EP4269790A1 - Dispositif hydraulique - Google Patents

Dispositif hydraulique Download PDF

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Publication number
EP4269790A1
EP4269790A1 EP22170932.2A EP22170932A EP4269790A1 EP 4269790 A1 EP4269790 A1 EP 4269790A1 EP 22170932 A EP22170932 A EP 22170932A EP 4269790 A1 EP4269790 A1 EP 4269790A1
Authority
EP
European Patent Office
Prior art keywords
cylinders
opening
cylinder
pressure port
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22170932.2A
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German (de)
English (en)
Inventor
Peter Augustinus Johannes Achten
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Innas BV
Original Assignee
Innas BV
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Filing date
Publication date
Application filed by Innas BV filed Critical Innas BV
Priority to EP22170932.2A priority Critical patent/EP4269790A1/fr
Publication of EP4269790A1 publication Critical patent/EP4269790A1/fr
Pending legal-status Critical Current

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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
    • F04B1/12—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
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0035—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
    • F01B3/0038—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons inclined to main shaft axis
    • 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
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • 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
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0636—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • 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
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0636—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F03C1/0639—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
    • F03C1/0642—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons inclined on main shaft axis
    • 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
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0636—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F03C1/0644—Component parts
    • F03C1/0652—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
    • F04B1/12—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
    • F04B1/2014—Details or component parts
    • F04B1/2035—Cylinder barrels
    • 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
    • F04B1/22—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 having two or more sets of cylinders or pistons
    • F04B1/24—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 having two or more sets of cylinders or pistons inclined to the main shaft axis
    • 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
    • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
    • F04B11/0091—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using a special shape of fluid pass, e.g. throttles, ducts
    • 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
    • F04B53/16—Casings; Cylinders; Cylinder liners or heads; Fluid connections
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0044—Component parts, details, e.g. valves, sealings, lubrication
    • F01B3/0052—Cylinder barrel

Definitions

  • the present invention relates to a hydraulic device comprising a rotor and a port member including a high-pressure port and a low-pressure port, wherein an outer surface of the rotor faces an outer surface of the port member and is rotatable with respect to the port member in a rotational direction about an axis of rotation, wherein the rotor is provided with a plurality of cylinders located at angular distance from each other about the axis of rotation and cooperating pistons which are movable within the respective cylinders, wherein the cylinders communicate with respective open ends at the outer surface of the rotor wherein each of the open ends alternatingly communicates with the high-pressure port and the low-pressure port under operating conditions, wherein the plurality of cylinders is subdivided in pairs of cylinders, wherein the cylinders of each pair are interconnected via a fluid displacement member having a first opening that communicates with one of the pair of cylinders, a second opening that communicates with the other one of the pair of cylinders
  • Such a hydraulic device is known from NL 1016738 .
  • the known hydraulic device has a rotor which is linked to a swashplate to move each of the pistons within the respective cylinders between bottom dead centre and top dead centre during rotation of the rotor. Under operating conditions a part of the cylinders communicate with the high-pressure port and another part of the cylinders communicate with the low-pressure port.
  • the plurality of cylinders is subdivided in pairs of cylinders.
  • the cylinders of each pair are interconnected via a fluid displacement member.
  • the fluid displacement member is provided with a closure element that is freely movable between a first opening and a second opening thereof.
  • the closure element can move to the first opening and substantially obstruct the first opening and if the pressure in the cylinder that communicates with the first opening is higher than the pressure in the cylinder that communicates with the second opening the closure element can move to the second opening and substantially obstruct the second opening.
  • a limited volume of hydraulic fluid flows between the pair of cylinders.
  • the pressure in the cylinder that communicates with the open end under consideration increases during travelling.
  • the successive cylinder of the pair of cylinders under consideration that still communicates with the low-pressure port will remain at a lower pressure such that the closure element of the fluid displacement member that interconnects this pair of cylinders will substantially obstruct one of the first and second openings thereof such that no or a limited amount of hydraulic fluid can flow to the successive cylinder.
  • the other successive cylinder that already communicates with the high-pressure port will initially have a higher pressure than the cylinder which communicates with the open end under consideration when that open end travels along the seal land such that the closure element of the fluid displacement member that interconnects these cylinders will also substantially obstruct the one of the first and second openings thereof.
  • the pressure in the corresponding cylinder exceeds the pressure at the high-pressure port, which equals the pressure in the successive cylinder which already communicates with the high-pressure port, the closure element of the fluid displacement member that interconnects this pair of cylinders will move from the one of the first and second openings to the other one of the first and second openings.
  • hydraulic fluid will flow from the cylinder which communicates with the open end under consideration to the fluid displacement member and displace its closure element, hence avoiding further pressure increase.
  • the open end under consideration starts communicating with the high-pressure port before the closure element of the fluid displacement member that interconnects the pair of cylinders, which pair of cylinders in that condition both communicate with the high-pressure port, has substantially obstructed the other one of the first and second openings, the pressure in the cylinder that communicates with the open end under consideration is balanced with the pressure at the high-pressure port and a severe pressure difference is avoided. If the closure element substantially obstructs the other one of the first and second openings already before the open end under consideration starts communicating with the high-pressure port, the pressure in the cylinder that communicates with the open end under consideration will further rise above the pressure at the high-pressure port.
  • the distance between the first opening and the second opening should be such that the travelling distance of the closure element is sufficient to avoid an undesired pressure difference at relatively low pressure at the high-pressure port.
  • a hydraulic device including shuttles is also known from European patent application 21171132.0 .
  • An object of the invention is to provide an improved hydraulic device.
  • An advantage of the invention is that the closure elements of the fluid displacement members are forced to predetermined positions before the open ends of the rotor reach a seal land between the low-pressure port and the high-pressure port.
  • each pair of cylinders which communicate with the low-pressure port create a flow of hydraulic fluid causing a pressure drop across the respective flow resistances in a direction from the corresponding open ends to the cylinders
  • each pair of cylinders which communicate with the high-pressure port create a flow of hydraulic fluid causing a pressure drop across the respective flow resistances in a direction from the corresponding cylinders to the open ends.
  • each fluid displacement member Since the first opening and the second opening of each fluid displacement member communicate with the cylinders of one pair of cylinders at opposite sides of the corresponding flow resistances, the closure element of each fluid displacement member interconnecting the pair of cylinders which communicate with either the low-pressure port or the high-pressure will be forced in the same direction. Consequently, when an open end which communicates with one of the pair of cylinders arrives at a seal land the closure element of the fluid displacement member which interconnects that cylinder with the other cylinder of the pair of cylinders that arrives later at the seal land will always substantially obstruct either the first opening or the second opening thereof. This provides the opportunity to start compression or expansion at the seal land at fixed reference conditions of the fluid displacement members. This prevents the closure elements from being positioned in dependency of centrifugal forces, for example.
  • each displacement member Since between each pair of cylinders a cylinder of another pair of cylinders is located, the fluid displacement members do not interconnect two neighbouring cylinders. In other words, each displacement member communicates between a pair of cylinders and passes over an intermediate cylinder that is located between the pair of cylinders. This allows the application of relatively long fluid displacement members.
  • the closure element of the fluid displacement member substantially obstructs the first opening or the second opening, it minimizes fluid flow through the first opening or the second opening, respectively.
  • the first opening or the second opening are fully closed or that a very small amount of fluid still flows through the first or second opening.
  • the fluid flow will usually be much smaller than the fluid flow through the first opening and the second opening when the closure element moves between the first opening and the second opening.
  • each of the cylinders communicates with the corresponding open end through a passage in which the flow resistance is provided.
  • the cross-sectional areas of the passages may be smaller than the cross-sectional areas of the respective cylinders.
  • the passages as well as the fluid displacement members may be formed in a rigid unit, for example a piston barrel of a slipper type axial piston pump.
  • the flow resistance may be formed by a local narrowing of the passage.
  • each fluid displacement member communicates with the corresponding cylinder via a first aperture in the passage and the second opening of each fluid displacement member communicates with the corresponding cylinder via a second aperture in the passage.
  • its first opening is fluidly connected with the first aperture of the passage corresponding to a first one of the pair of cylinders and its second opening is fluidly connected with the second aperture of the passage corresponding to a second one of the pair of cylinders which follows the first one under operating conditions.
  • the first aperture lies at a different distance from the open end than the second aperture, since in this embodiment the flow resistance may be formed by the length of the passage between the first and second apertures. This provides a simple flow resistance such that a local narrowing of the passage may be omitted.
  • Each of the fluid displacement members may comprise a straight channel between the first aperture of the passage corresponding to one of the pair of cylinders and the second aperture of the passage corresponding to the other one of the pair of cylinders, wherein the channel has a cylindrical portion between the first and second openings. Hence, the closure element travels within the cylindrical portion.
  • the closure element is a ball and the first and second openings are surrounded by respective seats which cooperate with the ball such that a fluid flow through the first opening is substantially obstructed when the ball is pressed against the seat at the first opening and a fluid flow through the second opening is substantially obstructed when the ball is pressed against the seat at the second opening.
  • the balls may be made of ceramic.
  • the ball of the fluid displacement member may be smaller than the diameter of the cylindrical portion between the first and second openings as long as the ball substantially obstructs the first or second opening when it is pressed against the corresponding seats.
  • alternative shapes of the closure elements and/or the seats are conceivable, for example small pistons or the like.
  • the closure element tightly fits within the cylindrical portion between the first and second openings.
  • corresponding seats at the first and second openings as described hereinbefore may be omitted, since the tightly fitting closure element automatically substantially obstructs the first and second openings when it is at respective opposite end positions within the cylindrical portion.
  • the closure element may allow a minimal leakage through the first opening or the second opening when it substantially obstructs the first opening or the second opening, respectively.
  • the cylindrical portion has a centreline which may lie in a plane that extends tangentially with respect to the axis of rotation at a rotational position where the cylindrical portion is located or which may be inclined with respect to that plane by an angle which is smaller than 45°, preferably smaller than 25°. This minimizes the influence of centrifugal forces on the closure elements, which might work against displacement of the closure elements by the pressure differences across the flow resistances.
  • an imaginary extension of the channel in a direction from the rotor to the port member passes through the open end of the passage where its second aperture is located, since this provides the opportunity to drill the channel through the open end. Hence, drilling a separate hole which needs to be partly closed and sealed afterwards can be omitted.
  • the outer surfaces lie in a common plane
  • the axis of rotation extends perpendicularly to the outer surfaces
  • centrelines of the cylinders extend parallel to the axis of rotation and the high-pressure port and the low-pressure port are arc-shaped about the axis of rotation.
  • the axis of rotation is a first axis of rotation and the rotor also comprises a shaft which is rotatable about a second axis of rotation and has a flange extending perpendicularly to the second axis of rotation, wherein the plurality of pistons are fixed to the flange at equiangular distance about the second axis of rotation, wherein the cylinders are separate sleeves which rest on a barrel plate in which the passages are provided, wherein the second axis of rotation intersects the first axis of rotation by an acute angle such that upon rotating the shaft each of the pistons moves reciprocatingly within the cooperating cylinder.
  • Such a configuration may be called a floating cup hydraulic device, since the positions of the cylinders on the barrel plate are dictated by the actual positions of the cooperating pistons.
  • the channel may have an imaginary extension in a direction from the port member to the cylinders which extension passes through an entrance of the passage opposite to the open end thereof, since this provides the opportunity to drill the channel through the entrance.
  • the outer surface of the port member has a first seal land between the low-pressure port and the high-pressure port where the cooperating piston of a passing open end reaches bottom dead centre and a second seal land between the low-pressure port and the high-pressure port where the cooperating piston of a passing open end reaches top dead centre, wherein the length of each of the first and second seal lands is larger than the length of each of the open ends, as measured in the rotational direction.
  • the distance between an edge of the first seal land adjacent to the low-pressure port and the location at the first seal land where the pistons reach bottom dead centre may be half of the length of each open end, as measured in the rotational direction, and/or the distance between an edge of the second seal land adjacent to the high-pressure port and the location at the second seal land where the pistons reach top dead centre may be half of the length of each open end, as measured in the rotational direction. This means that bottom dead centre and top dead centre are reached when the first and second seal lands start to close the corresponding passing open ends.
  • the length of the first seal land may be larger than the length of the second seal land, as measured in the rotational direction, since after leaving top dead centre only a dead volume in the cylinder must be expanded by the corresponding piston whereas after leaving bottom dead centre both the dead volume and a volume to be displaced by the piston must be compressed by the corresponding piston.
  • the hydraulic device may be a pump, motor or transformer.
  • Figs. 1-8 are the same as in European patent application 21171132.0 and incorporated herein in order to explain the functioning of the present invention.
  • Fig. 1 shows internal parts of a hydraulic device 1, such as a pump or hydromotor, which are fitted in a housing 2 in a known manner.
  • the hydraulic device 1 is provided with a shaft 3 which is rotatably supported by the housing 2.
  • One side of the housing 2 is provided with an opening through which a toothed shaft end 4 of the shaft 3 protrudes from the housing 2.
  • a motor can be coupled to the toothed shaft end 4 if the hydraulic device 1 is a pump, and a driven tool can be coupled thereto if the hydraulic device 1 is a motor.
  • the hydraulic device 1 comprises port members in the form of port plates 5 which are mounted inside the housing 2 at a distance from each other.
  • Fig. 2 shows one of the port plates 5 in more detail.
  • Each port plate 5 includes an arc-shaped high-pressure port 6 and an arc-shaped low-pressure port 7. Between the high-pressure port 6 and the low-pressure port 7 are a first seal land 8a and a second seal land 8b.
  • the port plates 5 have fixed positions with respect to the housing 2 in rotational direction thereof, but they may be rotatable with respect to the housing 2 in an alternative variant (not shown).
  • the shaft 3 extends through respective central through-holes in the port plates 5.
  • the shaft 3 is provided with a flange 9. At both sides of the flange 9 a plurality of pistons 10 are fixed through respective press fittings, in this case fourteen pistons 10 on either side.
  • the pistons 10 shown in Fig. 1 are made of separate parts, but they may also be single units. Each of the pistons 10 cooperates with a separate cylinder 11 to form a compression chamber 12 of variable volume.
  • the hydraulic device 1 as shown in Fig. 1 has 28 compression chambers 12.
  • Each of the cylinders 11 comprises a cylinder bottom 13 and a cylinder jacket 14 which extends from the cylinder bottom 13.
  • cylinder bottoms 13 of the respective cylinders 11 are supported by two barrel plates 16 which are fitted around the shaft 3 by means of respective ball hinges 17 and are coupled to the shaft 3 by means of keys 18. Consequently, the barrel plates 16 rotate together with the shaft 3 under operating conditions.
  • Fig. 3 shows one of the barrel plates 16 in more detail. It is noted that the cylinder bottoms 13 rest on the respective barrel plates 16 but they do not have a fixed position with respect to the respective barrel plates 16.
  • Fig. 1 shows that the barrel plates 16 rotate about respective first axes of rotation 19 which are angled with respect to a second axis of rotation 20.
  • the shaft 3 is rotatable about the second axis of rotation 20 and the flange 9 extends perpendicularly to the second axis of rotation 20.
  • the pistons 10 are located at equiangular distance about the second axis of rotation 20.
  • the pistons 10 have centrelines which extend parallel to the second axis of rotation 20.
  • the arc-shaped low-pressure port 7 and the arc-shaped high-pressure ports 6 of each port plate 5 extend about the corresponding first axis of rotation 19.
  • the angles between the second axis of rotation 20 and the respective first axes of rotation 19 are approximately nine degrees in practice, but may be smaller or larger.
  • each cylinder 11 makes a combined translating and swivelling motion around the cooperating piston 10.
  • Each piston 10 moves with respect to its cooperating cylinder 11 between bottom dead centre BDC and top dead centre TDC. As a consequence, the volume of the corresponding compression chamber 12 changes.
  • Each of the barrel plates 16 has an outer surface 21 which is directed away from the flange 9 and faces an outer surface 22 of the cooperating port plate 5, see Figs. 1-3 .
  • the barrel plates 16 are pressed against the respective port plates 5 by means of springs 23 which are mounted in holes in the shaft 3.
  • the outer surfaces 21, 22 extend perpendicularly to the respective first axes of rotation 19. Due to the inclined orientations of the outer surfaces 22 of the port plates 5 with respect to the flange 9 the barrel plates 16 pivot about the ball hinges 17 during rotation with the shaft 3.
  • each barrel plate 16 has fourteen successive open ends 25, which communicate with fourteen successive cylinders 11. Under operating conditions the open ends 25 alternatingly communicate via the high-pressure port 6 and the low-pressure port 7 with a high-pressure line and a low-pressure line (not shown), respectively, which are provided in the housing 2.
  • the shaft 3 the barrel plates 16, the pistons 10, the cylinders 11, the ball hinges 17, the keys 18 and the springs 23 may be considered as parts of a rotor which has opposite outer surfaces 21 which face the outer surfaces 22 of the respective port plates 5.
  • Figs. 3-5 show that each pair of successive passages 24 are interconnected via a fluid displacement member 26, which means that also each pair of successive cylinders 11 are interconnected via a fluid displacement member 26.
  • each barrel plate 16 is also provided with fourteen successive fluid displacement members 26.
  • Each of the fluid displacement members 26 comprises a channel between each pair of successive passages 24 and has a first opening 27 and a second opening 28 which are located at a distance from each other.
  • the channel has a cylindrical portion between the first and second openings 27, 28.
  • a closure element in the form of a ball 29 is freely movable between the first and second openings 27, 28.
  • Figs. 3-5 show two balls at one fluid displacement member 26 for explanatory reasons, but in reality each fluid displacement member 26 will have a single ball 29.
  • the first opening 27 communicates with the right one of the pair of successive passages 24 and the second opening 28 communicates with the left one of the pair of successive passages 24.
  • the first and second openings 27, 28 and the ball 29 are configured such that the ball 29 substantially obstructs the first opening 27 if under operating conditions the pressure in the passage 24 that communicates with the second opening 28, i.e. the left one in Fig. 4 , is higher than the pressure in the passage 24 that communicates with the first opening 27, i.e. the right one in Fig. 4 , whereas the ball 29 substantially obstructs the second opening 28 if under operating conditions the pressure in the passage 24 that communicates with the first opening 27, i.e. the right one in Fig. 4 , is higher than the pressure in the passage 24 that communicates with the second opening 28, i.e. the left one in Fig. 4 .
  • each of the passages 24 is provided with a flow resistance in the form of a restriction where the cross-sectional area of the passage 24 is locally narrowed.
  • Fig. 4 illustrates by arrows how the fluid displacement members 26 can be manufactured by drilling the channels in the form of elongate stepped holes between each two successive passages 24 by inserting a drill through the open end 25 and drilling in the direction of the arrows.
  • An advantage of this way of manufacturing is that the fluid displacement member 26 is entirely located within the barrel plate 26 which means that no sealings between different parts have to be applied.
  • Fig. 5 shows that the first opening 27 is close to the first aperture 31.
  • the first opening 27 is surrounded by a seat which cooperates with the ball 29 such that a fluid flow through the first opening 27 is obstructed when the ball 29 is pressed against the seat at the first opening 27.
  • the second opening 28 is surrounded by a seat which cooperates with the ball 29 such that a fluid flow through the second opening 28 is obstructed when the ball 29 is pressed against the seat at the second opening 28.
  • the seat at the second opening 28 is created by a tapered end of a socket screw 32 including a through-hole which is screwed into the drilled hole after introducing the ball 29 into the cylindrical portion of the stepped hole.
  • Alternative structural designs are conceivable, for example a seat which is pressed, clamped or glued in the drilled hole.
  • Each of the elongate stepped holes has a centreline which is slightly inclined with respect to a plane that extends tangentially with respect to the first axis of rotation 19 at a rotational position where the cylindrical portion of the fluid displacement member 26 is located.
  • the elongate stepped holes can also be drilled from the opposite side of the barrel plate 16 than illustrated by the arrows in Fig. 4 , preferably via entrances of the respective passages 24 which are located remote from the open ends 25, i.e. at the side of the barrel plate 16 on which the cylinder bottoms 13 rest.
  • the ball 29 tightly fits within the cylindrical portion of the fluid displacement member 26 as long as it substantially obstructs fluid flow when the ball 29 abuts the seat of the first opening 27 or the second opening 28 to minimize leakage.
  • Fig. 6 shows the port plate 5 including the high-pressure port 6 and the low-pressure port 7 linearly for explanatory reasons. Furthermore, only eleven pistons 10, cylinders 11, passages 24, flow resistances 30, open ends 25 and fluid displacement members 26 are shown. The passages 24 including the flow resistances 30 and the open ends 25, the cylinders 11 and the fluid displacement members 26 are represented as parts of a unit which moves along the linear port plate 5. The direction of movement of this unit with respect to the port plate 5 is indicated by an arrow X in Fig. 6 .
  • Each of the pistons 10 passes bottom dead centre BDC and top dead centre TDC during movement of the corresponding open end 25 along the first seal land 8a between the low-pressure port 7 and the high-pressure port 6 and the second seal land 8b between the high-pressure port 6 and the low-pressure port 7.
  • the length of each open end 25 in the direction of movement X is smaller than the length of each of the first and second seal lands 8a, 8b in that direction, which means that during passing each of the first and second seal lands 8a, 8b the open end 25 is closed by one of the first and second seal lands 8a, 8b within certain periods.
  • the distance between an edge of the first seal land 8a adjacent to the low-pressure port 7 and the location at the first seal land 8a where the pistons 10 reach bottom dead centre BDC is approximately half of the length of the open ends 25 in the direction of movement X, since compression in each of the passing cylinders 11 starts substantially in bottom dead centre BDC of the corresponding piston 10.
  • the distance between an edge of the second seal land 8b adjacent to the high-pressure port 6 and the location at the second seal land 8b where the pistons 10 reach top dead centre TDC is preferably approximately half of the length of the open ends 25 in the direction of movement X, since expansion in each of the passing cylinders 11 starts substantially in top dead centre TDC of the corresponding piston 10.
  • Fig. 2 indicates the half lengths by angles ⁇ . The half lengths are measured in rotational direction about the first axis of rotation 19.
  • the distance between the location at the first seal land 8a where the pistons 10 reach bottom dead centre BDC and an edge of the first seal land 8a adjacent to the high-pressure port 6 is larger than the distance between the location at the second seal land 8b where the pistons 10 reach top dead centre TDC and an edge of the second seal land 8b adjacent to the low-pressure port 7.
  • the distances are indicated by angles ⁇ 1 and ⁇ 2 in Fig. 2 , respectively, as measured in rotational direction.
  • ⁇ 1 is larger than ⁇ 2 is that after leaving top dead centre TDC only a dead volume in the cylinder 11 must be expanded whereas after leaving bottom dead centre BDC both the dead volume and a stroke volume to be displaced by the piston 10 must be compressed.
  • FIG. 6 one of the pistons 10, its cooperating cylinder 11, passage 24 and open end 25 are indicated by reference numbers 10', 11', 24' and 25', respectively.
  • the piston 10' approaches bottom dead centre BDC and the cylinder 11' still communicates with the low-pressure port 7 via the passage 24' and the open end 25'.
  • the fluid displacement member 26 at the left side of the passage 24' and the ball 29 thereof are indicated by reference numbers 26' and 29', respectively, whereas the successive fluid displacement member 26 at the right side and its ball 29 are indicated by reference numbers 26" and 29", respectively.
  • the successive passage 24 of passage 24' which cooperates with the fluid displacement member 26' is indicated by reference number 24'' and the successive passage 24 of passage 24' which cooperates with the fluid displacement member 26" is indicated by reference number 24′′′.
  • a further successive passage 24 of passage 24′′′ is indicated by 24 ⁇ .
  • the fluid displacement member 26' obstructs a flow from the passage 24' to the passage 24'' by closing the first opening 27 thereof, whereas the fluid displacement member 26" obstructs a flow from the passage 24′′′ to the passage 24' by closing the first opening 27 thereof.
  • the ball 29" of the fluid displacement member 26" is kept in that position due to the elevated pressure at the high-pressure port 6 which communicates with the passage 24′′′.
  • the ball 29' of the fluid displacement member 26' is kept in its position due to the presence of the flow resistance 30; the flow resistance 30 in the passage 24' is indicated by 30' and the flow resistance 30 in the passage 24'' is indicated by 30".
  • each of the balls 29 of the respective fluid displacement members 26 has a predefined position before the open ends 25 arrive at the respective first and second seal lands 8a, 8b. If, for example, the ball 29' in Fig. 6 would have an intermediate position anywhere between the first and second openings 27, 28 before arriving at the first seal land 8a the ball 29' would be moved first to its correct upper position upon closing the open end 25', which leads to a later start of compression in the cylinder 11', hence creating an undefined starting condition of compression in the cylinder 11' after the corresponding piston 10' passes bottom dead centre BDC.
  • Fig. 7 shows an alternative variant in which the arrangement of the fluid displacement members 26 is different, but functions in a similar way as the variant which is shown in Fig. 6 .
  • the open ends 25 which communicate with the low-pressure chamber 7 force the balls 29 of the corresponding fluid displacement members 26 upwardly.
  • Fig. 7 illustrates that the ball 29' of the fluid displacement member 26' obstructs the first opening 27 when the open end 25' arrives at the first seal land 8a. Since the open end 25" already communicates with the high-pressure port 6 the ball 29" of the fluid displacement member 29" is forced to a lower position and obstructs the second opening 28 thereof.
  • the first and second seal lands 8a, 8b of the arrangement of the fluid displacement members 26 as illustrated in Fig. 7 will be larger than of the arrangement of the fluid displacement members 26 as illustrated in Fig. 6 , as measured in the direction of movement X.
  • Fig. 8 shows another alternative variant in which the hydraulic device 1 is applied as a motor.
  • the passages 24 including the flow resistances 30 and the open ends 25, the cylinders 11 and the fluid displacement members 26 are represented as parts of a unit which moves along the linear port plate 5 in a direction of movement Y which is opposite to the direction of movement X in the variants as shown in Figs. 7 and 8 .
  • the functioning of the fluid displacement members 26 is comparable to the variants as illustrated in Figs. 6 and 7 .
  • Fig. 9 shows a part of an embodiment of a hydraulic device according to the invention.
  • the hydraulic device is a slipper type axial piston pump, but alternative hydraulic devices are conceivable. Parts which correspond to the variants as shown in Figs. 1-8 have the same reference numbers.
  • Fig. 9 shows a rotor in the form of a piston barrel 16 including nine cylinders 11 in which pistons are mounted and movable reciprocatingly through a swash plate (not shown).
  • the pump is also provided with a port member including a high-pressure port, a low-pressure port and seal lands between the high-pressure port and the low-pressure port (not shown).
  • the port member may have a similar shape as the port plate 5, as shown in Fig. 2 .
  • the cylinders 11 communicate via passages 24 with open ends 25 at an outer surface 21 of the piston barrel 16. Under operating conditions the open ends 25 alternatingly communicate via the high-pressure port and the low-pressure port of the port member with a high-pressure line and a low-pressure line in a housing of the pump.
  • each pair of cylinders are successive cylinders in rotational direction of the rotor, i.e. neighbouring cylinders, whereas in the embodiment as shown in Fig. 9 between each pair of cylinders 11 which are interconnected via a fluid displacement member 26 a cylinder 11 of another pair of cylinders 11 is located.
  • each displacement member 26 is fluidly connected to a pair of cylinders 11 and passes over an intermediate cylinder 11 that is located between the pair of cylinders 11. This allows relatively long fluid displacement members 26.
  • Each of the fluid displacement members 26 has also a first opening 27 and a second opening 28 which are located at a distance from each other and between which a channel extends.
  • a closure element in the form of a ball 29 is freely movable between the first and second openings 27, 28.
  • Each of the passages 24 communicates with the first opening 27 and the second opening 28 of two successive fluid displacement members 26, which are located at opposite sides of the passage 24.
  • the first opening 27 of one of the two successive fluid displacement members 26 is fluidly connected with the passage 24 via a first aperture 31 in the passage 24 and the second opening 28 of the other one of the two successive fluid displacement members 26 is fluidly connected with the passage 24 via a second aperture 32 in the passage 24.
  • the first aperture 31 lies at a larger distance from the open end 25 of the passage 24 under consideration than the second aperture 32.
  • a flow resistance 30 is present between the first aperture 31 and the second aperture 32 in the passage 24.
  • Fig. 10 which is comparable to Fig. 6 , illustrates the functioning of the pump.
  • the fluid displacement member 26' obstructs a flow from the passage 24' to the passage 24'' by closing the first opening 27 thereof
  • the fluid displacement member 26" obstructs a flow from the passage 24′′′ to the passage 24' by closing the first opening 27 thereof.
  • the ball 29" of the fluid displacement member 26" is kept in that position due to the elevated pressure at the high-pressure port 6 which communicates with the passage 24′′′.
  • the ball 29' of the fluid displacement member 26' is kept in its position due to the presence of the flow resistances 30' and 30" in the corresponding passages 24' and 24", respectively.
  • each of the balls 29 of each pair of fluid displacement members 26 which communicate with a cylinder 11 has a predefined position before the open end 25 communicating with that cylinder arrives at the respective first and second seal lands 8a, 8b.
  • the balls 29' and 29" have predefined positions when the open end 25' arrives at the first seal land 8a. If, for example, the ball 29' in Fig.
  • the ball 29" of the other fluid displacement member 26" that communicates with the cylinder 11' may be displaced towards the first opening 27 as soon as the pressure in the cylinder 11' becomes lower than the pressure at the low-pressure port 7.
  • the ball 29" will be moved to or remain automatically at the first opening 27, i.e. an upper position in Fig. 10 , before the open end communicating with the second opening 28 of the fluid displacement member 26" arrives at the first seal land 8a.
  • the hydraulic device may be a motor or a transformer.

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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)
EP22170932.2A 2022-04-29 2022-04-29 Dispositif hydraulique Pending EP4269790A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP22170932.2A EP4269790A1 (fr) 2022-04-29 2022-04-29 Dispositif hydraulique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22170932.2A EP4269790A1 (fr) 2022-04-29 2022-04-29 Dispositif hydraulique

Publications (1)

Publication Number Publication Date
EP4269790A1 true EP4269790A1 (fr) 2023-11-01

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ID=81449140

Family Applications (1)

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EP22170932.2A Pending EP4269790A1 (fr) 2022-04-29 2022-04-29 Dispositif hydraulique

Country Status (1)

Country Link
EP (1) EP4269790A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1016738C2 (nl) 2000-11-29 2002-05-31 Innas Free Piston Bv Hydraulische inrichting als een pomp of een motor.
EP3246567A1 (fr) * 2016-05-19 2017-11-22 Innas B.V. Dispositif hydraulique
GB2584202A (en) * 2019-05-21 2020-11-25 Danfoss As Device for supplying ports to a machine section of a hydraulic machine arrangement

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1016738C2 (nl) 2000-11-29 2002-05-31 Innas Free Piston Bv Hydraulische inrichting als een pomp of een motor.
EP3246567A1 (fr) * 2016-05-19 2017-11-22 Innas B.V. Dispositif hydraulique
GB2584202A (en) * 2019-05-21 2020-11-25 Danfoss As Device for supplying ports to a machine section of a hydraulic machine arrangement

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