High-temperature fluid control valve based on memory alloy

Abstract

The invention relates to the technical field of valves, and provides a high-temperature fluid control valve based on memory alloy, which comprises a valve body, a valve core, a valve rod, a driving module and a transmission mechanism. A fluid channel is arranged in the valve body, and the valve element is arranged in the channel. And one end of the valve rod is connected with the valve core and partially extends into the fluid channel. The driving module is located outside the valve body and comprises a transmission rod, a shape memory alloy spring and a bias spring, and the shape memory alloy spring and the bias spring act on the two ends of the transmission rod respectively and drive the transmission rod to axially and linearly move. The transmission mechanism is connected with the transmission rod and the valve rod, linear motion is converted into rotating motion of the valve rod, so that the valve element is controlled to be opened and closed, and the valve rod forms a heat transfer path for conducting heat of high-temperature fluid in the fluid channel to the driving module. According to the valve, heat management of passive driving and physical isolation is achieved, thermally induced deformation is converted into reliable action of the valve element through mechanical transmission, and passive intelligent regulation and control of the memory alloy on opening and closing of the valve in the high-temperature environment are achieved.

Description

Technical Field

[0001] This application relates to the field of valve technology, and in particular to a high-temperature fluid control valve based on shape memory alloy. Background Technology

[0002] In industrial sectors such as energy, chemical engineering, and aerospace, reliable control of fluids operating at temperatures above 200°C is one of the key technological challenges. While traditional valve actuators, such as electric and pneumatic actuators, can achieve regulation under high-temperature conditions, they generally rely on external power sources and complex control systems, resulting in large and heavy systems with reliability risks in high-temperature and vibration environments.

[0003] Shape memory alloys (SMAs), as a representative type of material, possess unique shape memory effects and superelasticity, enabling them to directly convert thermal energy into mechanical energy and displacement output. This provides an ideal approach for realizing compact actuators that integrate sensing and actuation. As a smart material capable of achieving "sensing-actuation integration," Ni-Ti SMAs, in particular, are considered ideal actuating components for constructing compact, passive smart valves due to their excellent shape memory effect and high power-to-weight ratio. However, the austenitic phase transformation end temperature of Ni-Ti SMAs (…) A f The temperature is usually below 150°C. If it is directly exposed to a high-temperature fluid environment above 200°C, the material will remain in the austenitic state and will not be able to trigger a phase transformation recovery due to temperature changes, resulting in complete failure of the driving function.

[0004] Although existing research has attempted to address this issue by developing novel high-temperature SMA materials or implementing localized insulation, the former faces bottlenecks in processability, cost, and cycle stability, while the latter lacks a systematic thermal management solution, making it difficult to ensure that the SMA can sensitively detect fluid temperature changes while effectively preventing its own overheating. Therefore, current technology lacks an autonomous control valve solution that enables the stable and reliable application of conventional Ni-Ti SMA in high-temperature fluid pipelines above 200°C. Summary of the Invention

[0005] In view of this, this application proposes a high-temperature fluid control valve based on shape memory alloy to solve the technical problem that conventional shape memory alloys cannot achieve autonomous and reliable actuation in high-temperature fluid environments due to their low phase transformation temperature.

[0006] The technical solution of this application is implemented as follows: This application provides a high-temperature fluid control valve based on shape memory alloy, including a valve body, a fluid channel formed inside the valve body, and a valve core disposed within the fluid channel, and further comprising: A valve stem, the valve stem being made of a thermally conductive material, having one end connected to the valve core, and at least partially extending into the fluid passage; A drive module is disposed outside the valve body. The drive module includes a transmission rod and a shape memory alloy spring and a bias spring acting on both ends of the transmission rod, respectively. The shape memory alloy spring and the bias spring are configured to drive the transmission rod to move linearly along its axial direction. A transmission mechanism is connected between the transmission rod of the drive module and the other end of the valve rod, and is used to convert the linear motion of the transmission rod into the rotational motion of the valve rod, so as to realize the opening and closing of the valve core in the fluid channel; The valve stem forms a heat transfer path that conducts the heat of the high-temperature fluid in the fluid channel to the drive module.

[0007] Based on the above technical solution, preferably, the portion of the valve stem that extends into the fluid channel is provided with an axial opening structure.

[0008] Based on the above technical solution, preferably, it also includes a valve box, the drive module is housed in the valve box, the transmission rod is horizontally arranged in the valve box and can move along the transmission rod axis, the two ends of the transmission rod have limiting parts respectively, the shape memory alloy spring and the bias spring are respectively sleeved on the two ends of the transmission rod and fixedly connected to the corresponding limiting parts, the ends of the shape memory alloy spring and the bias spring away from the limiting parts are respectively fixedly connected to the side wall of the valve box, and the end of the valve rod away from the valve core extends movably into the interior of the valve box and is connected to the transmission rod through the transmission mechanism.

[0009] Based on the above technical solution, preferably, the transmission mechanism includes a gear and a rack segment. The rack segment is disposed on the transmission rod and located between the shape memory alloy spring and the bias spring. The gear is fixedly connected to the end of the valve rod away from the valve core and meshes with the rack segment. The linear motion of the transmission rod is converted into the rotational motion of the valve rod through the meshing of the rack segment and the gear. The gear, rack segment, and transmission rod are all made of thermally conductive material to form a heat transfer path that transfers heat from the valve rod to the shape memory alloy spring.

[0010] Based on the above technical solution, preferably, the transmission rod is a hollow rod with a cooling channel formed inside.

[0011] Based on the above technical solution, preferably, the gear teeth include a first tooth segment and a second tooth segment, the rack segment includes a first rack portion that meshes with the first tooth segment and a second rack portion that meshes with the second tooth segment, the first tooth segment and the first rack portion are both made of a first thermally conductive material, the second tooth segment and the second rack portion are both made of a second thermally conductive material, and the thermal conductivity of the first thermally conductive material is higher than that of the second thermally conductive material.

[0012] Based on the above technical solution, preferably, a heat insulation structure is provided between the valve box and the valve body.

[0013] Based on the above technical solution, preferably, the valve box is provided with a first rolling bearing, and the upper end of the valve stem is rotatably supported on the first rolling bearing; the valve body is provided with at least one second rolling bearing, and the lower end of the valve stem is rotatably supported on the second rolling bearing.

[0014] Based on the above technical solution, preferably, the rack segment is a straight rack machined on the side wall of the transmission rod; or, the rack segment is an annular tooth structure formed on the outer periphery of the transmission rod and distributed along its axial direction.

[0015] Based on the above technical solution, preferably, the valve box is provided with several heat dissipation holes.

[0016] This application has the following advantages over the prior art: (1) The valve disclosed in this application constructs a compact and intelligent valve system capable of autonomously responding to temperature changes in high-temperature fluids through the collaborative design of a heat-conducting valve stem, an external drive module, and a motion conversion mechanism. This solution not only achieves passive drive and physically isolated thermal management, but also converts thermal deformation into reliable valve core action through precise mechanical transmission, realizing passive intelligent control of valve opening and closing by shape memory alloy in high-temperature environments.

[0017] (2) By combining the gear and rack transmission mechanism with thermally conductive materials, the mechanical transmission and thermal management functions are integrated. This scheme utilizes the gear and rack pair to efficiently and accurately convert the small linear displacement of the transmission rod into the rotational motion of the valve stem. The transmission chain is short and the structure is compact, significantly improving the response speed and reliability of the valve drive. At the same time, by making the gear, rack segment and transmission rod all made of thermally conductive materials, a continuous heat transfer path extending from the valve stem to the shape memory alloy spring is constructed. This ensures that the drive module can indirectly and reliably sense the fluid temperature change through this path, laying the core foundation for the autonomous intelligent control of the valve in high-temperature environments.

[0018] (3) By using a segmented material gradient design for the gear and rack meshing pair, an inherent thermal adaptive adjustment mechanism is created. This scheme automatically switches between high thermal conductivity and low thermal conductivity transmission paths at different stages of the transmission process, ensuring efficient and rapid heat transfer required in the early stage of valve actuation to achieve sensitive triggering, while effectively limiting heat flow in the later stage of operation to prevent overheating of the shape memory alloy. This cleverly balances the contradiction between response speed and overheat protection, significantly improving the reliability and durability of the valve in high-temperature environments.

[0019] (4) By designing the transmission rod as a hollow structure and integrating the cooling channel, a high degree of integration of mechanical transmission and thermal management functions is achieved. This solution not only solves the problem of rapid reset of shape memory alloy driven valves in high-temperature environments, but also achieves functional integration and space optimization through structural innovation, significantly improving the response speed and reliability of the valve under continuous working conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a three-dimensional structural schematic diagram of the high-temperature fluid control valve based on shape memory alloy disclosed in an embodiment of this application; Figure 2 This is a three-dimensional structural diagram of the high-temperature fluid control valve based on shape memory alloy disclosed in an embodiment of this application after the valve body has been removed. Figure 3 This is a schematic diagram of the assembly structure of the drive module and transmission mechanism disclosed in the embodiments of this application; Figure 4 This is a schematic diagram of the planar structure of the high-temperature fluid control valve based on shape memory alloy disclosed in an embodiment of this application; Figure 5 for Figure 4 Planar sectional view at point AA; Figure 6 for Figure 4 Plan view at point BB; Figure label: 1. Valve body; 11. Fluid passage; 2. Valve core; 3. Valve stem; 31. Opening structure; 4. Drive module; 5. Transmission mechanism; 41. Transmission rod; 42. Shape memory alloy spring; 43. Offset spring; 6. Valve box; 411. Limiting part; 51. Gear; 52. Rack segment; 511. First gear segment; 512. Second gear segment; 521. First rack part; 522. Second rack part; 7. Heat insulation structure; G1. First rolling bearing; G2. Second rolling bearing. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0024] In the description of the embodiments of this application, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0028] like Figure 1 As shown, combined with Figure 2-6 This application discloses a high-temperature fluid control valve based on shape memory alloy, designed for autonomous control of high-temperature fluid pipelines above 200°C. By setting up a thermal management structure and driving mechanism, conventional Ni-Ti shape memory alloy can be indirectly and stably operated in a high-temperature environment.

[0029] The valve disclosed in this embodiment includes a valve body 1, a valve core 2, a valve stem 3, a drive module 4, and a transmission mechanism 5.

[0030] The valve body 1 is the main structural frame and pressure boundary of the valve. Its internal machining forms a fluid channel 11, providing a path for the flow of high-temperature media. As the installation foundation of the entire valve, the valve body 1 bears the pressure and thermal load of all internal components and the pipeline medium. To ensure structural strength and long-term stability at high temperatures, the valve body 1 is made of high-temperature resistant metal materials such as stainless steel.

[0031] The valve core 2 is the core actuating component that performs fluid on / off control. It is located in the fluid channel 11 inside the valve body 1 and opens or closes the fluid by changing its position or angle relative to the flow channel. In a preferred embodiment of the invention, the valve core 2 is specifically a ball valve disc structure. When the valve stem 3 rotates the ball valve disc 90 degrees, the flow channel can be fully opened or fully closed. The ball valve structure has the advantages of low flow resistance, good sealing performance, and rapid opening and closing. The shape and size of the valve core 2 need to be precisely matched with the flow channel inside the valve body 1 to ensure effective sealing in the closed state. In addition to the ball valve disc, the valve core 2 can also be conceived in other forms, such as a disc valve disc, a wedge gate, or a conical plug, to adapt to different sealing and flow regulation requirements.

[0032] The valve stem 3 is a key transmission component connecting the valve core 2 and the external drive mechanism, and is also the core heat-conducting element for achieving indirect temperature sensing. In this embodiment, both the valve stem 3 and the transmission rod 41 are made of high thermal conductivity materials, such as copper, preferably copper alloy, ensuring high thermal conductivity while possessing high structural strength. One end is rigidly connected to the valve core 2, and the other end is connected to the transmission mechanism 5. At least a portion of the valve stem 3 extends into the fluid channel 11, allowing it to directly or indirectly contact the high-temperature fluid. The selection of high thermal conductivity materials ensures that heat can be efficiently transferred from the high-temperature fluid to the valve stem 3. In this design, the valve stem 3 serves a dual function: firstly, as a mechanical transmission component, it transmits the rotational motion generated by the drive module 4 to the valve core 2; secondly, as the core heat conduction path, it forms a bridge for transferring fluid heat to the drive module 4.

[0033] The drive module 4 is independently located outside the valve body 1, physically isolated from the high-temperature fluid. The drive module 4 includes a transmission rod 41 and shape memory alloy springs 42 and bias springs 43 acting at both ends of the transmission rod 41. The shape memory alloy spring 42 is made of Ni-Ti alloy with a phase transition temperature of approximately 90~120℃ and is pre-stretched to a certain length below the phase transition temperature. The bias spring 43 provides stable restoring force and is made of stainless steel. The two springs work together to drive the transmission rod 41 to reciprocate linearly along its axial direction. When the shape memory alloy spring 42 is heated above its phase transition temperature, it contracts, overcoming the resistance of the bias spring 43 and pulling the transmission rod 41 to move; when the temperature decreases, the bias spring 43 pushes the transmission rod 41 back to its original position.

[0034] The transmission mechanism 5 connects the transmission rod 41 of the drive module 4 to the other end of the valve stem 3, and is used to convert the linear motion of the transmission rod 41 into the rotational motion of the valve stem 3. Through a gear rack or equivalent mechanism, the microscopic axial displacement is amplified and converted into the precise rotation of the valve stem 3, ultimately driving the valve core 2 to reliably open and close within the fluid channel 11. This motion conversion mechanism ensures that the valve can autonomously complete the opening and closing operation according to temperature changes.

[0035] In the entire technical solution, the valve stem 3 constitutes the only heat transfer path for conducting heat from the high-temperature fluid in the fluid channel 11 to the drive module 4. Heat originates from the high-temperature fluid, is transferred upwards through the heat-conducting material of the valve stem 3, passes through the transmission mechanism 5, and finally reaches the shape memory alloy spring 42. This indirect temperature sensing method allows the drive module 4 to both sense changes in fluid temperature and maintain its own operating temperature within the safe range of material phase transformation, thus solving the core problem that conventional shape memory alloys cannot be directly used in high-temperature environments due to their excessively low phase transformation temperatures.

[0036] It should be noted that the pre-stretching treatment of the shape memory alloy spring below the phase transformation temperature aims to provide a defined and repeatable driving stroke for its austenitic phase transformation; the length of this pre-stretching directly determines the linear displacement that the spring can generate when it contracts upon heating. This precise linear displacement is converted into a specific rotation angle of the valve stem through a rack and pinion transmission mechanism. Therefore, by pre-setting and calculating the stretching stroke of the shape memory alloy spring, the final rotation angle of the valve stem can be precisely controlled, thereby achieving accurate and reliable adjustment of the valve core's opening and closing degree in the fluid channel.

[0037] The valve disclosed in this application, through the collaborative design of the thermally conductive valve stem 3, the external drive module 4, and the motion conversion mechanism, constructs a compact intelligent valve system capable of autonomously responding to temperature changes in high-temperature fluids. This solution not only achieves passive drive and physically isolated thermal management, but also converts thermally induced deformation into reliable action of the valve core 2 through precise mechanical transmission, realizing passive intelligent control of valve opening and closing by the shape memory alloy in high-temperature environments.

[0038] In some embodiments, the valve stem 3, as the core heat transfer element, has an axially oriented opening structure 31 in the portion extending into the fluid channel 11. The opening structure 31 is directly machined in the axial direction of the valve stem 3, forming a cavity extending inward from the end. This construction allows high-temperature fluid to directly enter the interior of the valve stem 3 through the opening, greatly increasing the contact area between the fluid and the inner wall of the valve stem 3. When high-temperature fluid flows through the valve, heat is not only conducted through the outer wall of the valve stem 3, but also forms convective heat transfer through the internal cavity, thereby creating a more efficient dual heat transfer path.

[0039] The depth of the opening structure 31 is a key design parameter for adjusting the heat transfer rate. Based on the fluid temperature and response speed requirements, the heat flux density can be precisely controlled by adjusting the opening depth. A deeper opening means a larger heat transfer area and a stronger fluid disturbance effect, enabling a faster temperature response and making it suitable for high-temperature scenarios requiring rapid action. The specific shape of the opening can be a straight hole, an oblique hole, or a complex structure with internal fins to adapt to different flow field characteristics and heat transfer requirements.

[0040] It is worth noting that during valve operation, the opening structure 31 also plays a role in dynamic thermal balance. When the low-temperature fluid flows in, the residual high-temperature fluid remaining in the cavity is rapidly replaced, accelerating the cooling process of the system. This structural design not only optimizes the heat transfer efficiency during the heating stage but also promotes the heat dissipation effect during the reset stage, enabling the drive module 4 to respond to temperature changes more quickly.

[0041] In some embodiments, a valve box 6 is also provided in order to provide a mounting carrier for the drive module 4.

[0042] The valve housing 6, as a sealed or semi-sealed cavity independent of the valve body 1, provides a dedicated installation space and protective environment for the drive module 4. The drive module 4 is entirely housed within the valve housing 6, achieving physical isolation from the high-temperature fluid and ensuring that the shape memory alloy spring 42 can operate within a safe temperature range.

[0043] In this embodiment, the transmission rod 41 is horizontally disposed inside the valve box 6 and can move along its axial direction. As some implementations, linear bearings are provided on the two opposing inner sidewalls of the valve box 6 so that the transmission rod 41 can pass through them, ensuring that the transmission rod 41 can move horizontally stably in the valve box 6.

[0044] Limiting portions 411 are machined at both ends of the transmission rod 41. These limiting portions 411 are annular grooves or shoulder structures used to precisely define the installation position of the springs. Shape memory alloy springs 42 and bias springs 43 are respectively sleeved on both ends of the transmission rod 41, with the ends closer to the transmission rod 41 mechanically fixed to the corresponding limiting portions 411. The ends of the springs away from the limiting portions 411 are fixedly connected to the inner sidewall of the valve box 6 through mounting seats or similar structures. This arrangement allows the two springs to act on the transmission rod 41 in opposite directions, providing the transmission rod 41 with driving forces in opposite directions, forming the core mechanical structure of the bias drive module 4.

[0045] The valve stem 3 serves as a bridge connecting the valve core 2 and the drive module 4, with its end away from the valve core 2 extending movably into the valve box 6. The valve stem 3 is connected to the horizontally arranged transmission rod 41 via the transmission mechanism 5. When the transmission rod 41 moves axially in a linear motion under the drive of two springs, the transmission mechanism 5 converts this linear motion into the rotational motion of the valve stem 3, thereby ultimately driving the valve core 2 to move.

[0046] In some embodiments, the transmission mechanism 5 employs a meshing pair of gear 51 and rack segment 52 to achieve motion conversion. Specifically, rack segment 52 is disposed on transmission rod 41 and located between shape memory alloy spring 42 and bias spring 43. This arrangement ensures that the linear driving force generated by drive module 4 can be captured and transmitted most directly and efficiently.

[0047] Gear 51 is fixed to the end of valve stem 3 furthest from valve core 2, i.e., the upper end of valve stem 3, via a key or similar rigid connection. When transmission rod 41 moves axially linearly under the drive of double springs, rack segment 52 drives gear 51, which meshes with it, to rotate, thus precisely converting the linear motion into the rotational motion of valve stem 3. This motion conversion mechanism is the core of realizing the valve opening and closing action; it amplifies the microscopic axial displacement of drive module 4 and converts it into the effective angular displacement of valve core 2.

[0048] In this embodiment, the gear 51, rack segment 52, and transmission rod 41 constituting the transmission mechanism 5 are all made of thermally conductive material. This material selection is not solely for mechanical performance considerations, but has a clear thermal function purpose. They are connected in series, forming a continuous heat transfer path extending from the valve stem 3 to the shape memory alloy spring 42. After heat is captured by the valve stem 3 from the high-temperature fluid end, it passes sequentially through the gear 51 and rack segment 52, and finally through the transmission rod 41 to the shape memory alloy spring 42, which requires thermal stimulation. This design allows the transmission mechanism 5 to not only perform mechanical transmission tasks but also become a high-speed channel for directional heat flow, ensuring that thermal energy can be efficiently and controllably delivered to the drive core.

[0049] In this embodiment, the gear and rack structure of the transmission mechanism 5 brings significant mechanical transmission advantages. Through the simple matching of gear radius and rack stroke, this mechanism can amplify and convert the minute linear displacement of the transmission rod 41 into a larger rotational angle output of the valve stem 3. This displacement amplification effect effectively improves the stroke control accuracy of the valve action, ensuring that the valve core 2 can achieve rapid and precise opening and closing operations.

[0050] Furthermore, the gear and rack transmission chain structure is extremely simple. The motion conversion from linear input via the transmission rod 41 to rotary output via the valve stem 3 is completed through only one meshing pair, resulting in a short transmission chain and high mechanical efficiency. This direct transmission method avoids the multi-stage gear 51 reduction mechanism or complex linkage mechanism commonly found in traditional valve drives. It not only significantly simplifies the overall structure, reduces the number of parts and assembly complexity, but also reduces clearance errors, friction losses, and potential failure points that may result from too many transmission links.

[0051] By creatively combining a gear and rack transmission mechanism with heat-conducting materials, an integrated system of mechanical transmission and thermal management functions is achieved. This solution utilizes the gear and rack pair 51 to efficiently and accurately convert the minute linear displacement of the transmission rod 41 into the rotational motion of the valve stem 3. The short transmission chain and compact structure significantly improve the response speed and reliability of the valve actuation. Simultaneously, by making gear 51, rack segment 52, and transmission rod 41 all made of heat-conducting materials, a continuous heat transfer path is constructed extending from the valve stem 3 to the shape memory alloy spring 42. This ensures that the drive module 4 can indirectly and reliably sense fluid temperature changes through this path, laying a core foundation for the valve's autonomous intelligent control in high-temperature environments.

[0052] In some embodiments, this application also illustrates a specific structural form of the rack segment 52.

[0053] The first form of the rack segment 52 is a straight rack disposed on the side wall of the transmission rod 41, with its teeth extending axially along the transmission rod 41 to form a standard parallel shaft meshing with the gear 51. Straight racks have mature manufacturing processes, high transmission efficiency, and good meshing smoothness, making them the most commonly used and reliable structural form in gear and rack transmissions. This design ensures that the linear motion of the transmission rod 41 can be accurately and with low loss converted into the rotational motion of the gear 51.

[0054] A second alternative to the rack segment 52 is a ring-shaped tooth structure formed on the outer periphery of the transmission rod 41 and distributed along its axial direction. This structure can be considered as a continuous ring-shaped tooth profile machined on the outer surface of the cylindrical body of the transmission rod 41, with the tooth profile direction having a certain angle with the axis of the transmission rod 41, for example, using helical teeth or herringbone teeth design. The ring-shaped tooth structure can bring potential advantages such as higher meshing overlap, smoother transmission, and stronger load-bearing capacity, and is especially valuable in applications that require the transmission of large torques or reduction of impact vibrations.

[0055] The choice between these two rack segment structures provides flexibility in valve design. Designers can select the most suitable rack configuration based on specific performance indicators, process conditions, and cost requirements. Straight racks emphasize structural simplicity and ease of manufacturing, while ring racks may optimize transmission smoothness and durability.

[0056] In some embodiments, this application introduces a material gradient-based thermal management design on the basis of the gear and rack transmission mechanism. By dividing the meshing pair into segments and assigning different thermal conductivity characteristics, intelligent control of the heat transfer process is achieved.

[0057] Specifically, the teeth of gear 51 are divided into a first tooth segment 511 and a second tooth segment 512. Correspondingly, rack segment 52 is also divided into a first rack portion 521 that meshes with the first tooth segment 511 and a second rack portion 522 that meshes with the second tooth segment 512. This partitioned design functionally divides the continuous meshing process in space. Crucially, both the first tooth segment 511 and the first rack portion 521 are made of a first thermally conductive material, while both the second tooth segment 512 and the second rack portion 522 are made of a second thermally conductive material, and the thermal conductivity of the first thermally conductive material is significantly higher than that of the second thermally conductive material.

[0058] Specifically, in this embodiment, the first thermally conductive material can be selected from high thermal conductivity metals such as copper, copper alloys, silver, and aluminum alloys, or their alloys; the second thermally conductive material can be selected from low thermal conductivity metals such as stainless steel, titanium alloys, and nickel-based high-temperature alloys, or their alloys. Typically, the first thermally conductive material is copper, and the second thermally conductive material is stainless steel. The first rack portion 521 is close to the shape memory alloy spring 42, and the second rack portion 522 is close to the bias spring 43. When the valve begins to operate, gear 51 and rack first engage between the first tooth section 511 and the first rack section 521. Because this engagement section uses highly thermally conductive materials, a highly efficient heat transfer path is formed from the valve stem 3 through gear 51 to the transmission rod 41. Heat is rapidly transferred, ensuring that the shape memory alloy spring 42 can quickly heat up above its phase transformation point, thereby generating sufficient driving force to trigger the valve operation and ensuring the valve's rapid response to high-temperature fluids. When the shape memory alloy spring 42 reaches its austenitic phase transformation point, the material undergoes phase transformation and contraction. This contraction force acts directly on the transmission rod 41 through its fixed connection point with the limiting part 411 of the transmission rod 41, pulling the transmission rod 41 axially towards the side where the SMA spring is located.

[0059] As the transmission process proceeds, the engagement point gradually transitions from the first section to the second tooth section 512 and the second rack section 522. At this time, the material of the heat transfer path changes to a pair of low thermal conductivity materials, significantly increasing the thermal resistance and effectively limiting the passage of heat. This automatic switching mechanism, after the main stage of valve operation is completed, effectively reduces the heat flux density that continues to be transferred to the shape memory alloy spring 42, thereby preventing it from overheating due to continuous heat absorption and avoiding material performance degradation or failure.

[0060] In this embodiment, the boundary positions between the first tooth segment 511 and the second tooth segment 512, and between the first rack portion 521 and the second rack portion 522, need to be designed in coordination with the heat required for the shape memory alloy spring 42 to complete the phase change drive and the corresponding displacement of the transmission rod 41. For example, the boundary point can be set at 70% of the total stroke of the transmission rod 41 to ensure rapid temperature rise triggering through pairing with high thermal conductivity materials in the initial stage of drive (displacement 0-70%), and to limit heat input and prevent overheating through pairing with low thermal conductivity materials in the later stage of drive (displacement 70%-100%).

[0061] In this embodiment, the core of the solution lies in passively and adaptively adjusting the heat transfer rate by utilizing position changes during the transmission process. It requires no additional control elements or sensors, achieving overheat protection for the driving element entirely through ingenious mechanical structure design and intelligent material selection, while ensuring trigger sensitivity.

[0062] By employing a segmented material gradient design in the gear-rack meshing pair, an intrinsic thermo-adaptive regulation mechanism is created. This scheme automatically switches between high and low thermal conductivity heat transfer paths at different stages of the transmission process. This ensures efficient and rapid heat transfer required in the initial stage of valve actuation for sensitive triggering, while effectively limiting heat flow in the later stages of operation to prevent overheating of the shape memory alloy. This cleverly balances the conflict between response speed and overheat protection, significantly improving the reliability and durability of the valve in high-temperature environments.

[0063] In some embodiments, the transmission rod 41 is designed as a hollow rod with continuous cooling channels formed axially inside. This structural design allows the transmission rod 41 to integrate active thermal management functions while performing mechanical transmission functions.

[0064] The hollow rod structure significantly increases the heat dissipation surface area and provides a dedicated path for the flow of cooling medium.

[0065] As one implementation method, when valve reset is required, automatic air convection can be achieved through hollow rods to achieve natural cooling of the shape memory alloy 42.

[0066] In other embodiments, cooling gas or liquid can be introduced into the hollow rod, and the cooling medium flows directly through the hollow rod to the central region of the transmission rod 41, achieving directional cooling of the shape memory alloy spring 42. This internal cooling method has higher heat exchange efficiency than external cooling because the cooling medium can directly contact the heat conduction core area of ​​the transmission rod 41.

[0067] In some specific embodiments, one end of the transmission rod 41 where the shape memory alloy spring 42 is located can be sealed, and a vent hole can be provided on the outer periphery of the transmission rod 41 at the position corresponding to the shape memory alloy spring 42. Cooling air can be introduced through the other end of the transmission rod 41 to achieve directional cooling of the shape memory alloy spring 42.

[0068] It is worth noting that the cooling channel disclosed in this application is perfectly integrated with the mechanical function of the transmission rod 41, without requiring additional structural space. During the axial linear motion of the transmission rod 41, the internal channel maintains its structural and functional integrity at all times, without affecting the meshing transmission accuracy of the gear 51 and rack.

[0069] When the valve needs to be reset from the closed state, the cooling medium is sprayed directly onto the central region of the transmission rod 41 through the hollow channel. Since the transmission rod 41 is connected to the shape memory alloy spring 42 through heat conduction, the cooling effect can be quickly transferred to the spring body, causing its temperature to drop rapidly below the martensitic phase transformation temperature, thereby completing the phase transformation recovery. This directional cooling method greatly shortens the valve's reset response time.

[0070] By designing the transmission rod 41 as a hollow structure and integrating a cooling channel, a high degree of integration between mechanical transmission and thermal management functions is achieved. This solution not only solves the problem of rapid reset of shape memory alloy driven valves in high-temperature environments, but also achieves functional integration and space optimization through structural innovation, significantly improving the valve's response speed and reliability under continuous operating conditions.

[0071] In some other embodiments, the valve box 6 is provided with a number of heat dissipation holes. By providing heat dissipation holes, it can be ensured that when cooling is required, external air can enter the valve box 5 through the heat dissipation holes to achieve natural cooling of the shape memory alloy 42.

[0072] When low-temperature gas flows over the surface of high-temperature components such as the transmission rod 41 and springs, it can quickly carry away the accumulated heat.

[0073] In some embodiments, a heat insulation structure 7 is provided between the valve housing 6 and the valve body 1. The heat insulation structure 7 is made of high-performance heat insulation materials such as ceramic fiber cotton, aerogel, or nanoporous heat insulation materials. Its main function is to introduce extremely high thermal resistance between the high-temperature valve body 1 and the valve housing 6 that houses the drive module 4, effectively blocking the direct conduction path of heat from the valve body 1 to the valve housing 6, thereby significantly reducing the heat conducted to the cavity of the drive module 4 through the metal valve body 1 itself.

[0074] During valve operation, the heat of the high-temperature fluid is primarily designed to be transferred through a pre-defined path via the highly thermally conductive valve stem 3. The presence of the heat insulation structure 7 ensures the directionality of heat transfer, forcing the vast majority of heat flow to be conducted axially upwards along the valve stem 3, ultimately reaching the drive module 4 to trigger the shape memory alloy spring 42. This design avoids heat short-circuiting through secondary paths such as the valve body 1 wall, preventing the overall temperature of the drive module 4 cavity from becoming excessively high. Without this heat insulation structure 7, high temperatures would rapidly diffuse through the metal valve body 1 to the entire valve box 6, causing the shape memory alloy spring 42 to remain in a high-temperature environment even when not needed. This would not only prevent normal temperature-triggered actuation but also lead to irreversible degradation of material properties due to overheating.

[0075] In some embodiments, a first rolling bearing G1 is provided on the valve housing 6, which is typically mounted in a bearing housing inside the valve housing 6. The upper end of the valve stem 3, i.e., the end connected to the transmission mechanism 5, is rotatably supported on the first rolling bearing G1. This design provides a precise pivot point for the top of the valve stem 3, effectively limiting the radial runout that may occur during transmission and ensuring the stability of meshing with transmission components such as the gear 51.

[0076] At least one second rolling bearing G2 is provided on the valve body 1, and the lower end of the valve stem 3, i.e., the end connected to the valve core 2, is rotatably supported on this second rolling bearing G2. This second bearing constitutes another key support point for the valve stem 3. For longer valve stems 3, an additional support bearing can be added in the middle of the valve stem 3, forming a "multi-point support" structure together with the bearings at the upper and lower ends. This layout can significantly improve the rigidity of the valve stem 3, suppress bending deformation caused by the weight of the valve stem 3 or fluid impact force, and ensure that the rotation axis of the valve stem 3 always remains in the designed position.

[0077] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A high-temperature fluid control valve based on shape memory alloy, comprising a valve body, wherein a fluid channel is formed inside the valve body, and a valve core disposed within the fluid channel, characterized in that, Also includes: A valve stem, made of a thermally conductive material, has one end connected to the valve core and at least partially extending into the fluid passage; A drive module is disposed outside the valve body. The drive module includes a transmission rod and a shape memory alloy spring and a bias spring acting on both ends of the transmission rod, respectively. The shape memory alloy spring and the bias spring are configured to drive the transmission rod to move linearly along its axial direction. A transmission mechanism is connected between the transmission rod of the drive module and the other end of the valve rod, and is used to convert the linear motion of the transmission rod into the rotational motion of the valve rod, so as to realize the opening and closing of the valve core in the fluid channel; The valve stem forms a heat transfer path that conducts the heat of the high-temperature fluid in the fluid channel to the drive module.

2. The high-temperature fluid control valve based on shape memory alloy as described in claim 1, characterized in that: The portion of the valve stem that extends into the fluid passage has an axial opening.

3. The high-temperature fluid control valve based on shape memory alloy as described in claim 1, characterized in that: It also includes a valve box, in which the drive module is housed. The transmission rod is horizontally positioned inside the valve box and can move axially along the transmission rod. Each end of the transmission rod has a limiting part. A shape memory alloy spring and an offset spring are respectively sleeved on both ends of the transmission rod and fixedly connected to the corresponding limiting parts. The ends of the shape memory alloy spring and the offset spring away from the limiting parts are fixedly connected to the side wall of the valve box. The end of the valve stem away from the valve core extends movably into the interior of the valve box and is connected to the transmission rod through a transmission mechanism.

4. The high-temperature fluid control valve based on shape memory alloy as described in claim 1, characterized in that: The transmission mechanism includes a gear and a rack segment. The rack segment is disposed on the transmission rod and located between the shape memory alloy spring and the bias spring. The gear is fixedly connected to the end of the valve rod away from the valve core and meshes with the rack segment. The linear motion of the transmission rod is converted into the rotational motion of the valve rod through the meshing of the rack segment and the gear. The gear, rack segment, and transmission rod are all made of thermally conductive material to form a heat transfer path that transfers heat from the valve rod to the shape memory alloy spring.

5. The high-temperature fluid control valve based on shape memory alloy as described in claim 4, characterized in that: The transmission rod is a hollow rod with a cooling channel inside.

6. The high-temperature fluid control valve based on shape memory alloy as described in claim 4, characterized in that: The gear teeth include a first tooth segment and a second tooth segment. The rack segment includes a first rack portion that meshes with the first tooth segment and a second rack portion that meshes with the second tooth segment. The first tooth segment and the first rack portion are both made of a first thermally conductive material, and the second tooth segment and the second rack portion are both made of a second thermally conductive material. The thermal conductivity of the first thermally conductive material is higher than that of the second thermally conductive material.

7. The high-temperature fluid control valve based on shape memory alloy as described in claim 3, characterized in that: A heat insulation structure is provided between the valve box and the valve body.

8. The high-temperature fluid control valve based on shape memory alloy as described in claim 3, characterized in that: The valve box is provided with a first rolling bearing, and the upper end of the valve stem is rotatably supported on the first rolling bearing; the valve body is provided with at least one second rolling bearing, and the lower end of the valve stem is rotatably supported on the second rolling bearing.

9. The high-temperature fluid control valve based on shape memory alloy as described in claim 4, characterized in that: The rack segment is a straight rack disposed on the side wall of the transmission rod; or, the rack segment is an annular tooth structure formed on the outer periphery of the transmission rod and distributed along its axial direction.

10. The high-temperature fluid control valve based on shape memory alloy as described in claim 3, characterized in that: The valve box is provided with several heat dissipation holes.

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