CN112654784A - Rolling pulley - Google Patents

Rolling pulley Download PDF

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Publication number
CN112654784A
CN112654784A CN201980058078.XA CN201980058078A CN112654784A CN 112654784 A CN112654784 A CN 112654784A CN 201980058078 A CN201980058078 A CN 201980058078A CN 112654784 A CN112654784 A CN 112654784A
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China
Prior art keywords
pulley
actuator
wire
sma
sma actuator
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CN201980058078.XA
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Chinese (zh)
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詹姆斯·豪沃思
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Cambridge Mechatronics Ltd
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Cambridge Mechatronics Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
    • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
    • F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
    • F03G7/065—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like using a shape memory element

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Lens Barrels (AREA)
  • Adjustment Of Camera Lenses (AREA)

Abstract

Broadly stated, embodiments of the present technology provide techniques for increasing the stroke of an actuator that includes a Shape Memory Alloy (SMA) actuator wire.

Description

Rolling pulley
The present application relates generally to Shape Memory Alloy (SMA) actuators, and more particularly to compact shape memory alloy actuators that include at least one pulley (pully) that enables the actuator to impart a relatively large output stroke.
In a first method of the present technique, there is provided an actuator comprising: a static component; a movable member movable relative to the stationary member; at least one pulley arranged to perform a rotational action and a translational action, thereby driving the movement of the movable part; and at least one Shape Memory Alloy (SMA) actuator wire coupled to the static component and the at least one pulley and arranged to drive rotational and translational motion of the at least one pulley.
In a second method of the present technology, there is provided an actuator comprising: a static component; a movable member movable relative to the stationary member; a pulley arranged to perform a rotational action, thereby driving a rotational movement of the movable part; a first Shape Memory Alloy (SMA) actuator wire coupled at one end to the static component and at another end to the pulley and arranged to drive rotational action of the pulley in a first direction; and a second SMA actuator wire coupled at one end to the static component and at another end to the pulley and arranged to drive rotational action of the pulley in a second direction opposite to the first direction.
In a third method of the present technique, there is provided an actuator comprising: a static component; a movable member movable relative to the stationary member; a pulley arranged to perform a rotational action and a translational action, disposed in abutting relationship between the static part and the movable part, and operatively arranged to roll along the static part, thereby driving a translational movement of the movable part; and a Shape Memory Alloy (SMA) actuator wire coupled to the static component and the pulley and arranged to drive rotational and translational action of the pulley.
In a fourth method of the present technology, there is provided an apparatus comprising: an actuator as described herein for moving a component of the apparatus, wherein the movable component of the actuator is coupled to the component of the apparatus to be moved.
The device may be any of the following: smart phones, cameras, foldable smart phones, foldable image capture devices, foldable smart phone cameras, image capture devices, servomotors, consumer electronics devices, mobile computing devices, laptops, tablet computing devices, security systems, gaming systems, augmented reality devices, virtual reality systems, virtual reality devices, wearable devices, unmanned aerial vehicles (airborne, waterborne, underwater, etc.), aircraft, spacecraft, submarines, vehicles, and autonomous vehicles. It should be understood that this is a non-exhaustive list of example devices.
Preferred features are set out in the appended dependent claims.
Embodiments of the present technology will now be described, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 shows an actuator comprising two opposing Shape Memory Alloy (SMA) actuator wires, each coupled at one end to a static component and at the other end to a movable component;
FIG. 2 shows an actuator comprising two opposed SMA actuator wires and two rollable/movable pulleys;
FIG. 3 shows an actuator comprising an alternative arrangement of two opposed SMA actuator wires and two rollable pulleys;
FIG. 4A shows a perspective view of an exemplary actuator including two opposing SMA actuator wires and a plurality of rollable pulleys;
FIG. 4B illustrates a plan view of the example actuator shown in FIG. 4A;
FIG. 5A illustrates a side view of the exemplary actuator shown in FIG. 4A arranged for linear motion;
FIG. 5B illustrates a side view of the exemplary actuator shown in FIG. 4A arranged for rotational motion;
FIGS. 6A and 6B show side views of an exemplary actuator including one SMA actuator wire and a rollable pulley;
FIG. 7A illustrates another example actuator including one SMA actuator wire and a rollable pulley;
FIG. 7B illustrates another example actuator including one SMA actuator and a rollable pulley;
FIG. 8 shows a schematic layout of pulleys having different inner diameters;
FIG. 9 shows another example actuator including two SMA actuator wires and two rollable pulleys;
FIG. 10 shows an exemplary actuator comprising two SMA actuator wires and a rollable pulley; and
fig. 11A-11D illustrate various techniques for disposing SMA actuator wires around a rollable pulley and how the rollable pulley can be rolled.
Broadly stated, embodiments of the present technology provide techniques for increasing the stroke of an actuator that includes a Shape Memory Alloy (SMA) actuator wire. In some cases, the increased stroke may be achieved with only a relatively small increase in actuator footprint (footprint) (e.g., actuator size or cost). SMA actuators with higher stroke may enable SMA actuators to be used in a wider range of applications, such as tele camera auto-focus and Optical Image Stabilization (OIS), shutter actuators (i.e., actuators that control the size of the camera aperture), servo motors, and fold/collapse cameras. It should be understood that this is a non-exhaustive list of potential applications.
Fig. 1 shows a schematic diagram of an actuator 100 comprising two opposing Shape Memory Alloy (SMA) actuator wires 102, 104, each coupled at one end to a static component and at the other end to a movable component 106. The actuator comprises a first SMA actuator wire 102, which first SMA actuator wire 102 is coupled at one end to a movable component 106 and at the other end to a static component by a crimp (crimp) 108. The actuator further comprises a second SMA actuator wire 104, the second SMA actuator wire 104 being coupled at one end to the movable component 106 and at the other end to the static component by a crimp 110. When the first SMA actuator wire 102 is driven (i.e. energised), the wire heats up and contracts, causing the movable member 106 to move in a first direction. This causes the second SMA actuator wire 104 to stretch. When the first SMA actuator wire 102 is no longer driven, the movable member 106 may stay in place (or may not move significantly from the position that the movable member 106 reached when the first SMA actuator wire 102 was driven). When the second SMA actuator wire 104 is driven (i.e. energised), the wire heats up and contracts, causing the movable member 106 to move in a second direction (opposite to the first direction). This causes the first SMA actuator wire to stretch. Thus, the movable member 106 can be linearly moved as indicated by arrow A
One limitation of SMA materials is the amount of travel they can provide, typically SMA materials undergo 4% contraction upon repeated heating above the transformation temperature. Thus, one way to achieve greater displacement (e.g., displacement of the movable component of the actuator) is to increase the length of the SMA actuator wire. However, if the lengths of the SMA actuator wires 102, 104 in fig. 1 are increased, the overall size of the actuator 100 will increase, which may be undesirable as the actuator 100 may need to be incorporated into a device having a particular size. Another way to solve the stroke problem is to use angled lines to amplify the stroke. However, this may result in a larger actuator footprint (e.g., larger size) in order to accommodate the angled wire arrangement in the actuator. Another approach to solving the stroke problem is to wrap SMA wire around a pulley or pulley fitting to increase the stroke without significantly increasing the footprint (e.g., size) of the actuator. However, this can lead to mechanical losses due to friction at the pulley shaft.
The present technique described below with reference to fig. 2 to 11D provides a solution to the above-described problem.
Broadly, the present technology provides an actuator comprising: a static component; a movable member movable relative to the stationary member; at least one pulley arranged to perform a rotational action and a translational action, thereby driving the movement of the movable part; and at least one Shape Memory Alloy (SMA) actuator wire coupled to the static component and the at least one pulley and arranged to drive rotational and translational action of the at least one pulley.
The at least one pulley may be arranged to drive a translational and/or rotational motion of the movable part.
In an embodiment, the at least one pulley may perform a translational action in addition to a rotational action.
At least one pulley may roll along the surface. In an embodiment, the pulleys may be arranged such that a circumferential edge of at least one pulley may roll along the surface. Alternatively, the pulleys may be arranged such that the shaft of at least one pulley may roll along the surface. In any case, the surface may be substantially flat or may be curved.
The at least one SMA actuator wire may be coupled to a shaft of the at least one pulley. Alternatively, the at least one SMA actuator wire may be disposed around at least a portion of a circumferential edge of the at least one pulley.
In an embodiment, the shaft of the at least one pulley may be fixedly attached to the surface and the at least one pulley rotates about its shaft. In this case, at least one of the pulleys is not capable of translational movement.
In an embodiment, the actuator may further comprise a resilient biasing member to resist actuation of the movable member by the at least one pulley. Alternatively, the at least one pulley may drive the movable component when the at least one SMA actuator wire is heated, and cooling of the SMA actuator wire drives movement of the movable component in the opposite direction, so that a resilient biasing member is not required.
In embodiments, the actuator may comprise two pulleys or more pulleys. The pulleys may be of different sizes. For example, the diameter of the pulleys may be different and/or the diameter or height of the pulley shafts may be different.
The actuator may comprise two SMA actuator wires, or two lengths of SMA actuator wire. The two SMA actuator wires (or lengths of SMA actuator wires) may be opposed wires such that a first SMA actuator wire (or length) is arranged to drive the rotational action of the at least one pulley in a first direction and a second SMA actuator wire (or length) is arranged to drive the rotational action of the at least one pulley in a second direction opposite to the first direction.
Fig. 2 shows an actuator 200 comprising two opposed SMA actuator wires and two rollable/movable pulleys. The actuator 200 includes a first SMA actuator wire 202, which first SMA actuator wire 202 is coupled at one end to a movable component 206 and at the other end to a static component by a crimp 208. The actuator 200 also includes a second SMA actuator wire 204, the second SMA actuator wire 204 being coupled at one end to the movable component 206 and at the other end to the static component by a crimp 210. When the first SMA actuator wire 202 is driven (i.e. energised), the wire heats up and contracts, causing the movable member 206 to move in a first direction. This causes the second SMA actuator wire 204 to stretch or expand (expand). When the first SMA actuator wire 202 is no longer driven, the movable member 206 may be stationary in place (or may not move significantly from the position that the movable member 206 reached when the first SMA actuator wire 202 was driven). Similarly, when the second SMA actuator wire 204 is driven (i.e. energised), the wire heats up and contracts, causing the movable member 206 to move in a second direction (opposite to the first direction). This causes the first SMA actuator wire to stretch. When the second SMA actuator wire 204 is no longer driven, the movable member 206 may be stationary in place (or may not move significantly from the position that the movable member 206 reached when the second SMA actuator wire 204 was driven). Accordingly, the movable member 206 can be linearly moved as indicated by arrow B.
The first SMA actuator wire 202 is disposed around a pulley or pulley fitting 212 such that a first length/of the first SMA actuator wire 2021Is arranged between the crimp 208 and the pulley 212 and a second length l of the first SMA actuator wire 2022Is disposed between the pulley 212 and the movable member 206. Thus, two lengths or segments (segments) of the first SMA actuator wire 202 may be considered parallel or substantially parallel. The pulley 212 may roll on the surface 216. In other words, the position of the pulley 212 is not fixed relative to the surface 216, and the pulley 212 is able to roll along the surface 216 in the direction indicated by arrow C. Surface 216 may be any hard surface. The surface 216 may be a substantially flat surface or may be a curved surface. When the wire is under tension, the pulley 212 may be held in place on the surface 216 by the force exerted on the pulley 212 by the wire 202. (between and/or according to actuator arrangementsThe amount of tension may vary for the particular application being used). When the first SMA actuator wire 202 contracts, the wire contracts around the pulley 212 causing the movable member 206 to move in a first direction towards the pulley 212. Movement of the first SMA actuator wire 202 around the pulley 212 exerts a force on the pulley 212 that may cause the pulley 212 to roll on the surface 216. As the first SMA actuator wire 202 contracts, the pulley 212 may roll in one direction (e.g., toward the left hand side in fig. 2). When the first SMA actuator wire 202 stops being driven, the pulley 212 may roll in the opposite direction (e.g., toward the right hand side of fig. 2). Thus, by enabling the pulley 212 to roll along the surface 216, mechanical losses due to friction may be reduced.
Similarly, a length of the second SMA actuator wire 204 is disposed around a pulley or pulley fitting 214. The two lengths or segments of the second SMA actuator wire 204 surrounding the pulley 214 may be considered parallel or substantially parallel. The pulley 214 may roll on the surface 218. In other words, the position of the pulley 212 is not fixed relative to the surface 218, and the pulley 214 is able to roll along the surface 218 in the direction indicated by arrow D. Surface 218 may be any hard surface. The surfaces 216 and 218 may be made of the same material or different materials. The surfaces 216 and 218 may be different surfaces of the actuator 200. When the wire is under tension, the pulley 214 may be held in place on the surface 218 by the force exerted on the pulley 214 by the wire 204. When the second SMA actuator wire 204 contracts, the wire contracts around the pulley 214 causing the movable member 206 to move in a second direction towards the pulley 218. The movement of the second SMA actuator wire 204 around the pulley 214 exerts a force on the pulley 214 that may cause the pulley 214 to roll on the surface 218. When the second SMA actuator wire 204 contracts, the pulley 214 may roll in one direction (e.g., toward the right-hand side in fig. 2). When the second SMA actuator wire 204 stops being driven, the pulley 214 may roll in the opposite direction (e.g., toward the left-hand side of fig. 2). Thus, by enabling the pulley 214 to roll along the surface 218, mechanical losses due to friction may be reduced or avoided.
As can be seen from fig. 2, the lengths of the first and second SMA actuator wires 202 and 204 may be increased relative to the lengths of the first and second SMA actuator wires 102 and 104 in fig. 1 without substantially affecting the footprint of the actuator (i.e. without substantially increasing the length of the actuator). Thus, the arrangement shown in fig. 2 may advantageously increase the length of the SMA actuator wires (and thus the stroke of the actuator 200) without significantly increasing the size of the actuator, and while also reducing mechanical/frictional losses. In some cases, the friction loss of the rolling pulley arrangement of fig. 2 may be as much as 100 times less than that which occurs when the pulley is fixed and only able to rotate about the fixed shaft.
In the arrangement shown in fig. 2, the SMA actuator wires are in segments/of each actuator wire1And l2Wound in a substantially parallel manner around their respective pulleys. Further, each SMA actuator wire is coupled to a different surface. Specifically, the actuator 200 includes two surfaces that oppose or face each other.
Fig. 3 shows an actuator 300 comprising an alternative arrangement of two opposed SMA actuator wires and two rollable pulleys. In fig. 3, the segment/of each actuator wire1And l1Rather than being parallel, they may be angled with respect to each other. For example, segment l1And l2May be perpendicular or substantially perpendicular to each other as shown in fig. 3. In other words, each SMA actuator 302, 304 is coupled to the same surface, or to two different surfaces disposed side-by-side. If the lengths of the SMA actuator wires are the same in fig. 2 and 3, the actuator arrangement shown in fig. 3 is wider than the arrangement shown in fig. 2. Thus, the arrangement of pulleys and wires may be selected to suit the size of the device into which the actuator may be incorporated.
The actuator 300 comprises a first SMA actuator wire 302, which first SMA actuator wire 302 is coupled at one end to a movable component 306 and at the other end to a static component by a crimp 308. The actuator 300 further comprises a second SMA actuator wire 304, which second SMA actuator wire 304 is coupled at one end to the movable component 306 and at the other end to the static component by a crimp 310. When the first SMA actuator wire 302 is driven (i.e. energised), the wire heats up and contracts, causing the movable member 306 to move in a first direction. This causes the second SMA actuator wire 304 to stretch or expand. When the first SMA actuator wire 302 is no longer driven, the movable member 306 may be stationary in place (or may not move significantly from the position that the movable member 306 reached when the first SMA actuator wire 302 was driven). Similarly, when the second SMA actuator wire 304 is driven (i.e., energized), the wire heats and contracts, causing the movable member 306 to move in a second direction (opposite the first direction). This causes the first SMA actuator wire to stretch. When the second SMA actuator wire 304 is no longer driven, the movable member 306 may stay in place (or may not move significantly from the position that the movable member 306 reached when the second SMA actuator wire 304 was driven). Thus, the movable member 306 can move linearly as indicated by arrow E.
A length of the first SMA actuator wire 302 is disposed around a pulley or pulley fitting 312. The pulley 312 may roll on the surface 316. In other words, the position of the pulley 312 is not fixed relative to the surface 316, and the pulley 312 is able to roll along the surface 316. Surface 316 may be any hard surface. When the wire is under tension, the pulley 312 may be held in place on the surface 316 by the force exerted on the pulley 312 by the wire 302. When the first SMA actuator wire 302 contracts, the wire contracts around the pulley 312 causing the movable member 306 to move in a first direction towards the pulley 312. The movement of the first SMA actuator wire 302 around the pulley 312 exerts a force on the pulley 312 that may cause the pulley 312 to roll on the surface 316. The pulley 212 may roll in one direction when the first SMA actuator wire 302 contracts, and the pulley 312 may roll in the opposite direction when the first SMA actuator wire 302 stops being driven. Thus, by enabling the pulley 312 to roll along the surface 316, mechanical losses due to friction may be reduced or avoided.
Similarly, a length of the second SMA actuator wire 304 is disposed around a pulley or pulley fitting 314. The pulley 314 may roll on the surface 318. In other words, the position of the pulley 314 is not fixed relative to the surface 318, and the pulley 314 is able to roll along the surface 318. Surface 318 may be any hard surface. Surfaces 316 and 318 may be made of the same material or different materials. Surfaces 316 and 318 may be different surfaces of actuator 300. When the wire is under tension, the pulley 314 may be held in place on the surface 318 by the force exerted on the pulley 314 by the wire 304. When the second SMA actuator wire 304 contracts, the wire contracts around the pulley 314 causing the movable member 306 to move in a second direction towards the pulley 318. Movement of the second SMA actuator wire 304 around the pulley 314 exerts a force on the pulley 314 that may cause the pulley 314 to roll on the surface 318. When the second SMA actuator wire 304 contracts, the pulley 314 may roll in one direction, and when the second SMA actuator wire 304 stops being driven, the pulley 314 may roll in the opposite direction. Thus, by enabling the pulley 314 to roll along the surface 318, mechanical losses due to friction may be reduced or avoided.
As can be seen from fig. 3, the lengths of the first and second SMA actuator wires 302, 304 may be increased relative to the lengths of the first and second SMA actuator wires 102, 104 of fig. 1 without substantially affecting the footprint of the actuator (i.e. without substantially increasing the length of the actuator). Thus, the arrangement shown in fig. 3 may advantageously increase the length of the SMA actuator wires (and thus the stroke of the actuator 300) without significantly increasing the size of the actuator, while also reducing mechanical/frictional losses. The pulleys may be of different sizes. For example, the diameter of the pulleys may be different, and/or the diameter or height of the shafts of the pulleys may be different. The angle θ that each surface 316, 318 forms with respect to a certain reference line (e.g., with respect to an edge or line of the static component along which the SMA actuator wires 302, 304 are coupled) may be the same or different.
Fig. 9 shows another example actuator 900 that includes two SMA actuator wires and two rollable pulleys. The actuator 900 comprises a first SMA actuator wire 902, which first SMA actuator wire 902 is coupled at one end to a movable component 906 and at the other end to a static component by a crimp 908. The first SMA actuator wire 902 is disposed around (e.g., looped around) a first pulley or pulley assembly 912. The first pulley 912 is arranged to roll on the first surface 920. The first SMA actuator wire 902 is disposed about a shaft 914 of a first pulley 912. When the first SMA actuator wire 902 is driven (i.e., energized), the wire heats up and contracts. The contraction of the first SMA actuator wire 902 results in a force being exerted on the pulley 912, which in turn causes the pulley 912 to roll along the surface 920 in one direction. As the pulley 912 rolls, the movable member 906 may move in a first direction (e.g., toward the left-hand side in fig. 9).
The actuator 900 further comprises a second SMA actuator wire 904, which second SMA actuator wire 904 is coupled at one end to the movable component 906 and at the other end to the static component by a crimp 910. The second SMA actuator wire 904 is disposed around (e.g., looped around) a second pulley or pulley fitting 916. The second pulley 916 is arranged to roll on the first surface 922. The second SMA actuator wire 904 is disposed about the shaft 918 of the second pulley 916. When the second SMA actuator wire 904 is driven (i.e., energized), the wire heats up and contracts. The contraction of the second SMA actuator wire 904 results in a force being exerted on the pulley 916, which in turn causes the pulley 916 to roll along the surface 922 in one direction. As the pulley 916 rolls, the movable member 906 may move in a second direction (e.g., toward the right hand side in fig. 9).
The arrangement of fig. 9 is similar to that shown in fig. 2, except that each SMA actuator wire is not parallel around a length or segment of each pulley. The V-shape of each SMA actuator wire may cause the movable member 906 to be pulled both by the contraction of the wire and by the rolling of the pulley. In either case, by enabling the pulleys 912, 916 to roll along their respective surfaces 920, 922, mechanical losses due to friction may be reduced.
As can be seen from fig. 9, the lengths of the first and second SMA actuator wires 902 and 904 may be increased relative to the lengths of the first and second SMA actuator wires 102 and 104 in fig. 1 without substantially affecting the footprint of the actuator (i.e. without substantially increasing the length of the actuator). Thus, the arrangement shown in fig. 9 may advantageously increase the length of the SMA actuator wires (and thus the stroke of the actuator 900) without significantly increasing the size of the actuator, while also reducing mechanical/frictional losses.
Thus, in an embodiment, the actuator may comprise first and second SMA actuator wires, and first and second pulleys.
In an embodiment, the first SMA actuator wire may be coupled at a first end to the static component and at a second end to the movable component, and a portion of the first SMA actuator wire may be disposed about the first pulley; and the second SMA actuator wire may be coupled at a first end to the static component and at a second end to the movable component, and a portion of the second SMA actuator wire may be disposed around the second pulley, wherein the movable component may be disposed between the first pulley and the second pulley.
In an embodiment, a first end of a first SMA actuator wire may be coupled to a first side of a static component; and the first end of the second SMA actuator wire may be coupled to a second side of the static component, wherein the second side of the static component is opposite the first side.
The first pulley may be very close to the second side of the static component; and the second pulley may be very close to the first side of the static component.
In an embodiment, the actuator may include: a first surface and a second surface, the first pulley being arranged on the first surface to perform a rotational action and a translational action; the second pulley is disposed on the second surface for rotational and translational movement.
The first and second surfaces may be substantially parallel to the first and second sides of the static component.
In an embodiment, the lengths of the first SMA actuator wires may be substantially perpendicular to the first surface and the lengths of the second SMA actuator wires may be substantially perpendicular to the second surface. (the lengths of SMA actuator wire may not need to be exactly perpendicular relative to the surface). Alternatively, the length of the first SMA actuator wire may form a first acute angle (<90 °) with the first surface, and the length of the second SMA actuator wire may form a second acute angle (<90 °) with the second surface. The first acute angle and the second acute angle may be equal or different.
In an embodiment, both the first end of the first SMA actuator wire and the first end of the second SMA actuator wire may be coupled to one side of the static component. The first and second pulleys may be arranged at a distance from the side of the static part. The actuator may further include: a first surface on which a first pulley is arranged to perform a rotational action and a translational action; and a second surface on which the second pulley is arranged to perform both rotational and translational motions. The first surface may form a first angle with respect to a side of the static component and the second surface may form a second angle with respect to the side of the static component. The first angle and the second angle may be equal or different.
Fig. 4A shows a perspective view of an example actuator 400 including two opposing SMA actuator wires and a plurality of rollable pulleys, and fig. 4B shows a plan view of the example actuator shown in fig. 4A. For simplicity, only one of the SMA actuator wires is shown in fig. 4A and 4B.
The actuator 400 includes a static component 420 and a movable component 406. The static component 420 includes a slot or aperture 418, and the movable component 406 is arranged to move or slide within the aperture 418. The movable member 406 may include two legs 426 that extend into the aperture 418 and are arranged to engage opposite sides of the aperture 418. Each leg 426 includes a foot 428, the foot 428 being disposed through the aperture 418 to engage the underside of the static member 420 and secure the movable member 406 to the aperture 418.
The actuator comprises a first SMA actuator wire 402, which first SMA actuator wire 402 is coupled at one end to a movable component 406 by a crimp 412 and at the other end to a static component 420 by a crimp 408. The actuator 400 also includes a second SMA actuator wire (not shown in fig. 4A and 4B) that is also coupled at one end to the movable component 406 by a crimp and at the other end to the static component 420 by a crimp 410. The static component 420 includes an electrical terminal 422, which may be located near the edge of the aperture 418. The electrical connector 424 electrically couples the crimp portion 412 and the electrical terminal 422 together. The electrical connector 424 may have an accordion-like, coil-like, or spring-like shape such that the electrical connector 424 is able to expand and contract with movement of the movable member 406. As a result, the movable member 406 can move in the hole 418 while maintaining the electrical connection between the crimp portion 412 and the terminal 422. The electrical terminals 422 may be coupled to a power source (not shown) that may be used to selectively drive the SMA actuator wires of the actuator 400. In an embodiment, each of the two SMA actuator wires of the actuator 400 may be coupled to a separate crimp on the movable component 406, with each crimp being coupled to a separate electrical terminal on the static component 420. In this case, the end of each SMA actuator wire coupled to the movable component 406 may be independently coupled to a power source. Alternatively, each of the two SMA actuator wires of the actuator 400 may be coupled to the same crimp 412 of the movable component 406. In this case, the end of each SMA actuator wire coupled to the movable component 406 may be coupled to the power source via the same terminal 422.
The actuator 400 includes a plurality of rollable pulleys. In the embodiment depicted in fig. 4A, the actuator has twelve rollable pulleys (six rollable pulleys per SMA actuator wire), but it should be understood that this is merely one non-limiting arrangement. More generally, the actuator 400 may include two or more rollable pulleys, i.e., such that each SMA actuator wire is disposed around one or more rollable pulleys.
In the embodiment shown in fig. 4A, the first SMA actuator wire 402 is disposed around (e.g., partially wound around) six rollable pulleys, a first set of rollable pulleys 414A being disposed on a first side of the static component 420, and a second set of rollable pulleys 414b being disposed on a second side of the static component 420 (where the first side is opposite the second side). In the depicted arrangement, the first set of rollable pulleys 414a includes three pulleys, and the second set of rollable pulleys 414b also includes three pulleys. The SMA actuator wire 402 is crimped at one end in a crimp 408 and, after being wrapped around the pulleys of the first set of rollable pulleys 414a in an alternating manner, is wrapped around the pulleys of the second set of rollable pulleys 414 b. Once the first SMA actuator wire 402 has been wrapped around all of the first and second sets of rollable pulleys 414a, 414b, the free end (i.e., the un-crimped end) of the first SMA actuator wire 402 is coupled to the crimp 412 on the movable component 406.
Similarly, a second SMA actuator wire (not shown) is disposed around (e.g., partially wrapped around) six rollable pulleys, a first set of rollable pulleys 416a being disposed on a first side of the static component 420 and a second set of rollable pulleys 416b being disposed on a second side of the static component. In the depicted arrangement, the first set of rollable pulleys 416a includes three pulleys, and the second set of rollable pulleys 416b also includes three pulleys. The second set of rollable pulleys 416b also includes three pulleys. A second SMA actuator wire is crimped at one end in crimp 410 and, after being wound around the pulleys of the second set of rollable pulleys 416b in an alternating manner, is wound around the pulleys of the first set of rollable pulleys 416 a. Once the second SMA actuator wire has been wrapped around all of the first and second sets of rollable pulleys 416a, 416b, the free end (i.e., the un-crimped end) of the second SMA actuator wire is coupled to the crimp 412 on the movable component 406.
When the first SMA actuator wire 402 is driven (i.e., energized), the wire is heated and contracts around each of the first and second sets of rollable pulleys 414a, 414 b. Contraction of the first SMA actuator wire 402 causes the movable member 406 to move in a first direction. In this case, the movable member 406 moves in the slot 418 in a direction toward the crimping portion 408. This movement of the movable member 406 causes the second SMA actuator wire to stretch or expand. When the first SMA actuator wire 402 is no longer driven, the movable member 406 may be stationary in place (or may not move significantly from the position that the movable member 406 reached when the first SMA actuator wire 402 was driven). Similarly, when a second SMA actuator wire (not shown) is driven (i.e. energised), the wire heats up and contracts, causing the movable part 406 to move in a second direction (opposite to the first direction). In this case, the movable member 406 moves in the slot 418 in a direction toward the crimping portion 410. This motion causes the first SMA actuator wire 402 to stretch. When the second SMA actuator wire is no longer driven, the movable member 406 may be in place (or may not move significantly from the position that the movable member 406 reached when the second SMA actuator wire 404 was driven). Thus, the movable member 406 may move linearly within the slot 418 of the stationary member 420.
Each rollable pulley of actuator 400 is not secured to static component 420. Instead, each rollable pulley is disposed in a slot 430 of the static component 420 and is held in place in the slot 430 by the force exerted by the SMA actuator wire wrapped around the pulley (when the wire is under tension). When one of the SMA actuator wires contracts, the wire contracts around the pulley and exerts a force on the pulley that can cause the pulley to move within its slot 430. (a cover (not shown) may be provided at each end of the stationary member at least above the slot 430 to prevent the rollable pulley from rolling out/moving out of the slot.) thus, by enabling the pulley to move freely using the slot 430 of the pulley, mechanical loss due to friction may be reduced.
As can be seen from fig. 4A, the lengths of the first and second SMA actuator wires may be increased relative to the lengths of the first and second SMA actuator wires 102, 104 of fig. 1 without substantially affecting the footprint of the actuator (i.e. without substantially increasing the length of the actuator). The length of each SMA actuator wire may be varied by varying the number of pulleys around which the SMA actuator wire is wound. Thus, the arrangement shown in fig. 4A may advantageously increase the length of the SMA actuator wires (and thus the stroke of the actuator 400) without significantly increasing the length of the actuator, while also reducing mechanical/frictional losses.
Fig. 5A illustrates a side view of the example actuator 400 shown in fig. 4A, wherein the actuator is configured for linear motion. Here, the movable member 406 is coupled to the slide element 500, the slide element 500 being capable of moving linearly (i.e., from side to side) as the movable member 406 moves linearly in the slot 418. The sliding element 500 may include a coupling feature 512 that enables the sliding element 500 to be coupled to any other component that needs to move in a linear manner.
Fig. 5B illustrates a side view of the example actuator 400 shown in fig. 4A, wherein the actuator is configured for a rotational action. Here, the movable member 406 is coupled to the sliding element 502, the sliding element 502 being linearly movable as the movable member 406 moves linearly in the slot 418. The sliding element 502 is configured to convert a linear motion into a rotational motion. The sliding element 502 includes a series of teeth 504. In this embodiment, the actuator 400 includes a gear 506, wherein the gear 506 includes a series of teeth corresponding to the teeth 504 of the sliding element 502. The gear 506 is arranged such that the teeth of the gear 506 engage with the teeth 504 of the sliding element. Thus, when the sliding element 502 is moved from side to side, linear motion is converted to rotational motion through the interaction between the gear 506 and the teeth 504. The gear 506 may include or be coupled to a pin 508 that rotates as the gear 506 rotates. The pin 508 may be coupled to any other component that requires rotation. Thus, the actuator 400 may be used to control the rotational motion of a component.
As previously described, at least the slot 430 and the pulley may be encapsulated or covered to prevent the pulley from rolling out of the slot. As shown in fig. 5A and 5B, the actuator 400 may be at least partially enclosed within a cover or housing 510. The cover 510 may be shaped to enclose some components of the actuator 400 (e.g., the actuator wires and the roller pulleys), while allowing other components (e.g., the sliding element 502, the coupling feature 512, and the pin 508) to protrude/extend through the cover.
Thus, in an embodiment, the actuator may comprise a first length of SMA actuator wire and a second length of SMA actuator wire, and at least two pulleys. Alternatively, the actuator may comprise a first length of SMA actuator wire and a spring or other resilient element in place of a second length of SMA actuator wire.
The static component may include a first side and a second side, and the movable component is disposed on a surface of the static component between the first side and the second side of the static component.
A first length of SMA actuator wire may be coupled at a first end to a first side of the static component and at a second end to the movable component; and a second length of SMA actuator wire may be coupled at a first end to a second side of the static component and at a second end to the movable component.
The at least one pulley may be disposed at a second end of the static component, and a portion of the first length of SMA actuator wire is disposed around the at least one pulley at the second end; and at least one pulley is disposed at a first end of the static component, and a portion of the second length of SMA actuator wire is disposed around the at least one pulley at the first end.
In an embodiment, the actuator may include a first set of pulleys, a second set of pulleys, a third set of pulleys, and a fourth set of pulleys, each set of pulleys may include at least one pulley. The first set of pulleys may be disposed at the second end of the static component, the second set of pulleys may be disposed at the first end of the static component, and the first length of SMA actuator wire may be wrapped around the pulleys of the first set of pulleys and the pulleys of the second set of pulleys in an alternating manner; and the third set of pulleys may be disposed at the first end of the static component, the fourth set of pulleys may be disposed at the second end of the static component, and the second length of SMA actuator wire may be wrapped around the pulleys of the third set of pulleys and the pulleys of the fourth set of pulleys in an alternating manner.
Each pulley may be disposed in a separate slot in the static component.
The electrical terminal may be provided on a surface of the static part on which the movable part is provided. An expandable electrical connector may be provided to couple the movable component to the electrical terminal.
The actuator may comprise a sliding element coupled to the movable part and arranged to perform a translational action. The sliding element may be arranged to convert a translational motion into a rotational motion.
The first and second lengths of SMA actuator wire may be part of a single SMA actuator wire. In this case, the first length and the second length may be driven/energized separately. Alternatively, the first length of SMA actuator wire may be provided by a first SMA actuator wire and the second length of SMA actuator wire may be provided by a second SMA actuator wire.
Fig. 6A illustrates a side view of another example actuator 600, the actuator 600 including one SMA actuator wire 602 and a rollable pulley 604. The SMA actuator wire 602 is wound or wrapped around the shaft 606 of the rollable pulley 604. Rollable pulley 604 includes a series of teeth along the circumferential edge of rollable pulley 604. That is, the rollable pulley 604 may take the form of a gear or cogwheel (cogwheel). The actuator 600 may include a static component 612. The static member 612 may include a surface carrying a series of teeth that correspond to the teeth of the rollable pulley 604 and engage the teeth of the rollable pulley 604. Each end of the SMA actuator wire 602 may be coupled to a crimp 608, 610. The crimp 608 may be disposed on the static component 612 or elsewhere. The actuator 600 may include a movable member 614. The movable member 614 may include a surface carrying a series of teeth that correspond to the teeth of the rollable pulley 604 and engage the teeth of the rollable pulley 604.
When the SMA actuator wire 602 is driven (i.e., energized), the wire heats up and contracts. Contraction of the axis about the shaft 606 may cause the shaft to rotate in one direction (e.g., clockwise or counterclockwise) and thus cause the pulley 604 to rotate in one direction (e.g., clockwise or counterclockwise). As the rollable pulley 604 rotates, the engagement of the teeth of the rollable pulley 604 and the teeth of the static member 612 causes the rollable pulley 604 to move along the static member 612. As the rollable pulley 604 moves, the movable member 614 also moves because the teeth of the movable member 614 engage with the teeth of the rollable pulley 604. Thus, the actuator 600 may be used to convert a rotational motion into a linear motion. When the SMA actuator wire 602 is no longer driven, the wire may expand, and this may cause the rollable pulley 604 to rotate in the opposite direction (e.g., counterclockwise or clockwise). Thus, the movable member 614 may be caused to move in the opposite direction.
Fig. 6A shows a rollable pulley 604 having teeth corresponding to the static part and the movable part. However, in alternative embodiments, none of these components may have teeth. Instead, the actuator may use friction to cause movement of the movable member 614. In this case, the rollable pulley 604 can be held relatively firmly between the static member 612 and the movable member 614. In this case, the surfaces that are in contact may be roughened or roughened to increase the friction between the various elements of the actuator 600. As the rollable pulley 604 rotates, the frictional force between the rollable pulley 604 and the static member 612 may be sufficient to cause the rollable pulley 604 to move along the static member. As the rollable pulley 604 moves, the friction between the rollable pulley 604 and the movable member 614 may be large enough to cause the movable member 614 to also move.
Fig. 6B shows a side view of another example actuator 600 ', the actuator 600' including one SMA actuator wire 602 'and a rollable pulley 604'. The SMA actuator wire 602 ' is wound or wrapped around the shaft 606 ' of the rollable pulley 604 '. The actuator 600 'may include a static component 612'. Each end of the SMA actuator wire 602 ' may be coupled to a crimp 608 ', 610 '. The crimp 608 'may be provided on the static part 612' or elsewhere. The actuator 600 'may include a movable member 614'. The actuator 600 'may include one or more straps or bands that assist in moving the rollable pulley 604' relative to the static element 612 'to cause movement of the movable element 614'. In the depicted arrangement, actuator 600 ' includes four strap members 618a ' through 618d '. Each strap member may be coupled at one end to the static component 612 ' or the movable component 614 ' by a coupling device 616 ' and may be coupled at the other end to the rollable pulley 604 ' by a coupling device 620 '. In the particular arrangement shown in fig. 6B, strap piece 618a ' is coupled at one end to static component 612 ' by coupling device 616a ' and at the other end to rollable pulley 604 ' by coupling device 620B '. Strap member 618b ' is coupled at one end to movable component 614 ' by coupling device 616b ' and at the other end to rollable pulley 604 ' by coupling device 620b '. Strap member 618c ' is coupled at one end to static component 612 ' by coupling device 616c ' and at the other end to rollable pulley 604 ' by coupling device 620a '. Strap member 618d ' is coupled at one end to movable component 614 ' by coupling device 616d ' and at the other end to rollable pulley 604 ' by coupling device 620a '. Each of the strap members 618a 'to 618 d' may be formed of an inelastic material.
When the SMA actuator wire 602' is driven (i.e., energized), the wire heats up and contracts. Contraction of the shaft about the axis 606 'may cause the shaft to rotate in one direction (e.g., clockwise or counterclockwise) and thus cause the pulley 604' to rotate in one direction (e.g., clockwise or counterclockwise). As the rollable pulley 604 ' rotates, the arrangement of the strap members 618a ' to 618d ' may cause the rollable pulley 604 ' to move in one direction along the static element 612 '. As the rollable pulley 604 'moves, the movable member 614' also moves due to the arrangement of the strap members. Thus, the actuator 600' may be used to convert a rotational motion into a linear motion. When the SMA actuator wire 602 'is no longer driven, the wire may expand, which may cause the rollable pulley 604' to rotate in the opposite direction (e.g., counterclockwise or clockwise). Thus, the movable member 614' may be caused to move in the opposite direction.
Since the rollable pulley 604 is free to move between the static member 612 and the movable member 614, the rollable pulley 604 is not fixed. Therefore, mechanical loss due to friction can be reduced.
In an embodiment, the actuator may comprise one SMA actuator wire and one pulley.
The pulley may be arranged to perform both a rotational and a translational action. The pulley may be disposed in abutting relationship between the static component and the movable component and operatively arranged to roll along the static component to drive translational movement of the movable component. The SMA actuator wires may be coupled to the static component and the pulley and arranged to drive rotational and translational action of the pulley.
The pulley may include a plurality of teeth along a circumferential edge of the pulley; the static component may include a surface carrying a series of teeth (which engage the teeth of the pulley); and the movable member may include a surface carrying a series of teeth that engage the teeth of the pulley. Optionally, the actuator may comprise at least two strap members, wherein a first strap member is coupled at one end to the static component and at another end to the pulley, and a second strap member is coupled at one end to the movable component and at another end to the pulley. In any case, the SMA actuator wire may be coupled to the static component at a first end and may be wound around the shaft of the pulley.
The pulley may be arranged to convert a rotational action into a translational action.
Fig. 7A shows another example actuator 700 that includes one SMA actuator wire 702 and a rollable pulley 708. The SMA actuator wires 702 may be coupled at one end to the movable component 706 and at the other end to the static component 704. The SMA actuator wire 702 is disposed around a rollable pulley 708. The rollable pulley 708 can be arranged to roll/move along the surface 710. When the SMA actuator wire 702 is driven (i.e., energized), the wire heats up and contracts. Contraction of the SMA actuator wires 702 causes the movable member 706 to move in the direction of the arrow. The rollable pulley 708 of the actuator 700 is not fixed in position relative to the surface 710. Instead, the rollable pulley 708 is held in place on/against the surface 710 by the force exerted by the SMA actuator wire 702 wound around the pulley (when the wire is under tension). When the SMA actuator wire 702 contracts, the wire contracts around the rollable pulley 708 and exerts a force on the pulley that can cause the pulley to move/roll along the surface 710. (a barrier or stop or similar element may be provided on the surface 710 to limit the rolling action of the rollable wheel 708.) thus, by enabling the rollable wheel 708 to move/roll along the surface 710, mechanical losses due to friction may be reduced. Furthermore, such an arrangement may enable a longer length of SMA actuator wire (and hence a greater actuator stroke) to be provided, relative to the arrangement shown in fig. 1, without substantially affecting the footprint of the actuator.
Fig. 7B shows another example actuator 750 including one SMA actuator wire 752 and a pulley 758. The SMA actuator wires 752 may be coupled at one end to the movable component 756 and at the other end to the static component 754. SMA actuator wire 752 is disposed around pulley 758. The pulley 758 may be a rollable pulley arranged to roll/move along a surface, or may be a static pulley fixed to a surface and capable of rotation (but not rolling/moving). In the former case, the rollable pulley 758 can be held in place on/against a surface by the force exerted by the SMA actuator wire 752 wound around the pulley (when the wire is under tension). In either case, when the SMA actuator wire 752 is driven (i.e., energized), the wire heats up and contracts. Contraction of the SMA actuator wire 752 causes the movable member 756 to move in the direction of the arrow. When the SMA actuator wire 752 contracts, the wire contracts around the pulley 758 and exerts a force on the pulley that can cause the pulley to move/roll along the surface, or rotate, depending on the particular configuration. (a barrier or stop or similar element may be provided on the rolling surface to limit the rolling action of the rollable pulley.) if the pulley 758 is a rollable pulley, mechanical losses due to friction may be reduced or avoided. Whether the pulley 758 is a rolling pulley or a static pulley, the arrangement of fig. 7B may enable a longer length of SMA actuator wire (and thus a greater actuator stroke) to be provided, relative to the arrangement shown in fig. 1, without substantially affecting the footprint of the actuator.
In an embodiment, the actuator may comprise one SMA actuator wire and one pulley.
The SMA actuator wire may be coupled at a first end to the static component and at a second end to the movable component, wherein a portion of the SMA actuator wire may be disposed around the pulley.
The actuator may comprise a surface on which the pulley is arranged to perform both a rotational and a translational action.
A first length of SMA actuator wire between the static component and the pulley may be substantially parallel to a second length of SMA actuator wire between the pulley and the movable component. Alternatively, a first length of SMA actuator wire between the static component and the pulley may be substantially non-parallel to a second length of SMA actuator wire between the pulley and the movable component.
Fig. 8 shows a side view of an arrangement 800 of pulleys having different inner diameters. As shown in fig. 4A, an actuator including a plurality of pulleys may be used to increase the stroke of the actuator. Fig. 8 may be considered to show a set of rollable pulleys in more detail, such as set 414A in fig. 4A. The individual rollable pulleys may not be in contact with each other (i.e., may not be in contact), and may be coupled together only by SMA actuator wires disposed around all of the pulleys. The SMA actuator wires 802 are disposed around pulleys 804, 806, 808, the pulleys 804, 806, 808 forming a set of pulleys in the manner described above with reference to fig. 4A. The SMA actuator wires 802 are disposed around an outer diameter or circumference of each of the pulleys 804, 806, 808. Each pulley 804, 806, 808 includes a different sized smaller shaft or similar protrusion 810 that forms the rolling element of each rollable pulley. The shaft 810 of each pulley 804, 806, 808 is arranged to roll on a surface (not shown). As shown, the shaft 810 of the pulley 804 has a small diameter D but a large height H. The shaft of the second pulley 806 has a larger diameter and a smaller height than the shaft of the pulley 804. The shaft of the third pulley 808 has a larger diameter and a smaller height than the shaft of the pulley 804.
Fig. 10 shows an example actuator 1000 that includes two SMA actuator wires and a rollable pulley. Thus, in an embodiment, the actuator may comprise first and second SMA actuator wires, and one pulley. The example actuator 1000 may be used in a servo motor.
The first SMA actuator wire 1002 may be coupled at a first end to a static component (not shown) and at a second end to a movable component 1006. The second SMA actuator wires 1004 may be coupled at a first end to a static member and at a second end to a movable member 1006. The movable member 1006 may be disposed on a pulley 1008. The first SMA actuator wire 1002 may be arranged to rotate the pulley 1008 in a first direction (e.g., counterclockwise) and the second SMA actuator wire 1004 may be arranged to rotate the pulley 1008 in a second, opposite direction (e.g., clockwise).
Fig. 11A-11D show various arrangements of SMA actuator wires around a rollable pulley and how the rollable pulley can be rolled. Some or all of these arrangements may enable the provision of actuators having a lower footprint (e.g., smaller size). In fig. 11A, SMA actuator wires 1100 are disposed around the circumferential edge of pulley 1102. The pulley 1102 includes a shaft 1104, the shaft 1104 being arranged to rotate and roll along a surface 1106. Here, as shaft 1104 rotates and rolls along surface 1106, and because shaft 1104 is smaller than pulley 1102, the overall translation of pulley 1102 is lower than if the circumferential edge of pulley 1102 rolls on the surface. For example, if the SMA actuator wire 1100 contracts 1mm, the shaft 1104 may only move ± 0.3mm on one side to the other, rather than ± 1 mm. Thus, a smaller actuator may be provided. In fig. 11B, SMA actuator wires 1100 are disposed around the circumferential edge of pulley 1102. The pulley 1102 is arranged to rotate and roll along a surface 1106. Here, as the pulley 1102 rotates and rolls along the surface 1106, a larger rolling surface 1106 is required relative to fig. 11A. For example, if the SMA actuator wires 1100 contract ± 1mm, the pulley 1102 may move ± 1mm from side to side along the surface 1106. Thus, this arrangement can provide an actuator with greater travel than an actuator in which the pulley does not roll, and relative to the arrangement of fig. 11A.
In fig. 11C, SMA actuator wires 1100 are disposed around the shaft 1104 of the pulley 1102. The pulley 1102 is arranged to rotate and roll along a surface 1106. This arrangement can convert small movements (rotations) of the shaft 1104 into large translations through the pulley 1102.
In fig. 11D, SMA actuator wires 1100 are disposed around the circumferential edge of pulley 1102. The pulley 1102 includes a shaft 1104, the shaft 1104 being arranged to be positioned with the slot 1110 of the mounting surface 1108. As the pulley 1102 rotates, the shaft 1104 may move within the slot 1110. The slot 1110 may be substantially straight as shown, or may be curved. Slot 1110 limits the movement of pulley 1102. In the arrangement of fig. 11A-11C, a stop or similar element may be required to limit the movement of the pulley 1102/shaft 1104 along the surface 1106 to prevent rolling to the point where the SMA actuator wires are over-stretched (which may lead to breakage).
The actuators described herein may be used in any scenario or device where large movements/displacements of components of the device are required, but it may not be feasible to provide long lengths of SMA actuator wire (e.g. the actuators need to be compact or miniature).
Accordingly, in an embodiment, there is provided an apparatus comprising: an actuator for moving a component of the apparatus, the actuator comprising: a static component; a movable component movable relative to the static component and coupled to a component of the apparatus; at least one pulley arranged to perform a rotational action and a translational action, thereby driving the movement of the movable part; and at least one Shape Memory Alloy (SMA) actuator wire coupled to the static component and the at least one pulley and arranged to drive rotational and translational motion of the at least one pulley.
The device may be any of the following: smart phones, cameras, foldable smart phones, foldable smart phone cameras, image capture devices, servomotors, consumer electronics devices, mobile computing devices, laptops, tablet computing devices, security systems, gaming systems, augmented reality devices, virtual reality systems, virtual reality devices, wearable devices, unmanned planes (aerial, waterborne, underwater, etc.), airplanes, space vehicles, submersible boats, vehicles, and autonomous vehicles. It should be understood that this is a non-exhaustive list of example devices.
One exemplary use of the actuator of the present technology may be in an image capture device. The actuators described herein may be incorporated into an image capture device and used to move an optical element such that the optical element at least partially covers an aperture (aperture) of the image capture device. The optical element may be a shutter, which may reduce the total amount of light passing through the aperture of the image capture device. The shutter may be fully open, partially open, and/or fully closed. The optical element may be a filter 10 capable of blocking certain wavelengths of light from passing through the optical aperture of the image capture device. In one example, the filter may be an infrared cut filter.
Other embodiments of the present technology are set forth in the following numbered clauses:
1. an actuator, comprising: a static component; a movable member movable relative to the stationary member; at least one pulley arranged to perform a rotational action and a translational action, thereby driving the movement of the movable part; and at least one Shape Memory Alloy (SMA) actuator wire coupled to the static component and the at least one pulley and arranged to drive rotational and translational motion of the at least one pulley.
2. The actuator according to clause 1, wherein the at least one pulley is arranged to drive a translational action of the movable part.
3. The actuator according to clause 1, wherein the at least one pulley is arranged to drive the rotational action of the movable member.
4. The actuator of clauses 1, 2 or 3, wherein at least one pulley rolls along a surface.
5. The actuator of clause 4, wherein the circumferential edge of the at least one pulley rolls along the surface.
6. The actuator of clause 4, wherein the shaft of the at least one pulley rolls along the surface.
7. The actuator of clauses 4, 5 or 6, wherein the surface is substantially flat.
8. The actuator of clauses 4, 5 or 6, wherein the surface is curved.
9. The actuator of any of clauses 1-8, wherein at least one SMA actuator wire is coupled to a shaft of at least one pulley.
10. The actuator of any of clauses 1-8, wherein at least one SMA actuator wire is disposed around at least a portion of a circumferential edge of at least one pulley.
11. The actuator according to any of the preceding clauses, further comprising a resilient biasing member to resist actuation of the movable member by the at least one pulley.
12. The actuator of any of clauses 1-11, further comprising two pulleys.
13. The actuator of any of clauses 1-11, comprising a plurality of pulleys.
14. The actuator according to clause 12 or 13, wherein the pulleys may be of different sizes.
15. An actuator according to any of the preceding clauses, comprising two SMA actuator wires.
16. An actuator according to any of the preceding clauses, wherein the two SMA actuator wires are opposed wires such that a first SMA actuator wire is arranged to drive the rotary action of the at least one pulley in a first direction and a second SMA actuator wire is arranged to drive the rotary action of the at least one pulley in a second direction opposite to the first direction.
17. The actuator of clause 1, wherein the actuator comprises first and second SMA actuator wires, and first and second pulleys.
18. The actuator of clause 17, wherein: a first SMA actuator wire coupled at a first end to the static component and at a second end to the movable component, and a portion of the first SMA actuator wire disposed about the first pulley; and a second SMA actuator wire coupled at a first end to the static component and at a second end to the movable component, and a portion of the second SMA actuator wire disposed around a second pulley, wherein the movable component is disposed between the first pulley and the second pulley.
19. The actuator of clause 18, wherein: a first end of a first SMA actuator wire is coupled to a first side of the static component; and the first end of the second SMA actuator wire is coupled to a second side of the static component, wherein the second side of the static component is opposite the first side.
20. The actuator of clause 19, further comprising: a first surface on which a first pulley is arranged to perform a rotational action and a translational action; and a second surface on which the second pulley is arranged to perform both rotational and translational motions.
21. An actuator according to any of clauses 18, 19 or 20, wherein the length of the first SMA actuator wire is substantially perpendicular to the first surface and the length of the second SMA actuator wire is substantially perpendicular to the second surface.
22. An actuator according to any of clauses 18 to 21, wherein the lengths of the first SMA actuator wires form a first acute angle with the first surface and the lengths of the second SMA actuator wires form a second acute angle with the second surface.
23. The actuator of clause 22, wherein the first acute angle and the second acute angle are equal.
24. The actuator of clause 18, wherein: the first ends of the first and second SMA actuator wires are both coupled to one side of the static component.
25. The actuator of clause 24, further comprising: a first surface on which a first pulley is arranged to perform a rotational action and a translational action; and a second surface on which the second pulley is arranged to perform a rotational action and a translational action.
26. The actuator of clause 25, wherein the first surface forms a first angle with respect to the side of the static component and the second surface forms a second angle with respect to the side of the static component.
27. The actuator of clause 26, wherein the first angle and the second angle are equal.
28. The actuator of clause 1, wherein the actuator comprises a first length of SMA actuator wire and a second length of SMA actuator wire, and at least two pulleys.
29. The actuator of clause 28, wherein the static component includes a first side and a second side, and the movable component is disposed on a surface of the static component between the first side and the second side of the static component.
30. The actuator of clause 29, wherein: a first length of SMA actuator wire coupled at a first end to a first side of the static component and at a second end to the movable component; and a second length of SMA actuator wire is coupled at a first end to a second side of the static component and at a second end to the movable component.
31. The actuator of clause 30, wherein: at least one pulley is disposed at a second end of the static component, and a portion of the first length of SMA actuator wire is disposed around the at least one pulley at the second end; and at least one pulley is disposed at a first end of the static component, and a portion of the second length of SMA actuator wire is disposed around the at least one pulley at the first end.
32. The actuator of clauses 30 or 31, wherein the actuator comprises a first set of pulleys, a second set of pulleys, a third set of pulleys, and a fourth set of pulleys, each set of pulleys comprising at least one pulley.
33. The actuator of clause 32, wherein: a first set of pulleys is disposed at the second end of the static component, a second set of pulleys is disposed at the first end of the static component, and a first length of SMA actuator wire is wrapped around the pulleys of the first set of pulleys and the pulleys of the second set of pulleys in an alternating manner; and a third set of pulleys is disposed at the first end of the static component, a fourth set of pulleys is disposed at the second end of the static component, and a second length of SMA actuator wire is wrapped around the pulleys of the third set of pulleys and the pulleys of the fourth set of pulleys in an alternating manner.
34. The actuator of any of clauses 31-33, wherein each pulley is disposed in a separate slot in the static component.
35. The actuator of any of clauses 29 to 34, further comprising: an electrical terminal on a surface of the stationary part on which the movable part is arranged; and an expandable electrical connector for coupling the movable member to the electrical terminal.
36. The actuator according to any of clauses 28 to 35, further comprising a sliding element coupled to the movable component and arranged to perform a translational action.
37. The actuator according to clause 36, wherein the sliding element is arranged to convert a translational motion into a rotational motion.
38. An actuator according to any of clauses 28 to 37, wherein the first and second lengths of SMA actuator wire are part of a single SMA actuator wire.
39. An actuator according to any of clauses 28 to 37, wherein the first length of SMA actuator wire is provided by a first SMA actuator wire and the second length of SMA actuator wire is provided by a second SMA actuator wire.
40. The actuator of clause 1, wherein the actuator comprises first and second SMA actuator wires, and a pulley.
41. The actuator of clause 40, wherein: a first SMA actuator wire coupled at a first end to the static component and at a second end to the movable component; and a second SMA actuator wire coupled at a first end to the static component and at a second end to the movable component; wherein the movable component is provided on a pulley and wherein the first SMA actuator wire is arranged to rotate the pulley in a first direction and the second SMA actuator wire is arranged to rotate the pulley in an opposite second direction.
42. The actuator of clause 1, wherein the actuator comprises an SMA actuator wire and a pulley.
43. The actuator of clause 42, wherein: the pulley is arranged to perform a rotational action and a translational action and is disposed in abutting relationship between the static component and the movable component and is operatively arranged to roll along the static component, thereby driving the translational action of the movable component; the SMA actuator wires are coupled to the static component and the pulley and are arranged to drive rotational and translational motion of the pulley.
44. The actuator of clause 43, wherein: the pulley includes a plurality of teeth along a circumferential edge of the pulley; the static component includes a surface carrying a series of teeth, the series of teeth of the surface of the static component engaging the teeth of the pulley; and the movable member includes a surface carrying a series of teeth that engage the teeth of the pulley.
45. The actuator of clause 43, further comprising: at least two strap members, wherein a first strap member is coupled at one end to the static component and coupled at another end to the pulley, and a second strap member is coupled at one end to the movable component and coupled at another end to the pulley.
46. The actuator of clause 44 or 45, wherein the SMA actuator wire is coupled to the static component at a first end and wound around the shaft of the pulley.
47. The actuator according to any of clauses 42 to 46, wherein the pulley is arranged to convert a rotational action into a translational action.
48. The actuator of clause 42, wherein the SMA actuator wire is coupled at a first end to the static component and at a second end to the movable component, wherein a portion of the SMA actuator wire is disposed about the pulley.
49. The actuator according to clause 48, further comprising: a surface on which the pulley is arranged to perform both a rotational and a translational action.
50. The actuator of clause 49, wherein a first length of the SMA actuator wire between the static component and the pulley is substantially parallel to a second length of the SMA actuator wire between the pulley and the movable component.
51. The actuator of clause 49, wherein a first length of the SMA actuator wire between the static component and the pulley is substantially non-parallel to a second length of the SMA actuator wire between the pulley and the movable component.
It should be appreciated by those of skill in the art that while the foregoing has described what is considered to be the best mode and other modes of carrying out the present technology where appropriate, the present technology should not be limited to the specific configurations and methodologies disclosed by such description of the preferred embodiments. Those skilled in the art will recognize that the present technology has a wide range of applications, and that the embodiments can be modified in a wide range without departing from any inventive concept defined by the appended claims.

Claims (24)

1. An actuator, comprising:
a static component;
a movable member movable relative to the static member;
at least one pulley arranged to perform a rotational action and a translational action, thereby driving the movement of the movable part; and
at least one Shape Memory Alloy (SMA) actuator wire coupled to the static component and the at least one pulley and arranged to drive the rotational and translational motion of the at least one pulley.
2. An actuator according to claim 1, wherein the at least one pulley is arranged to drive the translational action of the movable component.
3. An actuator according to claim 1, wherein the at least one pulley is arranged to drive the rotational action of the movable component.
4. An actuator according to claim 1, 2 or 3, wherein the at least one pulley rolls along a surface.
5. An actuator according to claim 4, wherein a circumferential edge of the at least one pulley rolls along the surface.
6. The actuator of claim 4, wherein the shaft of the at least one pulley rolls along the surface.
7. An actuator according to claim 4, 5 or 6, wherein the surface is substantially flat.
8. An actuator according to claim 4, 5 or 6, wherein the surface is curved.
9. An actuator according to any one of claims 1 to 8, wherein said at least one SMA actuator wire is coupled to a shaft of said at least one pulley.
10. An actuator according to any one of claims 1 to 8, wherein said at least one SMA actuator wire is disposed around at least a portion of a circumferential edge of said at least one pulley.
11. An actuator according to any preceding claim, further comprising a resilient biasing member to resist actuation of the movable component by the at least one pulley.
12. The actuator of any one of claims 1 to 11, further comprising two pulleys.
13. An actuator according to any of claims 1 to 11, comprising a plurality of pulleys.
14. An actuator according to claim 12 or 13, wherein the pulleys may be of different sizes.
15. An actuator according to any preceding claim, comprising two SMA actuator wires.
16. An actuator according to any preceding claim, wherein the two SMA actuator wires are opposed wires such that a first SMA actuator wire is arranged to drive the rotational action of the at least one pulley in a first direction and a second SMA actuator wire is arranged to drive the rotational action of the at least one pulley in a second direction opposite to the first direction.
17. An actuator according to claim 1, wherein the actuator comprises first and second SMA actuator wires, and first and second pulleys.
18. An actuator according to claim 1, wherein the actuator comprises a first length of SMA actuator wire and a second length of SMA actuator wire, and at least two pulleys.
19. An actuator according to claim 1, wherein the actuator comprises first and second SMA actuator wires, and a pulley.
20. An actuator according to claim 1, wherein the actuator comprises one SMA actuator wire and one pulley.
21. An actuator; comprises that
A static component;
a movable member movable relative to the static member;
a pulley arranged to perform a rotational action to drive a rotational movement of the movable member;
a first Shape Memory Alloy (SMA) actuator wire coupled at one end to the static component and at another end to the pulley and arranged to drive the rotational action of the pulley in a first direction; and
a second SMA actuator wire coupled at one end to the static component and at another end to the pulley and arranged to drive the rotational action of the pulley in a second direction opposite the first direction.
22. An actuator, comprising:
a static component;
a movable member movable relative to the static member;
a pulley arranged for rotational and translational movement, disposed in abutting relationship between the static component and the movable component, and operatively arranged to roll along the static component, thereby driving translational movement of the movable component; and
a Shape Memory Alloy (SMA) actuator wire coupled to the static component and the pulley and arranged to drive the rotational and translational motion of the pulley.
23. An apparatus, comprising:
an actuator according to claims 1 to 22 for moving a component of the apparatus, wherein the movable component of the actuator is coupled to the component of the apparatus.
24. The apparatus of claim 23, wherein the apparatus is any one of: a smartphone, a camera, a foldable smartphone, a foldable image capture device, a foldable smartphone camera, an image capture device, a servo motor, a consumer electronics device, a mobile computing device, a laptop, a tablet computing device, a security system, a gaming system, an augmented reality device, a virtual reality system, a virtual reality device, a wearable device, a drone, an aircraft, a spacecraft, a submersible vessel, a vehicle, and an autonomous vehicle.
CN201980058078.XA 2018-07-06 2019-07-05 Rolling pulley Pending CN112654784A (en)

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PCT/GB2019/051920 WO2020008216A1 (en) 2018-07-06 2019-07-05 Rolling pulleys

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GB202118964D0 (en) * 2021-12-23 2022-02-09 Cambridge Mechatronics Ltd Actuator assembly

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