Actuator and control method thereof

Abstract

The invention provides an actuator. The actuator comprises a hydraulic drive assembly, an electric drive assembly and a feedback piece. The hydraulic drive assembly comprises a cylinder barrel, a piston, a piston rod and a control valve assembly. The electric driving assembly is coupled with the feedback piece and drives the feedback piece to rotate; the feedback piece is matched with the piston rod, and when the feedback piece rotates, the piston rod is driven to move linearly. When the piston rod linearly moves, the feedback piece is driven to rotate; the control valve assembly is coupled with the feedback piece, and the flow of oil entering the cylinder barrel is controlled according to the rotating motion of the feedback piece. The invention further provides a control method of the actuator. According to the embodiment of the invention, the dual-mode actuator which can be hydraulically driven and electrically driven is realized, and the actuator can be controlled at high precision.

Description

Technical Field

[0001] The present disclosure relates to the technical field of drive equipment, and in particular to an actuator and a control method of the actuator. Background Art

[0002] High-precision servo valves are used in hydraulic servo cylinders to distribute the flow of hydraulic oil, thereby achieving precise control of the displacement and speed of the piston rod. Specifically, a displacement sensor is provided in the hydraulic servo cylinder to detect the position signal of the piston rod in real time and feed it back to the controller. The controller sends a signal to the servo valve according to the position signal of the piston rod, so that the servo valve controls the flow of hydraulic oil, thereby controlling the movement speed of the piston rod. However, the high-precision servo valve, displacement sensor, and high-precision servo cylinder are expensive, which limits the promotion and use of hydraulic servo cylinders in industrial production. Summary of the invention

[0003] Embodiments of the present disclosure provide an actuator and a method for controlling the actuator.

[0004] In a first aspect, an embodiment of the present disclosure provides an actuator, characterized in that it includes: a liquid drive component, an electric drive component, and a feedback component; the liquid drive component includes a cylinder, a piston, a piston rod, and a control valve component; the electric drive component is coupled to the feedback component to drive the feedback component to rotate; the feedback component cooperates with the piston rod, and when the feedback component rotates, it drives the piston rod to move linearly; when the piston rod moves linearly, it drives the feedback component to rotate; the control valve component is coupled to the feedback component to control the oil flow entering the cylinder according to the rotational movement of the feedback component.

[0005] In some embodiments, the feedback member is threadably engaged with the piston rod.

[0006] In some embodiments, a cylinder bottom is provided at one end of the cylinder barrel; a threaded portion is provided in the inner hole of the piston rod; the feedback member includes a screw rod, which passes through the cylinder bottom and is fixed on the cylinder bottom and can rotate relative to the cylinder bottom; the first end of the screw rod extends to the interior of the cylinder barrel, and the thread of the screw rod is engaged with the thread of the threaded portion; the second end of the screw rod is located outside the cylinder barrel, and is coupled to the electric drive assembly and the control valve assembly respectively.

[0007] In some embodiments, the threaded portion includes a mounting nut disposed in an inner hole of the piston rod, and the threads of the screw rod and the threads of the mounting nut are meshed with each other.

[0008] In some embodiments, the electric drive assembly includes a driving motor and a first transmission assembly; one end of the first transmission assembly is coupled to the motor, and the other end of the first transmission assembly is coupled to the second end of the lead screw.

[0009] In some embodiments, the first transmission assembly includes a first transmission shaft and a first drive shaft; one end of the first drive shaft is transmission-connected to the drive motor, the other end of the first drive shaft is transmission-connected to one end of the first transmission shaft through a gear pair, and the other end of the first transmission shaft is transmission-connected to the second end of the screw rod through a gear pair.

[0010] In some embodiments, bevel gears are provided at both ends of the first transmission shaft, a bevel gear is provided at one end of the first drive shaft, and a bevel gear is provided at the second end of the screw rod; the bevel gear at one end of the first transmission shaft is meshed with the bevel gear of the first drive shaft, and the bevel gear at the other end is meshed with the bevel gear at the second end of the screw rod.

[0011] In some embodiments, a rotating sealing ring is disposed on the first transmission shaft.

[0012] In some embodiments, the control valve assembly includes a valve seat, a valve stem, a control motor, and a second transmission assembly. The valve stem is arranged in the inner hole of the valve seat, and the control motor and the second transmission assembly are respectively arranged at both ends of the valve seat; the first end of the valve stem is coupled to the control motor through a second drive shaft, the second drive shaft can drive the valve stem to rotate, and the valve stem can move axially relative to the second drive shaft; the second end of the valve stem is connected to the second transmission assembly through a threaded pair, and the second transmission assembly is coupled to the second end of the screw rod.

[0013] In some embodiments, at least one axially extending protrusion and / or at least one axially extending groove is provided in the inner hole of the second drive shaft; at least one axially extending groove and / or at least one axially extending protrusion is provided on the outer periphery of the first end of the valve stem; the protrusion in the inner hole of the second drive shaft matches the groove on the outer periphery of the first end of the valve stem, and / or the groove in the inner hole of the second drive shaft matches the protrusion on the outer periphery of the first end of the valve stem, so that the second drive shaft can drive the valve stem to rotate and the valve stem can move axially relative to the second drive shaft.

[0014] In some embodiments, at least one axially extending protrusion and / or at least one axially extending groove is provided on the outer periphery of the second drive shaft; at least one axially extending groove and / or at least one axially extending protrusion is provided in the inner hole of the first end of the valve stem; the protrusion on the outer periphery of the second drive shaft matches the groove in the inner hole of the first end of the valve stem, and / or the groove on the outer periphery of the second drive shaft matches the protrusion in the inner hole of the first end of the valve stem, so that the second drive shaft can drive the valve stem to rotate and the valve stem can move axially relative to the second drive shaft.

[0015] In some embodiments, the second transmission assembly includes a second transmission shaft and a third transmission shaft, the second transmission shaft is fixed on the valve seat, one end of the third transmission shaft is connected to the second end of the second transmission shaft via a gear pair, and the other end is connected to the second end of the screw rod via a gear pair; an external thread is provided on the outer periphery of the second end of the valve stem, and an internal thread is provided in the inner hole of the first end of the second transmission shaft, the external thread of the second end of the valve stem is meshed with the internal thread of the first end of the second transmission shaft, so that when the valve stem and the second transmission shaft rotate relative to each other, the valve stem moves axially.

[0016] In some embodiments, the second transmission assembly includes a second transmission shaft and a third transmission shaft, the second transmission shaft is fixed on the valve seat, one end of the third transmission shaft is connected to the second end of the second transmission shaft via a gear pair, and the other end is connected to the second end of the screw rod via a gear pair; an external thread is provided in the inner hole of the second end of the valve stem, and an internal thread is provided on the outer periphery of the first end of the second transmission shaft, the external thread of the second end of the valve stem is meshed with the internal thread of the first end of the second transmission shaft, so that when the valve stem and the second transmission shaft rotate relative to each other, the valve stem moves axially.

[0017] In some embodiments, a bevel gear is provided at the second end of the second transmission shaft, and bevel gears are provided at both ends of the third transmission shaft; the bevel gear at one end of the third transmission shaft meshes with the bevel gear at the second end of the second transmission shaft, and the bevel gear at the other end meshes with the bevel gear at the second end of the screw rod.

[0018] In some embodiments, a rotating sealing ring is provided on the third transmission shaft.

[0019] In some embodiments, the actuator further includes a first clutch mechanism and / or a second clutch mechanism; the first clutch mechanism is used to couple or decouple the feedback member with the control valve assembly; the second clutch mechanism is used to couple or decouple the feedback member with the electric drive assembly.

[0020] In some embodiments, the actuator further includes a controller, and the controller is communicatively connected with the electric drive assembly and the control valve assembly.

[0021] In a second aspect, an embodiment of the present disclosure provides a control method for an actuator, characterized in that it is applied to the actuator described in the first aspect of the embodiment of the present disclosure, comprising: in a hydraulic drive mode, sending a control instruction to a control valve assembly of the actuator to make the control valve assembly work and control the oil flow entering the cylinder of the actuator to control the movement rate of the piston rod of the actuator; in an electric drive mode, sending a control instruction to an electric drive assembly of the actuator to make the electric drive assembly work and drive the piston rod to move; sending a control instruction to the control valve assembly to limit the oil from entering the cylinder.

[0022] The disclosed embodiment realizes a dual-mode actuator that can be driven both hydraulically and electrically. The movement rate of the actuator piston rod can be accurately controlled by electric drive; the piston rod, feedback member, and control valve assembly constitute a feedback loop for the movement of the piston rod, so that the movement rate of the actuator piston rod can also be accurately controlled during hydraulic drive. The disclosed embodiment improves the control accuracy of the actuator, and can also select the hydraulic drive mode or the electric drive mode according to different working conditions and environments, thereby expanding the application range of the actuator. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of an actuator in an embodiment of the present disclosure.

[0024] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the electric drive component.

[0025] Figure 3 yes Figure 1 A partial enlarged schematic diagram of the control valve assembly.

[0026] Figure 4 It is a flow chart of a control method of an actuator in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solution of the present disclosure, the technical solution of the present disclosure is described in detail below with reference to the accompanying drawings.

[0028] Example embodiments will be described more fully below with reference to the accompanying drawings, but the example embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, the purpose of providing these embodiments is to make the present disclosure thorough and complete and to enable those skilled in the art to fully understand the scope of the present disclosure.

[0029] In the absence of conflict, the various embodiments of the present disclosure and the various features therein may be combined with each other.

[0030] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0031] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and / or "made of" are used in this specification, the presence of the features, wholes, steps, operations, elements and / or components is specified, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof is not excluded.

[0032] The embodiments described herein may be described with reference to plan views and / or cross-sectional views by means of idealized schematic diagrams of the present disclosure. Therefore, the example illustrations may be modified according to manufacturing techniques and / or tolerances. Therefore, the embodiments are not limited to the embodiments shown in the accompanying drawings, but include modifications of the configurations formed based on the manufacturing process. Therefore, the regions illustrated in the accompanying drawings have schematic properties, and the shapes of the regions shown in the figures illustrate the specific shapes of the regions of the elements, but are not intended to be limiting.

[0033] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless explicitly defined as such herein.

[0034] Figure 1 It is a structural schematic diagram of an actuator in an embodiment of the present disclosure.

[0035] like Figure 1 As shown, the embodiment of the present disclosure provides a dual-mode actuator that can be driven both hydraulically and electrically, including a hydraulic drive component 1, an electric drive component 2, and a feedback component 3; the hydraulic drive component 1 includes a cylinder 11, a piston 12, a piston rod 13, and a control valve component 4; the electric drive component 2 is coupled to the feedback component 3 to drive the feedback component 3 to rotate; the feedback component 3 cooperates with the piston rod 13.

[0036] In the electric drive mode, when the electric drive assembly 2 drives the feedback member 3 to rotate, the piston rod 13 is driven to perform a linear movement of extension or retraction. The electric drive assembly 2 can achieve precise control of the linear movement rate of the piston rod 13.

[0037] In the hydraulic drive mode, under the control of the control valve assembly, the oil enters the cylinder 11, pushing the piston 12 to drive the piston rod 13 to perform a linear movement of extension or retraction. At this time, the linear movement of the piston rod 13 will drive the feedback member 3 to rotate; and the control valve assembly 4 is coupled to the feedback member 3, and the rotational movement rate of the feedback member 3 can reflect the linear movement rate of the piston rod 13, thereby forming a feedback loop about the linear movement rate of the piston rod 13, so that the control valve assembly 4 can control the oil flow entering the cylinder 11 according to the rotational movement of the feedback member 3, thereby accurately controlling the linear movement rate of the piston rod 13.

[0038] In some embodiments, the feedback member 3 and the piston rod 13 are threadedly matched, and when the feedback member 3 rotates, it can drive the piston rod 13 to move linearly; when the piston rod 13 moves linearly, it can drive the feedback member 3 to rotate. It should be noted that the feedback member 3 can only rotate relative to the cylinder 11, but cannot move axially, thereby ensuring that the piston rod 13 can extend or retract axially. The feedback member 3 and the piston rod 13 are threadedly matched, which can be the external thread of the feedback member 3 and the internal thread of the piston rod 13, or the internal thread of the feedback member 3 and the external thread of the piston rod 13. The embodiments of the present disclosure do not make special limitations on this.

[0039] The following explanation is given by taking the feedback member 3 as a screw rod as an example.

[0040] like Figure 1 As shown, a cylinder bottom 14 and a guide sleeve 15 are respectively provided at both ends of the cylinder barrel, and the piston rod 13 extends out of the cylinder barrel 11 from one end of the guide sleeve 15; an inner hole is provided at one end of the piston rod 13 near the cylinder bottom 14, and a threaded portion is provided in the inner hole, and the screw rod 3 passes through the cylinder bottom 14 and is fixed on the cylinder bottom 14, and can rotate relative to the cylinder bottom. The first end of the screw rod 3 extends into the interior of the cylinder barrel 11, and its external thread is meshed with the internal thread of the threaded portion in the inner hole of the piston rod 13.

[0041] In the embodiment of the present disclosure, the threaded portion may be an integral structure with the inner hole of the piston rod 13, and an internal thread is provided on the inner hole wall of the piston rod 13 to engage with the external thread of the screw rod 3; the threaded portion may also be a component independent of the inner hole of the piston rod 13, for example, Figure 1 As shown, the threaded portion is a mounting nut 131, which is threadedly engaged with the screw rod 3 and moves linearly with the piston rod 13. The mounting nut 131 can be a ball nut, a roller nut, or the like.

[0042] like Figure 1As shown, the second end of the screw rod 3 is located outside the cylinder 11, and is respectively coupled to the electric drive assembly 2 and the control valve assembly 4. In the electric drive mode, the electric drive assembly 2 can drive the screw rod 3 to rotate, and the screw rod 3 and the piston rod 13 are threadedly matched, thereby driving the piston rod 13 to move linearly; in the hydraulic drive mode, the piston rod 13 extends or retracts to make linear motion, and the screw rod 3 and the piston rod 13 are threadedly matched, thereby driving the screw rod 3 to rotate and feedback to the control valve assembly 4.

[0043] In the disclosed embodiment, the electric drive assembly 2 includes a drive motor 21 and a first transmission assembly, and the two ends of the first transmission assembly are respectively connected to the drive motor 21 and the second end of the screw rod 3, so that the drive motor 21 can drive the screw rod 3 to rotate.

[0044] In the embodiment of the present disclosure, the second end of the screw rod 3 can be coupled to the electric drive assembly 2 through a reduction gear, can be coupled to the electric drive assembly 2 through a pulley, or can be coupled to the electric drive assembly 2 through a gear transmission shaft. The embodiment of the present disclosure does not specifically limit this.

[0045] like Figure 1 As shown, the second end of the screw rod 3 is coupled to the electric drive assembly 2 through a gear transmission shaft. The first transmission assembly includes a first transmission shaft 22 and a first drive shaft 23. One end of the first drive shaft 23 is transmission-connected to the drive motor 21 and can rotate under the drive of the drive motor 21.

[0046] In the embodiment of the present disclosure, the first drive shaft 23 may be the output shaft of the drive motor 21, as a component of the drive motor 21; the first drive shaft 23 may also be independent of the drive motor 21, and the output shaft of the drive motor 21 is connected to one end of the first drive shaft 23 through a flat key or a spline. In the embodiment of the present disclosure, the first drive shaft 23 independent of the drive motor 21 is provided, which is convenient for disassembly and installation of the drive motor 21, convenient for maintenance, and also conducive to sealing, thereby improving the overall sealing effect in the actuator cavity.

[0047] The two ends of the first transmission shaft 22 are respectively connected to the first drive shaft 23 and the second end of the screw rod 3 through a gear pair. Figure 1 As shown, bevel gears are provided at both ends of the first transmission shaft 22, a bevel gear is provided at one end of the first drive 23 away from the drive motor 21, and a bevel gear is also provided at the second end of the screw rod 3. The bevel gear at one end of the first transmission shaft 22 is meshed with the bevel gear of the first drive shaft, and the other end is meshed with the bevel gear at the second end of the screw rod 3, thereby realizing a mechanically rigid transmission connection between the drive motor 21 and the screw rod 3, so that the drive motor 21 can more accurately drive the screw rod 3 to rotate, thereby more accurately controlling the extension and retraction of the piston rod 13.

[0048] For example, Figure 1As shown, the second end of the screw rod 3 is provided with a step, the step is provided with a keyway and an external thread, and a screw hole is provided on the end face. The bevel gear is fixedly mounted on the second end of the screw rod 3 by screws; a bearing is installed in the middle of the second end of the screw rod 3 through a transition sleeve, and the bearing is fixed to the cylinder bottom 14 by a compression nut, so that the screw rod 3 can only rotate relative to the cylinder bottom 14. Figure 2 yes Figure 1 A partial enlarged schematic diagram of the electric drive component 2. Figure 2 As shown, the motor mounting seat 5 is fixed to the cylinder bottom 14 by screws, the drive motor 21 is fixed to the motor mounting seat 5 by screws, the first drive shaft 23 is limited on the motor mounting seat 5 by bearings and elastic retaining rings, and the end of the first drive shaft 23 away from the drive motor 21 fixes the bevel gear on the first drive shaft 23 by screws, flat keys, pressure plates, and retaining rings; the first transmission shaft 22 is limited on the cylinder bottom by bearings, and two bevel gears are fixed at both ends of the first transmission shaft 22 by screws, pressure plates, flat keys and retaining rings, which are respectively meshed with the bevel gear of the first drive shaft 23 and the bevel gear at the second end of the screw rod 3, thereby realizing power transmission of the drive motor 21, the first drive shaft 23, the first transmission shaft 22, and the screw rod 3.

[0049] like Figure 1 , Figure 2 As shown, a rotating sealing ring is also provided on the first drive shaft 23 to prevent the hydraulic oil in the cylinder 11 from entering the chamber below the first transmission shaft 22 .

[0050] In the embodiments of the present disclosure, Figure 1 As shown, the control valve assembly 4 includes a valve seat 41, a valve stem 42, a control motor 43, and a second transmission assembly 44. The valve stem 42 is arranged in the inner hole of the valve seat 41, and the control motor 43 and the second transmission assembly are respectively arranged at both ends of the valve seat 41.

[0051] Figure 3 yes Figure 1 A partial enlarged schematic diagram of the control valve assembly 4. Figure 1 , Figure 3 As shown, the valve seat 41 is provided with a P port, a T port, an A port, and a B port. The P port is connected to the oil pressure, the T port is connected to the oil tank, the A port is connected to the large chamber of the hydraulic cylinder, and the B port is connected to the small chamber of the hydraulic cylinder. Figure 1 In the initial position (middle position) shown in FIG. 1 , any two of the P port, T port, A port, and B port are not connected to each other. Figure 1 When the valve stem 42 is in the middle left position, the left T port is connected to the B port, the P port is connected to the A port, the pressure oil enters the large chamber of the hydraulic cylinder, and the piston 12 drives the piston rod 13 to extend under the action of the pressure oil; when the valve stem 42 is in the Figure 1 When in the middle right position, the right T port is connected with the A port, the P port is connected with the B port, the pressure oil enters the small chamber of the hydraulic cylinder, and the piston 12 drives the piston rod 13 to retract under the action of the pressure oil.

[0052] like Figure 1 As shown, the first end of the valve stem 42 is coupled to the control motor 43 via the second drive shaft 44 . The second drive shaft 44 can drive the valve stem 42 to rotate, and the valve stem 42 can move axially relative to the second drive shaft 44 .

[0053] In the embodiment of the present disclosure, the first end of the valve stem 42 is connected to the second drive shaft 44 via a flat key or a spline.

[0054] In some embodiments, at least one axially extending protrusion and / or at least one axially extending groove is provided in the inner hole of the second drive shaft 44; at least one axially extending groove and / or at least one axially extending protrusion is provided on the outer periphery of the first end of the valve stem 42; the protrusion in the inner hole of the second drive shaft 44 matches the groove on the outer periphery of the first end of the valve stem 42, and / or the groove in the inner hole of the second drive shaft 44 matches the protrusion on the outer periphery of the first end of the valve stem 42, so that the second drive shaft 44 can drive the valve stem 42 to rotate, and the valve stem 42 can move axially relative to the second drive shaft 44.

[0055] In some embodiments, at least one axially extending protrusion and / or at least one axially extending groove is provided on the outer periphery of the second drive shaft 44; at least one axially extending groove and / or at least one axially extending protrusion is provided in the inner hole of the first end of the valve stem 42; the protrusion on the outer periphery of the second drive shaft 44 matches the groove in the inner hole of the first end of the valve stem 42, and / or the groove on the outer periphery of the second drive shaft 44 matches the protrusion in the inner hole of the first end of the valve stem 42, so that the second drive shaft 44 can drive the valve stem 42 to rotate, and the valve stem 42 can move axially relative to the second drive shaft 44.

[0056] In the disclosed embodiment, the second end of the valve stem 42 is connected to the second transmission assembly via a threaded pair, and the second transmission assembly is also coupled to the second end of the screw rod 3 .

[0057] In some embodiments, the second transmission assembly includes a second transmission shaft 45 and a third transmission shaft 46. The second transmission shaft 45 is fixed on the valve seat 41. One end of the third transmission shaft 46 is connected to the second end of the second transmission shaft 45 through a gear pair, and the other end is connected to the second end of the screw rod 3 through a gear pair. An external thread is arranged on the outer periphery of the second end of the valve stem 42, and an internal thread is arranged in the inner hole of the first end of the second transmission shaft 45. The external thread of the second end of the valve stem 42 is meshed with the internal thread of the first end of the second transmission shaft 45, so that when the valve stem 42 and the second transmission shaft 45 rotate relative to each other, the valve stem 42 moves spirally along the axial direction and generates displacement along the axial direction.

[0058] In some embodiments, the second transmission assembly includes a second transmission shaft 45 and a third transmission shaft 46. The second transmission shaft 45 is fixed on the valve seat 41. One end of the third transmission shaft 46 is connected to the second end of the second transmission shaft 45 through a gear pair, and the other end is connected to the second end of the screw rod 3 through a gear pair. An external thread is provided in the inner hole of the second end of the valve stem 42, and an internal thread is provided on the outer periphery of the first end of the second transmission shaft 45. The external thread of the second end of the valve stem 42 is meshed with the internal thread of the first end of the second transmission shaft 45, so that when the valve stem 42 and the second transmission shaft 45 rotate relative to each other, the valve stem 42 moves axially.

[0059] When the valve stem 42 rotates under the drive of the control motor 43, under the action of the threaded pair between the valve stem 42 and the second transmission shaft 45, the rotational movement of the valve stem 42 relative to the second transmission shaft 45 is converted into axial movement in the inner hole of the valve seat 41, thereby controlling the oil to enter the large chamber or the small chamber of the hydraulic cylinder to control the extension or retraction of the piston rod 13. It is also possible to control the oil flow entering the large chamber or the small chamber of the hydraulic cylinder by controlling the size of the valve opening, thereby controlling the extension or retraction rate of the piston rod 13.

[0060] During the process of extending or retracting the piston rod 13, the linear movement of the piston rod 13 will drive the screw 3 to rotate, and through the transmission action of the third transmission shaft 46 and the second transmission shaft 45, the second transmission shaft 45 will be driven to rotate. By setting the thread rotation direction, the second transmission shaft 45 rotates in the same direction as the valve stem 42, the rotation rate of the valve stem 42 relative to the second transmission shaft 45 decreases, and the rate of increase or decrease of the valve opening gradually decreases until the rotation rate of the valve stem 42 relative to the second transmission shaft 45 is 0, the size of the valve opening no longer changes, and the oil flow entering the hydraulic cylinder remains stable, so that the piston rod 13 is extended or retracted at a uniform speed, realizing closed-loop control in the hydraulic drive mode. By adjusting the speed of the control motor 43, the precise control of the extension or retraction rate of the piston rod 13 can be achieved.

[0061] like Figure 1 As shown, a bevel gear is provided at the second end of the second transmission shaft 45, and bevel gears are provided at both ends of the third transmission shaft 46; the bevel gear at one end of the third transmission shaft 46 meshes with the bevel gear at the second end of the second transmission shaft 45, and the bevel gear at the other end meshes with the bevel gear at the second end of the screw rod 3.

[0062] For example, Figure 1As shown, the valve seat 41 is fixed to the cylinder 11 by screws, the control motor 43 is fixed to the motor mounting flange by screws, the motor mounting flange is fixed to the valve seat 41 by screws, and is connected to the second drive shaft 44 by a flat key; the second drive shaft 44 is limited on the valve seat 41 by an elastic retaining ring and a bearing, and is connected to the valve stem by a flat key; the valve stem 42 is installed in the inner hole of the valve seat 41, the second transmission shaft 45 is limited on the valve seat 41 by a single-row retaining ring and a bearing, and the second end of the second transmission shaft 45 is fixed to the bevel gear by screws, flat keys, pressure plates, and retaining rings.

[0063] like Figure 1 As shown, a rotating sealing ring is provided on the third transmission shaft 46 to prevent the hydraulic oil in the cylinder barrel 11 from entering the chamber above the third transmission shaft 46 .

[0064] In some embodiments, the actuator further includes a first clutch mechanism and / or a second clutch mechanism; the first clutch mechanism is used to couple or decouple the feedback member 3 with the control valve assembly 4; the second clutch mechanism is used to couple or decouple the feedback member 3 with the electric drive assembly 2.

[0065] For example, in the hydraulic drive mode, the feedback component 3 is coupled to the control valve assembly 4 through the first clutch mechanism, and the feedback component 3 is separated from the electric drive assembly 2 through the second clutch mechanism; in the electric drive mode, the feedback component 3 is separated from the control valve assembly 4 through the first clutch mechanism, and the feedback component 3 is coupled to the electric drive assembly 2 through the second clutch mechanism.

[0066] By setting up a clutch mechanism, the two modes can be separated, thereby avoiding mutual interference between the components of the two modes and reducing the control complexity.

[0067] In some embodiments, the actuator further includes a controller 6, which is in communication with the electric drive assembly 2 and the control valve assembly 4. The controller 6 controls the electric drive assembly 2 and the control valve assembly 4 to switch between the hydraulic drive mode and the electric drive mode, and can also accurately control the moving speed of the piston rod 13 by controlling the electric drive assembly 2 and the control valve assembly 4.

[0068] Combine the following Figure 1 The working principle of the hydraulic drive mode of the actuator is explained.

[0069] like Figure 1 As shown, the valve seat 41 is provided with a P port, a T port, an A port, and a B port. When the valve stem 42 is in the position shown in FIG. Figure 1In the initial position shown (middle position), the P port, T port, A port, and B port are not connected to each other. When the controller sends a command to the control motor 43, the control motor 43 drives the second drive shaft 44 to rotate, and the second drive shaft 44 drives the valve stem 42 to rotate. By designing the spiral direction of the transmission thread of the right end of the valve stem 42 and the left end of the second transmission shaft 45 to cooperate, it can be achieved that when the valve stem 42 rotates, the valve stem 42 moves to the left under the action of the thread pair. When the valve stem 42 continues to move to the left, the P port is connected to the A port, and the T port is connected to the B port. At this time, the piston 12 drives the piston rod 13 to extend outward under the action of the pressure oil, and the ball nut 131 fixed on the piston rod 13 moves to the left with the piston rod 13. The ball nut 131 drives the screw rod 3 to rotate. The rotation of the screw rod 3 causes the third transmission shaft 46 and the second transmission shaft 45 to rotate through the bevel gear. Under the action of the thread pair of the second transmission shaft and the valve stem 42, when the second transmission shaft 45 rotates, the valve stem 42 will move horizontally. By designing the thread rotation direction of the screw rod 3, it is possible to realize that the screw rod 3 drives the second transmission shaft 45 to rotate and drives the valve stem 42 to move to the right. That is, the control motor 43 opens the valve port of the control valve assembly, the pressure oil enters the piston rod 13 and extends, the screw rod 3 feeds back to the valve stem 42, and the valve port of the control valve assembly is closed, forming a complete closed-loop control.

[0070] When the control motor 43 outputs at a certain speed, the P port and the A port gradually increase, the oil flow in the large chamber of the hydraulic cylinder gradually increases, the movement speed of the piston rod 13 also increases, and the rotation speed of the screw rod 3 also increases. When the rotation speed of the screw rod 3 transmitted to the second transmission shaft 45 increases to the same as the rotation speed of the valve stem 42 (the output speed of the control motor 43), the valve stem 42 stops moving to the left, and the second transmission shaft 45 rotates synchronously with the valve stem 42, and there is no relative displacement in the horizontal direction. At this time, the size of the valve opening remains unchanged, the oil flow entering the hydraulic cylinder remains unchanged, and the extension speed of the piston rod 13 remains stable. Since the movement speed of the piston rod 13 will match the output speed of the control motor 43, when the speed of the control motor 43 is increased, the movement speed of the piston rod 13 becomes faster, and when the speed of the control motor 43 is reduced, the movement speed of the piston rod 13 becomes slower, thereby achieving precise control of the extension speed of the hydraulic cylinder piston rod 13 by setting the speed of the control motor 43. When the valve stem 42 is in a position such as Figure 1 In the initial position shown (middle position), the control motor 43 is set to reverse, and similarly, the control motor 443 is used to accurately control the piston rod 13 to retract.

[0071] In the above control process, the control system controls the rotation of the valve stem 42, and controls the size of the valve opening by rotating the valve stem 42 to control the oil flow entering the hydraulic cylinder. The oil flow determines the extension speed of the hydraulic cylinder piston rod 13, and the extension speed of the piston rod 13 determines the rotation speed of the screw 3. The rotation speed of the screw 3 provides negative feedback on the size of the valve opening, thereby realizing the closed-loop control. Since the valve stem 42 and the second drive shaft 44 are connected by a flat key, the valve stem 42 and the second transmission shaft 45 are connected by a threaded pair, the second transmission shaft 45 and the third transmission shaft 46 are driven by a gear pair, the third transmission shaft 46 and the screw 3 are driven by a gear pair, and the screw 3 and the roller nut are connected by a threaded pair, all of which are mechanical rigid transmissions. Therefore, the transmission and feedback accuracy of the transmission structure are high, and high-precision control and feedback can be achieved.

[0072] Combine the following Figure 1 The operating principle of the electric drive mode of the actuator is explained.

[0073] like Figure 1 As shown, the driving motor 21 drives the first driving shaft 23 to rotate, the first driving shaft 23 drives the first transmission shaft 22 to rotate through the bevel gear, the first transmission shaft 22 drives the screw rod 3 to rotate through the bevel gear, the screw rod 3 drives the ball nut 131 to move linearly through the thread pair, thereby driving the piston rod 13 to telescopic movement. Since the driving motor 21 is a servo motor, and the driving motor 21 and the screw rod 3 are driven by a gear pair, and the screw rod 3 and the ball nut 131 are connected by a thread pair, both of which are rigid transmissions, therefore, the extension and retraction of the piston rod 13 can be accurately controlled by giving specific instructions to the driving motor 21.

[0074] Both modes can precisely control the extension and retraction of the piston rod 13 through the servo motor. The hydraulic drive is to control the extension and retraction of the piston rod 13 by the servo motor. The output force of the actuator is determined by the oil pressure and has nothing to do with the power of the servo motor. Therefore, the servo motor power needs to be relatively small. The screw rod 3 and the ball nut pair are only used to feedback the extension displacement of the piston rod and have a relatively small bearing force. The electric drive is to drive the screw rod 3 and the ball nut pair through the servo motor to drive the piston rod 13 to extend and retract. The output force of the actuator is determined by the power of the servo motor, the load that the screw rod 3 and the ball nut pair and the gear pair can bear. Therefore, the output force is relatively small. Both modes can drive the piston rod 13 to extend and retract separately. Therefore, the actuator can realize the dual-mode operation of hydraulic drive and electric drive. When one of the modes is selected, the servo motor of the other mode is given a follow-up command to keep synchronously following (or, when the hydraulic drive mode is adopted, the servo motor of the electric mode is in the "neutral" position to follow the rotation; when the electric mode is adopted, the speed of the two servo motors is set to match to ensure that the valve stem is in the middle position).

[0075] Figure 4 : is a flow chart of a control method of an actuator in an embodiment of the present disclosure, and the control method is applied to the actuator provided in an embodiment of the present disclosure, including:

[0076] S1. In the hydraulic drive mode, a control instruction is sent to the control valve assembly to make the control valve assembly work, thereby controlling the oil flow entering the cylinder of the actuator to control the movement rate of the piston rod of the actuator;

[0077] S2. In the electric drive mode, a control instruction is sent to the electric drive assembly to make the electric drive assembly work and drive the piston rod to move; a control instruction is sent to the control valve assembly to limit the oil from entering the cylinder.

[0078] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for limiting purposes. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly noted, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, those skilled in the art will appreciate that various changes in form and detail may be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. An actuator, characterized in that: include: Hydraulic drive components, electric drive components, feedback components; The liquid drive assembly includes a cylinder, a piston, a piston rod, and a control valve assembly; The electric drive assembly is coupled to the feedback member to drive the feedback member to rotate; The feedback member cooperates with the piston rod, and when the feedback member rotates, it drives the piston rod to move linearly; when the piston rod moves linearly, it drives the feedback member to rotate; The control valve assembly is coupled to the feedback member and controls the flow of oil entering the cylinder according to the rotational movement of the feedback member.

2. The actuator according to claim 1, characterized in that: The feedback member is threadably matched with the piston rod.

3. The actuator according to claim 2, characterized in that: A cylinder bottom is provided at one end of the cylinder barrel; a threaded portion is provided in the inner hole of the piston rod; the feedback member includes a screw rod, which passes through the cylinder bottom and is fixed on the cylinder bottom and can rotate relative to the cylinder bottom; the first end of the screw rod extends to the inside of the cylinder barrel, and the thread of the screw rod is engaged with the thread of the threaded portion; the second end of the screw rod is located outside the cylinder barrel, and is coupled to the electric drive assembly and the control valve assembly respectively.

4. The actuator according to claim 3, characterized in that: The threaded portion comprises a mounting nut arranged in the inner hole of the piston rod, and the thread of the screw rod is meshed with the thread of the mounting nut.

5. The actuator according to claim 3, characterized in that: The electric drive assembly includes a driving motor and a first transmission assembly; one end of the first transmission assembly is coupled to the motor, and the other end of the first transmission assembly is coupled to the second end of the lead screw.

6. The actuator according to claim 5, characterized in that: The first transmission assembly includes a first transmission shaft and a first drive shaft; one end of the first drive shaft is connected to the drive motor, the other end of the first drive shaft is connected to one end of the first transmission shaft through a gear pair, and the other end of the first transmission shaft is connected to the second end of the screw rod through a gear pair.

7. The actuator according to claim 6, characterized in that: Bevel gears are provided at both ends of the first transmission shaft, a bevel gear is provided at one end of the first drive shaft, and a bevel gear is provided at the second end of the screw rod; the bevel gear at one end of the first transmission shaft is meshed with the bevel gear of the first drive shaft, and the bevel gear at the other end is meshed with the bevel gear at the second end of the screw rod.

8. The actuator according to claim 6, characterized in that: A rotating sealing ring is arranged on the first transmission shaft.

9. The actuator according to claim 3, characterized in that: The control valve assembly includes a valve seat, a valve stem, a control motor, and a second transmission assembly. The valve stem is arranged in the inner hole of the valve seat. The control motor and the second transmission assembly are respectively arranged at two ends of the valve seat. The first end of the valve stem is coupled to the control motor via a second drive shaft, the second drive shaft can drive the valve stem to rotate, and the valve stem can move axially relative to the second drive shaft; The second end of the valve stem is connected to the second transmission assembly via a threaded pair, and the second transmission assembly is coupled to the second end of the screw rod.

10. The actuator according to claim 9, characterized in that: At least one axially extending protrusion and / or at least one axially extending groove is provided in the inner hole of the second drive shaft; The outer periphery of the first end of the valve stem is provided with at least one groove portion extending in the axial direction and / or at least one protrusion portion extending in the axial direction; The protrusion in the inner hole of the second drive shaft matches the groove on the outer periphery of the first end of the valve stem, and / or the groove in the inner hole of the second drive shaft matches the protrusion on the outer periphery of the first end of the valve stem, so that the second drive shaft can drive the valve stem to rotate and the valve stem can move axially relative to the second drive shaft.

11. The actuator according to claim 9, characterized in that: The outer periphery of the second drive shaft is provided with at least one protrusion extending in the axial direction and / or at least one groove extending in the axial direction; The inner hole at the first end of the valve stem is provided with at least one groove portion extending in the axial direction and / or at least one protrusion portion extending in the axial direction; The raised portion on the outer periphery of the second drive shaft matches the groove portion in the inner hole of the first end of the valve stem, and / or the groove portion on the outer periphery of the second drive shaft matches the raised portion in the inner hole of the first end of the valve stem, so that the second drive shaft can drive the valve stem to rotate and the valve stem can move axially relative to the second drive shaft.

12. The actuator according to claim 9, characterized in that: The second transmission assembly comprises a second transmission shaft and a third transmission shaft, the second transmission shaft is fixed on the valve seat, one end of the third transmission shaft is connected to the second end of the second transmission shaft through a gear pair, and the other end of the third transmission shaft is connected to the second end of the screw rod through a gear pair; An external thread is arranged on the outer periphery of the second end of the valve stem, and an internal thread is arranged in the inner hole of the first end of the second transmission shaft. The external thread of the second end of the valve stem is meshed with the internal thread of the first end of the second transmission shaft, so that when the valve stem and the second transmission shaft rotate relative to each other, the valve stem moves axially.

13. The actuator according to claim 9, characterized in that: The second transmission assembly comprises a second transmission shaft and a third transmission shaft, the second transmission shaft is fixed on the valve seat, one end of the third transmission shaft is connected to the second end of the second transmission shaft through a gear pair, and the other end of the third transmission shaft is connected to the second end of the screw rod through a gear pair; An external thread is provided in the inner hole of the second end of the valve stem, and an internal thread is provided on the outer periphery of the first end of the second transmission shaft. The external thread at the second end of the valve stem is meshed with the internal thread at the first end of the second transmission shaft, so that when the valve stem and the second transmission shaft rotate relative to each other, the valve stem moves axially.

14. The actuator according to claim 12 or 13, characterized in that: A bevel gear is provided at the second end of the second transmission shaft, and bevel gears are provided at both ends of the third transmission shaft; the bevel gear at one end of the third transmission shaft meshes with the bevel gear at the second end of the second transmission shaft, and the bevel gear at the other end meshes with the bevel gear at the second end of the screw rod.

15. The actuator according to claim 12 or 13, characterized in that: The third transmission shaft is provided with a rotating sealing ring.

16. The actuator according to any one of claims 1 to 13, characterized in that: The actuator further comprises a first clutch mechanism and / or a second clutch mechanism; The first clutch mechanism is used to couple or decouple the feedback member from the control valve assembly; The second clutch mechanism is used to couple or decouple the feedback member from the electric drive assembly.

17. The actuator according to any one of claims 1 to 13, characterized in that: The actuator further includes a controller, which is communicatively connected with the electric drive assembly and the control valve assembly.

18. A method for controlling an actuator, characterized in that: The actuator according to any one of claims 1 to 17 comprises: In the hydraulic drive mode, a control instruction is sent to the control valve assembly of the actuator to make the control valve assembly work, thereby controlling the oil flow entering the cylinder of the actuator to control the movement speed of the piston rod of the actuator; In the electric drive mode, a control instruction is sent to the electric drive component of the actuator to make the electric drive component work and drive the piston rod to move; a control instruction is sent to the control valve component to limit the oil from entering the cylinder.

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