Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/0404—Details or component parts
  • F04B1/0439—Supporting or guiding means for the pistons
• • 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
  • F03C1/047—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinders in star or fan arrangement the pistons co-operating with an actuated element at the outer ends of the cylinders
• • 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
  • F03C1/22—Reciprocating-piston liquid engines with movable cylinders or cylinder
  • F03C1/223—Reciprocating-piston liquid engines with movable cylinders or cylinder having cylinders in star or fan arrangement, the connection of the pistons with an actuated element being at the inner ends of the cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/047—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement with actuating or actuated elements at the outer ends of the cylinders
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/10—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement the cylinders being movable, e.g. rotary
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/10—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement the cylinders being movable, e.g. rotary
  • F04B1/107—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement the cylinders being movable, e.g. rotary with actuating or actuated elements at the outer ends of the cylinders
  • F04B1/1071—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement the cylinders being movable, e.g. rotary with actuating or actuated elements at the outer ends of the cylinders with rotary cylinder blocks
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B5/00—Machines or pumps with differential-surface pistons
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/14—Pistons, piston-rods or piston-rod connections

Definitions

• Hydraulic machines comprising a cylinder block having a plurality of housings in which pistons slide, including means for guiding the pistons in their housings.
• the document FR 2 727 471 in the name of the applicant presents for example a hydraulic machine structure in which the pistons are guided in translation by a U-shaped clip, inserted firstly in a recess of the cylinder block, and on the other hand part in a radial groove arranged on a wedge piece ensuring the maintenance of the piston roller.
• the present disclosure relates to a hydraulic mechanism, motor or pump, comprising a cam; a cylinder block rotatably mounted relative to the cam; at least one cylinder formed in this cylinder block; at least one piston assembly adapted to cooperate with a cylinder, this piston assembly comprising a piston slidably mounted inside said cylinder; a roller rotatably mounted on the piston and configured to cooperate with the cam, the roller being delimited by two transverse end faces; first and second wedging members each disposed between an end face of the roll and the inner face of the cylinder on which said chock member bears so as to maintain the axial position of the roll.
• the cylinder has a groove in its inner face, and the piston assembly has a projection configured to cooperate with the groove of the cylinder to maintain the orientation of the roll.
• the translational guidance is more robust: it is able in particular to withstand power surges of the hydraulic mechanism and abrupt movements of the piston that they can generate.
• the guide is here in the cylinder itself through the cooperation of the projection of the piston assembly with the groove of the cylinder.
• this projection can be shorter and this cooperation can be done more closely to the axis of the piston, which reduces the lever arm and therefore the importance of shear forces when the piston seeks to rotate in the cylinder .
• the projection can be an integral part of an existing part of the piston assembly, which reduces the number of parts used.
• the projection is integral with the piston.
• the guide of the piston in translation and its locking in rotation is therefore provided directly.
• the projection is an end portion of a pin inserted into a bore of the piston.
• a pin inserted into a bore of the piston.
• This pin can be fixed in the bore, for example by tight fitting, or slide freely in the bore.
• the pin is metallic.
• the projection is a protrusion forming an integral part of the piston.
• a one-piece piece can be obtained by removing material from a precursor piece to form this protrusion; it can also be obtained by molding or other techniques.
• the projection extends in a direction that does not intersect the main axis of the piston. In this way, the projection does not interfere with a possible member extending along the main axis of the piston, such as a center hole for example.
• the piston has a center hole, extending along its major axis from its lower face, and a bore for receiving a projection pin, the center hole and the bore not communicating with the within the piston.
• the lateral surface of the piston has a flat surface, the projection projecting from this flat surface.
• a flat facilitates the introduction of the projection: when the projection is a pin inserted into a bore of the piston, the bore is easier to drill on the flat surface of the flat; when the projection is an outgrowth of the piston made by removal of material, this flat may be the surface remaining after removal of material.
• such flat allows the passage of hydraulic fluid along this portion of the piston, which is particularly useful in the case of a stepped piston.
• the projection is shifted to a side edge of the flat relative to the center of said flat. This reduces the length of the projection, the distance separating the flat of the piston and the inner face of the cylinder being all the smaller as one approaches the lateral edges of the flat.
• the projection is a pin
• the projection is integral with the first wedging piece.
• the piston can be left intact, the function of translational guiding and rotational locking being integrated with the wedging function in the wedging piece. It is thus possible to use existing pistons in new cylinder blocks according to the invention by equipping them with this type of wedging piece.
• the projection is a boss integral with the first wedging member.
• the wedging piece can thus be obtained integrally, for example by molding. We thus obtain a more massive piece and therefore more solid.
• the first wedging piece is plastic.
• the groove extends to the outer end of said cylinder and opens into the outer face of the cylinder block.
• the projection can therefore possibly leave the groove for a short time when the piston follows the cam: in this way, the piston is not blocked in translation, which offers a large amplitude to the piston and thus improves performance hydraulic mechanism.
• said cylinder has an outer portion, having a first diameter, defining an outer chamber, and an inner portion, having a second diameter smaller than the first diameter, defining an inner chamber;
• the piston comprises an outer portion, having a first diameter, and an inner portion, having a second diameter smaller than the first diameter;
• the groove is formed in the inner portion of the cylinder and the projection projects on the inner portion of the piston.
• the groove extends to the outer end of the inner portion of the barrel and opens into the outer barrel chamber. This facilitates the mounting of the stepped piston and increases the section of passage of the hydraulic fluid.
• the projection extends perpendicularly to the axis of the piston.
• the projection has a tapered inner end.
• This shape can be assessed in a radial plane (orthogonal to the main axis of the mechanism) and / or in the axial plane (containing the main axis of the mechanism and the axis of the piston). This allows, in cases where the projection can exit the groove, facilitate its reinsertion into the groove and automatically refocus the piston. The assembly of the mechanism is also facilitated.
• the projection height of the projection decreases toward its inner end.
• the term "height of projection” the height of an element, at a given point, measured from the surface on which this element protrudes and perpendicular to this surface. This also makes it easier to insert the projection into the groove and to prevent it from catching on the edge of the cylinder.
• the hydraulic mechanism is devoid of any fastener mounted in an outer or lateral face of the cylinder block and overlapping the periphery of a cylinder. The manufacture of the cylinder block is thus facilitated and the risk of stall and loss of an element in the housing of the mechanism is reduced.
• the groove of the cylinder is formed in the thickness of the cylinder block. In some embodiments, the groove extends in a direction parallel to the cylinder axis.
• the piston is provided with a seal ensuring the seal between the piston and the inner face of the cylinder.
• the groove of the cylinder is provided to never be overlapped by the piston seal when the piston is guided by the cam. This prevents hydraulic fluid can escape from the piston chamber bypassing the seal by the groove.
• FIG 1 is a general view in axial section of a hydraulic mechanism.
• FIG 2A is a cross-sectional view of a cylinder block according to a first embodiment.
• FIG 2B is a sectional view along the IIB-IIB plane of FIG 2A.
• FIG 3A is a front view of a wedging piece according to the first embodiment.
• FIG 3B is a sectional view along the plane IIIB-IIIB of FIG 3A.
• FIG 4 is a partial cross-sectional view of the piston assembly engaged in the cylinder block of FIG2A.
• FIG 5A is a cross-sectional view of a cylinder block according to a second embodiment.
• FIG 5B is a view along the arrow VB of FIG. 5A.
• FIG 6 is a perspective view of a piston according to the second embodiment.
• FIG 7 is a perspective view in section of the piston assembly engaged in the cylinder block of FIG 5A.
• FIG 8 is in profile view of an alternative embodiment of the piston of FIG 6.
• FIG 9 is a cross-sectional view of a cylinder block according to this variant.
• the engine 1 of FIG. 1 comprises:
• An output shaft 4 rotatably mounted in the housing, about an axis 5, by means of two roller bearings 6, and whose inner end is provided with grooves 7;
• a cylinder block 8 which comprises a central recess provided with splines 9, associated with the splines 7 of the shaft for securing the shaft 4 in rotation with the cylinder block 8 and for centering the cylinder block with respect to this tree;
• a plurality of cylinders 10 arranged radially in a star with respect to the axis 5, each containing a piston 11, which is slidably mounted therein;
• a flat face 12 which is provided with the cylinder block 8, which is perpendicular to the axis of rotation 5, and in which open conduits 13 connected to the different cylinders 10;
• the axial face of the dispenser has a third circular groove 16 '.
• the groove 16 ' can be connected to the groove 16 or the groove 17 by a displacement selector (not shown) to operate the engine in large or in small displacement. It goes without saying that the invention applies equally to engines with one or more displacements.
• a cylindrical roller 23 is housed in a bearing 24 formed at the end of each piston 11, is rotatably mounted about a roller axis 25 orthogonal to the piston pin 26, coinciding with the axis of the cylinder 10, and is pressed against the cam 3.
• This roller 23 is capable of penetrating at least partially inside the cylinder, so that, on the side of each transverse face 27 delimiting the roller, a recess 28 is formed in the part of the piston 11 which supports this roll, which allows to form, on either side of said roll, spaces.
• Each recess corresponds at least to the space between at least the surface of the cylinder 10, the cylindrical surface of the roller 23 and the corresponding transverse face 27 of the roller, said space being moreover open to the outside of the piston, at least in the area where the roller is protruding out of the piston.
• the plane perpendicular to the axis 25 of the roller 23 and containing the axis 26 of the piston is a plane of symmetry for the piston 11, the bearing 24, the roller 23, and the two spaces. It would also be possible, and in accordance with the invention, to have an asymmetric arrangement in which the spaces would not be symmetrical to each other with respect to a plane perpendicular to the axis 25 of the roll.
• each space defined between a recess 28 of the piston 11 and the inner wall of the cylinder 10 contains a wedging piece 29a, 29b, of a shape corresponding to that of the recess and of cross section shaped substantially in a lunula.
• These wedging pieces 29a, 29b each have a flat face disposed facing one of the end faces 27 of the roll 23 and a cylindrical face bearing on the inner face of the cylinder 10. These parts thus perform the axial wedging of the roll.
• each transverse face 27 is in contact with the opposite face of the piece 29a, 29b.
• the inner wall of the cylinder 10 has a groove 31 extending radially inwards from the outer edge of the cylinder 10 in the axial plane containing the cylinder.
• axis 26 of the piston 11 and the axis 25 of the roll 23 this groove 31 thus opens within one of the recesses 28.
• the groove 31 extends over a length such as the seal 1 of the piston 11 never reaches it when the piston moves back and forth in the cylinder 10, guided by the cam 3; in other words, the position of the seal at the upper dead point of the piston is more internal than the inner end 32 of the groove 31.
• the length of the groove 31 may be less than half, or third, of the length of the cylinder 10, depending on the magnitude of the piston stroke 11.
• the groove 31 has a tapered shape. More precisely, it has the shape of a truncated cone cut in a longitudinal plane with an inner end 32 rounded: thus, both its tangential dimension and its axial dimension decrease when one approaches its inner end 32.
• the wedging piece 29a intended to fill the recess 28 in which the groove 31 is provided comprises in turn a boss 35 of shape substantially complementary to the groove 31.
• This boss 35 therefore extends radially inwards from the outer edge of the chock piece 29a over a substantially identical length, or shorter, than that of the groove 31.
• It also has a tapered shape, more precisely the shape of a trunk of cone cut in a longitudinal plane with one end inner 36 rounded; the angle of the cone may be for example about 5 °.
• such a boss 35 is therefore configured to engage in the groove 31 of the cylinder 10 in order to lock the roll 25 and thus the piston 11 in its entirety in rotation about its axis 26.
• the inner end 36 of the boss 35 rests at the inner end 32 of the groove 31; on the other hand, at the top dead center, the inner end 36 of the boss 35 protrudes beyond the outer edge of the cylinder 10 and thus leaves the groove 31.
• the cylinder 10 has a single groove 31 and only the first wedging piece 29a is provided with such a boss 35.
• two diametrically opposed grooves 31 may be provided in the cylinder 10; in this case, the second wedging piece 29b can also be provided with a boss 35.
• FIGS. 5 to 7 illustrate a second example of a hydraulic mechanism generally analogous to the first example, except that the cylinder block 108 here comprises stepped cylinders 110 configured to receive stepped pistons 111.
• stepped cylinders 110 comprise an outer section 110e, of a certain diameter, defining an outer chamber, and an inner section IlOi, having a smaller diameter, defining an inner chamber.
• the stepped pistons 111 have in turn an outer portion 111e, having a diameter substantially equal, with a clearance, to the diameter of the outer portion 100e of the cylinder 110, and an inner portion 111i, also called piston foot, having a diameter at less than the diameter of the inner portion IlOi of the cylinder 110.
• the sealing of the cylinder is performed by a seal provided at the outer portion 111e of the piston which is applied against the surface of the outer section 110e of the cylinder 110.
• the hydraulic fluid can thus be distributed in the inner chamber bypassing the inner portion llli of the piston to apply its hydraulic pressure both against the inner surface of the outer portion 111e of the piston 111 and against the inner surface of its inner portion llli.
• the outer portion 111e of the piston also supports, in a manner similar to the previous example, a roll 123 and wedges 129.
• the inner portion 111i has two flats 137 diametrically opposed, preferably arranged orthogonally to the axis 5 of the engine.
• a bore 138 is further pierced in the flat 137 opposite the fluid supply conduit 113.
• a metal pin 135 is inserted and retained in this bore 138 so that its distal end 136 protrudes orthogonally on the flat portion 117.
• This distal end 136 of the pin 135 is thus configured to engage in a groove 131 formed in the surface of the inner portion IlOi of the cylinder 110.
• This groove 131 thus extends radially inwardly from the outer edge of the inner portion. IlOi of the cylinder 110 over substantially the entire length of this inner portion IlOi. It thus opens all along the inner chamber and opens at its outer end into the outer chamber of the cylinder 110.
• This groove preferably extends in the axial plane containing the axis 26 of the piston 11 and the axis 25. of the roller 23, opposite the conduit 113 for supplying fluid.
• FIGS 8 and 9 illustrate an alternative embodiment of this second example in which the pin 235 is no longer centered on flat 237 but shifted towards a lateral edge 237a of the flat 237.
• FIG. 8 shows that the piston 211 has a center hole 239 which has allowed it to be machined, extending along its length. main axis 226 and that the latter is disjoint from, that is to say does not communicate with, the bore 238 in which the pin 235 is inserted.
• the groove position 231 is also modified to cooperate properly with the pin 235.
• the groove 231 extends in a direction offset from the axial plane of the motor passing through the piston.
• the length of the groove 131 is such that the pin can never leave the groove during operation of the engine 1.
• the pin 135 and / or the groove 131 of a tapered shape similar to that described with reference to the first embodiment.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Reciprocating Pumps (AREA)
• Hydraulic Motors (AREA)
• Actuator (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=52358898

Family Applications (1)

Country Status (4)

Families Citing this family (7)

Family Cites Families (10)

• 2014
  • 2014-10-03 FR FR1459509A patent/FR3026791B1/fr not_active Expired - Fee Related
• 2015
  • 2015-10-02 CN CN201580053964.5A patent/CN106795870B/zh active Active
  • 2015-10-02 WO PCT/FR2015/052646 patent/WO2016051107A1/fr not_active Ceased
  • 2015-10-02 EP EP15788134.3A patent/EP3201466B1/de active Active
• 2016
  • 2016-02-01 FR FR1650782A patent/FR3032241B1/fr not_active Expired - Fee Related

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