Solid-state refrigeration driver based on recovery of mechanical work of unloading, and refrigeration apparatus

Abstract

A rotary solid-state refrigeration driver based on recovery of mechanical work of unloading, and a solid-state refrigeration apparatus. The rotary solid-state refrigeration driver comprises: a rotary motor (9), a main transmission shaft (2) driven by the rotary motor (9) to rotate, N eccentric transmission mechanisms mounted at different axial positions of the main transmission shaft (2), N pistons (1) respectively driven by the N eccentric transmission mechanisms to move in a reciprocating manner, and N elastocaloric materials (10) periodically loaded and unloaded by means of the reciprocating motion of the N pistons (1), wherein the N eccentric transmission mechanisms have different phase angles, such that the N elastocaloric materials (10) are unloaded in different time periods; and during a process of being unloaded, each elastocaloric material (10) releases its own mechanical work to provide thrust for the rotation of the main transmission shaft (2), N being an integer greater than one.

Description

Solid-state refrigeration actuator and refrigeration equipment based on unloading mechanical work recovery

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202311708973.6, filed on December 13, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention belongs to the field of solid-state refrigeration technology, specifically relating to a rotary solid-state refrigeration actuator that recovers the mechanical work of unloading a spring-loaded material under rotational motion, and a solid-state refrigeration device including the rotary solid-state refrigeration actuator. Background Technology

[0004] Space cooling is crucial for maintaining a high quality of life in modern times, including using air conditioning to lower indoor temperatures and refrigerators to preserve food in specific spaces. However, under the challenges of future sustainable development, current gas compression-based refrigeration machines have exposed many problems: Firstly, the refrigerants used in gas compression refrigeration machines present numerous issues. Globally, large quantities of refrigerants (such as chlorinated and bromine-containing refrigerants) are manufactured and released into the environment. Although these refrigerants themselves are not toxic to living organisms, their evaporation in the atmosphere causes a sharp decline in ozone levels, resulting in irreversible damage to the Earth's atmosphere due to the chemical effects of these refrigerants. Under the influence of ozone depletion, the Earth's surface receives excessive ultraviolet radiation, not only raising overall global temperatures and triggering more extreme weather events, but also making organisms highly susceptible to adverse effects from excessive ultraviolet radiation (such as inducing skin cancer). Although technological advancements have led to the development of new refrigerants (such as fluorinated and ammonia refrigerants), reducing their environmental impact, these refrigerants remain flammable and explosive, posing significant safety risks to the public. Secondly, the energy conversion rate of current gas compression-based refrigeration is low; a large portion of the electricity generated by power plants is not effectively converted during the refrigeration process, resulting in a substantial waste of public resources. Currently, the energy efficiency ratio (EER) is used to evaluate the energy performance of refrigerators (based on the ratio of output cooling power to input electrical power). For example, the EER of commonly available air conditioners is approximately 2.3 to 3.5. If a higher EER (e.g., greater than 6) were used, the same cooling effect could be achieved with only half the electrical energy. However, due to the low entropy change in the gas-liquid two-phase transition, improving the EER of such refrigeration machines faces inherent technological bottlenecks. Therefore, the development and advancement of next-generation environmentally friendly and efficient refrigeration technologies have become crucial prerequisites for achieving sustainable development in the future.

[0005] Spin-calorie solid-state refrigeration is a novel refrigeration technology that utilizes the first-order phase change of solid materials. This technology induces a phase change in the material through mechanical deformation, resulting in the release and absorption of latent heat, thereby reducing the temperature of the target object. The spin-calorie refrigeration cycle generally includes four processes: loading, holding and heat exchange, unloading, and holding and heat exchange. Since this new technology was proposed by British scientists in 2004, it has attracted widespread attention from researchers worldwide. The most important reason is its high energy conversion efficiency and its safety and lack of additional emissions during use. In the 2014 U.S. Department of Energy's Guidelines for Future Refrigeration Technologies, spin-calorie solid-state refrigeration technology, employing spin-calorie materials, received the highest score and was assessed as one of the most likely refrigeration technologies to replace existing gas compression refrigeration. Spin-calorie materials refer to solid materials exhibiting the spin-calorie (thermal) effect. The spin-calorie effect is one type of thermal effect in solid materials, which is the release or absorption of heat caused by the strain resulting from the application of an external stress field. Spin-calorie materials, based on the phase change-induced spin-calorie effect, possess high entropy change characteristics, which can significantly improve energy conversion efficiency. Many materials possess the properties of spring-loaded refrigeration, including shape memory alloys, natural rubber, synthetic polymers, and plastic crystals. Among them, shape memory alloys (such as nickel-titanium alloys, copper-aluminum-manganese alloys, nickel-manganese-copper-cobalt alloys, and nickel-iron-gallium alloys) are widely used in spring-loaded solid-state refrigeration technology due to their extremely high phase transition entropy and material energy efficiency ratio. For example, the widely used nickel-titanium alloy can generate 0.32 J / cm² under adiabatic phase transition. 3 The entropy change of K is far greater than that of R-32 (hydrofluorocarbon), the most commonly used gaseous compressed refrigerant today (0.035 J / cm³). 3 Due to their high phase transformation entropy, shape memory alloys can achieve an energy efficiency ratio exceeding 30. In recent years, research on solid-state refrigeration using ballistic cartridges has yielded significant progress in prototype development, particularly in cooling performance, achieving a large temperature difference of 50K and a specific cooling power of 6W / g. However, the actual operating energy efficiency ratio of the prototype (around 1) is far lower than the material's energy efficiency ratio. Issues with energy utilization and conversion severely hinder the further commercialization of this technology.

[0006] The ineffective utilization of the mechanical work done by the spring-loaded material during its deformation and return to its original shape is one of the main reasons for the low energy efficiency ratio of the spring-loaded solid-state refrigeration prototype system. When the material is in a deformed state, it is in an energy-storing state. If the external constraints are removed, the spring-loaded material can release the mechanical energy stored inside. If this mechanical work can be utilized, the power requirements of the external actuator can be greatly reduced, thereby achieving a higher system energy efficiency ratio. Current spring-loaded refrigeration prototypes generally adopt a linear drive structure (hydraulic push rod, linear push rod, etc.). For example, a research team from the University of Michigan designed and developed a refrigeration prototype using a hydraulic actuator and a nickel-titanium alloy tube compression principle. Using water as the heat exchange medium, they achieved a maximum temperature difference of 20K, and their results were published in the international academic journal *Science*. A research team from the University of Ljubljana also used a hydraulic actuator as the actuator for their prototype, employing a sleeve structure to compress the nickel-titanium alloy tube to achieve a spring-loaded effect; their results were published in the international academic journal *Nature Energy*. Chinese patent CN201810660524.1 (publication number CN108954901A, publication date 2018.12.07) demonstrates a spring-loaded refrigeration device utilizing the compression deformation of a nickel-titanium alloy tube. Water is used as the heat transfer medium. The axial reciprocating motion of a linear motor compresses the nickel-titanium alloy tube, causing it to deform. An external water pump drives water circulation to perform convective heat exchange on the nickel-titanium alloy tube. Although linear drive is conceptually feasible, whether using a linear motor or a hydraulic device, the pressure head will be locked due to mechanical limitations when there is no external power supply. The actuator still requires electrical energy to retract the pressure head during the actual unloading process, which increases the actuator's power consumption. If the pressure head is not a moving part, the mechanical energy released from material unloading cannot be transferred to another stage and drive the next loading. In contrast, mechanical energy can be easily transferred through rotation. During unloading, the linear motion of the material can be used to drive the rotation of the shaft in the tangential direction, maintaining the shaft's rotation; and the rotating shaft can continuously drive the compression of the next stage. Furthermore, due to fewer mechanisms and components, the rotary drive system has higher mechanical efficiency (the ratio of electrical input power to mechanical output power). A high-efficiency rotary drive system has a mechanical efficiency of 90%, which can significantly reduce the power waste during its own energy conversion. Although rotary drive systems have great application potential in elastic refrigeration, to date, existing literature and patents have not provided a clear technical roadmap and structural design for the drive system.

[0007] Summary of the Invention

[0008] To address at least one of the aforementioned problems, this disclosure provides a rotary solid-state refrigeration actuator based on unloading mechanical work recovery and a solid-state refrigeration device including the rotary solid-state refrigeration actuator.

[0009] According to a first aspect of this disclosure, a rotary solid-state refrigeration actuator based on unloading mechanical work recovery is provided. The rotary solid-state refrigeration actuator includes: a rotary motor; a main drive shaft driven to rotate by the rotary motor; N eccentric transmission mechanisms mounted at different axial positions on the main drive shaft and all driven by the main drive shaft; N pistons reciprocatingly driven by the N eccentric transmission mechanisms; and N spring-loaded and unloaded materials periodically by the reciprocating motion of the N pistons, wherein N is an integer greater than 1; the N eccentric transmission mechanisms have different phase angles relative to the main drive shaft, such that the unloading time periods of the N spring-loaded materials are different; and each spring-loaded material provides thrust for the rotation of the main drive shaft by releasing its own mechanical work during the unloading process.

[0010] Optionally, along the axial direction of the main drive shaft, the difference in phase angle between any two adjacent eccentric drive mechanisms among the N eccentric drive mechanisms is 360 / N degrees.

[0011] Optionally, the eccentric transmission mechanism cooperates with the main drive shaft and the piston to form an eccentric connecting rod mechanism, an eccentric cam mechanism, an eccentric bearing mechanism, or a crank-connecting rod mechanism.

[0012] Optionally, at each of the different axial positions of the main drive shaft: the cross-section of the main drive shaft is circular and the center of the circle does not coincide with the axis of rotation of the main drive shaft; and the eccentric transmission mechanism includes a connecting rod portion and a pin, the end of the connecting rod portion away from the piston includes an annular portion, the annular portion is sleeved on the outer circumferential surface of the main drive shaft and can slide circumferentially relative to the outer circumferential surface of the main drive shaft, and the other end of the connecting rod portion is hinged to the end of the piston away from the spring clip material by the pin.

[0013] Optionally, the connecting rod portion includes an upper connecting rod portion and a lower connecting rod portion, and the annular portion is composed of the lower part of the upper connecting rod portion and the lower connecting rod portion, wherein the upper connecting rod portion and the lower connecting rod portion are connected together by screws.

[0014] Optionally, the rotary solid-state refrigeration actuator further includes a linear bearing, which is sleeved outside the corresponding piston to define the direction of the reciprocating motion of the piston and reduce radial friction.

[0015] Optionally, the rotary solid-state refrigeration actuator further includes: a first external frame that supports the corresponding piston and spring clip material, wherein the two ends of each spring clip material are fixed between the corresponding piston and the first external frame by means of direct contact, threaded connection, welding or bonding.

[0016] Optionally, the rotary solid-state refrigeration actuator further includes an upper housing portion and a lower housing portion, which are respectively used to carry the piston and the main drive shaft.

[0017] Optionally, the rotary motor is selected from: servo motor, stepper motor, torque motor, switched reluctance motor, and brushless DC motor.

[0018] Optionally, the rotary solid-state refrigeration driver further includes a speed reducer, which is used to increase the torque of the rotary motor.

[0019] Optionally, the rotary motor drives the reducer, which in turn drives the main drive shaft to rotate.

[0020] Optionally, the rotary solid-state refrigeration driver also includes a second external frame for securing the reducer and the eccentric transmission mechanism.

[0021] Optionally, the geometry of the spring material is selected from: cylindrical, cubic, cuboid, cylindrical, and rectangular.

[0022] Optionally, the spring clip material is selected from: shape memory alloy, natural rubber, synthetic polymer, and plastic crystal.

[0023] Optionally, the spring clip material is selected from: nickel-titanium alloy, copper-aluminum-manganese alloy, nickel-manganese-titanium alloy, nickel-titanium-cobalt alloy, nickel-titanium-copper-cobalt alloy, and nickel-iron-gallium alloy.

[0024] Optionally, the deformation mode of the loading-unloading process of the spring material is uniaxial linear deformation, wherein the uniaxial linear deformation includes linear compression and linear tension.

[0025] According to a second aspect of this disclosure, a solid-state refrigeration device is provided, comprising a rotary solid-state refrigeration actuator based on unloading mechanical work recovery according to a first aspect of this disclosure, and further comprising a heat exchange structure for exchanging heat with the cartridge material to transfer the heat and cold generated by the cartridge material.

[0026] Compared with the prior art, the rotary solid-state refrigeration actuator and solid-state refrigeration device disclosed herein have the following advantages:

[0027] 1. Rotary loading method: Compared with existing hydraulic or linear motor drives, it greatly reduces the number of mechanical transmission devices, thereby reducing mechanical and electrical energy losses.

[0028] 2. Unloading mechanical work recovery is achieved: This disclosure adopts a multi-cylinder structure including multiple eccentric transmission mechanisms and multiple pistons, which can recover the unloading mechanical work of one of the cartridge materials and reuse it to load another cartridge material, thereby realizing energy recovery and utilization and reducing energy consumption.

[0029] 3. Large and adjustable temperature drop of solid refrigerant: By adjusting the eccentric distance, the maximum temperature drop of the spring-loaded material can be 30 degrees Celsius in a single operation.

[0030] 4. Continuous output of cooling capacity: Compared with traditional spring-loaded materials that need to wait for heat dissipation before cooling capacity can be used, this invention adopts a multi-cylinder design, which allows the intermittent cooling of multiple spring-loaded materials to be superimposed into continuous cooling, greatly improving efficiency and cooling power.

[0031] 5. Miniaturization and commercialization: Compared with existing hydraulic or linear motor drives, the overall weight and volume are greatly reduced, and safety and portability are improved.

[0032] 6. High-frequency operation: It can reach a maximum operating frequency of 5Hz, which improves the cooling power. Attached Figure Description

[0033] Figure 1 is a schematic diagram illustrating the unloading mechanical work recovery principle according to the present disclosure;

[0034] Figure 2 is a perspective view showing a portion of a rotary solid-state cooling driver according to an exemplary embodiment of the present disclosure;

[0035] Figure 3 is a front view schematic diagram showing the structure and installation process of a portion of a rotary solid-state refrigeration driver according to an exemplary embodiment of the present disclosure;

[0036] Figure 4 is a front view schematic diagram showing a portion of a rotary solid-state refrigeration driver according to an exemplary embodiment of the present disclosure;

[0037] Figure 5 is a perspective view showing a portion of a rotary solid-state cooling driver according to an exemplary embodiment of the present disclosure;

[0038] Figure 6 is a graph showing the change of torque on the main drive shaft relative to the rotation angle according to exemplary embodiments and comparative examples of this disclosure.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Piston 2. Main drive shaft 3. Connecting rod section

[0041] 3a Upper part of the connecting rod; 3b Lower part of the connecting rod; 4 pins

[0042] 5a Upper part of the housing 5b Lower part of the housing 6 Linear bearing

[0043] 7a Second external gantry 7b First external gantry 8 Reducer

[0044] 9 Rotary motor 10 Spring clip material 0 Rotary axis Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions of this disclosure, the unloading mechanical power recovery form and the unloading power recovery driver structure applying its principle provided in this disclosure will be described in detail below with reference to the accompanying drawings.

[0046] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. The term "and / or" as used in this disclosure includes any and all combinations of one or more of the associated enumerated entries. The singular forms "a" and "the" as used in this disclosure are also intended to include the plural forms, unless the context clearly indicates otherwise. The terms "comprising," "made of," etc., as used in this disclosure specify the presence of the stated feature, integral, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof.

[0047] In the description of this disclosure, it should be noted that the orientations or positional relationships indicated by terms such as "top," "bottom," "upper," "lower," "left," "right," "inner," and "outer" are based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product is usually placed during use. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to 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 this disclosure.

[0048] Unless otherwise specified, all terms used in this disclosure (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined in this disclosure.

[0049] Figure 1 illustrates the principle of unloading mechanical work recovery according to this disclosure. Based on the principle of object deformation, when an object deforms (stretching, compressing, torsion, bending, etc.), it stores elastic deformation mechanical energy. As deformation ends, the object outputs the stored mechanical energy to the outside world. The same applies to spring-loaded refrigeration materials. Generally, materials used in spring-loaded refrigeration possess hyperelasticity (or pseudoelasticity), meaning they can undergo large elastic deformation and recover to their original state without residual strain. Based on this characteristic, this disclosure employs an eccentric transmission mechanism to drive the deformation of the spring-loaded material, and utilizes the elastic deformation mechanical energy stored in the spring-loaded material to drive the transmission shaft of the eccentric mechanism to rotate in the reverse direction. Simultaneously, the spring-loaded material itself undergoes a phase change when subjected to external deformation, releasing or absorbing heat, thereby enabling refrigeration.

[0050] For simplicity, Figure 1 uses an eccentric wheel as an example of an eccentric transmission mechanism. When the distal part of the eccentric wheel rotates to the bottom of the spring-loaded material, it presses against the material, causing it to compress and release heat. As the eccentric wheel continues to rotate, after passing the highest point of the distal part, the spring-loaded material enters the unloading process, releasing elastic deformation mechanical energy and absorbing heat from the surrounding environment. The mechanical energy released by the spring-loaded material can be transferred to the eccentric wheel, thus helping to drive its rotation. The inventors also discovered that because the transmission shaft is connected to the motor, the motor's gear structure is self-locking and cannot instantly change speed (i.e., it cannot maintain rotation through inertia). If only a single-cylinder design is used, i.e., the device only has one spring-loaded material, the mechanical work of unloading instantaneously transferred to the transmission shaft cannot be stored and transferred to the loading of the same spring-loaded material in the next time period. Therefore, this disclosure adopts a multi-cylinder mechanism design (at least two cylinders), and through the phase angle design of the eccentric position, i.e., satisfying the loading of one material while the other is unloading, the torque on the transmission shaft will be reduced due to the simultaneous action of the two materials. This means that driving two materials simultaneously requires less torque than driving them separately, because unloading work recovery occurs. Based on this principle, the unloading work recovery ratio of the actuator can be roughly calculated using the following formula:

[0051] Where W1 refers to the mechanical work required for a single piece of spring material to deform under load without unloading and energy recovery; n refers to the number of actuator cylinders (i.e., how many pieces of material are in the actuator); W inW1 refers to the total mechanical work (measured value) required to achieve the driving process under actual operating conditions using the rotary solid-state refrigeration actuator disclosed herein; W2 refers to the unloading mechanical work contained in a single material under operating conditions. Generally, for materials with a constant elastic modulus, such as springs, W1 equals W2. In actual operating conditions, due to the two-phase change process during the phase transformation of shape memory alloys, its Young's modulus is constantly changing, which leads to hysteresis. A portion of the unloading mechanical work is converted into hysteresis heat and thus lost. Therefore, for the analysis of shape memory alloy systems, W1 is greater than W2.

[0052] Based on the above principles, an exemplary embodiment of this disclosure provides a rotary solid-state refrigeration actuator (hereinafter referred to as the rotary solid-state refrigeration actuator) that recovers the mechanical work of unloading and clamping materials under rotational motion. As shown in Figures 2 to 5, the rotary solid-state refrigeration actuator includes: a rotary motor 9, a main drive shaft 2, two eccentric transmission mechanisms, two pistons 1, and two clamping materials 10.

[0053] A rotary motor 9 drives the main drive shaft 2 to rotate. Two eccentric transmission mechanisms are installed at different axial positions on the main drive shaft 2. The function of the eccentric transmission mechanisms is to convert the rotational motion of the main drive shaft 2 into the linear reciprocating motion of the piston 1. The two spring clips 10 are periodically loaded and unloaded by the reciprocating motion of the two pistons 1. The two eccentric transmission mechanisms are 180 degrees out of phase with respect to the main drive shaft 2 (rotation axis O), so that the time periods of unloading (or loading) the two spring clips 10 are staggered. In other words, when one spring clip 10 is loaded, the other spring clip 10 is unloaded. During the unloading process, each spring clip 10 will generate a downward thrust on one of the pistons 1, which will push the piston 1 downward, thereby driving the eccentric transmission mechanism to move downward at the same time. The transmitted thrust will act tangentially on the main drive shaft 2, providing thrust for its rotation. Since the two spring clip materials 10 do not simultaneously provide thrust to the main drive shaft 2, the thrust does not hinder the rotation of the main drive shaft 2, but rather promotes the rotation of the main drive shaft 2, reducing the input power of the rotary motor 9.

[0054] Specifically, as shown in Figure 2, the main drive shaft 2 can rotate around the rotation axis 0. The cross-section of the portion of the main drive shaft 2 where the eccentric transmission mechanism is mounted is circular, and the center of this circle does not coincide with the rotation axis 0. In other words, the portion of the main drive shaft 2 where the eccentric transmission mechanism is mounted has an eccentric circular structure relative to the rotation axis 0 of the main drive shaft 2, meaning the main drive shaft 2 has a (partial) eccentric shaft structure. There is a 180-degree radial angular deviation between the two eccentric circular portions, meaning the phase angles of the two eccentric circular portions differ by 180 degrees. Furthermore, the eccentricity of each eccentric circular portion can be set to 1.5 mm, meaning the radial distance between the centers of the two eccentric circular portions is 3 mm.

[0055] As shown in Figure 2, each eccentric transmission mechanism includes a connecting rod portion 3 and a pin 4. The connecting rod portion 3 includes an upper connecting rod portion 3a and a lower connecting rod portion 3b connected together by screws. The lower end of the upper connecting rod portion 3a and the lower connecting rod portion 3b together form an annular portion. The inner diameter of this annular portion matches the outer circumferential diameter of the eccentric circular structure, so that the annular portion can be fitted onto the outer circumferential surface of the eccentric circular portion of the main drive shaft 2 and slide (rotate) circumferentially relative to this outer circumferential surface. The other end of the connecting rod portion 3, that is, the upper end of the upper connecting rod portion 3a, is hinged to the lower end of the piston 1 by the pin 4, thereby restricting the piston 1 from moving back and forth or left and right. In addition, since the annular portion of the connecting rod portion 3 is fitted onto the eccentric circular portion with an eccentricity of 1.5 mm, when the main drive shaft 2 rotates, the connecting rod portion 3 can swing relative to the piston 1 around the pin 4, while the upper end of the connecting rod portion 3 drives the piston 1 to perform a reciprocating motion with a stroke of about 3 mm through the pin 4.

[0056] As shown in Figures 3 and 5, the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may further include two linear bearings 6. Each linear bearing 6 is sleeved on the corresponding piston 1 to provide constraint for the piston 1 and reduce frictional losses when the piston 1 moves up and down.

[0057] As shown in Figure 5, the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may further include two first external frames 7b. The first external frames 7b are support structures for supporting the respective piston 1 and the spring clip material 10. The first external frames 7b can also be used to fix the respective spring clip material 10. The two ends of the spring clip material 10 are fixed between the respective piston 1 and the first external frames 7b by direct contact, threaded connection, welding, or bonding. The first external frames 7b can be mounted on a linear bearing 6 and may include a plurality of screws fixed to the top surface of the linear bearing 6 and a top cover fixed to the screws by nuts. The position of the top cover can be adjusted by the respective nuts, and receiving blind holes or screw holes for receiving the ends of the spring clip material 10 may be provided on the bottom surface of the top cover and the top surface of the piston 1.

[0058] As shown in Figure 4, the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may further include a reducer 8. The rotary motor 9 is connected to the main drive shaft 2 via the reducer 8. The reducer 8 is axially connected to the rotary motor 9 and the main drive shaft 2, and is used to increase the torque on the main drive shaft 2. Furthermore, the rotary motor 9 of the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may be a servo motor, a stepper motor, a torque motor, a switched reluctance motor, a brushless DC motor, etc., or may be a mechanical device capable of rotational motion.

[0059] As shown in Figures 3 and 4, the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may further include a second external frame 7a for fixing the reducer 8 and the eccentric transmission mechanism.

[0060] Furthermore, as shown in FIG3, the rotary solid-state refrigeration actuator of the exemplary embodiment of this disclosure may further include an upper housing portion 5a and a lower housing portion 5b. The upper housing portion 5a and the lower housing portion 5b serve as housing support portions, respectively supporting the piston 1 and the main drive shaft 2. The linear bearing 6 may be fixed to the upper housing portion 5a. The lower housing portion 5b may be fixedly connected to the second external frame 7a.

[0061] It should be noted that although the rotary solid-state refrigeration actuator in the exemplary embodiment of this disclosure adopts a two-cylinder structure, that is, the number of eccentric transmission mechanisms, pistons, and spring clips are all two, the present invention is not limited to this. The rotary solid-state refrigeration actuator may also adopt a three-cylinder, four-cylinder, or more-cylinder structure. Optionally, in the case of an N-cylinder structure where N>2, the difference in phase angle between any two adjacent eccentric transmission mechanisms is 360 / N degrees. In other words, for any intermediate eccentric transmission mechanism, if its phase angle is α, then the phase angles of its preceding and following adjacent eccentric transmission mechanisms can be α+360 / N and α+360 / N, respectively; or, the phase angles of multiple eccentric transmission mechanisms do not need to have an increasing / decreasing relationship, as long as they are evenly distributed within the range of 360 degrees.

[0062] Under operating conditions, the rotary motor 9 drives the main drive shaft 2 to rotate via the reducer 8. The eccentric circular portion, connecting rod portion 3, pin 4, and piston 1 of the main drive shaft 2 constitute a crank-connecting rod structure. When the main drive shaft 2 rotates, the eccentric circular portion drives the connecting rod portion 3 to vibrate up and down and swing left and right through the ring portion. At the same time, since the upper end of the connecting rod portion 3 is connected to the piston 1, and the piston 1 is constrained by the linear bearing 6, the rotation of the main drive shaft 2 is converted into the linear reciprocating motion of the piston 1. The piston 1 loads and unloads the spring-loaded material 10 on it through this reciprocating motion, thereby inducing the spring-loaded effect. The spring-loaded effect refers to the spring-loaded material 10 releasing heat into the environment when compressed and absorbing heat from the environment after recovering from deformation. Since the multiple eccentric transmission mechanisms have different phase angles relative to the main drive shaft 2, the non-simultaneous linear reciprocating motion of multiple pistons 1 is realized, which in turn causes the time periods for each spring-loaded material 10 to be unloaded (or loaded) by the piston 1 to be different, so that each spring-loaded material 10 is in a different deformation stage. During the unloading process, i.e., the deformation stage from compression deformation to deformation recovery, each spring material 10 generates a downward thrust on the piston 1. This thrust pushes the piston 1 downward, thereby driving the eccentric transmission mechanism to move downward simultaneously. The transmitted thrust acts tangentially on the main drive shaft 2, providing thrust for its rotation. Since multiple spring materials 10 do not simultaneously provide thrust to the main drive shaft 2, this thrust can reduce the torque required to load other spring materials, achieve work recovery, promote uniform rotation of the main drive shaft 2, reduce the input work of the rotary motor 9, and achieve energy saving.

[0063] Optionally, while the eccentric transmission mechanism according to this disclosure preferably has the structure described in the above embodiments, it may also have other structures. For example, the eccentric transmission mechanism can cooperate with the main drive shaft 2 and the piston 1 to form an eccentric connecting rod mechanism, an eccentric cam mechanism, an eccentric bearing mechanism, or a crank-connecting rod mechanism. For example, when using an eccentric cam mechanism, the main drive shaft 2 may not have an eccentric circular structure, and a cam fixed on the main drive shaft 2 can directly replace the connecting rod portion 3. The cam surface of the cam contacts the bottom of the piston 1 (so that it pushes the piston 1 when loading the cartridge material or is pushed by the piston 1 when unloading the cartridge material), and each cam has a different phase angle.

[0064] Optionally, the spring clip material 10 is selected from shape memory alloys, natural rubber, synthetic polymers, plastic crystals, etc. When the spring clip material 10 is a shape memory alloy, it can be selected from the group including: nickel-titanium alloy, copper-aluminum-manganese alloy, nickel-manganese-titanium alloy, nickel-titanium-cobalt alloy, nickel-titanium-copper-cobalt alloy, and nickel-iron-gallium alloy.

[0065] Optionally, the eccentric transmission mechanism, piston 1, main drive shaft 2, linear bearing 6, upper housing portion 5a and lower housing portion 5b are formed from plastic, metal, resin or other materials by additive manufacturing (3D printing, etc.) or subtractive manufacturing (wire cutting, etc.).

[0066] Optionally, the rotation mode of the main drive shaft 2 can be set to uniform rotation, differential rotation, or gap rotation.

[0067] Optionally, the deformation mode of each spring clip material 10 during the loading-unloading process is a uniaxial linear deformation including linear compression and linear tension.

[0068] The following section provides a further explanation of the rotary solid-state refrigeration actuator disclosed herein, in conjunction with experimental results.

[0069] Related experiments

[0070] The rotary solid-state refrigeration actuator structure used in this experiment is shown in Figures 2 to 5. The linear bearing 6, second external frame 7a, first external frame 7b, reducer 8, and spring clip material 10 are commercial standard parts; the piston 1, main drive shaft 2, upper part of connecting rod 3a, lower part of connecting rod 3b, pin 4, upper part of housing 5a, and lower part of housing 5b are machined alloy components. The components are connected to each other by screws. The rotary motor 9 is a servo motor. In the experiment, a spring was used instead of spring clip material 10 for better demonstration results.

[0071] The operation of this rotary solid-state refrigeration actuator is shown in Figure 1. The rotation of the rotary motor 9 causes the main drive shaft 2 to rotate. The eccentric transmission mechanism converts this rotation into the linear reciprocating motion of the piston 1, thereby compressing the spring. Reverse unloading elastic mechanical work recovery refers to the process where the spring, after being unloaded, pushes the main drive shaft 2 to rotate, thus reducing the torque required for the other loaded spring.

[0072] A torque sensor is axially mounted between the main drive shaft 2 and the reducer 8 to measure torque changes on the main drive shaft 2. Two springs, replacing the spring clip material 10, are respectively installed in the two cylinders of the rotary solid-state refrigeration actuator of this disclosure. Initially, one spring is in a compressed state, i.e., in a loaded state; the other spring is in an undeformed state, i.e., in an unloaded state. After the springs are installed, the rotary motor 9 is started and set to operate in a uniform rotation mode with a speed of 16 revolutions per minute. Data on the torque change on the shaft with the rotation angle of the drive shaft is collected and recorded by the torque sensor. For comparison, the torque change is collected when only a single spring is installed in the solid-state refrigeration actuator.

[0073] The experimental results are shown in Figure 6. The area enclosed by the torque variation curve on the shaft and the horizontal axis of rotation angle represents the input power of the rotary motor 9. It can be seen that the input power required to simultaneously drive two materials and utilize the elastic unloading power of one material to drive the loading of the other material is less than the input power required to drive the two materials separately (the area enclosed by twice the torque curve of a single material is greater than the area enclosed by the torque curves of two materials). Based on the previously described principle, the unloading power recovery ratio of the actuator can be roughly calculated using the following formula:

[0074] Where W1 refers to the mechanical work required for a single piece of spring material to deform under load without unloading energy recovery, here representing the area enclosed by the torque curve of a single piece of material; the number 2 represents the number of actuator cylinders (i.e., how many pieces of material are in the actuator); W in W1 refers to the total mechanical work (measured value) required to achieve the driving process under actual operating conditions using the rotary solid-state refrigeration actuator of this disclosure, specifically the area enclosed by the torque curves of the two materials; W2 refers to the unloading mechanical work contained in a single material under operating conditions. Generally, for materials with a constant elastic modulus, such as springs, W1 equals W2. Calculations show a work recovery rate of 53%, indicating that the rotary solid-state refrigeration actuator of this disclosure has an unloading work recovery function. By recovering the unloading elastic mechanical work of the materials, the input work required by the rotary motor will be reduced, thus maintaining system operation and achieving the requirement of energy reduction.

[0075] Accordingly, compared with the prior art, the rotary solid-state refrigeration actuator of this disclosure has the following advantages:

[0076] 1. Structural Design: This disclosure adopts a rotary loading method, which greatly reduces the number of mechanical transmission devices compared to existing hydraulic or linear motor drives, thereby reducing mechanical and electrical energy losses. The use of a multi-cylinder arrangement significantly reduces the overall length, making the overall structure more compact.

[0077] 2. Energy Utilization: The rotary solid-state refrigeration actuator disclosed herein realizes unloading mechanical work recovery, which is then used to load another piece of material, thus achieving energy recovery and utilization and reducing energy consumption. Compared with traditional material loading devices that require waiting for heat dissipation before cooling can be used, this actuator adopts a multi-cylinder design, where the intermittent cooling of multiple material loading devices can be superimposed into continuous cooling, greatly improving efficiency and cooling power. By adjusting the eccentric distance, the maximum temperature drop of a single material loading device can be 30 degrees Celsius. Unloading mechanical work recovery does not require additional waiting time, and the overall drive operating frequency can be increased, reaching a maximum operating frequency of 5Hz, thereby obtaining a large cooling power.

[0078] 3. Commercial applications: Compared with existing hydraulic or linear motor drives, the rotary solid-state refrigeration actuator disclosed herein has a significantly reduced overall weight and volume, and improved safety and portability. At the same time, since the actuator only involves rotational motion during operation and has no additional mechanical transmission device, it has high overall mechanical stability and a high safety factor. Most importantly, it realizes unloading mechanical work recovery, and the energy consumption coefficient of the cartridge solid-state refrigeration unit will exceed that of existing air conditioners, which not only reduces consumers' electricity expenditure, but also meets the requirements of environmental protection and carbon neutrality.

[0079] In summary, the rotary solid-state refrigeration actuator disclosed herein utilizes the elastic mechanical energy stored in the spring-loaded material during unloading, thereby recovering and utilizing the unloading mechanical work, reducing the overall power consumption required by the actuator, improving the energy efficiency ratio and the stability of the actuator under operating conditions, and providing new possibilities for the development of lightweight, commercially viable spring-loaded solid-state refrigeration devices.

[0080] Secondly, this disclosure also provides a solid-state refrigeration device, which includes the rotary solid-state refrigeration driver based on unloading mechanical work recovery as described above, and further includes a heat exchange structure for exchanging heat with the cartridge material to transfer the heat and cold generated by the cartridge material.

[0081] Optionally, the heat exchange structure can be a solid heat exchanger (which transfers heat directly through solid-solid contact) or a fluid heat exchanger (which uses gas, liquid, liquid metal, etc. to perform solid-liquid convection heat exchange).

[0082] Since this solid-state refrigeration device includes the rotary solid-state refrigeration driver described above, it has all the advantages of that rotary solid-state refrigeration driver.

[0083] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A rotary solid-state refrigeration actuator based on unloading mechanical work recovery, characterized in that, The rotary solid-state refrigeration actuator includes: a rotary motor, a main drive shaft driven to rotate by the rotary motor, N eccentric transmission mechanisms installed at different axial positions on the main drive shaft and all driven by the main drive shaft, N pistons reciprocating by the N eccentric transmission mechanisms, and N spring-loaded materials periodically loaded and unloaded by the reciprocating motion of the N pistons. N is an integer greater than 1; The N eccentric transmission mechanisms have different phase angles relative to the main drive shaft, resulting in different time periods for the N spring clip materials to be unloaded; and During the unloading process, each cartridge material provides thrust for the rotation of the main drive shaft by releasing its own mechanical work.

2. The rotary solid-state cooling actuator according to claim 1, characterized in that, Along the axial direction of the main drive shaft, the difference in phase angle between any two adjacent eccentric drive mechanisms among the N eccentric drive mechanisms is 360 / N degrees.

3. The rotary solid-state cooling actuator according to claim 1 or 2, characterized in that, The eccentric transmission mechanism cooperates with the main transmission shaft and the piston to form an eccentric connecting rod mechanism, an eccentric cam mechanism, an eccentric bearing mechanism, or a crank-connecting rod mechanism.

4. The rotary solid-state cooling actuator according to claim 1 or 2, characterized in that, At each of the different axial positions of the main drive shaft: The main drive shaft has a circular cross-section, and the center of this circle does not coincide with the axis of rotation of the main drive shaft; and The eccentric transmission mechanism includes a connecting rod portion and a pin. The end of the connecting rod portion away from the piston includes an annular portion, which is sleeved on the main transmission mechanism. The connecting rod is located on the outer circumferential surface of the drive shaft and can slide circumferentially relative to the outer circumferential surface of the main drive shaft. The other end of the connecting rod is hinged to the end of the piston away from the spring clip material via the pin.

5. The rotary solid-state cooling actuator according to claim 4, characterized in that, The connecting rod portion includes an upper connecting rod portion and a lower connecting rod portion. The annular portion is composed of the lower part of the upper connecting rod portion and the lower connecting rod portion. The upper connecting rod portion and the lower connecting rod portion are connected together by screws.

6. The rotary solid-state cooling actuator according to claim 5, characterized in that, Also includes: A linear bearing, which is sleeved outside the corresponding piston, is used to limit the direction of the reciprocating motion of the piston; The first external frame supports the corresponding piston and spring clip material. The two ends of each spring clip material are fixed between the corresponding piston and the first external frame by direct contact, threaded connection, welding or bonding. and / or The upper outer shell and the lower outer shell are used to support the piston and the main drive shaft, respectively.

7. The rotary solid-state cooling actuator according to claim 1 or 2, characterized in that, The rotary motor is selected from: servo motors, stepper motors, torque motors, switched reluctance motors, and brushless DC motors. The rotary solid-state refrigeration driver also includes a speed reducer, through which the rotary motor drives the main drive shaft to rotate.

8. The rotary solid-state cooling actuator according to claim 7, characterized in that, It also includes a second external frame for fixing the reducer and the eccentric transmission mechanism.

9. The rotary solid-state cooling actuator according to claim 1 or 2, characterized in that, The geometric shape of the spring-loaded material is selected from: cylindrical, cubic, cuboid, cylindrical, and rectangular tubular shapes; and The spring clip material is selected from: shape memory alloy, natural rubber, synthetic polymer, and plastic crystal.

10. The rotary solid-state cooling actuator according to claim 1 or 2, characterized in that, The deformation mode of the loading-unloading process of the elastic card material is uniaxial linear deformation, which includes linear compression and linear tension.

11. A solid-state refrigeration device, comprising: A rotary solid-state refrigeration actuator based on unloading mechanical work recovery according to any one of claims 1 to 10; and A heat exchange structure is used to exchange heat with the spring material to transfer the heat and cold generated by the spring material.

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