the first external connector, and/or to the first distribution ducts (45a and 45c) corresponding to the undulations of both groups of undulations being permanently isolated from the first external connector (46-47) and/or to the second distribution ducts corresponding to the undulations of both groups of undulations being permanently isolated from the second external connector.

2. Pressurized fluid, engine or pump, mechanism, e.g. a hydraulic motor having at least two selectable distinct non-zero cylinder capacities, the mechanism being constituted by:

- at least one first external connector for connection to a source of fluid under pressure, and at least one second external connector for connection to a fluid exhaust;

- at least one cam whose profile corresponds to a plurality of successive undulations, said undulations being divided at least into first and second groups of undulations with each undulation with each undulation comprising a first slope and a second slope;

- a cylinder block mounted to rotate relative to said cam about an axis of rotation and which includes a plurality of cylinders disposed substantially radially relative to said axis of rotation;

- each cylinder having at least one piston slidably mounted therein and suitable for bearing against the cam and delimiting, within said cylinder, a working chamber which is connected to a communication face of the cylinder block;

- a plurality of cylinder ducts each connecting one of the working chambers to said communication face of the cylinder block;

- a fluid distribution face constrained to rotate with the cam, said face permanently bearing against the communication face of the cylinder block and having first and second fluid distribution orifices opening out therein and corresponding to said first and second slopes of each of the undulations, said distribution ducts being suitable for being put into communication, during relative rotation of the cylinder block and the cam, with the cylinder ducts of the various cylinders;
and

- cylinder capacity selection means comprising at least a first cylinder-capacity selection slide valve disposed between said first and second external connectors and the first and/or second distribution ducts corresponding to the undulations of the second group of undulations; said first cylinder capacity selection slide valve having a first position suitable for corresponding: a) to the first distribution ducts corresponding to the undulations of both groups of undulations being put into communication with the first external connector, and b) to the second distribution ducts corresponding to the undulations of both groups of undulations being put into communication with the second external connector, and having a second position suitable for corresponding: a) to the first distribution ducts corresponding to the undulations of the first group of undulations being put into communication with first external connector, b) to the second distribution ducts corresponding to the undulations of said first group of undulations being put into communication with the second external connector, and c) to the first distribution ducts corresponding to the undulations of the second group of undulations being permanently isolated from the first external connector and/or to the second distribution ducts corresponding to the undulations of the second group of undulations being permanently isolated from the second external connector;
characterized in that said cylinder capacity selection means further includes a second cylinder-capacity selection slide valve which also has two positions and which is disposed between the first and second external connectors and the first and/or second distribution ducts corresponding to the undulations of the first group of undulations, said second cylinder-capacity selection slide valve having a first position which correspond a) to the first distribution ducts corresponding to the undulations of the first group of undulations being put into communication with first external connector, b) to the second distribution ducts corresponding to the undulations of said first group of undulations being put into communication with the second external connector and having a second position which corresponds to the first distribution ducts corresponding to the undulations of the first group of undulations being permanently isolated from the first external connector and/or to the second distribution ducts corresponding to the undulations of said first group of undulations being permanently isolated from the second external connector.

3. Mechanism according to any one of the claims 1 and 2, characterized in that

a) three distinct distribution manifolds (21, 22, 23) are provided linked (11) to the cam (12), with the first distribution ducts (45a) corresponding to the undulations (12a, 12d) of the first group of undulations opening out into a first one (21) of said distribution manifolds, with the first distribution ducts (45c) corresponding to the undulations (12o-12b) of the second group of undulations opening out into a second (22) of said distribution manifolds, and with the second distribution ducts (45d, 45b) corresponding to the undulations of both the first and the second groups of undulations opening out into the third (23) of said distributor manifolds;

b) each of the first (17) and second (18) cylinder-capacity selection slide valves is movably mounted in a corresponding bore (19, 20) provided in a valve body (1c) with each bore having a corresponding first (24; 27), second (25; 28), and a third (26; 29) transit chambers provided in said body and opening out into said bore;

c) each slide valve slide member (17; 18) has a communication chamber (30; 31) formed therein and opening out peripherally;

d) the following permanent connections are provided:

- the first transit chamber (24; 27) corresponding to each slide valve is connected to the first external connector (46 - 47);

- the second transit chamber (25) corresponding to the first slide valve (17) is connected to the second distribution manifold (22);

- the second transit chamber (28) corresponding to the second slide valve (18) is connected to the first distribution manifold (21); and

- the third transit chambers (26 and 29) corresponding to both slide valves are connected to the third distribution manifold (23) and to the second external connector (48 - 49); and

e) the following connections are provided in the first and/or second positions of each of the cylinder-capacity selection slide valves:

- in the first position of the first slide valve (figure 1 and 7), the first (24) and second (25) transit chambers corresponding to said first slide valve (17) are put into communication via the communication chamber (30) of said first slide valve (17);

- in the second position of the first slide valve, (figure 6 and 8), the second (25) and third (26) transit chambers corresponding to said first slide valve (17) are put into communication via the communication chamber (30) of said first slide valve (17);

- in the first position of said second slide valve (figure 1 and 6), the first (27) and second (28) transit chambers corresponding to said second slide valve (18) are put into communication via the communication chamber (31) of said second slide valve (18); and

- in the second position of the second slide valve (figure 7 and 8), the second (28) and third (29) transit chambers corresponding to the second slide valve (18) are put into communication via the corre- spnding chamber (31) of said second slide valve (18).

4. Mechanism according to any one of the claims 1 to 3 characterized in that the second cylinder- cpacity selection slide valve (18) is identical to the first cylinder-capacity selection slide valve (17).

5. Mechanism according to any one of the claims 1 to 4, and claim 3, characterized in that the cam (12) is an integral part (1þ) of a housing (1a-1b-1c) which itself constitutes the slide valve body (1c) in which the bores (19-20) of the first (17) and second (18) cylinder-capacity selection slide valve are formed.

6. Mechanism according to any one of claims 1 to 5, characterized in that each slide valve is mounted to slide in translation within the corresponding bore.

7. Mechanism according to claim 6, characterized in that each bore comprises at least one end and provides a chamber (34, 35) between said end and one of the ends of the corresponding slide of the cylinder-capacity slide valve, said chambers receiving fluid under pressure to adjust the position of said cylinder-capacity selection slide valve (17, 18).

8. Mechanism according to any one of claims 1 to 7, characterized in that the cam has an even number of undulations (12a-12d; 12c-12b). with the undulations (12a-12d) of the first group of undulations each having a first amplitude which corresponds to a first stroke (C1) of a piston (14) bearing against said undulation during relative rotation between the cylinder block and the cam, and with the undulations of the second group of undulations each having a second amplitude corresponding to a second stroke (C2) of a piston (14) bearing against said second undulation during relative rotation of the cylinder block (6) relative to the cam (12), with said first (C1) and second (C2) strokes having different values, and with the various undulations following one another in such a manner that each of the undulations (12c-12b) of the second group of undulations lies between two undulations (12a-12d) of the first group of undulations.

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