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
  • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
  • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
  • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
  • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
  • F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
  • F15B13/0438—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being of the nozzle-flapper type
• • 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
  • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
  • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
  • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
  • F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
  • F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
  • F15B13/0436—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being of the steerable jet type

Definitions

• the invention relates to the field of hydraulic servo valves and more particularly to servovalves with a pilot stage comprising a linear actuator.
• a conventional servovalve consists of a control stage controlling a mobile power distribution member of a power stage.
• the function of the power stage is to deliver a pressure or a flow rate proportional to an instruction transmitted to the pilot stage.
• the pilot stage comprises two hydraulic elements, namely a hydraulic emitter (nozzle or ejector) and a hydraulic receiver (pallet, deflector or fixed receiver) whose modification of their relative position generates pressure differentials which are used to finely move a mobile power distribution member from the power stage of the servovalve.
• This mobile power distribution member slides in a cylindrical jacket located in the body of the servovalve.
• the position of the hydraulic transmitter or receiver is controlled by a torque motor which moves one of the hydraulic elements of the control stage opposite the other.
• the movement of the mobile power distribution member in its jacket then puts in communication a set of drilled channels and openings, the arrangement of which makes it possible to deliver a pressure or a flow rate, proportional to the displacement of said mobile distribution member. power.
• a mechanical feedback rod rigidly integral with that of the hydraulic transmitter or receiver which is movable is connected to the mechanical distribution member.
• a position sensor measures the position of the power component and controls the linear actuator via dedicated power electronics to provide electronic feedback similar to that performed mechanically by the feedback rod in the case of 'a servovalve.
• Such electronics are expensive and have an unfavorable impact on the size, weight and reliability of a valve service.
• the invention intended to improve the reliability of a servovalve.
• a servovalve with a piloting stage comprising a hydraulic element for ejecting a jet of fluid and a hydraulic element for receiving the jet of fluid, the hydraulic elements being able to be moved relative to each other. so as to modify their relative position and thus generate a pressure differential which can be used to move a power distribution member of the servovalve, one of the two elements being fixedly mounted on a body of the servovalve and the other of the elements.
• the control stage comprising a linear actuator comprising a main pusher arranged to selectively exert on the support a force tending to modify the relative position of the hydraulic elements , the control stage also comprising a lever provided with a force transfer interface comprising a first point of application of an output force from the main pusher the on the lever and a second point of transmission of the output force from the lever to the support, the lever also being connected at a third point of connection with the power distribution member, the first point of application and the second transmission point being located on either side of a first plane extending parallel to an exit direction of the main pusher and perpendicular to a neutral fiber of the lever.
• a servovalve is then obtained provided with a position feedback device which allows the use of a linear actuator without recourse to a displacement sensor of the power distribution member. The fully mechanical feedback greatly improves the reliability of the servovalve according to the invention.
• connection interface is arranged so that the connection at the first point of application or the second transmission point is a point connection or a ball joint or a linear connection or a pivot connection.
• the vibration behavior of the servovalve is improved when the force transfer interface comprises a cam or even when the cam is arranged to provide a pivot connection at the second transmission point and / or when the support is connected to the body of the valve. the servovalve by a recess.
• the force transfer interface comprises a first portion extending in a first direction secant to the neutral fiber of the lever and a second portion extending in a second direction secant to the first direction. and / or that the force transfer interface also comprises a third portion extending in a third direction secant to the neutral fiber of the lever and a fourth portion extending in a fourth direction secant to the third direction.
• the second transmission point acts on an auxiliary pusher which comes into contact with the rod in order to push the latter.
• the fixed hydraulic element can be a fluid receiver and the hydraulic element carried by the rod is a fluid ejector or the fixed hydraulic element can be a fluid ejector and the movable element a fluid receiver.
• the linear actuator comprises a piezoelectric actuator.
• FIG. 1 is a schematic view of the servovalve according to a first embodiment of the invention
• FIG. 2 is a schematic view of a lever according to a first embodiment of the invention
• FIG. 3 is a schematic view of the servovalve of Figure 1 in a first transient state
• - Figure 4 is a schematic view of the servovalve of Figure 1 in a second transient state
• FIG. 5 is a schematic view of the servovalve of Figure 1 in a third transient state.
• FIG. 6 is a schematic view of the servovalve of Figure 1 in a fourth transient state
• FIG. 7 is a schematic view of the servovalve of Figure 1 in a fifth transient state
• - Figure 8 is a schematic detail view of a sink according to a second embodiment of the invention
• FIG. 9 is a schematic front view of the lever of Figure 8 placed in position
• FIG. 10 is a schematic top view of the sink of Figure 9;
• FIG. 1 it is a schematic detail view of a sink according to a third embodiment of the invention.
• FIG. 12 is a schematic detail view of the sink of Figure 10 in a first state
• - Figure 13 is a schematic detail view of the sink of Figure 10 in a second state
• - Figure 14 is a schematic detail view of a sink according to a fourth embodiment of
• the invention is illustrated here in application to a two-stage barometric flow control servovalve, including a pilot stage.
• the invention is not limited to this application, and could be used for other types of servovalves.
• the servovalve generally designated 100, comprises a body 1 in which a power distribution member 2 is mounted to slide in a sealed manner in a cylindrical housing 3, forming the distribution stage.
• the power distribution member 2 is movable between two extreme positions and is shaped to delimit in the housing 3 sealed chambers C1, C2, C3, C4 to put in communication respectively, according to the extreme position of the power distribution member 2 in relation to a centered position (or neutral position):
• the control of the sliding of the power distribution member 2 in the housing 3 is provided by means of pilot chambers 4, 5 which are supplied with pressurized fluid by a pressure distribution member, in this case a fixed receiver 6.
• the receiver 6 comprises two orifices 7 and 8 and a receptacle 9.
• the orifices 7 and 8 are respectively placed in fluid communication, via conduits 10 and 11, with the pilot chambers 4 and 5.
• the receptacle 9 is for its part connected. the return R via a conduit 12.
• the control stage 20 of the servovalve 100 com takes a rod 21 rotatably mounted at its first end 22 on the body 1.
• the rod 21 comprises a second free end 23 on which is mounted a fluid ejector 30 which comes opposite the receiver 6.
• a pressure spring 24 mounted to bear between the body 1 and a portion 25 of the rod 21 exerts a return force on the rod 21 to cause it to rotate around the first end 22 in a counterclockwise direction according to the representation of FIG. 1.
• the rod 21 comprises an internal duct 31 for supplying fluid to the fluid ejector 30. This internal duct 31 is fluidly connected to the supply port P of the servovalve 100 by a 32 drilled pipe in the body 1.
• the control stage 20 comprises a piezoelectric linear actuator 40 which comprises a main pusher. cipal 41 to selectively exert a force on the rod 21.
• the piloting stage also comprises a lever 50 placed between the main pusher 41 and a first end 61 of an auxiliary pusher 60 slidably mounted on the body 1.
• the second end 62 of the auxiliary push 60 comes into contact with the portion 25 of the rod 21.
• the lever 50 is provided at its first end 51 with a force transfer interface 52.
• the force transfer interface 52 comprises a first ceramic half-sphere 53 with a first center 53.1 and which protrudes from the first face 54 of lever 50.
• a second ceramic hemisphere 55 with a second center 55.1 projects from the second face 56 of lever 50 opposite to the first face 54.
• the first hemisphere 53 and the second hemisphere 55 are located so that the first orthogonal projection 57.1 of the first center 53.1 on a neutral fiber 57 of the lever 50 and the second orthogonal projection 57.2 of the second center on a neutral fiber 57 of the lever 50 are separated by a distance d53-55 no nothing.
• the second end 58 of the lever 50 comprises a tungsten carbide ball 59 which is received in a groove 13 of the power distribution member 2.
• an output force Fs from the main pusher 41 is applied to a first point 70 of the first half-sphere 53.
• the output force Fs is then transmitted through a second point 71 of the second half-sphere 55 to the first end 61 of the auxiliary pusher 60.
• the second end 62 of the auxiliary pusher 60 then acts on the rod 21 against the force of the spring 24 to move the fluid ejector 30 towards the first orifice 7.
• a withdrawal of the main pusher 41 causes, in a homologous manner, it displaces ment of the fluid ejector 30 towards the second orifice 8 under the effect of the spring 24.
• the latter exerts a force on the rod 21 which tends to move the fluid ejector 30 mounted on the end 23 of the rod 21 towards the receiver 6.
• the first point 70 corresponds to a first point
• the ball 59 constitutes a third point of connection 73 with the power distribution member 2.
• the first point 70 of application of the output force Fs of the main pusher 41 on the lever 50 and the second point 71 of transmission of the output force Fs from the lever 50 to the rod 21 are located on either side of a first plane Pi extending parallel to a direction Oy of exit from the main pusher 41 and perpendicular to the neutral fiber 57 of the lever 50.
• the pressure differential thus created between the pilot chambers 4 and 5 causes a displacement of the power distribution member 2 in its housing 3 to the right according to the representation of FIGS. 1 and 3 (increase in the volume of the piloting 4).
• the use port U1 is then placed in fluid communication with the supply port P (FIG. 4).
• the third point 73 translates to the right (according to the representation in FIG. 4) which causes the lever 50 to pivot around the third point 73.
• This translation causes a displacement of the second point of contact 71 to the right (according to the representation of FIG. 4), which reduces the force transmitted by the second point 71 of the lever 50 to the auxiliary pusher 60 (FIG. 4) and causes a return of the rod 21 in its initial position ( Figure 5).
• the servovalve then returns to its equilibrium state.
• Figures 4 and 5 decompose the movement of the lever 50 and the auxiliary pusher 60 and show a distance from the second point 71 of the lever 50 and the first end 61 for clarity ( Figure 4).
• Figure 4 Those skilled in the art will understand on reading the description that the rotational movement of the lever 50 around the third point 73 and the displacement of the auxiliary pusher 60 to the left according to the representation of FIGS. 4 and 5) are simultaneous.
• Ue When a zero input voltage Ue is applied to the terminals of the actuator 40, this voltage Ue causes a retraction of the main pusher 41 which, under the effect of the spring 24, causes a rotation Ri of the lever 50 around the third point 73 (in a clockwise direction according to the representation of FIG.
• a servovalve 100 provided with a position feedback device which allows the use of a linear actuator without recourse to a displacement sensor of the power distribution member 2.
• the entirely mechanical feedback greatly improves the performance. reliability of the servovalve according to the invention.
• the first link point and the second link point are always located on either side in the foreground PI regardless of the position of the power distribution member 2 in its housing.
• the force transfer interface 52 comprises a cam 80.
• the cam 80 is here a disc with center O provided in its lower right quarter (according to the representation of FIG. 8). of a first bore 81.
• the cam 80 is received in a groove 82 opening onto the end 61 of the auxiliary pusher 60.
• a pin 83 is engaged in a second bore 84 of the auxiliary pusher 60 and passes through the first bore 81 to produce a pi vot 83.1 link at the second link point 71.
• the first connection point 70 is provided by the right quadrants
• the interface 52 is made of steel and comprises a first portion 90 extending in a first direction 090 secant to the neutral fiber 57 of the lever 50 and a second portion 91 extending in a second direction 091 secant to the first direction 090.
• the first portion 90 is of section smaller than the section of the second portion 91 and produces a first inflection point 92 allowing rotation of the second portion 91 relative to the first portion 90.
• the interface 52 comprises a third portion 93 extending in a third direction 093 secant to the neutral fiber 57 of the lever 50 and a fourth portion 94 extending in a fourth direction 094 secant to the third direction 083.
• the third portion 93 is of section smaller than the section of the fourth portion 94 and achieves a second inflection point 95 allowing rotation of the fourth portion 94 relative to the third portion 93.
• the first point of inflection 92 and the second point of inflection 95 correspond respectively to the first point 70 of connection and to the second point 71 of the connection.
• Figures 11 and 12 show two states of the interface 52 and of the lever 50 subjected to the movements of the main pusher 41 and of the auxiliary pusher 60.
• the lever 50 acts directly on the rod 21 to push the latter.
• the first point 70 is a first point of application of the output force Fs of the actuator 40.
• the second point 71 is a second point of transmission of the output force Fs of the actuator 40.
• connection point or other types of connection such as a ball joint, a linear link or a link its pivot;
• the invention also applies to other types of connections of the rod on the body of the servovalve, such as for example a recess or a torsion column attached to a welded frame, machined in the body of the servovalve, or still fitted onto the body of the servovalve;
• the rod comprises an internal conduit for supplying fluid to the fluid ejector
• the invention also applies to other types of fluid supply such as for example a supply by flexible or by an external duct attached to the rod;
• the actuator is a piezoelectric actuator
• the invention also applies to other types of linear actuators such as for example an electric, pneumatic or hydraulic cylinder
• the fixed hydraulic element is a fluid receiver and the element mounted at the end of the rod is a fluid emitter
• the invention also applies to a fluid emitter fixed to a body of the servovalve and to a fluid receiver, such as for example a deflector or a pallet, mounted at the end of the rod;
• pilot stage comprises a rod on which is mounted a fluid ejector
• the invention applies to other types of support such as for example a blade
• control stage comprises a spring pressing on the rod
• the invention also applies to other means of return in position, such as for example a fitting of the rod or a hydraulic spring.
• the invention is moreover operational without means for returning the support to position, for example when a second piezoelectric actuator is positioned facing the first on the other side of the rod and its control is matched to that of the first.
• the transfer interface is positioned at a first end of the lever
• the invention also applies to a transfer interface located at a distance from one end of the lever;
• the second end of the rod comprises a tungsten carbide ball which is received in a groove of the power distribution member, the invention applies to other connecting means for producing a third connection point such as a ball joint, a pivot.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Servomotors (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70738721

Family Applications (1)

Country Status (5)

Family Cites Families (10)

• 2020
  • 2020-03-13 FR FR2002524A patent/FR3108153B1/fr active Active
• 2021
  • 2021-03-12 US US17/911,084 patent/US11994154B2/en active Active
  • 2021-03-12 EP EP21711240.8A patent/EP4118344A1/fr active Pending
  • 2021-03-12 WO PCT/EP2021/056407 patent/WO2021180960A1/fr unknown
  • 2021-03-12 CN CN202180035320.9A patent/CN116157603A/zh active Pending

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