Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
  • F03C1/00—Reciprocating-piston liquid engines
  • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
  • F03C1/04—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinders in star or fan arrangement
  • F03C1/0447—Controlling
  • F03C1/045—Controlling by using a valve in a system with several pump or motor chambers, wherein the flow path through the chambers can be changed, e.g. series-parallel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
  • F03C1/00—Reciprocating-piston liquid engines
  • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
  • F03C1/04—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinders in star or fan arrangement
  • F03C1/0403—Details, component parts specially adapted of such engines
  • F03C1/0435—Particularities relating to the distribution members
  • F03C1/0444—Particularities relating to the distribution members to plate-like distribution members

Definitions

• the present invention relates to a hydraulic motor with radial pistons comprising a cam and a cylinder block capable of rotating relative to one another about an axis of rotation.
• the cylinder block has radial cylinders connected by cylinder conduits to communication ports located in a communication face of the cylinder block which is perpendicular to the axis of rotation.
• Pistons slidably mounted in the cylinders are able to cooperate with the cam and the latter has several lobes each having two ramps which each include a convex region and a concave region.
• the engine further comprises a fluid distributor having a distribution face which is perpendicular to the axis of rotation and which is able to bear against the communication face of the cylinder block, this distribution face having dispensing orifices comprising orifices suitable for being connected to a fluid supply and orifices suitable for being connected to a fluid exhaust.
• the fluid distributor is integral in rotation with the cam so that a ramp of the cam corresponds to each dispensing orifice (that is to say that each dispensing orifice is situated in angular correspondence with a ramp of the cam ), said dispensing orifices being able to communicate one after the other with the communicating orifices during the relative rotation of the cylinder block and the distributor, the edge of each dispensing orifice having a leading portion through which the communication between the dispensing orifice and the communication orifices opens during the relative rotation between the cylinder block and the distributor in a given relative direction of rotation, as well as a separation portion through which the communication between the The dispensing orifice and the communication orifices close during the relative rotation between the cylinder block and the distributor in the same direction of relative rotation.
• each communication orifice is successively opposite a distribution orifice connected to the fluid supply and opposite a distribution orifice connected to the fluid exhaust.
• the connection to the dispensing orifice which is connected to the supply has the effect of pushing radially outwards the piston contained in the cylinder connected to the communication orifice considered, while the connection of the same communication orifice to a dispensing orifice connected to the fluid exhaust allows this piston to enter in its cylinder, towards the axis of the engine.
• each piston cooperates successively with the different parts of the cam lobes to allow the relative rotation of the cylinder block and the cam.
• the spacings between the dispensing orifices and the spacings between the communication orifices are such that a communication orifice is not simultaneously connected to two dispensing orifices connected respectively to the fluid supply and to the fluid exhaust.
• the working chambers of the cylinders that is to say the parts of these cylinders delimited below the pistons, are alternately placed at high pressure and at low pressure. Pressure changes in these working chambers therefore generally take place at a very rapid rate.
• These pressure changes subject the pistons to proportional forces, and these forces are transmitted by the pistons to the cam.
• the components of the motor in particular, its casing, are subjected to the variation in load which causes vibrations generating noise, the intensity of the noises produced mainly depending on the speed of the increases and pressure drops in the working chambers.
• the pressure difference between the fluid supply and the fluid exhaust is large.
• the present invention aims to limit the phenomena of relaxation and the shock effects which result therefrom, by tending to allow the engine to operate substantially smoothly.
• leading portion and the edge separation portion of at least certain dispensing orifices each have an edge arrangement comprising at least one notch, said edge arrangements of a dispensing orifice being different, the edge arrangement of a dispensing orifice which is arranged in angular correspondence with the convex region of the ramp of the cam corresponding to the dispensing orifice considered being able to allow the passage of a volume of fluid pressure compensation between a communication orifice and the dispensing orifice smaller than the volume of pressure compensating fluid, the edge arrangement of the same dispensing orifice which is arranged in angular correspondence with the concave region of said ramp is suitable for allowing passage.
• These volumes of compensation fluid are the volumes of fluid capable of passing through the notches of these edge arrangements as long as the communication between the dispensing orifice and a communication orifice takes place only through the notch (s) of the arrangement board considered.
• the invention proposes to equip the attack portion and the edge separation portion with at least certain dispensing orifices each of an edge arrangement having at least one notch.
• the communication orifice of the cylinder of this piston leaves the separation portion of a dispensing orifice or approaches the attack portion of the next dispensing orifice by an edge arrangement having at least one notch capable of passing a small volume of pressure compensation fluid between the orifices.
• the communication orifice of the cylinder of this piston leaves the separation portion of a distribution orifice or approaches the attack portion of the neighboring distribution orifice by an edge arrangement having at least one notch capable of passing a larger volume of pressure compensation fluid between the orifices.
• the invention allows the connection between each communication orifice and each distribution orifice to be progressive, either by means of the notch (s) of the on-board arrangement allowing the passage of a small volume disposed on one of the edges of the dispensing orifice, arrangement known as “with a small notched section”, either by means of the notch (s) of the edge arrangement allowing the passage of a large volume disposed on the other edge, arrangement said "with large notched section”. This limits the relaxation phenomena mentioned above.
• connection between a communication orifice and the edge arrangement with a small notched section of a dispensing orifice is made when the volume of the working chamber of the cylinder connected to the communication orifice considered is minimal, while that the connection between the same communication orifice and the edge arrangement with a large notched section of a dispensing orifice takes place when the volume of the working chamber of the cylinder associated with the same communication orifice is maximum.
• the edge arrangement of the leading portion of at least one dispensing orifice comprises at least one notch which, relative to a notch of the edge arrangement of the separation portion of said dispensing orifice , is arranged at a different radial distance from the axis of rotation.
• the fact that these two notches are located at different radial distances from the axis of rotation can make it possible to make notches of different lengths. These different lengths are used to optimally define the variation in the pressure drop in the notch during the relative rotation of the fluid distributor and the cylinder block.
• this arrangement makes it possible during the relative rotation of the fluid distributor and of the cylinder block to ensure that a communication orifice communicates for a period of time more large with edge arrangement with large notched section than with the other.
• This difference in communication time is one of the factors which make it possible to homogenize the decompression or compression of the volume of fluid contained in the working chamber of the cylinder block which communicates with the communication orifice considered.
• the period of time during which the notch furthest from the axis of rotation belonging to the edge arrangement with large notched section communicates with a communication orifice is generally greater since, for a given relative angle of rotation between the cylinder block and the distributor, the distance to be covered by a point distant from the axis of rotation is greater than that which is crossed by a point closer to this axis.
• Another use of the length of the notch consists, for a very long notch, in limiting the communication of this notch with a communication orifice, to only a small part of the length of the notch (i.e. -to say on a small angular sector of relative rotation between the cylinder block and the distributor), before the frank communication is established with the very edge of the dispensing orifice.
• this long cut constitutes a restriction of great length which only authorizes, over the small part considered, the passage of a small volume of pressure compensation fluid.
• This long notch therefore corresponds to the small notched section defined above.
• the notch on the other edge of the dispensing orifice disposed at a smaller radial distance from the axis of rotation, has a shorter length but is used over its entire length over an angular sector substantially identical to that of the limited communication of the long notch with the communication orifice before frank communication is established with the very edge of the dispensing orifice.
• This short notch therefore allows the passage of a larger volume of pressure compensation and corresponds to the large notched section defined above.
• the distance of a notch of short length from the axis of rotation is less than the distance of a notch of great length from rotation axis.
• the edge arrangement which is arranged in angular correspondence with the concave region of the cam ramp corresponding to the dispensing orifice considered comprises at least one notch which extends over a sector angular, measured between two radii starting from the axis of rotation, which is larger than the angular sector, measured in the same way, over which extends the notch which is arranged in angular correspondence with the convex region of the ramp .
• the edge arrangement which is arranged in angular correspondence with the concave region of the cam ramp corresponding to said orifice has a notched section larger than that of the edge arrangement which is arranged in angular correspondence with the convex region of the ramp.
• the edge arrangements of at least one dispensing orifice each have the same number of notches (advantageously only one notch), the notch (s) of one of these arrangements being different from that (s) of the other edge arrangement.
• the edge arrangements of at least one dispensing orifice each have similar notches, the number of notches of one of these edge arrangements being different from the number of notches of the other edge layout.
• similar notches means notches having substantially the same section and can be made with the same tool.
• two similar notches respectively present on the leading portion and on the separation portion of a dispensing orifice are such that the image of one of these notches obtained by symmetry with respect to a plane of symmetry of the dispensing orifice has an identical or almost identical conformation to that of the other notch.
• cam top zones and these cam bottom areas are referred to as "cam flats”.
• the substantially zero stroke of a piston which cooperates with a cam plate is made to coincide with an insulation of the communication orifice of the cylinder of this piston, with respect to any distribution orifice.
• This avoids any significant compression or decompression of fluid in the working chamber of the cylinder block, the piston of which is in contact with a cam top region or a cam bottom region.
• FIG. 2 is a sectional view along line II-II of Figure 1;
• - Figure 3 is a partial section along the arc of a circle designated by III-III in Figure 2;
• - Figure 4 illustrates the relative positions between a communication orifice and a dispensing orifice, during the relative rotation between the cylinder block and the distributor, this figure also shows how the dispensing orifice is arranged relative to a ramp of a cam lobe;
• - Figure 5 shows, according to a variant, a communication orifice disposed between two dispensing orifices during the relative rotation between the cylinder block and the distributor;
• FIG. 6 to 10 are variants each showing a dispensing orifice disposed between two communication orifices, during the relative rotation between the cylinder block and the distributor.
• FIG. 1 shows a hydraulic motor comprising a fixed casing in three parts, 2A, 2B and 2C, assembled by screws 3.
• the invention is not limited to hydraulic motors with fixed casing, but it also applies to hydraulic motors with rotating casing which are well known to those skilled in the art.
• the part 2C of the casing is closed axially by a 2D radial plate also fixed by screws.
• a wavy reaction cam 4 is produced on part 2B of the casing.
• the engine comprises a cylinder block 6 which is mounted for relative rotation about an axis of rotation 10 relative to the cam 4 and which comprises a plurality of radial cylinders, capable of being supplied with fluid under pressure and at inside which the radial pistons are slidably mounted
• the cylinder block 6 rotates a shaft 5 which cooperates with it by splines 7.
• This shaft carries an outlet flange 9.
• the engine also includes an internal fluid distributor 16 which is integral with the casing with respect to the rotation about the axis 10. Between the distributor 16 and the internal axial face of part 2C of the casing are formed distribution grooves, respectively a first groove 18, a second groove 19 and a third groove 20.
• the distribution conduits of distributor 16 are distributed in a first group of conduits which, like conduit 21, are all connected to the groove 18, a second group of conduits (not shown) which are connected to the groove 19 and a third group of conduits which, like conduit 22, are connected to the groove 20.
• the first groove 18 is connected to a first main conduit 24 to which are therefore connected all the distribution orifices of the distribution conduits of the first group, such as the orifice 21A.
• the third groove 20 is connected to a second main conduit 26 to which are therefore connected all the distribution orifices of the conduits of the third group, such as the orifice 22A of the conduit 22.
• the main conduits 24 and 26 are respectively an exhaust conduit and a fluid supply conduit, or the reverse.
• the distribution conduits open into a distribution face 28 of the distributor 16, which bears against a communication face 30 of the cylinder block.
• Each cylinder 12 has a cylinder conduit 32 which opens into this communication face so that, during the relative rotation of the cylinder block and the cam, the cylinder conduits are alternately in communication with the distribution conduits of the different groups.
• the motor of FIG. 1 also comprises a device for selecting the displacement which, in this case, includes a bore 40, which extends axially in the part 2C of the casing and in which there is disposed an axially movable selection slide 42 .
• the bore 40 comprises three communication channels, respectively 44, 46 and 48, which are respectively connected to the grooves 18, 19 and 20, by connection conduits, respectively 44 ', 46' and 48 '.
• the slide 42 is movable between two extreme positions inside the bore 40 in which it communicates the tracks 44 and 46 or the tracks 46 and 48 by its groove 43.
• the distribution orifices considered successively in the direction of relative rotation between the cylinder block and the distributor, comprise a pair of orifices 21A, 23A, respectively connected to the grooves 18 and 19, and a pair of orifices 21A, 22A, respectively connected to the grooves 18 and 20.
• the grooves 19 and 20 both communicate with fluid supply.
• a communication orifice 32A is successively set to high and to low pressure by communicating with the orifices of the two aforementioned pairs.
• the selector 42 When, on the other hand, the selector 42 is moved in the direction of the arrow F so as to make the grooves 18 and 19 communicate with each other, then the two distribution orifices 21A, 23A of the first aforementioned pair are both set to the same pressure.
• This pair is therefore deactivated since, when a communication orifice passes from one to the other of the two distribution orifices of this pair, the pressure in the cylinder duct connected to said communication orifice does not change.
• the next pair is active, since a communication orifice communicating respectively with the two orifices 21A, 22A of this pair is successively placed at high and at low pressure.
• the portions Bl of the edges of the dispensing orifices constitute attack portions, through which the communication of an orifice begins. communication with a dispensing orifice, while the portions B2 of the edges of the dispensing orifices constitute separation portions, by which this placing in communication ceases.
• the portions B2 which constitute the attack portions and the portions Bl which constitute the separation portions are the portions B2 which constitute the attack portions and the portions Bl which constitute the separation portions.
• the leading portions B1 and the separation portions B2 of each dispensing orifice each have an edge arrangement, comprising a notch.
• these notches are of different dimensions, the notches 54A of the edge arrangements 53A of the edges Bl of the distribution orifices 23A and 22A, as well as the notches 54A of the edge arrangements 53A of the edges B2 of the orifices 21A being small notches , these edges therefore having small notched sections, while the notches 54B of the edge arrangements 53B of the edges B2 of the distribution orifices 23A and 22A, as well as the notches 54B of the arrangements of edge 53B of the edges Bl of the orifices 21A being large notches, these edges therefore having large notched sections.
• Each lobe of the cam includes two ramps, which each have a convex region and a concave region.
• ramps 50 whose convex region, closer to the axis of rotation 10, is designated by the reference 51, and whose concave region, less close to this axis, is designated by the reference 52.
• a cam lobe is formed by this ramp 50, and by another symmetrical ramp of the ramp 50 with respect to the radius R passing through the axis of rotation of the engine.
• the adjacent cam lobe has a ramp 50 ′, symmetrical with the ramp 50 with respect to the radius RS.
• a dispensing orifice is associated with each ramp of the cam. There is therefore an angular correspondence between each dispensing orifice and a ramp of the cam. Although the dispensing orifices are not in the same radial plane as the cam, FIG. 4 illustrates the angular correspondence between a dispensing orifice 23A and the ramp 50 of the cam. Furthermore, for the sake of clarity, the proportions have not been respected, the communication and distribution orifices being shown closer to the cam than in reality. Overall, the orifice 23A is arranged so that the inscribed circle passing through the end of the notches is substantially symmetrical with respect to a radius RC of the cam which intersects the latter substantially in an inflection zone between its convex regions 51 and concaves 52.
• the notch 54A of the portion Bl of the edge of the orifice 23A is a small notch
• the notch 54B of the portion B2 of the edge of the orifice 23A is a large notch.
• the small notch 54A is in angular correspondence with the convex portion 51 of the cam, that is to say that a radius of the cam, extending radially from the axis of rotation 10 of the motor and passing through the notch 54A intersects the ramp 50 in the convex region 51 of the latter.
• FIG. 4 also shows the different positions of a communication orifice relative to the distribution orifice 23A during the relative rotation of the cylinder block and the distributor. It is considered, for example, that the cylinder block rotates in the direction R2 relative to the cam, the direction for which the portions B2 and B1 of the edge of the orifice 23A respectively constitute the attack portion and the separation portion.
• the communication orifice gradually covers the notch 54B of the orifice 23A and, on an angular displacement ⁇ 2, for example of the order by 2 °, it communicates with the dispensing orifice 23A only through this notch 54B, until it occupies a position 32A2.
• the communication orifice gradually covers the whole of the orifice 23A, and there is a position 32A3, in which the dispensing orifice 23A is completely covered by the communication orifice, the communication section between the dispensing orifice and the communication orifice then being maximum.
• the communication section decreases and the communication orifice reaches a position 32A4 in which it no longer communicates with the dispensing orifice 23A only by means of the notch 54A on the edge from this hole. He then has to travel an angular travel ⁇ 3, for example of the order of 1 °, so that the communication with the dispensing orifice 23A ceases completely. It then remains for the communication orifice to travel an angular travel ⁇ 4, for example of the order of 1 °, before communication begins with the distribution orifice 21A which is located after the distribution orifice 23A in the direction of rotation R2, by the notch 54A of this orifice 21A.
• the total section of the communication passage between this orifice and the distribution orifice 23A is greater than the section of the communication passage which is established, by the small notch 54A, between the same dispensing orifice and the communication orifice when it occupies its position 32A4.
• the ratio between these passage sections is advantageously chosen as a function of the ratio between the volumes of the working chamber of the cylinder 12 supplied by the communication orifice 32A considered when the communication orifice occupies its positions 32A2 and 32A4 respectively.
• the ratio between the communication sections authorized by the notches 54B and 54A is proportional to the ratio between the volume presented by the working chamber of the cylinder supplied by the orifice 32A when this orifice is in its position 32A2 and the volume of the same working chamber when the orifice 32A is in its position 32A4.
• the large notch 54B extends over an angular sector ⁇ 2, measured between two radii starting from the axis of the engine, which is greater than the angular sector ⁇ 3, also measured between two radii starting from the axis of the motor, over which extends the small notch 54A.
• the ramp 50 of the cam is connected to the adjacent ramp 50 'by a cam top region 56, which extends between the convex region 51 of the ramp 50 and the convex region of the ramp 50', and it is connected to the other ramp which is adjacent to it, namely the ramp 50 ", by a cam bottom zone 58 which extends between the concave region 52 of the ramp 50 and the concave region of the ramp 50".
• Cam top areas are those where the radial distance from the cam to the axis of rotation is minimal, while the cam bottom areas are those where the radial distance from the cam to the axis of rotation is Max.
• the cam bottom zone 58 is substantially an arc centered on the axis of rotation. This means that this cam bottom zone is either an arc of a circle centered on the axis of rotation, or a region which, over the entire angular distance 2 ⁇ 'l which it covers, has a radial distance from the axis of rotation of the motor which is substantially equal to the maximum radial distance from the cam to the axis of rotation 10.
• the angle ⁇ '2 over which the part of the cam top zone 56 situated on one side of the radius of symmetry RS extends, corresponds to the path described by the communication orifice 32A between its position 32A4 and its position 32A5, in which it is ready to approach the dispensing orifice 21A which follows the orifice 23A in the direction R2, by the small notch 54A of this dispensing orifice 21A.
• the area at the top of the cam 56 substantially describes an arc of a circle centered on the axis of rotation. It can either actually form such an arc of a circle, or present, over the entire angular distance 2 ⁇ '2 which it covers, a radial distance to the axis of rotation of the motor which is substantially equal to the minimum radial distance from the cam to the axis of rotation 10, by deviating for example at most about 0.5% of this radial distance.
• FIG. 5 shows a communication orifice 32A which is circular, arranged between two distribution orifices, respectively 123A and 121A, which are non-circular.
• the leading portion (B2, if the cylinder block rotates in the direction R2 relative to the distributor and Bl, if the direction of this relative rotation is RI), as well as the portion of separation (Bl if the relative direction of rotation is R2 and B2 if the relative direction of rotation is RI) are both generally convex, seen from the interior of the orifice.
• the leading portions and the separation portions form arcs of circles which, during the relative movement of the distributor and the cylinder block, cover the edge of a communication orifice, when the latter occupies a position corresponding to position 32A2 or to position 32A4 shown in FIG. 4.
• the dispensing orifices generally have the shapes described in patent application FR-A-2 587 761.
• the communication orifice 32A has a substantially circular section, and the aforementioned convex shape of the edges of the orifices of the distributions 121A and 123A is that which makes it possible to increase the communication between the communication orifice as quickly as possible. the distribution orifices, after a first communication via the notches 54A and 54B.
• leading portion and the separation portion of the dispensing orifices are shapes which are substantially complementary to the forms which the edges of the communication orifices have through which the communication between the orifices opens or closes. distribution and communication ports.
• FIG. 6 shows a dispensing orifice 221A disposed, during the relative rotation of the cylinder block and the distributor, between two communication orifices, respectively 32A and 32'A, while being simultaneously isolated from these two orifices.
• the distance from the small notch 254A to the axis of rotation of the motor is less than the distance from the large notch 254B to this axis and the angular sector over which the large notch limits the communication between the orifices is larger than the angular sector of the small notch.
• This allows, during the relative rotation between the distributor cylinder block, to ensure that the period of time during which the distribution orifice 221A communicates with the communication orifice 32A only through the notch 254B is greater than that during which the dispensing orifice communicates with the communication orifice 32'A only through the notch 254A.
• the length of the notch 254B measured tangentially with respect to the axis of rotation of the motor, is greater than that of the notch 254A.
• the notches 254A and 254B both have substantially the same thickness e, measured along a radius passing through the axis of rotation of the motor.
• Figure 7 differs from Figure 6 only in that the notch 254'B of the separation portion B2 of the dispensing orifice 221A is slightly different from the notch 254B.
• the notch 254'B of the edge arrangement 253'B has a maximum thickness el, measured along a radius passing through the axis of rotation, which is greater than the thickness e, also measured along a radius. passing through the axis of rotation, of the notch 254A of the edge arrangement 253A.
• the thickness el is substantially equal to twice the thickness e.
• the large notch 254'B forms a larger opening than the small notch 254A.
• the dispensing orifice 221A is oblong, its largest dimension being measured along a radius passing through the axis of rotation.
• the dispensing orifice 321A has, considering that the cylinder block rotates in the direction RI with respect to the cam, a separation portion B2 whose edge arrangement 353B comprises a notch 354B of upper section to that of the notch 354A of the edge arrangement 353A of the leading portion Bl.
• the separation portion B2 of the dispensing orifice has substantially the shape of an arc of a circle whose center is located at the inside this hole.
• the notch 354A is for example analogous to the notch 254A of FIGS. 6 and 7.
• This attack portion Bl has a shape substantially complementary to that of the edge C of the communication orifice 32'A by which the communication between the 'communication port and the distribution port opens when the cylinder block rotates in the direction of rotation RI relative to the distributor. It is also by this edge C that the communication between the distribution orifice and the communication orifice 32'A closes when the cylinder block rotates relative to the distributor in the direction R2 opposite to the sense RI.
• the leading portion B1 is convex, when viewed from the inside of the dispensing orifice 321A. It has substantially the shape of an arc of a circle capable of covering the arc of a circle formed by the portion C1 of the communication orifice 32'A.
• the communication between the distribution orifice 321A and the communication orifice 32'A is done first by a very small section, due to the notch 354A, then it increases very quickly due to the shape of the attack portion Bl.
• dispensing orifices having generally the same shape as the orifice 321A with notches similar to any of the notches 54A, 54B, or 254A, 254B previously mentioned.
• the dispensing orifice 421A generally has the shape of a circle except for its notches. It can be seen that the notches 454A of the edge arrangement 453A of its leading portion B1 and 454B of the edge arrangement 453B of its separation portion B2 (in the direction of rotation RI) are located at different radial distances the axis of rotation of the motor.
• FIGS. 1-10 the dispensing orifice 421A generally has the shape of a circle except for its notches.
• the small notch 254A or 354A is substantially situated on an arc of a circle, centered on the axis of rotation of the motor and passing through the geometric centers of the communication orifices 32A and 32'A, while the large notch 254B, 254'B or 354B is located beyond this circular arc, away from the axis of rotation.
• the “small” cut 454A is the cut of greatest length and is located beyond an arc of a circle A, passing through the geometric centers of the communication orifices 32A and 32′A and centered on the axis of rotation, while the “large” notch 454B is the shortest notch and is situated below this arc of a circle.
• Notches 454A and 454B have identical sections.
• This arrangement of the notch 454A of greater length makes it possible to limit the volume of fluid passing through the notch over the small part of its length in communication with the communication orifice, before frank communication is established with the edge. even from the dispensing opening.
• This volume limitation is due to the pressure drop generated by the great length of restriction that this notch achieves.
• the notch 454B of shorter length is used over its entire length on the same angular sector centered on the axis of rotation as that of the limited communication of the long notch 454A with the communication orifice before the open communication with the very edge of the dispensing orifice. The notch 454B therefore allows the passage of a larger volume of pressure compensation.
• the advantage of this arrangement is to keep the circular communication and distribution orifices of the standard distributors (without notches) and in addition to make the notches defined for each application as a function of the working pressures, the rotation speeds and the volumes of the working chambers at top and bottom dead centers.
• edges of all the dispensing orifices have notches, respectively on their leading portions and on their separation portions.
• the large notches 54B are all the same size, while the small notches 54A are all the same size.
• each pair of consecutive dispensing orifices (21A, 23A; 21A, 22A) comprises an orifice (22A or 23A) connected to the fluid supply and an orifice (21A) connected to the fluid exhaust.
• this large displacement is obtained when the selector 42 is in the position shown.
• the motor also includes a small active operating displacement in which certain pairs of consecutive distribution orifices (21A, 22A) are active and include an orifice (22A) connected to the fluid supply and an orifice (21A) connected to the fluid escape, while other pairs of dispensing orifices (21A, 23A) are inactive and include two orifices placed at the same pressure.
• the edges of the dispensing orifices of the active pairs in small displacement may have edge arrangements having notched sections larger than those of the edge arrangements of the dispensing orifices of the inactive pairs in small displacement.
• the edge arrangements of the distribution orifices of the active pairs in small displacement include a small notch and a large notch respectively arranged in angular correspondence with a convex zone and with a concave zone of the cam, while the edge arrangements of the orifices inactive pairs in small displacement also include a small notch and a large notch respectively located opposite a convex zone and a concave zone of the cam, but these notches of the inactive orifices in small displacement are smaller than those of the orifices active in small displacement.
• each edge arrangement of a dispensing orifice has a single notch and the small or large notched sections are obtained by the choice of a small or a large notch.
• the edge arrangements 553A and 553B of the dispensing orifice 521A include similar notches but in different numbers.
• the edge arrangement 553A thus comprises a notch 554A, while the edge arrangement 553B comprises two notches, 554B and 554'B.
• the single notch 554A therefore defines, for the arrangement 553A, a smaller notched section than that which, for the arrangement 553B, define the two notches 554B and 554'B.

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• General Engineering & Computer Science (AREA)
• Hydraulic Motors (AREA)

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• 2001
  • 2001-12-24 FR FR0116815A patent/FR2834011B1/fr not_active Expired - Fee Related
• 2002
  • 2002-12-20 AU AU2002364477A patent/AU2002364477A1/en not_active Abandoned
  • 2002-12-20 DE DE60218351T patent/DE60218351T2/de not_active Expired - Lifetime
  • 2002-12-20 US US10/499,948 patent/US6978713B2/en not_active Expired - Lifetime
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