• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Servovalve (100, 200) having a driving stage (20, 120) having a hydraulic element (30, 130) for ejecting a jet of fluid and a hydraulic element (6, 106) for receiving the jet of fluid, the hydraulic elements (30, 130, 6, 106) being movable relative to each other so as to modify their relative position and thereby generate a usable pressure differential for moving a power distribution member (2, 102) of the servovalve (100, 200), one of the two elements (6, 106) being fixedly mounted on a body (1, 101) of the servovalve (100, 200) and the other of the elements (30, 130) being mounted in the free end (29, 129) of a rod (22, 122) secured to the body (1, 101) of the servovalve (100, 200) by securing means (23, 24, 67), the floor driving apparatus (20, 120) comprising a linear actuator (42, 80, 142) arranged to selectively exert on the rod (22, 122) a force tending to modify the relative position of the hydraulic elements (30, 130, 6, 106).
    公开号:FR3051027A1
    申请号:FR1653987
    申请日:2016-05-03
    公开日:2017-11-10
    发明作者:Catherine Mailhan；Emmanuel Doyen；Bailliencourt Olivier De
    申请人:Zodiac Hydraulics SAS；
    IPC主号:
    专利说明:

    FIELD OF THE INVENTION The invention relates to a servovalve control stage, which can serve as a first stage in a two-stage servovalve.
    BACKGROUND OF THE INVENTION
    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 proportional to an instruction transmitted to the control stage. The control stage comprises two hydraulic elements, namely a hydraulic transmitter (nozzle or ejector) and a hydraulic receiver (pallet, deflector or fixed receiver) whose modification of their relative position generates pressure differentials which are exploited to move finely. a movable power distribution member of the power stage of the servovalve. This mobile power distribution member slides in a cylindrical jacket implanted in the body of the servovalve. Generally, the position of the transmitter or the hydraulic receiver is controlled by a torque motor which moves one of the hydraulic elements of the control stage facing the other. The displacement of the mobile power distribution member in its jacket then communicates a set of drilled channels and lights whose arrangement allows to deliver a pressure or a flow, proportional to the displacement of said movable power distribution member.
    The numerous moving parts of the servovalve, in particular those of the torque motor, induce a sufficiently low natural frequency (between 600 Hz and 1000 Hz in the functional axis, ie the axis of displacement of the hydraulic element mobile that corresponds to an axis passing through the two orifices of the hydraulic receiver in the case of a servo valve whose hydraulic transmitter is movable) so that the servovalve can be requested in operation at this frequency and see its operation disturbed. The reliability of the operation of the servovalve and especially its sensitivity are affected by this resonance.
    OBJECT OF THE INVENTION The object of the invention is to improve the vibration behavior of a servovalve.
    BRIEF DESCRIPTION OF THE INVENTION
    In order to achieve this goal, a servo-control servovalve is provided with a hydraulic element for ejecting a jet of fluid and a hydraulic element for receiving the jet of fluid. The hydraulic elements can be moved relative to each other so as to modify their relative position and thus generate a differential of. According to the invention, one of the two elements is fixedly mounted on one body of the servovalve and the other of the elements is mounted at the free end of a rod secured to the body of the servovalve by securing means, control stage comprising at least one linear actuator arranged to selectively exert on the rod a force tending to modify the relative position of the hydraulic elements.
    Thus, the movable element of the servovalve is actuated by a linear actuator which proves to be less sensitive to vibrations than a conventional torque motor actuator of the prior art.
    Advantageously, the fixed hydraulic element is a fluid receiver and the hydraulic element carried by the rod is a fluid ejector. An ejector-type servovalve is thus obtained which offers a better tolerance to fluid pollution due to a greater distance between the fluid ejector and the receiver. According to a particular embodiment of such a servovalve, the rod comprises an internal conduit for supplying fluid to the fluid ejector.
    Advantageously, at least a portion of the rod is of square section. This section provides good stiffness characteristics without restricting the stroke of the linear actuator.
    According to a preferred embodiment, the rod is rigid and the solidarity means are flexible. The deformation at the origin of the relative displacement of the hydraulic elements on the flexible means and not the rigid rod is then carried. This makes it easy to characterize the link between the force applied by the actuator and the relative displacement of the hydraulic elements. Advantageously, the securing means of such a servovalve comprise an internal fluid supply conduit in communication with the internal conduit for supplying fluid to the rod, making the device more compact and more reliable.
    Alternatively, and for the same reasons as those sought above, the rod is flexible and the solidarisâtion means are rigid.
    According to a preferred embodiment, the linear actuator comprises a piezoelectric actuator. These actuators are reliable, light and powerful and have very few moving parts, thus offering excellent vibration behavior. It is also possible that the control stage comprises two piezoelectric actuators mounted on either side of a section of the elastic rod. This allows easy adaptation of a first control stage of a servovalve according to the invention to the servovalves of the prior art whose safety position (hydraulic zero) corresponds to the magnetic balance of the pallets and therefore to a median position the hydraulic ejector next to the receiver. Other features and advantages of the invention will emerge in the light of the following description of particular non-limiting embodiments of the invention.
    BRIEF DESCRIPTION OF THE FIGURES
    Reference is made to the appended figures among which: FIG. 1 is a schematic representation of the application of the invention to a servovalve according to a first particular embodiment of the invention; FIG. 2 is a sectional detail view of the zone II-II identified in FIG. 1; FIG. 3 is a schematic representation of the application of the invention to a servovalve according to a second particular embodiment of the invention; FIG. 4 is a view identical to that of FIG. 2 of a fourth embodiment of the invention.
    DETAILED DESCRIPTION OF THE FIGURES
    With reference to FIGS. 1 and 2, the invention is here illustrated in application to a two-stage barometric flow control servovalve including a control stage. Of course, the invention is not limited to this application, and may 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 sealingly in a cylindrical housing 3 forming the distribution stage. The power distribution member 2 is movable between two extreme positions and is shaped to define in the housing 3 of the sealed chambers C1, C2, C3, C4 and C5 (to put in communication respectively, according to the extreme position of the organ of power distribution 2 with respect to a centered position (or neutral position): either a power supply port P with a first use port Ul, and a return port R with a second usage port U2; either the power supply port P with the second usage port U2, and the return port R with the first usage port Ul.
    The sliding control of the power distribution member 2 in the housing 3 is ensured by means of control chambers 4,5 which are fed with fluid under pressure by a pressure distribution member, in this case a receiver 6 fixed. The receiver 6 comprises two orifices 7 and 8 respectively in fluid communication, via conduits 10 and 11, with the control chambers 4 and 5. A receptacle 9 located substantially vertically above the receiver 6 collects the hydraulic fluid when the latter is directed towards none of the orifices 7 or 8. The receptacle 9 is connected to the return R by a conduit 12. A LVDT type linear sensor 13 measures the position of the mobile power distribution member 2 in its housing 3. The core 14 of the sensor 13 is connected to the movable power distribution member 2 by a rod passing through one end of the cylindrical housing 3. The piloting stage 20 of the servovalve 1 comprises a frame 21 of square form reported by bolting on the body 1 of the servovalve 100. A rod 22 projecting from the plane of the frame 21 is secured thereto by two journals 23 and 24 are torsionally projecting from two inner faces 21.1 and 21.2 parallel to the frame 21. The two journals 23 and 24 are here machined in the same block as the frame 21 and connect it to a portion 25 of square section of the rod 22. The rod 22 also comprises a portion 26 of circular section The portion 26 of the rod 22 has a first end 27 brazed on one end 28 of the portion 25 and a second free end 29 on which is mounted a fluid ejector 30 which faces the receiver 6. As can be seen in FIG. 2, the rod 22 comprises an internal conduit 31 for supplying fluid to the fluid ejector 30. This inner duct 31 is fed by two internal ducts 32 and 33 respectively drilled into the journals 23 and 24. Internal conduits 32 and 33 open respectively through ports 34 and 35 on one face of the frame 21. The ports 34 and 35 are fluidly connected to the power supply port P of the servovalve 100 via a conduit 36. A support 40 projecting from the plan of the frame 21 is located in line with the rod 22. The support 40 is of parallelepipedal shape and comprises in its center a cylindrical housing 41 which accommodates a piezoelectric actuator 42. The actuator 42 comprises a pusher 43 which comes into contact with the portion 25 of the rod 22. The end 44 of the pusher 43 which is in contact with the portion 25 of the rod 22 is, here, spherical of large radius compared to the width of the pusher 43. 1 / actuator 42 is connected to a PID regulator 50 receiving an error signal coming from the difference between the setpoint exerted on a control drive 51, here a shutter output control, and on the measurement the position of the power distribution member 2 transmitted by the sensor 13 whose signal is previously processed by a conditioner 52.
    Depending on the voltage applied across the actuator 42, it exerts a force on the rod 22 which tends to move the fluid ejector 30 mounted on the end 29 of the rod 22 opposite the receiver 6. In FIG. 2, for a voltage zero or less than half of the maximum voltage applied across the actuator 42, the ejector 30 ejects a jet of fluid towards the orifice 8. When the voltage applied across the actuator 42 is equal to half of the applicable maximum voltage, the actuator 42 extends halfway and the ejector ejects a jet of fluid midway between the two. orifices. No pressure differential is created between the control chambers 4 and 5 and the power distribution member 2 remains stationary
    When the voltage applied across the actuator 42 is greater than half the applicable maximum voltage, the actuator 42 extends beyond the half-stroke and the ejector ejects a jet of fluid to the orifice 7. The pressure differential thus created between the control 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 FIG. 1 (increase in the volume of the chamber 4). In this embodiment, the rod 22 is rigid and the journals 23 and 24 are comparatively flexible. This means that the deformation is applied to the trunnions (torsional deformation) and not to the rigid rod.
    Elements identical or similar to those previously described will bear a numerical reference increased by one hundred in the following description of the second and third embodiments of the invention.
    With reference to FIG. 3, the pilot stage 120 of the servovalve 200 comprises a parallelepipedal plate 60 bolted onto the body 101 of the servovalve 200. A rod 122 included in the plane of the plate 60 projects from the face 61 of a side 62 of the plate 60. A recess 67 connects the rod 122 to the face 61 of the plate 60. The rod 122 and the plate 60 are here made in one piece by machining in the mass. The rod 122 comprises a portion 125 of square section at the end 128 of which is brazed a portion 126 of circular section. A fluid ejector 130 is mounted on the free end 129 of the rod 122 and is opposite the receiver 106. The rod 122 comprises an internal conduit 131 for supplying fluid to the fluid ejector 130. This inner conduit 131 is fed by an internal conduit 63 drilled in the plate 60 and opening through a port 64 on the lower face 65 of the plate 60. As shown in Figure 3, the lower face 65 is here perpendicular to the side 62. The port 64 is fluidly connected to the power supply port P of the servovalve 100 via a conduit 136. A piezoelectric actuator 142 comprises a pusher 143 which comes into contact with the portion 125 of the rod 122. The end 144 of the pusher 143 which is contact with the portion 125 of the rod 122 is, here, spherical large radius.
    Depending on the voltage applied across the actuator 142, it exerts a force on the rod 122 which tends to move the fluid ejector 130 mounted on the end 129 of the rod 122 facing the receiver 106. Zero voltage applied across the actuator 142, the ejector 130 ejects a jet of fluid toorificel08. The differential pressure thus created between the control chambers 104 and 105 causes a displacement of the power distribution member 102 in its housing 103 to the left according to the representation of Figure 3 (increase of the volume of the control chamber 5 ). The displacement of the power distribution member 2 in its housing 3 changes the rates sent to the output ports U1 and U2.
    When the voltage applied across the actuator 142 is equal to half of the applicable maximum voltage, the actuator 142 extends halfway and the ejector 130 ejects a jet of fluid midway between the two orifices. . No pressure differential is created between the control chambers 104 and 105 and the power distribution member 102 remains stationary When the voltage applied across the actuator 142 is greater than half the applicable maximum voltage, the actuator 142 extends beyond the half-stroke and the ejector 130 ejects a jet of fluid toorificel07. The differential pressure thus created between the control chambers 104 and 105 causes a displacement of the power distribution member 102 in its housing 103 to the right according to the representation of Figure 3 (increase of the volume of the control chamber 104 ). In this embodiment, the rod 122 is flexible and the installation of the rod 122 on the plate 60 is comparatively rigid. This means that the deformation is carried on the rod 122 (bending deformation) and not on the recess 67.
    FIG. 4 illustrates a third embodiment in which the hydraulic zero of the control stage 120 corresponds to a position of the ejector 130 in which the same flow of fluid is sent to each of the orifices 107 and 108. This position corresponds at the equilibrium position of the rod 122 when it is not subjected to any control effort. This occurs in particular in the event of a short circuit (no control voltage applied to the actuator). The actuator 80 comprises a first piezoelectric actuator 142 and a second piezoelectric actuator 70 mounted on either side of a section of the elastic rod 122. The second piezoelectric actuator 70 can exert a coaxial force on the rod 122. that exerted by the first actuator 142, in an opposite direction.
    Depending on the voltage applied across the actuators 142 and 70, one of them retracts and the other extends, exerting a force on the rod 122 which tends to move the mounted fluid ejector 130 on the end 129 of the rod 122 in a first direction, a pressure differential is created between the control chambers 104 and 105 and the power distribution member 102 moves. The voltages applied across the actuators 142 and 70 provide push-pull control. This means that when one actuator extends, the other actuator retracts simultaneously. When the actuators 142 and 70 are halfway, that is to say that the voltage applied across the terminals of each of the actuators is equal to half of the maximum voltage, the ejector 130 ejects the same flow of fluid to each of the orifices 107 and 108. No pressure differential is created between the control chambers 104 and 105 and the power distribution member 102 remains stationary. In this position, the control pressure sent to ports U1 or U2 remains unchanged.
    When a voltage is applied across the actuator 142 to control the extension of a quantity δ and a voltage is applied to the actuator 70 to control the withdrawal of the same quantity δ, the actuator piezoelectric 142 extends and the ejector 130 ejects a quantity of fluid to the orifice 107 greater than the amount of fluid received by the orifice 108. The pressure differential thus created between the control chambers 104 and 105 causes a displacement the power distribution member 102 in its housing 103 to the left according to the representation of Figure 4 (increasing the volume of the control chamber 104). The displacement of the power distribution member 102 in its housing 103 modifies the rates sent to the output ports U1 and U2.
    Such a configuration allows easy adaptation of a first control stage of a servovalve according to the invention to the servovalves of the prior art whose safety position (hydraulic zero) corresponds to the magnetic balance of the pallets and therefore to a middle position of the hydraulic ejector opposite the receiver.
    Tests and calculations of the vibration behavior of the servovalve according to the invention have made it possible to demonstrate the improvement of the vibration behavior of the servovalve. The table below compares the eigenvalues in vibration of a servovalve of the prior art and of a servovalve provided with a mobile assembly according to the invention. These elements were obtained using a finite element calculation tool. The elements used to identify the directions concerned by the eigen modes are those of FIG. 1. The X axis corresponds to the direction of movement of the pusher 43 and the Y axis is perpendicular to the X axis in the plane of the receiver 6 The Z axis is orthogonal to a plane containing the X and Y axes.
    From these representations, it is clear that the frequencies of the first two eigen modes are displaced. Their values are doubled.
    Thus, the sensitivity to the vibration of the servovalve according to the invention is improved The invention is of course not limited to what has just been described, but encompasses any variant within the scope defined by the claims.
    In particular, although here the core of the LVDT sensor is connected to the mobile power distribution member by a rod passing through one of the ends of the cylindrical housing, the invention also applies to other means of detecting the position of the slide, such as other types of passive or active position sensors: resistive, capacitive, or optical for example; - Although here the frame is square, the invention also applies to other types of support for the rod such as an open frame U-shaped, or a triangular frame, circular or any ; - Although here the frame is bolted to the body of the servovalve, the invention also applies to other means of fixing the frame on the body of the servovalve, such as a welded frame, machined in the body the servovalve, or fitted on the body of the servovalve; - Although here the rod comprises an internal conduit for supplying fluid to the fluid ejector, the invention is also applicable to other types of fluid supply such as for example a hose feed or a external duct attached to the stem; - Although here the rod has a portion of square section and a portion of circular section, the invention also applies to rods of constant section, variable or comprising more than two portions of different section; -Although here the rod is secured to the body of the servovalve by two journals machined in the same block as that of the frame, the invention also applies to other means of solidarisâtion of the rod to the servovalve as for example welded journals, supports in the form of a straight cylinder or parallelepiped; - Although here the support of the piezoelectric actuator is of parallelepipedal shape, the invention is also applicable to other types of support such as for example an annular support or a support integral with the body of the servovalve and not the frame; although here the actuator is a piezoelectric actuator, the invention is also applicable to other types of linear actuators such as an electric cylinder, pneumatic or hydraulic; - Although here the actuator is connected to a PID regulator, the invention is also applicable to other types of regulator such as proportional regulators pure or derived pure or proportional derivative; - Although here the embedding of the rod on the plate, itself integral with the body of the servovalve, is achieved by machining in the mass, the invention also applies to other means of solidarisâtion of the rod the body of the servovalve such as a solder, a solder or a fitting; although here 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 on a body of fluid. the servovalve and to a fluid receiver, such as a deflector or a pallet, mounted at the end of the rod - although here the supply pressure is delivered to the chambers C4 and C1 and that the chamber C5 is put in return, the invention also applies to a power stage in which these power supplies would be reversed; -but here the relative displacement of the transmitter and the hydraulic receiver of the third embodiment of the invention is achieved by elastic deformation of the rod, the invention also applies to a relative displacement of the transmitter and of the hydraulic receiver in which the deformation causing the displacement is made to bear on the securing means of the rod to the body of the servovalve and not on the rod; -but here the servovalve is a two-stage servovalve comprising a power stage comprising a power distribution member whose position modification is controlled by the pressure differential generated by the first stage, the invention applies also to a single stage servovalve in which the pressure differential is directly used to control an actuator or a hydraulic load.
    权利要求:
    Claims (10)
    [1" id="c-fr-0001]
    A servovalve (100, 200) having a driving stage (20, 120) having a hydraulic element (30, 130) for ejecting a jet of fluid and a hydraulic element (6, 106) for receiving the jet of fluid, the hydraulic elements ( 30, 130, 6, 106) being movable relative to each other so as to change their relative position and thereby generate a pressure differential, one of the two members (6, 106) being fixedly mounted on one body (1, 101) of the servovalve (100, 200) and the other of the elements (30, 130) being mounted at the free end (29, 129) of a rod (22, 122) secured to the body (1, 101) of the servovalve (100, 200) by means of solidarisa-tion (23, 24, 67), the control stage (20, 120) comprising at least one linear actuator (42, 80, 142) arranged to selectively exert on the rod (22, 122) a strong effect tending to modify the relative position of the hydraulic elements (30, 130, 6, 106).
    [2" id="c-fr-0002]
    2. A servovalve (100, 200) according to claim 1, wherein the linear actuator (42, 80, 142) comprises a pusher (43) which comes into contact with the rod (22, 122) to urge it .
    [3" id="c-fr-0003]
    The servovalve (100, 200) according to claim 1, wherein the fixed hydraulic element is a fluid receiver (6, 106) and the hydraulic element carried by the rod (22, 122) is a fluid ejector ( 30, 130).
    [4" id="c-fr-0004]
    4. Servovalve (100, 200) according to claim 1, wherein at least a portion (25, 125) of the rod (22, 122) is of square section.
    [5" id="c-fr-0005]
    The servovalve (100, 200) according to claim 3, wherein the rod (22, 122) comprises an internal fluid supply conduit (31, 131) to the fluid ejector (30, 130).
    [6" id="c-fr-0006]
    6. Servovalve (100, 200) according to claim 1, wherein the rod (22, 122) is rigid and the securing means (23, 24) are flexible.
    [7" id="c-fr-0007]
    7. Servovalve (100, 200) according to claim 1, wherein the rod (122) is flexible and the securing means (67) are rigid.
    [8" id="c-fr-0008]
    8. Servovalve (100, 200) according to claim 5, wherein the securing means (23, 24, 67) comprise an inner conduit (32, 33, 63) fluid supply in communication with the inner conduit (31). 131) for supplying fluid to the rod (22, 122).
    [9" id="c-fr-0009]
    The servovalve (100, 200) according to any one of the preceding claims, wherein the linear actuator comprises a piezoelectric actuator (42, 70, 80, 142).
    [10" id="c-fr-0010]
    10. The servovalve according to claim 9, wherein the control stage (120) comprises two piezoelectric actuators (70, 142) mounted on either side of a section (25 or 125) of the rod (22). or 122).
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    同族专利:
    公开号 | 公开日
    FR3051027B1|2019-06-14|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US2742919A|1951-06-30|1956-04-24|Gen Controls Co|Electromagnetically operated balanced pilot valve|
    US3282283A|1963-12-23|1966-11-01|Gocko Regulator Co Ltd|Hydraulic regulating system and apparatus|
    US3424183A|1967-03-15|1969-01-28|Abex Corp|Solenoid controlled servovalve with lineal output|
    EP0504465A1|1991-03-21|1992-09-23|MOOG GmbH|Fluid transducer with piezo-electric actuator|
    DE4431600A1|1994-09-05|1996-03-07|Rexroth Mannesmann Gmbh|Jet-pipe stage for servo valve auxiliary or pilot control|CN109580139A|2018-12-14|2019-04-05|上海航天控制技术研究所|A kind of servo valve armature component integral stiffness test device|
    US10651364B2|2016-05-03|2020-05-12|Zodiac Hydraulics|Servo valve with asymmetrical redundant piezoelectric actuator|
    EP3384102B1|2015-12-01|2021-07-07|Myd"L"|Device for helping a vehicle pass over an obstacle|
    法律状态:
    2017-05-23| PLFP| Fee payment|Year of fee payment: 2 |
    2017-11-10| PLSC| Search report ready|Effective date: 20171110 |
    2018-05-22| PLFP| Fee payment|Year of fee payment: 3 |
    2019-05-23| PLFP| Fee payment|Year of fee payment: 4 |
    2020-04-22| PLFP| Fee payment|Year of fee payment: 5 |
    2021-04-21| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1653987|2016-05-03|
    FR1653987A|FR3051027B1|2016-05-03|2016-05-03|SERVOVALVE PILOTAGE STAGE, WHICH CAN SERVE AS A FIRST FLOOR IN A SERVOVALVE WITH TWO FLOORS.|FR1653987A| FR3051027B1|2016-05-03|2016-05-03|SERVOVALVE PILOTAGE STAGE, WHICH CAN SERVE AS A FIRST FLOOR IN A SERVOVALVE WITH TWO FLOORS.|
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