Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/18—Combined units comprising both motor and pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/08—Characterised by the construction of the motor unit
  • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
  • F15B15/1423—Component parts; Constructional details
  • F15B15/1447—Pistons; Piston to piston rod assemblies
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
  • F15B15/08—Characterised by the construction of the motor unit
  • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
  • F15B15/1423—Component parts; Constructional details
  • F15B15/1466—Hollow piston sliding over a stationary rod inside the cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/205—Systems with pumps
  • F15B2211/20507—Type of prime mover
  • F15B2211/20515—Electric motor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/205—Systems with pumps
  • F15B2211/2053—Type of pump
  • F15B2211/20538—Type of pump constant capacity
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
  • F15B2211/205—Systems with pumps
  • F15B2211/2053—Type of pump
  • F15B2211/20561—Type of pump reversible
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
  • F15B2211/00—Circuits for servomotor systems
  • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
  • F15B2211/785—Compensation of the difference in flow rate in closed fluid circuits using differential actuators

Definitions

• the invention relates to an electrohydraulic actuator with pump integrated in the piston.
• Electrohydraulic actuators having a body defining a cylindrical cavity in which a piston slides sealingly and divides the interior of the cavity into two chambers.
• the piston is associated with at least one rod that passes through one of the fundus of the body.
• the actuator also includes a bidirectional pump that is powered by an electric motor and has two ports each connected to one of the chambers of the cylinder. The pump makes it possible to transfer fluid from one chamber to another to move the piston and therefore the rod, the quantity of fluid corresponding to the volume differential between the chambers being supplied or absorbed by a compensating member, for example a accumulator.
• These electrohydraulic actuators are generally relatively bulky since the electric motor and the pump are placed on the side of the cylinder.
• Document FR 2 831 226 discloses elongated electrohydraulic actuators in which the motor, the pump and the accumulator are placed in the extension of the cylinder. Pipes pierced in the walls of the cylinder allow the ports of the pump to be connected to the two chambers.
• This arrangement is very compact, but the engine is completely flooded, and a motor failure makes its replacement complex, because it is necessary to disassemble the actuator entirely.
• the invention relates to a compact electrohydraulic actuator, while still being easy to maintain.
• an electrohydraulic actuator comprising a body which defines a cylindrical cavity in which a piston slides sealingly and divides an internal volume of the chamber into two chambers of variable volume, the piston being associated at least one rod which passes through a bottom of the cavity, the actuator comprising a bidirectional pump having two ports each connected to one of the chambers, an electric motor for selectively driving the pump in one direction or in the the other, the pump being placed in the piston of the actuator to be movable with it, each of the ports opening directly into one of the chambers.
• the electric motor is placed at the end of the actuator and drives in rotation a shaft of non-circular section which extends in the cylinder through the piston, the pump comprising a homologous drive member freely sliding on the along the shaft during movements of the rod but driven in rotation when the shaft rotates under the action of the electric motor.
• the pump remains integrated inside the cylinder between the chambers, the engine remains at its end and can be easily dismantled in case of failure which, statistically, is more likely than a failure of the pump.
• FIG. 1 is a sectional view of an actuator according to a particular embodiment of the invention
• Figure 2 is a sectional view along the line II-II of Figure 1 of the piston of the actuator integrating the pump
• Figure 3 is a sectional view similar to that of Figure 2 of an alternative embodiment of the invention.
• the actuator comprises a body 1 which delimits a cylindrical cavity 2 extending along a longitudinal axis X.
• a piston 3 is mounted with a leaktight sliding in the cylindrical cavity and defines therein two hydraulic chambers A, B.
• the piston 3 is associated with a rod 4 which passes through a bottom of the body sealing 1. The various joints making the sealing mentioned are not shown here.
• a bidirectional pump 5 is disposed directly in the piston 3.
• the bidirectional pump 5 comprises carries two ports Pl, P2 which open respectively into one of the chambers A, B.
• the bidirectional pump 5 comprises a rotary member (for example a barrel, a gear, a hub, etc.) that can be rotated to cause fluid transfer from a chamber to the chamber. other, and hence a displacement of the piston 3 in the cylindrical cavity 2.
• a rotary member for example a barrel, a gear, a hub, etc.
• the actuator comprises a splined shaft 6 which extends in the cylindrical cavity 2 parallel to the axis X is rotated by means of an electric motor 8 disposed here at the outside of the cavity 2.
• the splined shaft 6 passes through the piston 3 which can slide freely along the splined shaft 6.
• a rotation of the splined shaft 6 under the effect of a rotation of the electric motor 8 causes rotation of the rotary member of the bidirectional pump 5, which causes a transfer of fluid from one chamber to another, and hence the displacement of the piston 3 in the cylindrical cavity 2.
• the actuator comprises compensating means for compensating a flow difference between the two chambers during a displacement of the piston 3 in the cavity
• these compensating means comprise an accumulator 9 connected hydraulically connected to the chamber B.
• the excess fluid which passes from the chamber A to the chamber B during a depression of the rod 4 is recovered in the 9.
• the deficit of fluid passing from the chamber B to the chamber A during an output of the rod 4 is provided by the accumulator 9.
• the bidirectional pump 5 is, in the example shown, the vane type.
• the bidirectional pump 5 comprises a central hub 11 internally splined which is driven in rotation by the splined shaft 6 and which carries pallets 12 (only one of the pallets is referenced) which cooperate with an inner side wall 13 of the piston 3 and internal flanks thereof to define volumes for fluid transfer from one to the other of the ports.
• the bidirectional pump 5 is of the gear type. It comprises an internally splined pinion gear 21 which is rotated by the splined shaft 6, which co-operates with a driven pinion 22.
• the two pinions 21, 22 cooperate in sealing with an internal lateral wall 23 to define volumes allowing fluid transfer from one to the other of the ports.
• any type of hydraulic pump can be used as long as it is integrated in the piston of the rod.
• the shaft 6 is here fluted, it may more generally have a non-circular section adapted to cause a rotational drive of a homologous drive member of the pump with which it cooperates.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Actuator (AREA)
• Reciprocating Pumps (AREA)
• Lubrication Of Internal Combustion Engines (AREA)
• Valve Device For Special Equipments (AREA)
• Hydraulic Clutches, Magnetic Clutches, Fluid Clutches, And Fluid Joints (AREA)
• Hydraulic Motors (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40225294

Family Applications (1)

Country Status (12)

Families Citing this family (9)

Family Cites Families (9)

• 2008
  • 2008-06-17 FR FR0803370A patent/FR2932539B1/fr not_active Expired - Fee Related
• 2009
  • 2009-06-12 WO PCT/FR2009/000701 patent/WO2009153444A1/fr active Application Filing
  • 2009-06-12 CA CA2728152A patent/CA2728152C/fr active Active
  • 2009-06-12 ES ES09766006T patent/ES2382269T3/es active Active
  • 2009-06-12 CN CN2009801228332A patent/CN102066773B/zh not_active Expired - Fee Related
  • 2009-06-12 BR BRPI0914832A patent/BRPI0914832A2/pt not_active IP Right Cessation
  • 2009-06-12 AT AT09766006T patent/ATE545786T1/de active
  • 2009-06-12 US US12/999,577 patent/US8863510B2/en not_active Expired - Fee Related
  • 2009-06-12 RU RU2011101465/06A patent/RU2457369C1/ru not_active IP Right Cessation
  • 2009-06-12 EP EP09766006A patent/EP2288814B1/de active Active
  • 2009-06-12 JP JP2011514082A patent/JP5421363B2/ja not_active Expired - Fee Related
• 2010
  • 2010-12-15 IL IL210008A patent/IL210008A0/en unknown

Non-Patent Citations (1)

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