JP2007239974A - Actuator with excellent snubbing function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator with an excellent snubbing function, capable of optimumly damping shocks with minimum energy in an EHA device used for an aircraft. <P>SOLUTION: An actuator main body is equipped with a displacement sensor to thereby control an operating speed of the actuator at an arbitrary position. Even in the case of making changes of design relating the snubbing function at a development stage of the actuator, it is possible to cope with the design changes only by changing software parameters aimed at controlling the number of revolutions of a motor. Thus, it becomes unnecessary to reproduce a shock absorption device, so that the production cost and the number of steps can be reduced. Further, by sequentially detecting stroke speed of the actuator with respect to various aerodynamic conditions received during real flight so as to control the number of revolutions of the motor, it is made possible to optimumly lift a leg with minimum energy consumed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an EHA (Electro Hydrostatic Actuator) in which a motor, a pump, an actuator, and a controller are integrated, and more specifically, snubbing for the purpose of cushioning an impact at a leg raising position and a leg lowering position when an aircraft is lifted or lowered. The present invention relates to an actuator excellent in function.

  Conventionally, medium-sized and larger aircraft are equipped with a hydraulic pressure supply system, and the hydraulic pressure is used to lift and lower the legs using actuators. In the case of an actuator for lifting and lowering a leg, a snubbing mechanism for reducing the operating speed of the piston is provided for the purpose of reducing the impact caused by the collision between the piston and the cylinder at the leg raising position and the leg lowering position.

  The above-described snubbing mechanism normally includes an impact mitigation device for preventing the piston from colliding with the cylinder bottom or the ground nut inside the cylinder of the actuator. For example, Patent Document 1 relates to a hydraulic cylinder used for an aircraft landing gear or the like, and a snubbing piston is further arranged between a piston head and a cylinder bottom in the cylinder, and the piston is operated at a stroke end during compression. There has been proposed a hydraulic cylinder that performs speed reduction control.

  Patent Document 2 also relates to a hydraulic cylinder that is also used for aircraft landing gears and the like, and a snubbing piston that can move between the required strokes from the cylinder bottom is disposed to form a buffer oil chamber, and a predetermined amount when the piston is extended. Is introduced into the buffer oil chamber through the orifice, and when the piston abuts the snubbing piston during compression, a predetermined amount of fluid is discharged through the orifice to control the operation speed of the piston at a reduced speed. Hydraulic cylinders have been proposed. As described above, various snubbing mechanisms for the purpose of shock reduction have been proposed, and any of them has a structure in which the shock relaxation device is disposed inside the cylinder of the actuator.

  On the other hand, with regard to the actuator body, in recent years, the hydraulic supply system equipped in aircraft has been abolished, and it is moving toward full electrification with the aim of improving fuel efficiency, so that individual actuators can perform self-contained operation with electric power. If it becomes, it will attract attention as a next-generation reliable flight system with improved fuel efficiency.

  At present, two types of actuators have been put into practical use, one of which is EHA, and the other is EMA (Electro Mechanical Actuator). The EHA has a hydraulic system inside an actuator, and power is supplied from the outside to a motor for a hydraulic pump that operates the hydraulic system. On the other hand, the EMA has a structure that is operated by an electric motor, and completely excludes the hydraulic system.

  When EHA and EMA are compared, since the hydraulic system is not included, EMA has a simpler structure and is more advantageous in terms of size reduction and weight reduction. However, for actuators that require high reliability for aircraft, EHA is the mainstream because high reliability cannot be secured with EMA at the current technology level, as EHA is often used. For example, Patent Document 3).

  With this situation, EHA is being developed and researched in various fields. However, as for actuators for lifting and lowering aircraft, actuators using EMA have already been proposed for small aircraft with relatively low reliability requirements, but actuators using EHA are still under development. No proper structure has been proposed.

Japanese Patent Application Laid-Open No. 07-208410 JP-A-08-61310 JP 2002-54604 A

  As described above, the conventionally proposed snubbing mechanism for an actuator for lifting and lowering a leg of an aircraft has an object of reducing an impact when the piston and the cylinder collide by disposing an impact reducing device inside the cylinder of the actuator. Has been achieved.

  However, in the development stage of the actuator, it is necessary to test and test the impact mitigation device when developing a new actuator. If the specified impact mitigation cannot be achieved, a new impact mitigation device is manufactured. It will be necessary. Furthermore, depending on the development status, such trial production and testing may be repeated several times. For this reason, when newly developing an actuator for lifting and lowering an aircraft leg, there is a risk of an increase in the manufacturing cost of the aircraft and a prolonged development period.

  Also, during actual flight of the aircraft, the aerodynamic state acting on the aircraft is not uniform, and when a leg is lifted, a wind load is applied in the same direction as the leg-lifting direction, or the direction opposite to the leg-raising direction. It is also assumed that a wind load acts on the windshield. However, in a conventional actuator for lifting and lowering legs using a hydraulic supply system, the amount of energy supplied to the actuator cannot be controlled in accordance with the aerodynamic conditions acting on the airframe. When the wind load acts in the direction, the legs are lifted at a speed higher than necessary due to the influence of the wind load.

  In the above case, since it is not necessary to raise the legs at a predetermined speed or higher, it is desirable to reduce the energy supply amount corresponding to the wind load acting on the legs from the energy supply amount to the actuator. In this way, if the amount of energy supplied to the actuator can be controlled in response to the aerodynamic conditions acting on the aircraft, it will be possible to effectively use energy and control the operating speed of the actuator. System construction is required.

  The present invention has been made in view of the above-described problems, and by developing a displacement sensor that does not rely on a conventional impact mitigation device, it avoids risks such as an increase in manufacturing cost at the development stage, and further reduces the actual performance of an aircraft. It is an object of the present invention to provide an actuator that can cope with various aerodynamic conditions acting on the airframe during flight and can perform optimum leg lifting with minimum energy.

  The present inventors have made various studies on the optimum snubbing function for a leg lifting actuator. As a result, actuator snubbing is not performed by a method of decelerating the operating speed of the actuator using an impact mitigation device at the cylinder bottom or gland nut as in the conventional case, but the operating speed at an arbitrary sliding position of the piston is controlled. It has been found that this is effective, and such a system can be realized by combining an EHA and a displacement sensor, which have the advantage of being able to control the stroke speed of the piston by changing the rotational speed of the motor.

The present invention has been completed on the basis of the above findings, and the gist thereof is an actuator having the following snubbing functions (1) to (3).
(1) An actuator comprising a cylinder-type actuator body and a piston that slides in a cylinder of the actuator body, a motor, a pump that supplies fluid according to the rotation of the motor, and the movement of the piston A controller for controlling the rotation of the motor according to the pressure and a reservoir for adjusting a fluid supply amount corresponding to a flow rate difference generated according to the movement of the piston, and outputting a signal according to the sliding position of the piston. An actuator excellent in a snubbing function, which is equipped with a displacement sensor that controls the operation speed at an arbitrary sliding position of the piston by controlling the rotation of the motor in response to the signal.
(2) In the actuator excellent in the snubbing function described in (1) above, it is desirable to use LVDT as the displacement sensor because it can be easily incorporated into a control device and a compact design can be achieved as a whole device.

  Furthermore, if the actuator excellent in the snubbing function described in the above (1) or (2) is used for lifting and lowering the legs of the aircraft, it is possible to achieve impact mitigation at the leg raising position and the leg lowering position, and by actual flight of the aircraft It can cope with various aerodynamic conditions and can minimize energy consumption.

  In the present invention, `` excellent in the snubbing function '' means that, as described above, it can avoid risks such as an increase in manufacturing cost in the development stage, and can cope with various aerodynamic conditions acting on the fuselage during actual flight of the aircraft, It means that it is possible to perform the optimal foot lift with minimum energy.

  According to the actuator excellent in the snubbing function of the present invention, by installing an optimal displacement sensor, even when a design change related to the snubbing function is performed at the actuator development stage, a software parameter for controlling the motor rotation speed is set. Since it can respond only by changing, it is not necessary to add a process such as remanufacturing of the impact mitigation device, and it is possible to reduce the construction cost and the process.

  In addition, since the operating speed of the actuator can be freely set by controlling the number of rotations of the motor, it is possible to realize optimum shock relaxation that could not be achieved by a conventional shock relaxation device.

  Furthermore, during actual flight of the aircraft, the actuator's operating speed is sequentially detected for various aerodynamic conditions acting on the aircraft, and the motor speed is controlled to minimize the energy consumption and the optimal leg. Lifting and lowering is also possible.

  Hereinafter, embodiments of an actuator excellent in the snubbing function of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an actuator excellent in the snubbing function of the present invention. The actuator of the present invention is used as an EHA device that operates for an aircraft landing gear, for example. The actuator shown in FIG. 1 includes a cylinder-type actuator body 2 and a piston 4 that slides within the cylinder 3 of the actuator body 2, and is equipped with a motor 5, a pump 6, and a controller 7.

  When a load is applied to the actuator 2, the pump 6 supplies fluid into the cylinder 3 of the actuator body 2 according to the rotation of the motor 5, and opposes the load applied from the outside. At this time, whether the cylinder 3 performs the stretching motion or the compression motion depends on whether the fluid is supplied to the stretching side or the fluid is supplied to the compression side. The rotation direction of the motor 5 is switched according to the movement, and the rotation speed is adjusted.

  In the actuator shown in FIG. 1, a hydraulic manifold 8 is provided instead of the configuration in which the pump 6 and the actuator 2 are connected by fluid piping. The hydraulic manifold 8 is formed by forming a flow path that forms a hydraulic circuit inside a rectangular parallelepiped metal. By connecting the hydraulic circuit to a single location without connecting it directly to the actuator, it is possible to remove and attach components efficiently. It can be performed well, and is more advantageous in terms of miniaturization and weight reduction of the circuit than using a single component, and has the great advantage that the number of pipes can be reduced.

  The displacement sensor provided in the actuator of the present invention is not particularly limited, and may be a linear type or a rotary type. As applicable displacement sensors, various potentiometers (joystick, rotary type, linear type), differential transformers (LVDT, RVDT), and the like can be appropriately selected.

  The potentiometer is a displacement sensor having the same structure as the variable resistor, and can obtain an electrical output proportional to the mechanical position. However, potentiometers are generally sensitive to current, and especially when current flows through a sliding contact, the contact part generates heat and the resistance surface burns, causing noise generation. It becomes.

  The RVDT (Rotary Variable Differential Transformer) is a displacement sensor that generates an induced voltage as the measuring unit rotates and outputs a frequency proportional to the rotational displacement, and needs to be directly installed or connected to the rod end 10 at the piston tip. There is. Therefore, to connect with the controller 7, a length of wiring considering the stroke of the piston 4 is required.

  The actuator shown in FIG. 1 uses an LVDT (Linear Variable Differential Transformer) 9 as a displacement sensor. The LVDT 9 is a differential transformer, which is a displacement sensor that directly converts a mechanical displacement amount into an electrical signal. As shown in the figure, the LVDT 9 is composed of a probe 9a and a case 9b. The core in the case 9b is displaced in accordance with the sliding of the probe 9a, and an AC voltage proportional to the amount of displacement of the core is generated. For this reason, the actuator of the present invention matches the sliding direction of the piston 4 and the linear position detection direction of the LVDT 9, fixes the LVDT case 9 b to the actuator body 2, and connects the LVDT probe 9 a to the piston 4, It can be installed easily and without space, and it has excellent detection accuracy of sliding displacement.

  Next, the operation of the actuator excellent in the snubbing function of the present invention will be described.

  FIG. 2 is a cross-sectional configuration diagram showing an embodiment of an actuator excellent in the snubbing function of the present invention, wherein FIG. 2 (a) is a diagram showing a compression motion of the cylinder, and FIG. 2 (b) is a diagram showing an extension motion of the cylinder. FIG. The actuator shown in FIGS. 2A and 2B includes a cylinder-type actuator body 2 and a piston 4 that slides within the cylinder 3 of the actuator body. The motor 5, the pump 6, the controller 7, and the reservoir 11 are included in the actuator. Equipped.

  When a load is applied to the actuator, the pump 6 supplies a fluid into the cylinder 3 of the actuator body 2 in accordance with the rotation of the motor 5 and opposes the load applied from the outside. For this reason, the pump 6 is connected to the fluid piping connected to the annulus oil chamber 13 and the reservoir 11 and the pump portion 6a, and to the fluid piping connected to the bore oil chamber 12 and the pump portion 6b.

  Further, the LVDT 9 is used as a displacement sensor, the sliding direction of the piston 4 and the linear position detection direction of the LVDT 9 are matched, the LVDT case 9b is fixed to the actuator body 2, and the LVDT probe 9a is connected to the piston 4. Yes.

  As shown in FIG. 2 (a), when the cylinder 3 performs a compressing motion (the white arrow in the figure), the pump part 6b is moved to the inlet side and the pump part 6a is moved to the outlet side by a signal from the controller 7. Thus, the rotation of the motor 5 is switched. In this state, the fluid in the bore side oil chamber 12, the annulus side oil chamber 13, and the reservoir 11 is released.

  By the operation of the fluid pump 6, the fluid in the bore side oil chamber 12 is supplied to the annulus side oil chamber 13, but a part of the fluid is stored in the reservoir 11 through the fluid pipe. Thus, when the fluid is sufficiently supplied to the annulus oil chamber 13, the piston 4 moves to the compression side so as to resist the external load.

  When the piston 4 slides in the cylinder 3 and approaches the cylinder bottom 14, the LVDT 9 provided in the actuator 2 sequentially detects the sliding position of the piston 4 and transmits a signal to the controller 7. The controller 7 calculates the sliding speed at an arbitrary sliding position of the piston 4 from the signal transmitted from the LVDT 9, controls the rotational speed of the motor 5 according to the setting of the program, and decelerates the sliding speed of the piston 4. This achieves optimal impact mitigation.

  Also, as shown in FIG. 2B, when the cylinder 3 performs an extending motion (black arrow in the figure), the pump part 6a is moved to the entrance side and the pump part 6b is ejected by a signal from the controller 7. The rotation of the motor 5 is switched so as to be on the side. In this state, the fluid in the bore side oil chamber 12, the annulus side oil chamber 13, and the reservoir 11 is released.

  The fluid stored in the annulus oil chamber 13 and the reservoir 11 is supplied to the bore oil chamber 12 by the operation of the fluid pump 6. Thus, when the fluid is sufficiently supplied to the bore side oil chamber 12, the piston 4 moves to the extending side so as to resist the load from the outside.

  When the piston 4 slides in the cylinder 3 and approaches the ground nut 15, the LVDT 9 provided in the actuator 2 sequentially detects the sliding position of the piston 4 and transmits a signal to the controller 7. After that, as in the case of the compression motion, the controller 7 controls the rotational speed of the motor 5, the sliding speed of the piston 4 is reduced, and the optimum impact relaxation is achieved.

  For example, when the stroke of the actuator is about 500 mm, the stroke for performing the snubbing (hereinafter referred to as “snubbing stroke”) may be about 25 to 50 mm. In this case, when the piston slides in a section other than the snubbing stroke, the motor speed is set to 3000 rpm and the motor speed at the snubbing stroke is controlled to 1000 rpm. Optimal impact mitigation is achieved. Furthermore, it is possible to further reduce the impact by gradually decreasing the number of rotations of the motor in the snubbing stroke from 1000 rotations / minute and finally stopping (0 rotations / minute).

  Further, it is possible to control the operation speed at an arbitrary sliding position of the piston over the entire stroke of the actuator. With such a configuration, even if the aerodynamic force acting on the fuselage changes, for example, even when a wind load acts in the same direction as the leg raising direction, the sliding speed of the piston is detected sequentially, and the wind Since the number of rotations of the motor is selected in consideration of the influence of the load, the energy consumption can be suppressed to the necessary minimum, and the optimum shock relaxation can be achieved.

  The actuator of the present invention can exhibit an excellent snubbing function when combined with the above-described actions, for example, when applied for lifting and lowering an aircraft.

  According to the actuator excellent in the snubbing function of the present invention, by installing an optimal displacement sensor, even when a design change related to the snubbing function is performed at the actuator development stage, a software parameter for controlling the motor rotation speed is set. Since it can respond only by changing, it is not necessary to add a process such as remanufacturing of the impact mitigation device, and it is possible to reduce the construction cost and the process.

  In addition, since the operating speed of the actuator can be freely set by controlling the number of rotations of the motor, it is possible to realize optimum shock relaxation that could not be achieved by a conventional shock relaxation device.

  Furthermore, during actual flight of the aircraft, the actuator's operating speed is sequentially detected for various aerodynamic conditions acting on the aircraft, and the motor speed is controlled to minimize the energy consumption and the optimal leg. Lifting and lowering is also possible.

  As a result, an excellent snubbing function can be exhibited as an actuator used in an aircraft, and it can be widely used.

It is a perspective view which shows an example of the actuator excellent in the snubbing function of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional block diagram which shows one Embodiment of the actuator which is excellent in the snubbing function of this invention, (a) is a figure which shows the compression motion of a cylinder, (b) is a figure which shows a extending | stretching motion.

Explanation of symbols

1. EHA Actuator 3. Cylinder 4. Piston 5. Motor 6. Pumps 6a, 6b. Pump site 7. Controller 8. 8. Hydraulic manifold LVDT
9a. Probe 9b. Case 10. Rod end 11. Reservoir 12. Bore side oil chamber 13. Annulus oil chamber 14. Cylinder bottom 15. Ground nut

Claims (2)

An actuator comprising a cylinder-type actuator body and a piston that slides within the cylinder of the actuator body,
A motor, a pump for supplying fluid according to the rotation of the motor, a controller for controlling the rotation of the motor according to the movement of the piston, and a fluid supply corresponding to a flow rate difference generated according to the movement of the piston A reservoir for adjusting the amount,
A displacement sensor that outputs a signal according to the sliding position of the piston is equipped, and the controller controls the rotation of the motor in response to the signal, so that the operating speed at an arbitrary sliding position of the piston can be controlled. Actuator with excellent snubbing function, characterized by enabling control. The actuator with excellent snubbing function according to claim 1, wherein LVDT is used as the displacement sensor.

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