Bilinear shape memory alloy wire for actuator

Abstract

A shape memory alloy (SMA) wire assembly includes a first crimp, a second crimp, a metal bridge, a first SMA wire, and a second SMA wire. The metal bridge includes a first line end and a second line end opposite the first line end. The first SMA wire is configured to be linearly oriented and includes a first mounting end and a first bridge end opposite the first mounting end. The first bridge end is fixedly coupled to the first wire end of the metal bridge via a first crimp. The second SMA wire is configured to be linearly oriented and includes a second mounting end and a second bridge end opposite the second mounting end. The second bridge end is fixedly coupled to the second wire end of the metal bridge via a second crimp.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to a shape memory alloy (SMA) wire assembly for an actuator that can be included in a vehicle. BACKGROUND

[0002] The information provided in this section is presented to generally summarize the context of the disclosure. To the extent the descriptions in this section describe presently named inventors' work, and to the extent the descriptions in this section may not constitute prior art to the present disclosure, neither expressly nor inherently, are such descriptions admitted to be prior art against the present disclosure.

[0003] Actuators can be included in vehicles to perform various functions and operations based on corresponding vehicle components. For example, an actuator can be included in a vehicle seat assembly to control air flow to an air cell lumbar through operation of the actuator. Such actuators generally include an SMA wire that controls operation of the actuator, which in turn controls air flow to the air cell lumbar of the vehicle seat.

[0004] The SMA wire includes a curved portion that is pressed against a plastic body of the actuator. The plastic body interfaces with a spring of the actuator, and the SMA wire includes two ends that are fixed to the actuator. The SMA wire also includes two linear portions, each connecting the curved portion to each end of the SMA wire. In most cases, all portions of the SMA wire are continuous and are a single wire. During operation, the SMA wire included in the actuator receives an electrical charge, allowing current to flow through the SMA wire. When current flows through the SMA wire, the SMA wire experiences a solid-state phase change along at least one linear axis, allowing the SMA wire to contract. Since the two ends of the SMA wire are fixed to the actuator, when the SMA wire contracts, the force exerted from the SMA wire to the plastic body increases, forcing the plastic body to move linearly and compress the spring. When the current stops flowing through the SMA wire, the SMA wire returns to its initial orientation, allowing the spring to decompress and return the plastic body to its initial position.

[0005] The motion of the plastic body facilitated by the phase change of the SMA wire enables operation of the vehicle component that the actuator interfaces with, such as, continuing the example described above, the air cell lumbar of the vehicle seat assembly. The actuator controls air flow into and out of the air cell lumbar based on the motion of the plastic body in the actuator. However, since the SMA wire includes a curved portion that partially wraps around the plastic body, failure and breakage of the SMA wire can occur where the curved portion meets each linear portion. When the SMA wire receives current, failure can generally be caused by a thermal difference between the curved portion and the linear portions of the SMA wire since the curved portion is pressed against the plastic body and the linear portions are in free space. When failure occurs, the SMA wire suddenly breaks, rendering the actuator inoperable. It would be desirable to have a SMA wire that is reinforced where the linear portions meet the curved portion, thereby reducing the likelihood of failure of the SMA wire. SUMMARY

[0006] One aspect of the present disclosure provides a shape memory alloy (SMA) wire assembly. The SMA wire assembly includes a first crimp, a second crimp, a metal bridge, a first SMA wire, and a second SMA wire. The metal bridge includes a first wire end and a second wire end opposite the first wire end. The first SMA wire is configured along a linear orientation and includes a first mounting end and a first bridge end opposite the first mounting end. The first bridge end is fixedly coupled to the first wire end of the metal bridge via the first crimp. The second SMA wire is configured along a linear orientation and includes a second mounting end and a second bridge end opposite the second mounting end. The second bridge end is fixedly coupled to the second wire end of the metal bridge via the second crimp.

[0007] Embodiments of the present disclosure can include one or more of the following optional features. In some examples, the first SMA wire has a first length and a first tension, the second SMA wire has a second length and a second tension, the first length is equal to the second length, and the first tension is equal to the second tension.

[0008] In some embodiments, the first crimp and the second crimp are integrally formed with the metal bridge, the first crimp is disposed at the first wire end of the metal bridge, and the second crimp is disposed at the second wire end of the metal bridge.

[0009] In some aspects, the first wire end of the metal bridge is configured to receive the first crimp, and the second wire end of the metal bridge is configured to receive the second crimp.

[0010] In some configurations, the SMA wire assembly further includes an actuator including a plastic body, wherein the metal bridge is coupled to the plastic body.

[0011] In some further configurations, the first crimp and the second crimp are rigidly and fixedly attached to the plastic body of the actuator.

[0012] In some other further configurations, the metal bridge is configured to be overmolded to the plastic body of the actuator.

[0013] In some other further configurations, the metal bridge is configured to engage with a pocket of the plastic body of the actuator.

[0014] In some examples, the first SMA wire and the second SMA wire each include an electrically conductive material configured to accommodate a linear solid state phase change of the first SMA wire and the second SMA wire.

[0015] Another aspect of the disclosure provides an actuator. The actuator includes a plastic body and an SMA wire assembly. The SMA wire assembly includes a first crimp, a second crimp, a metal bridge, a first SMA wire, and a second SMA wire. The metal bridge includes a first wire end and a second wire end opposite the first wire end. The first SMA wire is linearly configured and includes a first mounting end, a first bridge end opposite the first mounting end, and a conductive material. The first bridge end is fixedly coupled to the first wire end of the metal bridge via the first crimp, and the conductive material is configured to accommodate a linear solid state phase change of the first SMA wire. The second SMA wire is linearly configured and includes a second mounting end, a second bridge end opposite the second mounting end, and a conductive material. The second bridge end is fixedly coupled to the second wire end of the metal bridge via the second crimp, and the conductive material is configured to accommodate a linear solid state phase change of the second SMA wire.

[0016] Implementations of this aspect of the disclosure can include one or more of the following optional features. In some examples, the first SMA wire has a first length and a first tension, the second SMA wire has a second length and a second tension, the first length is equal to the second length, and the first tension is equal to the second tension.

[0017] In some implementations, the first crimp and the second crimp are integrally formed with the metal bridge, the first crimp is disposed at the first wire end of the metal bridge, and the second crimp is disposed at the second wire end of the metal bridge.

[0018] In some aspects, the first wire end of the metal bridge is configured to receive the first crimp, and the second wire end of the metal bridge is configured to receive the second crimp.

[0019] In some configurations, the metal bridge is coupled to the plastic body.

[0020] In some examples, the metal bridge is configured to be overmolded to the plastic body.

[0021] In some implementations, the metal bridge is configured to engage a pocket of the plastic body.

[0022] Yet another aspect of the present disclosure provides a vehicle. The vehicle includes an actuator. The actuator includes a plastic body and an SMA wire assembly. The SMA wire assembly includes a first crimp, a second crimp, a metal bridge, a first SMA wire, and a second SMA wire. The metal bridge includes a first wire end and a second wire end opposite the first wire end. The first SMA wire is linearly configured and includes a first mounting end and a first bridge end opposite the first mounting end and a conductive material. The first bridge end is fixedly coupled to the first wire end of the metal bridge via the first crimp, and the conductive material is configured to accommodate a linear solid state phase change of the first SMA wire. The second SMA wire is linearly configured and includes a second mounting end and a second bridge end opposite the second mounting end and a conductive material. The second bridge end is fixedly coupled to the second wire end of the metal bridge via the second crimp, and the conductive material is configured to accommodate a linear solid state phase change of the second SMA wire.

[0023] Implementations of this aspect of the present disclosure can include one or more of the following optional features. In some examples, the first crimp and the second crimp are integrally formed with the metal bridge, the first crimp is disposed at the first wire end of the metal bridge, and the second crimp is disposed at the second wire end of the metal bridge.

[0024] In some implementations, the first wire end of the metal bridge is configured to receive the first crimp, and the second wire end of the metal bridge is configured to receive the second crimp.

[0025] In some aspects, the metal bridge is coupled to the plastic body. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure.

[0027] Figure 1 is a perspective view of a vehicle including an actuator according to the present disclosure;

[0028] Figure 2A is a side view of the actuator in a first position including a dual linear shape memory alloy wire according to the present disclosure;

[0029] Figure 2B is a side view of the actuator in a second position including a dual linear shape memory alloy wire according to the present disclosure; Figure 2A Figure 2A

[0030] Figure 3 is a perspective view of a dual linear shape memory alloy wire according to the present disclosure;

[0031] Figure 4 is a side view of a dual linear shape memory alloy wire and a plastic body;

[0032] Figure 5A ​​is a side cross-sectional view of an actuator in a first position, including a bilinear shape memory alloy wire according to the present disclosure;

[0033] Figure 5B is a side cross-sectional view of an actuator in a second position, Figure 5A including a bilinear shape memory alloy wire according to the present disclosure; Figure 5A of the present disclosure;

[0034] Figure 6 is a side view of a bilinear shape memory alloy wire and a plastic body with a bridge pocket feature; and

[0035] Figure 7 is a side view of a bilinear shape memory alloy wire and an overmolded plastic body.

[0036] In all the drawings, like reference numerals refer to like parts throughout the several views. DETAILED DESCRIPTION

[0037] Example configurations will now be described with reference to the drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Specific details are set forth in order to provide a thorough understanding of the example configurations. It will be apparent to those skilled in the art, however, that the example configurations can be practiced without these specific details, that numerous implementation-specific decisions can be made to the example configurations, and that the specific configurations and examples presented herein are provided for purposes of example and illustration only. Accordingly, it will be understood that the example configurations are not limited to the specifics of the example configurations.

[0038] The terminology used herein is for the purpose of describing particular example configurations only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" can be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order

[0039] When an element or layer is referred to as being “on”, “engaged to”, “connected to”, “attached to” or “coupled to” another element or layer, it can be directly on, engaged, connected, attached or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being “directly on”, “directly engaged to”, “directly connected to”, “directly attached to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0040] The terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections. These elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Terms such as “first”, “second” and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example configurations.

[0041] In this application, including the following claims, the term module can be replaced by the term circuit. The term “module” can refer to, be part of, or include an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combination of

[0042] The term code, as used above, can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, and / or objects. The term shared processor is inclusive of a single processor executing portions of code from multiple modules. The term group processor is inclusive of a processor executing some or all code from one or more modules in combination with additional processors. The term shared memory is inclusive of a single memory storing some or all code from multiple modules. The term group memory is inclusive of a memory storing some or all code from one or more modules in combination with additional memory. The term memory can be a subset of the term computer- readable medium. The term computer-readable medium does not include transitory propagating signals and electromagnetic signals per se, and can be considered tangible, non-transitory memory. Non-limiting examples of non-transitory memory include tangible computer- readable medium, including non-volatile memory, magnetic memory, and optical memory.

[0043] The apparatus and methods described in this application can be implemented in whole or part by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer programs can also include and / or rely on stored data.

[0044] A software application (i.e., a software resource) can refer to computer software that causes a computing device to perform a task. In some examples, a software application can be referred to as an “application program,” an “app,” or a “program.” Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0045] A non-transitory memory can be a physical device that is used to temporarily or permanently store a program (e.g., a sequence of instructions) or data (e.g., program state information) for use by a computing device. A non-transitory memory can be a volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electrically erasable programmable read-only memory (EEPROM) (e.g., commonly used for firmware, such as a boot program). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), and magnetic or optical disks.

[0046] These computer programs (also known as programs, software, software applications or code) include machine instructions for a programmable processor, and can be implemented in a high-level procedural and / or object-oriented programming language, and / or in assembly / machine language. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer readable medium, apparatus and / or device (e.g., magnetic discs, optical disks, memory, Programmable Logic Devices (PLDs)) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0047] Various implementations of the systems and techniques described here can be realized in digital electronic and / or optical circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0048] The processes and logic flows described in this specification can be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for performing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical, or optical disks, or a removable memory card. However, a computer need not have such devices. Computer readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0049] To provide for interaction with a user, one or more aspects of the disclosure can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube), LCD (liquid crystal display), or touch screen, for displaying information to the user and optionally a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input. In addition, a computer can interact with a user by sending documents to and receiving documents from a device used by the user; for example, by sending web pages to a web browser on a user’s client device in response to requests received from the web browser.

[0050] References Figure 1 and 2A, the vehicle 10 includes an actuator 12 configured to facilitate operation of a vehicle component within the vehicle 10. It should be noted, however, that the specific configuration of the actuator 12, the vehicle component operated by the actuator 12, and the operation performed can vary without departing from the context of the present disclosure. The actuator 12 includes a lower body 14a, an upper body 14b, and a cavity 16 at least partially defined by the lower body 14a and the upper body 14b. The upper body 14b is movable relative to the lower body 14a, as the lower body 14a is fixed and immovable. Further, the actuator 12 includes a first mounting point 18a and a second mounting point 18b fixed at the lower body 14a of the actuator 12. A spring 20 is contained within the cavity 16 of the actuator 12 and is fixed to the lower body 14a and the upper body 14b. The spring 20 exerts a compression force F 20 .

[0051] A plastic body 22 is included within the cavity, which is hingedly connected to the lower body 14a and the upper body 14b. The plastic body 22 is free of conductive material and is linearly and hingedly movable relative to the lower body 14a. For example, linear movement of the upper body 14b and the plastic body 22 results in an increase or decrease in the compression force F 20 of the spring 20. Although the spring 20 can be in various states of compression during operation of the actuator 12, some states of compression being greater than others, the spring 20 remains a certain degree of compression during operation and non-operation of the actuator 12. The compression force F 20 of the spring 20 varies during operation of the actuator 12, the details of which will be explained in greater detail below.

[0052] Referring to Figure 2A and 2B , during operation of the actuator 12, the actuator 12 can be in a first state 200 or a second state 202. When the actuator 12 is in the first state 200, the spring 20 of the actuator 12 is in a first compression state 300. When the actuator 12 is in the second state 202, the spring 20 of the actuator 12 is in a second compression state 302. The spring 20 is compressed less and exerts a smaller compression force F 20 compared to the spring 20 in the second compression state 302. Further, during operation of the actuator 12, the spring 20 can travel between the first compression state 300 and the second compression state 302. In other words, the spring 20 compresses when the actuator transitions from the first state 200 to the second state 202. Alternatively, the spring 20 can at least partially decompress when the actuator 12 transitions from the second state 202 to the first state 200.

[0053] Further referring to Figure 2A and 2BWhen the actuator 12 is in the first state 200 and the spring 20 is in the first compressed state 300, the spring 20 forces the upper body 14b into forced engagement with the sealing tip 24 of the actuator 12. Further, when the actuator 12 is in the first state 200, the plastic body 22 is located at or near the air shield 26 of the actuator 12. The air shield 26, along with the lower body 14a and the upper body 14b, define the cavity 16 of the actuator 12. When the upper body 14b is in forced engagement with the sealing tip 24, the sealing tip 24 is sealed and gas is prevented from entering or escaping the cavity 16 of the actuator 12. However, when the actuator 12 is in the second state 202 and the spring 20 is in the second compressed state 302, the spring 20 is compressed to a greater extent than the spring 20 in the first compressed state 300. Since the spring 20 is fixed to the upper body 14b and the plastic body 22 is hingedly connected to the upper body 14b, the plastic body 22 hinges and linearly moves with the linear movement of the upper body 14b and the increased compression of the spring 20. The upper body 14b, the plastic body 22, and the spring 20 move when the actuator 12 transitions between the first state 200 and the second state 202 and the spring 20 moves between the first compressed state 300 and the second compressed state 302. The aforementioned movement is facilitated by a plurality of hingeable bends 30a, 30b, 32a, 32b included in the actuator 12. The plurality of hingeable bends 30a, 30b, 32a, 32b can have a material and thickness that accommodates plastic deformation, thereby enabling the hingeable bends 30a, 30b, 32a, 32b to hinge.

[0054] As a result of the actuator 12 transitioning from the first state 200 to the second state 202, the plastic body 22 moves away from the air shield 26 and the upper body 14b disengages from the sealing tip 24. When the upper body 14b disengages from the sealing tip 24, gas is able to enter and escape the cavity 16 of the actuator 12. When the actuator 12 transitions from the second state 202 to the first state 200, the upper body 14b reengages with the sealing tip 24, again sealing the actuator 12 and preventing gas from entering or escaping the cavity 16. Facilitating the actuator 12 transitioning between the first state 200 and the second state 202 and the joint movement of the spring 20 between the first compressed state 300 and the second compressed state 302 is provided by a shape memory alloy (SMA) wire assembly 100 included in the actuator 12, the operation of which will be described in further detail below.

[0055] Reference is now made to Figure 2A-4, the SMA wire assembly 100 includes a pair of SMA wires 102 including a first SMA wire 102a and a second SMA wire 102b. The first SMA wire 102a includes a first mounting end 104a and a first bridge end 106a. The first mounting end 104a is located on a distal end of the first SMA wire 102a opposite the first bridge end 106a. Similarly, the second SMA wire 102b includes a second mounting end 104b and a second bridge end 106b. The second mounting end 104b is located on a distal end of the second SMA wire 102b opposite the second bridge end 106b.

[0056] When installed in the actuator 12, the pair of SMA wires 102 are linearly oriented. In this regard, the SMA wire assembly 100 has a dual linear configuration. In other words, the pair of SMA wires 102 are straight and uncurved between the first and second mounting ends 104a, 104b and the bridge ends 106a, 106b. Further, the pair of SMA wires 102 include an electrically conductive material having a solid-state phase change characteristic. In other words, the pair of SMA wires 102 can linearly contract, compress, or shorten when an electrical current flows through the SMA wire assembly 100. When the electrical current stops flowing through the SMA wire assembly 100, the pair of SMA wires 102 elongate or decompress such that the pair of SMA wires 102 no longer contract. Due to the dual linear configuration of the pair of SMA wires 102, the SMA wire assembly 100 does not degrade or otherwise decrease in integrity after contraction and decompression of the pair of SMA wires 102.

[0057] The SMA wire assembly 100 also includes a bridge 108. The bridge 108 is a metallic, electrically conductive material that enables an electrical current to flow between the first SMA wire 102a and the second SMA wire 102b. It is important to note that the bridge 108 does not have a solid-state phase change characteristic. In other words, the bridge 108 maintains a single shape, orientation, and size regardless of the electrical current flowing through the SMA wire assembly 100. Based on the configuration of the actuator 12, the bridge 108 can be configured as a tubular wire, a flat ribbon, a flat tab, or any feasible configuration. The bridge 108 includes a first SMA wire end 110a and a second SMA wire end 110b opposite the first SMA wire end 110a.

[0058] Still referring to Figure 2A-4 The first SMA wire end 110a of the bridge 108 is electrically connected and secured to the first bridge end 106a of the first SMA wire 102a via a first crimp 112a. The first crimp 112a facilitates the securement and electrical connection between the bridge 108 and the first SMA wire 102a. Likewise, the second SMA wire end 110b of the bridge 108 is electrically connected and secured to the second bridge end 106b of the second SMA wire 102b by a second crimp 112b. The first crimp 112a and the second crimp 112b can be integrated into the configuration of the bridge 108. For example, the first crimp 112a and the second crimp 112b can be integrally formed with the bridge 108 as shown in FIG. 1.Figure 3 Alternatively, the first crimp 112a and the second crimp 112b can be independent of the configuration of the bridge 108, as shown in FIG. 2B. In this case, the first SMA wire end 110a and the second SMA wire end 110b of the bridge 108 can be configured as tabs or include a tab-like orientation to enable the first crimp 112a to be received at the first SMA wire end 110a and the second crimp 112b to be received at the second SMA wire end 110b. Figure 4

[0059] When the SMA wire assembly 100 is installed within the cavity 16 of the actuator 12, the first mounting end 104a of the first SMA wire 102a is fixedly attached to the first mounting point 18a of the actuator 12. Likewise, the second mounting end 104b of the second SMA wire 102b is fixedly attached to the second mounting point 18b of the actuator 12. The attachment of the first mounting end 104a to the first mounting point 18a and the attachment of the second mounting end 104b to the second mounting point 18b can be achieved through crimping, welding, bolting, or any viable means based on the configuration of the actuator 12. When installed at the actuator 12, both SMA wires 102 remain linear and uncurved. Furthermore, depending on the configuration of the actuator 12, the pair of SMA wires 102 can be parallel to each other or angled with respect to each other. The first SMA wire 102a includes a first length L 102a , and the second SMA wire 102b includes a second length L 102b . Both the first length L 102a and the second length L 102b may vary during operation of the actuator 12 and can be equal to each other based on the configuration of the actuator 12. Furthermore, the first SMA wire 102a includes a first tension T 102a , which can be equal to a second tension T 102b of the second SMA wire 102b. The first tension T 102a is exerted on the first SMA wire end 110a of the bridge 108 and the first mounting point 18a, and the second tension T 102b is exerted on the second SMA wire end 110b of the bridge 108 and the second mounting point 18b. The first tension T 102a of the first SMA wire 102a and the second tension T 102b of the second SMA wire 102b vary during operation of the actuator 12 and will be explained in more detail below.

[0060] ​The shape and orientation of the bridge 108 are designed to correspond to the shape and orientation of the plastic body 22. For example, in many configurations, the bridge 108 is curved or bent to accommodate the shape and orientation of the plastic body 22. In other words, when the plastic body 22 is positioned between the bridge 108 and the first and second mounting ends 104a, 104b of the first and second SMA wires 102a, 102b, the bridge 108 is partially wrapped around the plastic body 22. The bridge 108 is forcedly engaged and pressed against the plastic body 22. Likewise, the plastic body 22 is forcedly engaged against the bridge 108. The compression force F 20 is transferred to the plastic body 22, causing the plastic body 22 to be forcedly engaged with the bridge 108. As a result of the compression force F 20 being transferred and applied on the plastic body 22, the first tension T 102a of the first SMA wire 102a and the second tension T 102b of the second SMA wire 102b, the SMA wire assembly force F 100 is applied on the plastic body 22. The SMA wire assembly force F 100 is applied on the bridge 108 against the plastic body 22. The SMA wire assembly force F 100 is variable based on the operation of the actuator 12. Moreover, the SMA wire assembly force F 100 corresponds to the first tension T 102a of the first SMA wire 102a and the second tension T 102b of the second SMA wire 102b.

[0061] With continued reference to Figure 2A-4 , the control current flowing through the SMA wire assembly 100 enables the operation of the actuator 12. For example, when the current flows through the SMA wire assembly 100, the actuator performs an action. Likewise, when the current stops flowing through the SMA wire assembly 100, the actuator performs an alternative action. For example, the actuator 12 can be installed at a vehicle seat assembly to control the inflation of a lumbar portion of the seat assembly, and a user can activate a lumbar control switch to change the amount of lumbar at the seat assembly. When the lumbar control switch is activated, the current can flow through the SMA wire assembly 100. Likewise, when the lumbar control switch is deactivated, the current can stop flowing through the SMA wire assembly 100.

[0062] When no current flows through the SMA wire assembly 100, the actuator 12 is in the first state 200 and the spring 20 is in the first compressed state 300. In the first compressed state 300 of the spring 20, the compression force F 20 of the spring 20 is greater than the SMA wire assembly force F 100 , the force F 100The upper body 14b is forced to seal and forcibly engage the sealing tip 24. Additionally, in the first state 200 of the actuator, the plastic body 22 is engaged or nearly engaged with the air shield 26. As described above, when the upper body 14b is forcibly engaged with the sealing tip 24, the sealing tip 24 is sealed, preventing gas from entering or escaping the cavity 16 of the actuator 12.

[0063] Alternatively, when current flows through the SMA wire assembly 100, the actuator 12 is in the second state 202 and the spring 20 is in the second compressed state 302. When current begins to flow through the SMA wire assembly 100, due to the solid-state phase transition properties of the pair of SMA wires 102, the pair of SMA wires 102 contracts and the first wire length L 102a and the second wire length L 102b of the second SMA wire 102b decrease. As the pair of SMA wires 102 undergoes a linear solid-state phase transition by contracting and shortening, the first tension T 102a and the second tension T 102b of the second SMA wire 102b increase, thus causing the SMA wire assembly force F 100 to simultaneously increase. Since each of the first and second mounting ends 104a, 104b of the first and second SMA wires 102a, 102b are fixed to the first and second mounting points 18a, 18b, the increasing SMA wire assembly force F 100 causes a linear motion of the bridge 108 towards the mounting points 18a, 18b. Once the SMA wire assembly force F 100 is greater than the compression force F 20 of the spring 20, the linear motion of the bridge 108 towards the mounting points 18a, 18b occurs together with a linear motion of the upper body 14b.

[0064] Once the SMA wire assembly force F 100 exceeds the compression force F 20 of the spring 20, the SMA wire assembly force F 100 exerted by the bridge 108 on the plastic body 22 (which is transferred to the upper body 14b) moves the spring 20 from the first compressed state 300 to the second compressed state 302. When the spring 20 transitions from the first compressed state 300 to the second compressed state 302, the compression force F 20 of the spring 20 increases. When the spring 20 reaches the second compressed state 302, the compression force F 20 of the spring 20 is equal to the SMA wire assembly force F 100 , which stops further compression of the spring and further contraction of the pair of SMA wires 102. Thus, when the compression force F 20 is equal to the SMA wire assembly force F 100 , any further motion of the bridge 108, the plastic body 22, and the upper body 14b stops.

[0065] In the second state 202 of the actuator 12, when current is flowing through the SMA wire assembly 100, the upper body 14b is no longer in forced engagement with the sealing tip 24, which results in the sealing tip 24 unsealing and accommodating gas flow into or out of the cavity 16. Additionally, the plastic body 22 is positioned away from the air shield 26. Continuing with the inflatable lumbar example described above, in the second state 202 of the actuator 12 and the associated second compressed state 302 of the spring 20, air can flow through the cavity 16 of the actuator 12 and into or out of the inflatable lumbar, depending on the user's selection of the lumbar switch, to increase or decrease the lumbar.

[0066] As the spring 20 moves from the second compressed state 302 to the first compressed state 300, the actuator 12 transitions from the second state 202 to the first state 200 when the current stops flowing through the SMA wire assembly 100. When the current stops flowing through the SMA wire assembly 100, for example when the user deactivates the lumbar control switch, the pair of SMA wires 102 again undergoes a linear solid state phase change by elongating and not contracting, decreasing the first tension T 102a and the second tension T 102b of the first SMA wire 102a and the second SMA wire 102b, respectively. As the pair of SMA wires 102 elongate and do not contract, the compression force F 20 of the spring 20 again becomes greater than the SMA wire assembly force F 100 . The spring 20 exerts a compression force F 20 on the upper body 14b, which is transferred to the plastic body 22 and ultimately to the bridge 108. Accordingly, the bridge 108 can move linearly with the linear motion of the plastic body 22 and the upper body 14b while the first wire length L 102a and the second wire length L 102b increase until the upper body 14b is in forced engagement with the sealing tip 24. When the upper body 14b is in forced engagement with the sealing tip 24 and prevents additional linear motion of the upper body 14b and the plastic body 22, the sealing tip 24 is again sealed, preventing gas flow into or out of the cavity 16 of the actuator 12. In doing so, with reference to the inflatable lumbar example, the lumbar of the seat assembly stops adjusting until the lumbar control switch is again activated, repeating the phase change process of the pair of SMA wires 102 as described above. However, it should be noted that the actuator 12 can be used in any number of ways within the vehicle 10 and the inflatable lumbar example described above is merely one example.

[0067] When current flows through the SMA wire assembly 100, the thermal characteristics of the pair of SMA wires 102 can differ from the thermal characteristics of the bridge 108. The difference in thermal characteristics is due to the different configuration of the bridge 108 compared to the configuration of the pair of SMA wires 102. The difference in thermal characteristics can also be a result of the bridge 108 being in engagement with the plastic body 22 compared to the pair of SMA wires 102 being suspended within the cavity 16.

[0068] With specific reference Figure 5A-5B , an actuator 12a is provided. In view of the substantial similarity in structure and function of the components associated with the actuator 12, the same reference numerals are used in the following description and in the drawings to identify the same components, while the same reference numerals including letter and / or numerical extensions are used to identify those components that have been modified.

[0069] The actuator 12a includes a housing 14a1 that defines a cavity 16a of the actuator 12a. A first mounting point 18a1 and a second mounting point 18b1 are located at opposite ends of the housing 14a1. The first mounting point 18a1 and the second mounting point 18b1 are both fixedly attached to the actuator 12a and are not movable relative to the housing 14a1. A spring 20a is located equidistant from the mounting points 18a1, 18b1, etc. The spring 20a is fixed to a plastic body 22a that is fixedly engaged with an air shield 26a. During a first state 200a of the actuator 12a and a first compressed state 300a of the spring 20a, the spring 20a forces the plastic body 22a and the air shield 26a against a sealed end 24a of the actuator 12a. The plastic body 22a and the air shield 26a are pressed against the sealed end 24a, preventing gas from entering or escaping the cavity 16a of the actuator 12a. Alternatively, during a second state 202a of the actuator 12 and a second compressed state 302a of the spring, the plastic body 22a and the air shield 26a are moved away from the sealed end 24a, which allows gas flow to enter and exit the cavity 16a of the actuator 12a at the sealed end 24a.

[0070] The actuator 12a includes an SMA wire assembly 100a. The SMA wire assembly 100a includes a first SMA wire 102a1 and a second SMA wire 102b1. Further, the SMA wire assembly 100a includes a bridge 108a that is engaged with the plastic body 22a. The first SMA wire 102a1 is linearly configured and fixed at opposite distal ends of the first SMA wire 102a1 to the first mounting point 18a1 and the bridge 108a. The second SMA wire 102b1 is linearly configured and fixed at opposite distal ends of the second SMA wire 102b1 to the second mounting point 18b1 and the bridge 108a.

[0071] The first SMA wire 102a1 includes a first tension T 102a1 , and the second SMA wire 102b1 includes a second tension T 102b1. The first tension T 102a1 is applied between the bridge 108a and the first mounting point 18al, while the second tension T 102b1 is applied between the bridge 108a and the second mounting point 18bl. As a result of the first tension T 102a1 and the second tension T 102b1 , an SMA wire assembly force F 100a is generated at the bridge 108a. The SMA wire assembly force F 100a is transferred to the plastic body 22a and is directed downward toward the spring 20a. The spring 20a exerts a compression force F 20a on the plastic body 22a. The amount of compression force F 20a generated by the spring 20a differs between the first compression state 300a and the second compression state 302a.

[0072] With continued reference to Figure 5A-5B , when no current is flowing through the SMA wire assembly 100a, the actuator 12a is in the first state 200a and the spring 20a is in the first compression state 300a Figure 5A ). Alternatively, when current is flowing through the SMA wire assembly 100a, the actuator 12a is in the second state 202a and the spring 20a is in the second compression state 302a Figure 5B ). When current begins to flow through the SMA wire assembly 100a, the first and second SMA wires 102al, 102bl contract and shorten in length due to the solid-state phase transition properties of the first and second SMA wires 102al, 102bl. As the first and second SMA wires 102al, 102bl experience linear solid-state phase transitions by contracting and shortening, the first tension T 102a1 of the first SMA wire 102al and the second tension T 102b1 of the second SMA wire 102bl increase, thus causing the SMA wire assembly force F 100a to simultaneously increase. As a result of the first and second SMA wires 102al, 102bl being fixed to the first and second mounting points 18al, 18bl, the increasing SMA wire assembly force F 100 causes linear motion of the bridge 108a, the plastic body 22a, and the air shield 26a away from the sealed tip 24a and toward the spring 20a. Linear motion occurs as a result of the SMA wire assembly force F 100a increasing to an amount greater than the compression force F 20a of the spring 20a. This motion compresses the spring 20a from the first compression state 300a to the second compression state 302a. Once the compression force F 20 of the spring 20a increases to equal the SMA wire assembly force F 100athe second compressed state 302a of the spring 20a and the second state 202a of the actuator 12a, current continues to flow through the SMA wire assembly 100a.

[0073] In the second state 202a of the actuator 12a, when current is flowing through the SMA wire assembly 100a, the air shield 26a is no longer in forced engagement with the sealing tip 24a, which results in the sealing tip 24a unsealing and accommodating gas flow into or out of the cavity 16a. Continuing with the inflatable lumbar example described above, in the second state 202a of the actuator 12a and the associated second compressed state 302a of the spring 20a, air can flow through the cavity 16a of the actuator 12a and into or out of the inflatable lumbar, depending on the user's selection of the lumbar switch, to increase or decrease the lumbar.

[0074] When current stops flowing through the SMA wire assembly 100a, the actuator 12a transitions from the second state 202a to the first state 200a, just as the spring 20a moves from the second compressed state 302a to the first compressed state 300a. When current stops flowing through the SMA wire assembly 100a, for example when the user deactivates the lumbar control switch, the first and second SMA wires 102al, 102bl again experience a linear solid state phase change by increasing in length and not contracting, decreasing the first tension T 102a1 and the second tension T 102b1 of the first SMA wire 102al and the second SMA wire 102bl, respectively. As the first and second SMA wires 102al, 102bl elongate and do not contract, the compression force F 20a of the spring 20a becomes greater than the SMA wire assembly force F 100a . The compression force F 20a of the spring 20a is transferred to the bridge 108a and the air shield 26a. Accordingly, the bridge 108a can move linearly with the linear motion of the plastic body 22a and the air shield 26a until the air shield 26a is in forced engagement with the sealing tip 24a. When the air shield 26a is in forced engagement with the sealing tip 24a and prevents additional linear motion of the bridge 108a, the plastic body 22a, and the air shield 26a, the sealing tip 24a is again sealed, preventing gas flow into or out of the cavity 16a of the actuator 12a. In doing so, with reference to the inflatable lumbar example, the lumbar of the seat assembly stops adjusting until the lumbar control switch is again activated, repeating the phase change process of the first and second SMA wires 102al, 102bl as described above. It should be noted, however, that the actuator 12 can be used in any number of ways within the vehicle 10 and the inflatable lumbar example described above is merely one example.

[0075] With specific reference Figure 6 SMA wire assembly 100c is provided. In view of the substantial similarity in structure and function of the components related to SMA wire assembly 100, like reference numerals are used in the following description and in the drawings to identify like components, while like reference numerals containing letter and / or number extensions are used to identify those components that have been modified.

[0076] SMA wire assembly 100c includes bridge 108c, which engages with plastic body 22c when installed in actuator 12 (FIG. 2). Bridge 108c, a portion of first crimp 112a, and a portion of second crimp 112b are positioned within recess 28c of plastic body 22c. For example, recess 28c can be described as an indentation, cavity, or any other recessed opening that receives bridge 108c as well as at least a portion of first and second crimps 112a, 112b. The shape of recess 28c of bridge 108c is designed to correspond to the shape and configuration of bridge 108c and crimps 112a, 112b. Further, first crimp 112a and second crimp 112b can be rigidly and fixedly attached to plastic body 22c at recess 28c. As bridge 108c engages with plastic body 22c at recess 28c, bridge 108c moves with plastic body 22c during operation of actuator 12, as described above. Plastic body 22c is non-conductive such that electrical current can flow through bridge 108c without any electrical current flowing through plastic body 22c. Thus, electrical current is prevented from flowing to other elements contained within cavity 16 of actuator 12 via plastic body 22c.

[0077] With specific reference Figure 7 SMA wire assembly 100d is provided. In view of the substantial similarity in structure and function of the components related to SMA wire assembly 100, like reference numerals are used in the following description and in the drawings to identify like components, while like reference numerals containing letter and / or number extensions are used to identify those components that have been modified.

[0078] The SMA wire assembly 100d includes a bridge 108d that is engaged with the plastic body 22d when installed in the actuator 12 (FIG. 2). The bridge 108d is overmolded in the plastic body 22d, which secures the bridge 108d to the plastic body 22d. For example, the bridge 108d can be integrally formed with the plastic body 22d. Thus, during operation of the actuator 12, the bridge 108d and the plastic body 22d can move linearly as a single unit. Further, the first crimp 112a and the second crimp 112b are external to the plastic body 22d while still being electrically and fixedly engaged with the bridge 108. Because the plastic body 22d is not electrically conductive, electrical current can flow through the bridge 108d without any current flowing through the plastic body 22d, which prevents current from flowing to other elements contained within the cavity 16 of the actuator 12 via the plastic body 22d.

[0079] Referring again to Figure 1-7 , the SMA wire assembly 100 is included in the actuator 12. The actuator 12 can transition between a first state 200 and a second state 202. During the transition of the actuator 12 between the first state 200 and the second state 202, the pair of SMA wires 102 undergoes a linear solid state phase change. The first crimp 112a and the second crimp 112b provide a secure method of connecting the pair of SMA wires 102 to the bridge 108 in an effort to prevent the SMA wire assembly 100 from breaking or fracturing at the point where the pair of SMA wires 102 meet the bridge 108. Further, compression and elongation during the linear solid state phase change of the pair of SMA wires 102 only occurs linearly when the pair of SMA wires 102 are configured in a linear orientation because any bends or kinks included in the SMA wire assembly 100 are only accommodated by the bridge 108. Because the bridge 108 does not have solid state phase change properties, the bridge 108 remains a single shape, orientation, and size regardless of the current flowing through the SMA wire assembly 100. In contrast to solid state phase changes that occur at wires configured in a bend or kink, solid state phase changes that occur at wires configured in a linear orientation reduce the likelihood of the wire failing or breaking.

[0080] A number of implementations have been described. Nevertheless, it will be understood that various modifications can be made without departing from the spirit and scope of this disclosure. Accordingly, other implementations are within the scope of the following claims.

[0081] The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable with other configurations as appropriate, even if not specifically shown or described. The same can also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A shape memory alloy (SMA) wire assembly comprising: a first crimp; a second crimp; a metal bridge comprising a first wire end and a second wire end opposite the first wire end; a first SMA wire configured in a linear orientation and comprising a first mounting end and a first bridge end opposite the first mounting end, the first bridge end fixedly coupled to the first wire end of the metal bridge via the first crimp; and a second SMA wire configured in a linear orientation and comprising a second mounting end and a second bridge end opposite the second mounting end, the second bridge end fixedly coupled to the second wire end of the metal bridge via the second crimp. the first SMA wire has a first length and a first tension, and the second SMA wire has a second length and a second tension, the first length being equal to the second length, and the first tension being equal to the second tension.

2. The SMA wire assembly of claim 1, wherein, the first and second crimps are integrally formed with the metal bridge, the first crimp disposed at the first wire end of the metal bridge, and the second crimp disposed at the second wire end of the metal bridge.

3. The SMA wire assembly of claim 1, wherein, the first wire end of the metal bridge is configured to receive the first crimp, and the second wire end of the metal bridge is configured to receive the second crimp.

4. The SMA wire assembly of claim 1, wherein, 5. The SMA wire assembly of claim 1, further comprising an actuator comprising a plastic body, the metal bridge coupled to the plastic body. the first and second crimps rigidly and fixedly attached to the plastic body of the actuator.

6. The SMA wire assembly of claim 5, wherein, the metal bridge is configured to be overmolded to the plastic body of the actuator.

7. The SMA wire assembly of claim 5, wherein, the metal bridge is configured to engage a pocket of the plastic body of the actuator.

8. The SMA wire assembly of claim 5, wherein, the first and second SMA wires each comprise an electrically conductive material configured to accommodate a linear solid state phase change of the first and second SMA wires.

9. The SMA wire assembly of claim 1, wherein, 10. An actuator comprising: a plastic body; and an SMA wire assembly comprising: a first crimp; a second crimp; a metal bridge comprising a first wire end and a second wire end opposite the first wire end; a first SMA wire configured in a linear orientation and comprising a first mounting end, a first bridge end opposite the first mounting end, and an electrically conductive material, the first bridge end fixedly coupled to the first wire end of the metal bridge via the first crimp, the electrically conductive material configured to accommodate a linear solid state phase change of the first SMA wire; and a second SMA wire configured in a linear orientation and comprising a second mounting end, a second bridge end opposite the second mounting end, and an electrically conductive material, the second bridge end fixedly coupled to the second wire end of the metal bridge via the second crimp, the electrically conductive material configured to accommodate a linear solid state phase change of the second SMA wire. ​ ​

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