Patent Application
20180195563
The present subject matter relates to a motion control device. In particular, the present subject matter relates to motion control devices that couple an external motive input to a rotary output device.
Modern vehicles incorporate different types of actuators for driving different types of devices, or portions thereof. For example, modern vehicles may include actuated valves, dampers, compressors, cylinders, exhaust components, pumps, engine components, or the like.
Conventional locking devices often exhibit limited functionality, however, as they can only lock the position of the actuated device, or portions thereof, in one extreme state or another, namely in a purely “start” or “stop” state and/or a purely “open” or “closed” state. Accordingly, such devices are generally unable to provide precise position locking at positions between the two extreme states, which can provide desirable results in some configurations, such as to decrease sound, increase torque at low RPM, increase performance, etc.
Accordingly, it would be advantageous for improved devices, systems, and methods to be able to brake, lock, and/or otherwise hold the position of an actuated device at various positions between extreme states (e.g., between fully open and/or fully closed states).
In one aspect, a motion control device for a rotary actuator system is provided. The motion control device comprising a brake core, a rotor, a brake band, an external motive input a rotary output device and an external control input. The brake core includes a coil configured to generate an electromagnetic field when an electric current is applied. The rotor is positioned about and rotatable relative to the brake core. The brake band is positioned between the rotor and the brake core, the brake band being coupled to the rotor for rotation therewith and includes a magnetically responsive material. The external motive input is coupled to the rotor and configured for angular movement upon rotation of the rotor relative to the brake core. The rotary output device is coupled to the rotor and configured for angular movement upon rotation of the rotor relative to the brake core. The external control input is configured to selectively provide the electric current to the coil. Wherein, energizing the coil causes the brake band to be magnetically coupled with the brake core to prevent relative movement between the rotor and the brake core.
In another aspect, a method for adjusting, changing, and/or locking a position of an actuated device to any of a range of desired positions between two extreme states is provided. The method comprises the steps of providing a rotor about and rotatable relative to a brake core, the brake core including a coil configured to generate an electromagnetic field when an electric current is applied; providing a brake band between the rotor and the brake core, the brake band being coupled with the rotor for rotation therewith, the brake band including a magnetically responsive material; coupling an external motive input to the rotor, the external motive input being movable to cause the rotor to rotate relative to the brake core; coupling a rotary output device to the rotor, the rotary output device being configured for angular movement upon rotation of the rotor relative to the brake core; upon receipt of a first control input, controlling a position of the rotary output device by applying the electric current to the coil, wherein applying the electric current to the coil causes the brake band to be magnetically coupled to the brake core to prevent relative movement between the rotor and the brake core; and upon receipt of a second control input, disconnecting the electric current from the coil, wherein disconnecting the electric current from the coil causes the brake band to be decoupled from the brake core to allow free rotation therebetween.
Although some of the aspects of the subject matter disclosed herein have been stated hereinabove, and which are achieved in whole or in part by the presently disclosed subject matter, other aspects will become evident as the description proceeds when taken in connection with the accompanying drawings as best described hereinbelow.
The present subject matter provides motion control systems, devices, and methods for rotary actuators systems. In particular, the present subject matter provides systems, devices, and methods that function to adjust, change, and/or lock the position of an actuated (i.e., movable) device to any of a range of desired positions between two extreme states, such as any position between a purely “start” state and a purely “stop” state (also known as “on” and “off” or “open” and “closed”). In some embodiments, for example, the present subject matter provides for high-resolution of position control, which is sometimes referred to as infinitely variable position control. To achieve such control, the present systems, devices, and methods include an electromagnetic braking element that is selectively operable to stop the position of the actuated device at a desired state and/or position. As used herein, the term “brake” is used to describe the embodiments of the present subject matter in which a torque-generating device creates a dissipative torque in response to signals received or generated by the device.
In this regard,
In any configuration, external motive input 200 is configured to be selectively movable between first and second operating states (e.g., “ON” and “OFF”), which correspond to first and second operating positions of rotary output device 300 (e.g., “open” and “closed”). In some embodiments, for example, one or more controller 400 is in communication with external motive input 200 and/or with one or both of brake assembly 100 or rotary output device 300 and is configured to selectively actuate the external motive input 200 to move between its first and second operating states and/or to selectively activate brake assembly 100 to generate and apply a holding force (e.g., a force that is greater than the actuating force) to portions of external motive input 200 for locking rotary output device 300 attached thereto in any desired position, including any of a range of intermediate states between the first and second operating states. In some embodiments, a current source 410 is provided in communication between controller 400 and brake assembly 100 and is operable to selectively energize an electromagnetic element of brake assembly 100. In some embodiments, controller 400 is a black box provided by the customer providing on/off input.
Furthermore, in some embodiments, controller 400 receives input from at least one sensor (See, e.g., dashed lines in
As indicated above, to achieve the desired control over the resulting position of external motive input 200, brake assembly 100 includes an electromagnetic braking element that is selectively operable to stop the position of the actuated device at a desired state. In one embodiment illustrated in
A rotor 120 is positioned about and rotatable relative to brake core 110, such as by way of one or more bearings 126. A brake band 130 is positioned between rotor 120 and brake core 110, brake band 130 being coupled to rotor 120 for rotation therewith and comprising a magnetically responsive material (e.g., iron, nickel, cobalt, a ferromagnetic material, steel). In some embodiments, such as is shown in
Alternatively,
Regardless of the particular configuration, brake band 130 is operable to selectively exert a holding force on rotor 120 upon activation of coil 112. Specifically, when coil 112 is in a non-energized state, brake band 130 is rotatable with rotor 120 relative to brake core 110 such that movement of rotor 120 is substantially unimpeded. In some embodiments, brake assembly 100 comprises lubricant (e.g., oil, grease) between at least rotor 120 and brake core 110. This lubricant reduces friction between brake band 130 and brake core 110 and improves the wear resistance of the components. The lubricant has an additional benefit of improving braking performance by substantially reducing the coefficient of static friction to be reduced; in some instances, the coefficient of static friction can be reduced such that it is substantially similar to the coefficient of kinetic friction.
Upon energizing coil 112, however, brake band 130 is magnetically coupled to brake core 110. In some embodiments, where brake band 130 has a split ring shape as shown in
Further alternative configurations of brake band 130 are contemplated for use with brake assembly 100 to provide additional control over the holding force generated when coil 112 is energized. For example, referring to
By comparison, in a further alternative configuration illustrated in
In some embodiments, the holding force applied is otherwise controllable by changing the coefficient of friction for the surfaces of brake core 110, rotor 120, cup 122, friction pad 124, and/or brake band 130 by a plating process, altering the material composition of one or more of these structures, or applying a surface coating or texture thereto.
In any of the above-described configurations, since the rotation of rotor 120 is coupled with brake band 130 (e.g., by the engagement of tabs 132 with recess 123, as discussed above), this electromagnetic engagement of brake band 130 with brake core 110 likewise couples rotor 120 with brake core 110, thereby preventing relative movement between rotor 120 and brake core 110. In some embodiments where the components involved in applying the holding force are relatively small, lightweight, and of compact size, the activation of brake assembly 110 has a fast response time (e.g., on the order of milliseconds), which results in effectively instantaneous locking and unlocking. For brake assembly 100 to act as a braking mechanism, in some embodiments, brake core 110 is fixedly connected to a surrounding support structure so that its position is substantially fixed with respect to the movable components of brake assembly 100. Accordingly, when coil 112 of brake core 110 is energized and brake band 130 engages brake core 110, the resulting coupling of rotor 120 to brake core 110 effectively holds rotor 120 in a substantially fixed angular position.
As discussed above, brake assembly 100 is configured to serve as a motion control device between external motive input 200 and rotary output device 300. In this regard, external motive input 200 is coupled to rotor 120, external motive input 200 being movable to cause rotor 120 to rotate relative to brake core 110, and rotor 120 is further coupled to rotary output device 300. In this arrangement, rotary output device 300 is configured for angular movement upon rotation of rotor 120 relative to brake core 110. An external control input (e.g., controller 400 shown in
In particular, external motive input 200 is coupled to rotor 120 by a coupling element 150 comprising any of a variety of mechanisms, For example, coupling element 150 can comprise a rack and pinion arrangement (See, e.g.,
Referring now to
Pinion 154 and/or rotor 120 are then further connected to an output shaft 310 configured for connection to rotary output device 300. Accordingly, brake assembly 100 is provided in the coupling connection between external motive input 200 and rotary output device 300 such that actuation of brake assembly 100 (e.g., by energizing coil 112 of brake core 110) resists the actuation force of external motive input 200 to hold output shaft 310 in place to keep rotary output device 300 in a desired operating position. For example, where rotary output device is a butterfly valve, brake assembly 100 can be selectively actuated to hold the valve in an intermediate position between first and second angular positions that correspond to the fully “open” or “closed” positions of the valve.
Furthermore, as shown in
In an alternative configuration shown in
In this way, actuation of external motive input 200 that causes a movement of connecting rod 156 is translated into a rotation of rotor 120 by crank arm 157. In contrast, brake core 110 is held in a substantially fixed position, such as by connection to a bracket element 162 or other surrounding support structure. Accordingly, upon energizing coil 112 of brake core 110, brake band 130 engages brake core 110 as discussed above, which couples rotor 120 to brake core 110. Since brake core 110 is held in a substantially fixed position, rotation of rotor 120 is resisted, thereby holding output shaft 310 in a desired angular position.
In another alternative configuration shown in
In any configuration, brake assembly 100 is selectively operable to either prevent or allow the translation of motion from external motive input 200 to rotary output device 300, and in some situations, brake assembly 100 is operable to hold rotary output device 300 at a desired position. In this regard, upon receipt of a first control input (e.g., from controller 400), an electric current is applied to coil 112, which causes brake band 130 to be magnetically coupled to brake core 110 to prevent relative movement between rotor 120 and brake core 110. In this way, the position of rotary output device 300 is effectively fixed at a desired state or position. Conversely, upon receipt of a second control input, the electric current is disconnected from coil 112, which causes brake band 130 to be decoupled from brake core 110 to allow free rotation thereof.
In addition to the embodiments discussed above, those having skill in the art will recognize that the principles discussed herein can be implemented using other electromagnetically-actuated configurations. For example, rather than using a brake band positioned between a rotor and a brake core as discussed above, rotor 120 is encapsulated within a housing that contains a field responsive material. For example, the principles disclosed at Column 6, lines 1-20, at Column 7, lines 54-61, and at Column 9, lines 53-57, of commonly owned and assigned U.S. Pat. No. 6,854,573, the entire disclosure of which is hereby incorporated herein by reference, can be applied to achieve a controllable brake in which a rotor is housed within a chamber containing a field controllable material. In this configuration, the field controllable material is selectively acted upon by a magnetic field generator to change the rheology of the material and thereby impede movement of the rotor. (See, also, corresponding disclosures found in commonly owned and assigned U.S. Pat. Nos. 7,198,140, and 8,397,883)
In some embodiments, devices, systems, and methods provided herein are configured to be “fail-safe”, meaning that the locking device will automatically revert the position of the actuated device a default or “safe” position upon actuation failure and/or failure of any electrical and/or magnetic member or component associated with the devices and/or systems described herein. Such a default state can be achieved by including a biasing element (e.g., an unpowered spring) in one or more of brake assembly 100, external motive input 200, and/or rotary output device that urges the system towards the fail-safe position (e.g., a fully-open position) when no actuating forces are applied.
Electromagnetic locking devices and systems described herein may be devoid of multiple bearings and/or gears therein. The electromagnetic devices and systems provided herein may be sealed from the outside via a single bearing or seal, but may be devoid of additional bearings. The electromagnetic devices and systems provided herein may be operable between and including temperatures of at least about −40° C. to about 220° C., although those having ordinary skill in the art will recognize that the temperature range in which the present devices and systems are operable can be adjusted selectively through the use of coil wire insulation material or other known means for temperature control.
Other embodiments of the current subject matter will be apparent to those skilled in the art from a consideration of this specification or practice of the subject matter disclosed herein. Thus, the foregoing specification is considered merely exemplary of the current subject matter with the true scope thereof being defined by the following claims.
This application relates to and claims priority to U.S. Provisional Patent Application Ser. No. 62/195,012, filed on Jul. 21, 2015, U.S. Provisional Patent Application Ser. No. 62/195,004, filed on Jul. 21, 2015, and U.S. Provisional Patent Application Ser. No. 62/222,981, filed on Sep. 24, 2015, the disclosures of which are incorporated by reference herein in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2016/043349 | 7/21/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62222981 | Sep 2015 | US | |
| 62195004 | Jul 2015 | US | |
| 62195012 | Jul 2015 | US |
