Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/20—Varying fuel delivery in quantity or timing
  • F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
  • F02M59/243—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movement of cylinders relative to their pistons
  • F02M59/246—Mechanisms therefor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
  • F02M59/04—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft or swash-plate type pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
  • F02M59/08—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by two or more pumping elements with conjoint outlet or several pumping elements feeding one engine cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
  • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
  • F02M59/105—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive hydraulic drive
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/12—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps having other positive-displacement pumping elements, e.g. rotary
  • F02M59/14—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps having other positive-displacement pumping elements, e.g. rotary of elastic-wall type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
  • F02M59/20—Varying fuel delivery in quantity or timing
  • F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
  • F02M59/243—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movement of cylinders relative to their 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
  • 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
  • F04B1/14—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 stationary 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
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/02—Machines, pumps, or pumping installations having flexible working members having plate-like flexible members, e.g. diaphragms
  • F04B43/06—Pumps having fluid drive
  • F04B43/067—Pumps having fluid drive the fluid being actuated directly by a piston
• • 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
  • F04B53/142—Intermediate liquid-piston between a driving piston and a driven piston

Definitions

• the present invention relates to a pump capable of pumping and pumping under high pressure virtually any liquid such as: water, petrol, diesel, oils, corrosive chemical liquids and sludge; but more particularly for the high pressure supply of fuel injectors for internal combustion engines.
• the membrane is on one side driven by mechanical means (cam, lever or the like) and is on the other subject to the discharge pressure: it follows that, as soon as the pressure becomes high the membrane deteriorates at the points of application of the mechanical forces.
• a first pump which is a hydraulic pump which pumps and sucks up hydraulic liquid which drives the movable elements of the machine alternately.
• a second pump sucking and pressurizing the liquid to be pumped.
• These mobile elements which provide the physical separation between the hydraulic fluid and the fluid to be pumped, while being driven by an alternating movement by the hydraulic fluid, are either deformable membranes or free pistons.
• the free pistons have a defect with regard to tightness, a defect which is unavoidable in cases where one must have an absolute seal. If a seal is placed between the free piston and the cylinder in which it moves, it is not possible to obtain a perfect seal. If the seal is removed: either there is a very thin film of oil between the friction surfaces and therefore micro-leaks; or there is no oil film and the friction surfaces will heat up. In the particular case of high-pressure petrol injection, no leakage, however small, is admissible and, obviously, any heating may cause an explosion.
• the present invention therefore relates to a pumping device in which the mobile elements, driven by an alternating pumping movement by the hydraulic pump and ensuring a completely sealed separation between the "motor" hydraulic liquid and the liquid to be pumped are deformable membranes.
• pumps of this type with deformable membranes have at least one, if not several, of the following drawbacks: a - if the separation and pumping membrane is mechanically linked to the piston of the hydraulic pump, there is no pressure on each side of the flexible membrane and the latter does not hold over time, it deteriorates;
• the diaphragm is completely free, that is to say it is not linked to any drive mechanism and is driven only by the hydraulic liquid pumped by the pump, there is pressure between the two ribs of the diaphragm .
• the volume of hydraulic pumped fluid increases with each cycle and eventually becomes larger than that which the membrane can pump: there then occurs a hydraulic blockage creating an overpressure such as either of the two pumps breaks.
• the injection of high pressure petrol if it is the element which delivers the high pressure petrol which breaks, the fire is inevitable;
• German patent 2,447,741 WANNER describes a diaphragm pump which is mechanically linked to a piston which slides inside a hydraulic pump piston.
• the disadvantages are the same as for US Pat. No. 4,392,787 cited above.
• the present invention provides a device in which each membrane is free and in which, at the end of each cycle of a piston, the dead chamber, located downstream of the top dead center of this piston (compression position maximum), in which the liquid in contact with the membrane is placed, is placed in communication with the hydraulic fluid reserve; so that the liquid which is there is pushed back towards this reserve first by the expansion of the liquid, then by effect of pushing back by the membrane which is constrained by a spring.
• the present invention relates to a pump making it possible to pump any kind of liquid while imparting to it a very high discharge pressure, of the type constituted by the association of two pumps: on the one hand, a pump hydraulic; on the other hand, a second pump whose mobile means, carrying out the suction and the delivery of the liquid to be pumped, are flexible membranes driven by an alternating movement in one direction more in the other by the displacement of the hydraulic liquid pumped then re-aspirated by the first pump characterized in that the pistons of the first pump are hollow and traversed by the hydraulic liquid which, during the suction phase passes through a lunula or groove dug in the face of the bias or cam plate; the deformable membranes being each constrained by a spring so that at the end of the compression stroke of each piston, communication is established between the chamber where the hydraulic liquid is forced against the membrane and the suction chamber, this liquid being, on the one hand, sucked in by the movement of the piston and discharged by the membrane under the action of its
• the second pump has as many volumes or bores as the first pump has bores, each bore of the second pump communicating directly with the corresponding bore of the first pump so that each piston of the first pump delivers and aspirates cyclically hydraulic fluid in the corresponding bore of the second pump.
• each bore of the second pump is divided into two parts by a deformable membrane counter-clamped by a spring, the part communicating with the corresponding bore of the first pump and receiving the hydraulic fluid discharged and re-sucked by it, the other part, fitted with suction and discharge valves, suction and delivery of the product to be pumped.
• the hydraulic fluid reservoir is external to the first pump and communicates with the latter by a pipe opening into the chamber.
• the pump according to the invention is intended for supplying fuel injectors for internal combustion engines under high pressure, the hydraulic fluid of the first pump (I) possibly being the oil of said engine.
• the present invention relates to means making it possible to vary the displacement of the first pump and therefore the fuel flow rate to the injection devices.
• These means are: either the arrangement of a tilting platform with variable inclination, or the arrangement of means in the pistons of the hydraulic pump, having the function of short-circuiting all or part of the volume of hydraulic fluid introduced into the bore during the suction phase.
• each hollow piston of the hydraulic pump is provided with openings which can be concealed in whole or in part by a movable jacket, all the movable shirts being moved together by a control member controlled by the operating conditions of the engine.
• This device may also include one or other of the following provisions:
• a - the pistons slide in two supports pierced with orifices, these two supports being separated from each other by an annular space, constituting a chamber, in which the liners move between two extreme positions, one for which the orifices not being masked by the liners all the liquid discharged by each piston back into the annular chamber through the orifices of the pistons the flow rate of the pump (I) being zero: the other for which all the orifices being masked by the liners each piston delivers all of the hydraulic fluid drawn in, the pump flow rate then being maximum.
• the liners can occupy all the intermediate positions between the two extreme positions; so that the pump flow (I) can be regulated for all values between a zero flow and a maximum flow.
• the liners are coupled to a common control member which is controlled by any suitable control device to regulate the flow of gasoline at high pressure according to the supply needs of the engine without high pressure gasoline being returned to the tank.
• a damping device can be arranged downstream of the outlet of the second pump (II) and upstream of the injectors to cancel the pulsation effect caused by the first pump (I).
• the damping device can be a large volume capacity in relation to the fuel flow rate, maintained under the injection pressure by any appropriate means and behave substantially like a hydromechanical accumulator.
• FIG. 6 a longitudinal sectional view of the pump of Figure 1 in which the individual membranes have been replaced by a single membrane.
• FIG 9 a longitudinal sectional view of an alternative embodiment of the pump according to the invention in which the suction valves have been removed.
• the device according to the invention comprises a first pump, designated by the general reference I and a second pump, designated by the general reference II.
• the first pump I is a pump with axial pistons driven in an alternating movement back and forth by a bias plate 1.
• the bias plate 1 is integral with a motor shaft 2 (driven by any means not shown) carried by bearings 3.
• a plurality of hollow pistons 4 bear against the oblique face of the plate 1 each by means of a sliding stud 5, which is pierced in its center with a bore 6.
• Each piston 4 is held by a spring 7 against its stud.
• On the front face 1 is engraved a lunula 8.
• This chamber 9 opens, by a plurality of holes 22, passing through the body 21 of the pump I, in a reservoir 11.
• This reservoir 11 is constituted by a cylindrical envelope 23 which surrounds the body 21.
• the face of the bias plate 1 oscillates in the chamber 9 so that the pistons 4 are moved back and forth: in the direction which corresponds to the suction, the pistons 4 are moved by their spring 7; in the other direction which corresponds to the delivery under pressure, they are pushed back against the spring 7 by the bias plate 1.
• the hydraulic fluid which is in the chamber 9 penetrates to the inside of the pistons 4 passing through the lunula 8 and the bore 6 of the studs 5.
• each bore 12 in which a hollow piston 4 slides has at its end a non-return valve; so that all of said pistons 4 causes a flow under pressure (and even at high pressure since it can exceed 1000 bars with this type of pump).
• none of the bores 12 in which the pistons 4 slide have a non-return valve.
• a pump II is associated with the pump I immediately downstream of the latter.
• Each bore 12 of the pump I, in which a piston 4 slides, corresponds, in the pump II, a chamber or bore 13 divided into two parts 13a and 13b by a flexible membrane 24 supported by a spring 15.
• the part 13a communicates directly with the end of the bore 12, while the part 13b is provided at its end opposite to the membrane 24 with a suction valve 16 and a discharge valve 17. All the valves 17 flow into a common pipe 18.
• each spring 15 bears on the rear face of the membrane 24 by means of a cup 20.
• the shape of the cup 20 is determined so that the support of the cup 20 on the rear face of the membrane 24 does not cause any deterioration thereof.
• the displacement of the membrane 24 in the direction of the arrow f2 has the effect of sucking the product to be pumped into the part 13b of the bore 13, through the non-return intake valve 16 and of discharging the hydraulic fluid found in part 13a.
• Each membrane 24 is subjected, on its two front and rear faces and this uniformly distributed over the entire surface of the membrane, to the same pressure: on one side the pressure of the hydraulic motor fluid, on the other the pressure of the pumped liquid.
• the membrane therefore does not undergo any mechanical stress and therefore cannot tear.
• the pump according to the present invention is therefore a diaphragm pump in which each diaphragm is, in the delivery phase, in equipression on each side, which makes it possible to have a delivery pressure equal to the hydraulic pressure that the first pump I.
• the pump according to the present invention can be used, inter alia, to pressurize liquids having no greasing power.
• it can be used to supply injectors for internal combustion engines (car engines) supplied with super-fuel and / or liquid LPG as a substitute fuel for example.
• the super-fuel is sucked in by the valves 16, discharged under high pressure (more than 50 bars) by the valves 17 without the fuel ever being brought into contact with metal members that have to slide against each other.
• the engine oil itself can advantageously be used as hydraulic fluid by having the chamber 9 communicate directly with the engine oil distribution circuit, the temperature of this oil being regulated by the appropriate engine members.
• the pump according to the invention can also be used to circulate drilling mud under pressure.
• the suction force of the second pump II which is linked to the power of the springs 15, allows the membranes 24 to return to their initial position, due to the communication with the chamber 9.
• Figures 3 to 5 relate to an improvement to the device of Figures 1 and 2 by means of which it will be possible to vary at will the flow rate of the liquid to be pumped.
• this liquid is petrol intended to supply an engine
• the displacement of the pump In order for a motor to be able to run at full speed, the displacement of the pump must be determined according to the extreme conditions of use of the motor, namely: operation at maximum speed and full load. This therefore defines a maximum flow rate of the pump which is supplied continuously; so that, outside of these extreme conditions of use, the pump provides an excess flow, which is returned to the tank.
• gasoline thus returned to the tank is found to have been heated by compression, so that hot gasoline is constantly returned to the tank.
• the gasoline becomes increasingly hot so that it may appear in the tank of unwanted gasoline vapors whose treatment is made difficult by standards more and more severe especially with regard to direct injection petrol engines.
• the first solution consists in producing the first pump I, in the form of a variable flow pump using a bias plate 1 with variable inclination as is done in certain pumps produced by the applicant.
• the device according to this second solution is characterized in that it comprises a double pump such as that described in patent application 96.07043, but in which each piston of the hydraulic pump is provided with means making it possible to cancel all or part the flow pumped by said piston.
• Figures 3 and 4 describe a double pump similar to that of Figures 1 and 2 in which the same elements have the same references.
• each hollow piston 4 is traversed right through by a pipe 30.
• the pistons 4 are carried by two supports 31 and 32 pierced with orifices in which said pistons slide.
• the holes drilled in the support 31 are designated by the reference 33, while the holes drilled in the support 32 constitute the cylinders 12 mentioned above.
• the thickness of the support 32 is greater than the maximum stroke of the pistons 4.
• the space between the supports 31 and 32 constitutes an annular chamber 35.
• each piston 4 is partially covered by a sliding jacket 34.
• These sliding shirts are all connected to a connecting rod control 38 so as to be able to slide all together between two extreme positions, the first being illustrated in FIG. 3, the second being illustrated in FIG. 4.
• the springs 7 of FIGS. 1 and 2 which have the function of keeping the heads of the pistons in abutment against their sliding stud 5 are replaced by a pusher 7b which acts on a collar 6 which is supported on the rear of each head of piston 4.
• the pusher 7b is constrained by a spring 7a.
• the pusher 7b, cortenant the flange 6 of each piston head is crossed by a pipe 37 which communicates between them the two chambers 9 and 35.
• the output flow rate of the pump II is regulated as a function of the gas flow rate which is necessary for injection and that the excess gasoline returns to the tank are reduced to the maximum.
• the fuel flow rate thus obtained is a pulsed flow rate.
• the liners 34 are in a position such that only 10% of the maximum flow rate of the pump I is delivered in the part 13a of the volume 13, this means that this pump I does not provide any flow rate for 90% of the stroke of each piston or that there is flow only over 10% of the stroke of each piston. This has the effect that the flow is a pulsed flow.
• This device can advantageously be constituted in a similar manner to a hydraulic accumulator, that is to say constituted by a capacity having a large volume relative to the flow rate supplied to the injectors and maintained under constant pressure.
• FIG. 6 represents a pump similar to the pump of FIG. 1, in which the same elements have the same references.
• the reservoir 11 of FIG. 1 which envelops the hydraulic pump is replaced by an external reservoir 11a; for the rest, all the components are identical with the only exception of the diaphragm of pump II of FIG. 1.
• each volume 13 is divided into two parts 13a, 13b by a membrane 24 pushed back by a spring 15 bearing on the membrane 24 by means of a cup 20.
• the pump of FIG. 6, like that of FIG. 1, comprises a one-piece pump casing 40, in two cylindrical parts 40a and 40b, the part 40b having an internal diameter greater than that of the part 40a.
• part 40a are arranged the bearings 3, the drive shaft 2, the bias plate 1, the supply chamber 9 and the rear part 41a of a part 41 in which the bores are drilled 12.
• the front part 41b of this part is located in the upper diameter portion 40b of the casing 40; so that this front part 41b rests against the shoulder which separates the two parts 40a and 40b of the casing 40.
• the bores 12 of the pistons 4 open out at the front face of this part 41b.
• a circular plate 42 is disposed against said part 41b and is immobilized in position relative to the latter by a pin 42a.
• This plate 42 has as many holes 43 as there are bores 12 and chamber 13.
• the chambers 13 are formed in a part 45 which is screwed to the open end of the part 40b of the casing 40.
• a membrane 44 which has the shape of a disc having the same diameter as the plate 42.
• the membrane 44 is pinched between the plate 42 and the end of the part 45.
• Each bore 43 communicates with a bore 12 of the pump I and is located opposite a volume 13.
• FIG. 9 represents an alternative embodiment of the pump of FIGS. 6 to 8.
• the essential difference relates to the mechanical constitution of the hydraulic pump I.
• This hydraulic pump I comprises, like the pumps of FIGS. 1, 3 and 6, a bias plate 1 against which rest hollow pistons 4 by means of sliding studs 5, pierced with a bore 6 intended to overlap a lunula 8.
• the bias plate 1 is disposed at the end of a motor shaft 2 carried by bearings 3; while in the pump of Figure 9, the bias plate 1 is integrated in a ball bearing.
• This ball bearing comprises an outer cage 61 fixed inside the casing 60 of the pump and an inner cage 62 to which the bias plate 1 is fixed, a set of balls 63 being disposed between the two cages 61 and 62.
• the bias plate 1 comprises a housing 64 into which the end of a motor shaft, not shown, can fit.
• the pump II is identical to that described in relation to FIG. 6, the same elements bearing the same references.
• suction check valves 16 are omitted and that it is the diaphragm 44 itself which is used to fulfill the role of the check valves.
• each chamber 13 is associated with a conduit 50 connected to a chamber 51 where the liquid to be pumped arrives via a conduit 52
• the duct 50 is pierced through the mass of the part 45 and opens, at its end opposite the chamber 51 against the membrane 44.
• the plate 42 which is interposed between the part 41, in which the bores 12 of the pistons are formed 4 and the part 45, in which the chambers 13 are formed, comprises two housings 53 and 54 connected by a pipe 55.
• the housing 53 is hollowed out in the face of the part 42 which is in contact with the membrane 44; while the housing 54 is hollowed out in the face which is in contact with the part 41.
• the housing 54 has a configuration such that it communicates with the bore 12; and the housing 53 reaches up to the level of the chamber 13.
• the liquid to be pumped (which is for example petrol) arrives via the pipe 52 at a low pressure, of the order of 1 to 2 bars, given by an electric pump of known type, so that , as soon as the hydraulic pressure disappears in the housing 53, the membrane 44 is pushed back to clear the passage 56.
• each pipe orifice 50 the membrane 44 be provided with a reinforcement cup 57, of a diameter greater than that of the orifice, the object of which is to prevent the membrane is pushed by the pressure in the orifice of the pipe 50 and thus deteriorated. It is also advantageous to shape the membrane by molding so that at rest, in the absence of any pressure, it fills the housing 53 and clears the passage 56.
• the membrane 44 is deformed between a position where it is at the bottom of the housing 53 and a position where it closes the suction duct 50 acts as a non-return suction valve.
• conduits 50, housing 53, conduit 55, housing 54 as there are bore 12 and chamber 13.
• FIGS. 9 and 9a The arrangement thus described in relation to FIGS. 9 and 9a is independent of the configuration of the hydraulic pump I and can be transposed in the pump of FIGS. 6 to 7 as shown in FIG. 9.
• the hydraulic pump I is a swash plate or bias plate pump and the pistons are axial pistons.
• FIG. 11 Such a radial piston pump is shown in FIG. 11.
• This pump comprises a cam 101, which is an eccentric carried by a motor shaft 102, carried by bearings 103.
• Each piston is a hollow piston 104 counterbalanced by a spring 107, so that its head 104a is in abutment against the cam 101 by means of a sliding stud 105 crossed by an orifice 106.
• the cam 101 struggles in a chamber 109 communicating with a reservoir of hydraulic liquid (not shown). The communication between the chamber 109 and the interior of each hollow piston 104 is established when the stud 105 overlaps the groove 108 dug in the cam 101.
• the pump II is identical to that of FIG. 1, the same elements bearing the same references.
• the cam 101 corresponds to the bias plate 1; pistons 104 to pistons 4; the pads 105 to the pads 5; the groove 108 at the lunula 8 and the chamber 109 at the chamber 9.

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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)

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Applications Claiming Priority (5)

Related Child Applications (3)

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ID=26232746

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• 1997
  • 1997-05-30 DE DE69732802T patent/DE69732802T2/de not_active Expired - Lifetime
  • 1997-05-30 US US09/194,437 patent/US6264437B1/en not_active Expired - Lifetime
  • 1997-05-30 PT PT00202790T patent/PT1048849E/pt unknown
  • 1997-05-30 EP EP97926060A patent/EP0901575B1/de not_active Expired - Lifetime
  • 1997-05-30 WO PCT/FR1997/000943 patent/WO1997047883A1/fr active Application Filing
  • 1997-05-30 EP EP00202790A patent/EP1048849B1/de not_active Expired - Lifetime
  • 1997-05-30 JP JP50127298A patent/JP3990732B2/ja not_active Expired - Lifetime
  • 1997-05-30 ES ES00202790T patent/ES2238968T3/es not_active Expired - Lifetime

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