The present invention generally relates to linear actuators and, more particularly to an electromechanical actuator (EMA) that exhibits relatively high load and relatively high shock capability.
Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various control surfaces or components. In many applications electromechanical actuators (EMAs) are used. An EMA typically includes an electric motor that, when properly energized, supplies a torque to a suitable actuation device, which in turn positions a component.
In some applications, there is a need for actuators that exhibits relatively high load and relatively high shock capability, while at the same time fitting within a relatively small space envelope. For example, certain waterborne military platforms, such as submarines, need actuators that can fit within its relatively confined space and that also exhibit high load and shock capability. One specific submarine system that relies on actuators with these characteristics is a hatch actuation control system. In the past, these systems have included hydraulic-type actuators, which can be relatively heavy, complex, and maintenance intensive.
Hence, there is a need for an EMA that exhibits relatively high load and relatively high shock capability, while at the same time fits within a relatively small space envelope, such as a submarine. The present invention addresses at leas this need.
In one embodiment, and by way of example only, a high load lift and shock linear actuator includes a power-screw actuator, a manual operator, a bidirectional brake, an actuator motor, and a motor brake. The power-screw actuator is coupled to receive a drive torque and is operable, upon receipt thereof, to translate. The manual operator is configured to be manually rotated and is operable, upon being manually rotated, to supply a manual input torque. The bidirectional brake has an input and an output. The bidirectional brake input is coupled to the manual operator. The bidirectional brake is configured to transfer manual input torque from the bidirectional brake input to the bidirectional brake output, and prevent torque supplied to the bidirectional brake output from being transferred to the bidirectional brake input. The actuator motor is coupled to the power-screw actuator and is adapted to be selectively energized. The actuator motor is operable, upon being energized, to supply the drive torque to the power-screw actuator. The actuator motor includes a stator, a rotor, a ring gear, and a differential carrier assembly. The rotor is disposed within, and is spaced apart from, the stator, and has an inner surface that defines an inner volume. The ring gear is mounted on the rotor inner surface. The differential carrier assembly is disposed within the rotor inner volume and includes a carrier, a sun gear, and a plurality of planet gears. The carrier is rotationally mounted within the rotor and is coupled to the power-screw actuator. The sun gear is rotationally mounted within the carrier and is coupled to the bidirectional brake output. Each planet gear is disposed between and engages the sun gear and the ring gear. The motor brake is mounted adjacent the actuator motor and is selectively movable between an engaged position, in which the motor brake at least inhibits rotation of the actuator motor rotor, and a disengaged position, in which the motor brake does not at least inhibit rotation of the actuator motor rotor.
In another exemplary embodiment, a high load lift and shock actuation control system includes the above-described actuator and an actuator controller that is operable to controllably energize the actuator motor and to controllably energize and deenergize the motor brake.
In yet another exemplary embodiment, a submarine hatch position control system uses the above-described system to controllably move a submarine hatch.
Other desirable features and characteristics of the actuator and actuation control system will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. In this regard, although the actuator and actuation control system are described as being implemented in a submarine environment, and to control a submarine hatch, the actuator and associated control system may be implemented in numerous other environments and/or to control numerous other devices or components.
Referring now to
The hatch 102 is moved between the closed and full-open positions via the hatch actuation control system 100. As noted above, the hatch actuation control system 100 includes the actuator controller 104 and the actuator 106. The actuator controller 104 is coupled to receive commands from a remote, non-illustrated external system, or via a non-illustrated user interface. The actuator controller 104 is responsive to these commands, whether received remotely or input locally, to control the actuator 106. More specifically, and as will be described in more detail further below, the actuator 106 includes a motor. Thus, the actuator controller 104 controllably energizes the motor from a non-illustrated power supply to control the position of the actuator 106, and hence the position of the hatch 102.
The actuator 106 is coupled to the hatch 102 and, at least in the depicted embodiment, is mounted to the silo 108. The actuator 106 is structurally configured as a relatively high load and relatively high shock device and, as may be seen more clearly in
To provide this functionality the power-screw actuator 112 may be implemented as any one of numerous suitable power-screw actuators. For example, it may be implemented as a ball screw actuator, a roller screw actuator, or an acme screw actuator, just to name a few. In the depicted embodiment, as is depicted more clearly in
The ballscrew 304 extends axially through the ballnut 302, and into a ballscew shield 316 that is coupled to the ballscrew housing 312. The ballscrew 304 has grooves 318 formed on a portion of its outer surface that are configured identical, or at least substantially identical, to the grooves 308 on the ballnut 302. The balls 306 are disposed between the ballnut 302 and the ballscrew 304 within a least a portion of the grooves 308, 318. The ballscrew 304 is constrained against rotation, but may move axially. Thus, whenever the ballnut 302 rotates, the ballscrew translates axially in either a first direction 322 or a second direction 324, depending upon the direction in which the ballnut 302 is rotated. Because the ballscrew 304 is coupled to the plunger 202, axial movement of the ballscrew 304 in the first direction 322 will result in the hatch 102 moving toward the full-open position, as shown in
As was noted above, the power-screw actuator 112, and more specifically the ballnut 302, receives a drive torque from either the manual operator 114 or the actuator motor 116. Turning now to
The manual operator 114 and the actuator motor 116, as has been repeatedly described, may supply a drive torque to the power-screw actuator 112 via the just-described output shaft 602 and output gears 604. The configuration of the manual operator 114 and actuator motor 116 that implement this functionality will now be described, beginning with the manual operator 114. With continued reference to
The bidirectional brake 608, as is conventional, is configured to transfer manual input torque, supplied to the bidirectional brake input 612 via the manual operator 114, from the bidirectional brake input 612 to the bidirectional brake output 614. The bidirectional brake 608 is also configured, as is conventionally known, to prevent torque supplied to the bidirectional brake output 614, via the manual input shaft 618 and input gears 616, from being transferred to the bidirectional brake input 612. With this configuration, the bidirectional brake 608 prevents the manual input shaft 618 from rotating in response to any torque acting on the manual input shaft 618 that does not originate from the bidirectional brake input 612.
Turning now to a description of the actuator motor 116, and with continued reference to
The differential carrier assembly 644, at least in the depicted embodiment, includes a carrier 702, a sun gear 704, and a plurality of planet gears 706 (e.g., 706-1, 706-2, 706-3). The carrier 702 includes an output shaft interface 708, and a plurality of planet gear slots 712. The sun gear 704 is rotationally mounted within the carrier 702 via suitable bearings 714. The sun gear 704 includes a manual input shaft interface 716, and engages each of the planet gears 706. The planet gears 706 are rotationally mounted within the carrier 702, via shafts 718 and bearings 722. Each of the planet gears 706 engages the sun gear 704 and extends through one of the planet gear slots 712.
Returning now to
As
Having described the overall construction and configuration of the hatch actuation control system 100, a brief description of its operation will now be provided. First, it is assumed that the hatch 102 is in the closed position and is going to be moved to its fully-open position using the actuator motor 116. The actuator controller 104, in response to externally supplied or manually inputted commands, controllably energizes the motor brake 654 to move it to the disengaged position, and controllably energizes the actuator motor 116 to rotate it in the appropriate direction. More specifically, the actuator controller 104 controllably energizes the actuator motor stator 626 to generate a torque in the actuator motor rotor 628 and cause the actuator motor rotor 628 to rotate in the appropriate direction.
As the actuator motor rotor 628 rotates, the ring gear 642 also rotates. The ring gear 642, as noted above, engages the planet gears 706, and thus imparts a torque to both the carrier 702 and sun gear 704. The bidirectional brake 608, as described above, constrains the sun gear 704 from rotating in response to this torque. The carrier 702, however, does rotate, and supplies a torque to the power-screw actuator 112, via the output shaft 602 and output gears 604, to impart a drive force to the hatch 102. As the hatch 102 is moved to the fully-open position, continuous position feedback is supplied to the actuator controller 104 from the position sensor 603. When the hatch 102 reaches the fully-open position, the actuator controller 104 will cease controllably energizing the actuator motor 116, and will deenergize the motor brake 654, thereby moving the motor brake 654 to its engaged position.
To move the hatch 102 to the closed position, the actuator controller 104 again energizes the motor brake 654, and selectively energizes the actuator motor 116 to rotate in the direction opposite to the direction that causes the hatch 102 to open. All other operations of the actuator 106 are identical, or at least substantially identical, to the above description. As such, the description will not be repeated. A description of how the hatch 102 is moved from its closed position to its fully-open position using the manual operator 114 will now be described.
When a manual input torque is supplied to the manual operator 114, the manual input torque is supplied, via the bidirectional brake 608 and input gears 616, to the manual input shaft 618. The manual input shaft 618 transfers the input torque to the sun gear 704, causing the sun gear 704 to rotate, which in turn causes the planet gears 706 to rotate. Because the motor brake 654 is engaged, the actuator motor rotor 628 and ring gear 642 are constrained from rotating. The planet gears 706 thus cause the carrier 702 to rotate and supply a drive torque, via the output shaft 602 and output gears 604, to the power-screw actuator 112. The power-screw actuator 112 will in turn supply a drive force to the hatch 102. The direction that the hatch 102 moves will depend, of course, on the direction in which the manual operator 114 is turned.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.