A training device for a shape memory alloy wire

Abstract

The application provides a training device for shape memory alloy wire to obtain wire with continuous shape and arbitrary length. The training device comprises a seat body, a wire feeding assembly, a pulley assembly, a wire collecting assembly and a temperature control assembly. The seat body comprises a mounting wall which is vertically arranged. The wire feeding assembly comprises a first winding drum which is mounted on the mounting wall and can rotate relative to the mounting wall. The first winding drum is used for winding the shape memory alloy wire. The pulley assembly comprises a movable pulley which is located below the first winding drum. The wire wound from the first winding drum can pass through the movable pulley from below the movable pulley. The movable pulley bears on the wire. The wire collecting assembly comprises a second winding drum which is mounted on the mounting wall and can rotate relative to the mounting wall. The second winding drum is located above the movable pulley and is used for winding the wire wound by the pulley assembly. The temperature control assembly is used for controlling the temperature of the wire between the first winding drum and the second winding drum to induce phase transition of the wire.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical equipment, and particularly relates to a training device for shape memory alloy wires. BACKGROUND

[0002] Shape memory alloy is a functional material composed of two or more metal elements, which has shape memory effect through thermoelasticity and martensitic transformation and its reverse transformation, is often designed for intelligent sensing or driving devices, and has very broad application prospects in the fields of medical devices, aerospace, robots, etc. Shape memory alloy needs to be trained to achieve the required shape memory effect, so as to eliminate the non-uniform structure in the martensitic transformation process and promote the stable output of the mechanical behavior of the shape memory alloy in the working process. The training methods in the prior art are carried out in the laboratory, however, these training methods can only train wires with fixed length and relatively short length, and there is a problem that they cannot be used for industrialization promotion. SUMMARY

[0003] The present application provides a training device for shape memory alloy wires, which can obtain shape memory alloy wires with continuous shape and after training under the premise of ensuring the mechanical properties of the shape memory alloy wires, and helps to realize the industrialization promotion of the training method.

[0004] In a first aspect, the present application provides a training device for shape memory alloy wires, which can include a seat body, a wire feeding assembly, a pulley assembly, a wire collecting assembly and a temperature control assembly. The seat body can include a vertically placed mounting wall. The wire feeding assembly can include a first winding drum, which is arranged on the mounting wall and can rotate relative to the mounting wall. The first winding drum can be used to wind and collect untrained shape memory alloy wires. The pulley assembly can include a movable pulley, which can be located below the first winding drum. The shape memory alloy wire wound out by the first winding drum can pass through the movable pulley from below, so as to support the movable pulley on the shape memory alloy wire. Under the action of the gravity of the movable pulley, the shape memory alloy wire is tensioned. The wire collecting assembly can include a second winding drum, which is arranged on the mounting wall and can rotate relative to the mounting wall. The second winding drum is located above the movable pulley and can be used to wind and collect the shape memory alloy wire wound out by the pulley assembly. The temperature control assembly can be used to control the temperature of the shape memory alloy wire between the first winding drum and the second winding drum, so as to induce the phase change of the shape memory alloy wire.

[0005] In the above scheme, the shape memory alloy wire is in tension under the gravity of the movable pulley, and the temperature of the shape memory alloy wire wound on the pulley assembly is controlled by the temperature control assembly, which can cause the shape memory alloy wire to repeatedly undergo martensitic transformation and reverse transformation. In combination with the continuous release and collection of the shape memory alloy wire by the wire feeding assembly and the wire collecting assembly, the training of the shape memory alloy wire with continuous shape can be realized, so that the trained shape memory alloy wire with continuous shape can be obtained under the premise of ensuring the mechanical properties of the shape memory alloy wire, which is helpful to the industrialization promotion of the training method.

[0006] In some possible embodiments, the wire feeding assembly can further include a first winding shaft, and the first winding drum is rotatably arranged on the first winding shaft, and the first winding shaft is fixed on the mounting wall. In this way, when the first winding drum rotates around the first winding shaft, the shape memory alloy wire wound on the first winding drum can be released to the pulley assembly.

[0007] Similarly, the wire collecting assembly can also include a second winding shaft, and the second winding drum is rotatably arranged on the second winding shaft, and the second winding shaft is fixed on the mounting wall. In this way, when the second winding drum rotates around the second winding shaft, the shape memory alloy wire wound out by the pulley assembly can be wound and collected.

[0008] In some possible embodiments, the number of movable pulleys can be one, and the movable pulley can be located between the first winding drum and the second winding drum. In this case, the wire wound out by the first winding drum can pass through the movable pulley from below and be wound on the second winding drum, and the movable pulley can automatically adjust to a certain position on the center line between the first winding drum and the second winding drum under the action of gravity.

[0009] In some possible embodiments, the pulley assembly can further include at least one fixed pulley. Specifically, the at least one fixed pulley can be arranged on the mounting wall and can rotate relative to the mounting wall. The fixed pulley is located above the movable pulley, and the at least one fixed pulley can be arranged at intervals between the first winding drum and the second winding drum. In this case, the number of movable pulleys can also be at least two, and specifically, the at least two movable pulleys can be respectively located between the first winding drum and the fixed pulley adjacent to the first winding drum, between the second winding drum and the fixed pulley adjacent to the second winding drum, and the other movable pulleys can be located between any two adjacent fixed pulleys.

[0010] Alternatively, the number of movable pulleys can be at least two, and the at least two movable pulleys can be respectively located between any two adjacent fixed pulleys. Further alternatively, one of the movable pulleys can be located between the first winding drum and the fixed pulley adjacent to the first winding drum or between the second winding drum and the fixed pulley adjacent to the second winding drum, and the other movable pulleys can be located between any two adjacent fixed pulleys.

[0011] In the above scheme, the shape memory alloy wire wound from the first winding drum can be wound up and down through the fixed pulleys and the movable pulleys in the direction from the first winding drum to the second winding drum, and the shape memory alloy wire is wound over each fixed pulley. In this scheme, the more the number of fixed pulleys and movable pulleys, the longer the training time of the shape memory alloy wire, thereby facilitating to increase the training times of the shape memory alloy wire and improving the training effect on the shape memory alloy wire.

[0012] In some possible embodiments, the at least one fixed pulley, the first winding drum and the second winding drum can be located at substantially the same height on the mounting wall, and the plurality of fixed pulleys can be arranged at substantially equal intervals. This design facilitates to maintain the consistency of the force on the shape memory alloy wire, thereby improving the training effect on the shape memory alloy wire.

[0013] When the fixed pulleys are rotatably arranged on the mounting wall, the pulley assembly can further include a plurality of fixed shafts corresponding to the plurality of fixed pulleys. The fixed shafts can be fixedly arranged on the mounting wall, and the fixed pulleys can be rotatably arranged on the corresponding fixed shafts. For example, the fixed pulleys and the fixed shafts can be rotatably connected through bearings to reduce the rotation resistance of the fixed pulleys and improve the rotation stability of the fixed pulleys.

[0014] In some possible embodiments, the weights of the movable pulleys can be equal, so that the movable pulleys are located at substantially the same height, thereby making the force on the shape memory alloy wire at each movable pulley equal, and facilitating to improve the training effect on the shape memory alloy wire.

[0015] In some possible embodiments, the number of fixed pulleys can be equal to the number of movable pulleys, or the number of fixed pulleys can be one more than the number of movable pulleys, or the number of fixed pulleys can be one less than the number of movable pulleys. In these three cases, the shape of the shape memory alloy wire wound in the pulley assembly is substantially zigzag.

[0016] In some possible embodiments, the temperature control assembly can include a heater and a box. The box can be used to contain a heat-conducting liquid, and the heater can be used to heat the heat-conducting liquid contained in the box. The box can be placed below the pulley assembly, and an end of the box facing the pulley assembly can be an open end. The movable pulleys can be immersed in the heat-conducting liquid in the box through the open end of the box, so that the part of the shape memory alloy wire wound from the movable pulleys is also immersed in the heat-conducting liquid, and the phase change of the shape memory alloy wire is induced by the temperature of the heat-conducting liquid.

[0017] Exemplarily, the heater can be a heating tube or an electric heating wire, which can be directly placed in the heat-conducting liquid in the box and heat the heat-conducting liquid after being powered on. Alternatively, the heater can be an electromagnetic oven or a stove, which can heat the box and the heat-conducting liquid in the box from below.

[0018] It should be noted that the temperature of the heat-conducting liquid is related to the phase transition temperature of the shape memory alloy wire, and a too low temperature will affect the training efficiency, while a too high temperature will increase the overall energy consumption of the training device. In a specific implementation, the temperature of the heat-conducting liquid can be set to A f +T, where A f is the final temperature at which the shape memory alloy wire changes from martensite to austenite, and T can be in the range of 5-20K.

[0019] In some possible embodiments, the temperature control assembly can include a power module and connecting wires, where the power module can include a first electrode end and a second electrode end, the first electrode end can be electrically connected to one end of the shape memory alloy wire wound around the first winding drum through the connecting wires, and the second electrode end can be electrically connected to one end of the shape memory alloy wire wound around the second winding drum through the connecting wires. The power module is turned on to pass current through the shape memory alloy wire, which can be heated, and the tension of the pulley assembly on the shape memory alloy wire can induce phase transition of the shape memory alloy wire.

[0020] In a specific implementation, the first winding drum and the second winding drum can both be made of an electrically conductive material, and the two ends of the shape memory alloy wire can be electrically connected when in contact with the first winding drum and the second winding drum. The first electrode end and the second electrode end of the power module can be electrically connected to the first winding drum and the second winding drum through the connecting wires, respectively, so that the shape memory alloy wire can be connected in the power loop.

[0021] In some possible embodiments, the current output by the power module can be a pulse current, such as a triangular wave form, a sinusoidal wave form, or a square wave form, etc. In one cycle of the pulse current, when the current intensity is high, the temperature of the shape memory alloy wire is relatively high, and the shape memory alloy wire can change from martensite to austenite; when the current intensity is low, the temperature of the shape memory alloy wire is relatively low, and the shape memory alloy wire can change from austenite to martensite. Under the action of continuous pulse current, the wire repeatedly cycles through the martensite-austenite-martensite transition process until it is collected on the second winding drum, i.e., the training is completed. This training method can improve the temperature control response speed, and thus the training efficiency is relatively high.

[0022] In some possible embodiments, the wire collecting assembly can further include a wire collecting motor, an output shaft of the wire collecting motor being in driving connection with the second winding drum to drive the second winding drum to rotate and realize automatic winding and collection of the trained shape memory alloy wire.

[0023] In some possible embodiments, the wire feeding assembly can further include a wire feeding motor, an output shaft of the wire feeding motor being in driving connection with the first winding drum to drive the first winding drum to rotate and realize automatic release of the untrained shape memory alloy wire. Through cooperation of the wire feeding motor and the wire collecting motor, the risk of force imbalance of the shape memory alloy wire at the wire feeding assembly side and the wire collecting assembly side can be reduced, thereby facilitating improvement of the training effect on the shape memory alloy wire.

[0024] In some possible embodiments, the diameter D of the fixed pulley can be in a range from 1 cm to 50 cm. The diameter d of the movable pulley can be less than the diameter D of the fixed pulley, and in particular design, the diameter d of the movable pulley and the diameter D of the fixed pulley satisfy 1 / 10≤d / D≤1 / 3.

[0025] In some possible embodiments, the training device can further include a displacement detection module, which can be used to detect a position change of the movable pulley in the vertical direction in the process of phase change of the shape memory alloy wire, so as to determine the length expansion and contraction of the shape memory alloy wire and judge whether the wire reaches the expected training effect.

[0026] Exemplarily, the displacement monitoring module can be an infrared displacement sensor, a potentiometer type displacement sensor, an inductance type displacement sensor, a capacitance type displacement sensor, an eddy current type displacement sensor or a Hall type displacement sensor, etc.

[0027] In a second aspect, the present application further provides a training process of a shape memory alloy wire, which can be implemented by using the training device in any of the possible embodiments described above. The training process can include:

[0028] winding the shape memory alloy wire to be trained on the first winding drum, and fixing one end of the shape memory alloy wire wound out of the first winding drum on the second winding drum through the pulley assembly;

[0029] rotating the first winding drum and the second winding drum to drive the shape memory alloy wire to transmit from the first winding drum to the second winding drum;

[0030] controlling the temperature of the shape memory alloy wire between the first winding drum and the second winding drum by the temperature control assembly, so that the shape memory alloy wire is transformed from martensite to austenite when the temperature is increased, and is transformed from austenite to martensite when the temperature is decreased, until the shape memory alloy wire is collected on the second winding drum.

[0031] The shape memory alloy wire between the first winding drum and the second winding drum can be repeatedly subjected to martensitic phase transformation and reverse phase transformation by using the above training process, and the continuous release and collection of the shape memory alloy wire by the wire feeding assembly and the wire collecting assembly, so that the shape memory alloy wire with continuous shape can be trained, thereby obtaining the shape memory alloy wire with continuous shape and trained under the premise of ensuring the mechanical properties of the shape memory alloy wire, which is helpful to realize the industrialization of the training method and provides a reasonable technical and equipment idea for industrial training. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A structural schematic diagram of a shape memory alloy wire training device provided by an embodiment of the present application;

[0033] Figure 2 A side view of a shape memory alloy wire training device provided by an embodiment of the present application;

[0034] Figure 3 A structural schematic diagram of another shape memory alloy wire training device provided by an embodiment of the present application;

[0035] Figure 4 A structural schematic diagram of another shape memory alloy wire training device provided by an embodiment of the present application;

[0036] Figure 5 A structural schematic diagram of another shape memory alloy wire training device provided by an embodiment of the present application;

[0037] Figure 6 A structural schematic diagram of another shape memory alloy wire training device provided by an embodiment of the present application.

[0038] Reference signs:

[0039] 100 - training device; 10 - seat body; 20 - wire feeding assembly; 30 - wire collecting assembly; 40 - pulley assembly; 50 - temperature control assembly;

[0040] 21 - first winding drum; 31 - second winding drum; 60 - wire; 11 - mounting wall; 12 - base; 121 - first surface of the base;

[0041] 22 - first winding drum shaft; 32 - second winding drum shaft; 41 - fixed pulley; 42 - movable pulley; 43 - fixed shaft; 51 - heater;

[0042] 52 - box body; 53 - power supply; 54 - connecting wire. DETAILED DESCRIPTION

[0043] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings.

[0044] Shape memory alloys (SMA) are functional materials composed of two or more metal elements that have shape memory effect through thermoelasticity and martensitic phase transformation and its reverse phase transformation. The so-called shape memory effect refers to the phenomenon that after the alloy undergoes martensitic phase transformation, the alloy is heated to above the memory temperature, the low-temperature martensite is reversely transformed into the high-temperature parent phase to restore the original shape before deformation, or returns to the martensitic shape again through the release of internal elastic energy in the subsequent cooling process. That is to say, shape memory alloys can remember the shape of the low-temperature martensite phase, and after a significant plastic deformation, the shape memory alloy can automatically restore to the original shape of the parent phase by being raised to a certain temperature. Shape memory alloys are often designed for intelligent sensing or driving devices, and have very broad application prospects in the fields of medical devices, aerospace, robots, etc. In intelligent sensing or driving devices, the application form of shape memory alloys is generally wire or film, and the application of micron-level shape memory alloy wires as driving elements has been relatively mature. The preparation process of shape memory alloy wires is very complex, and usually includes multiple processes such as smelting, forging, rolling, hot drawing and heat treatment, which puts strict requirements on the material manufacturing process.

[0045] The preparation of shape memory alloy wires has a unique process: training. From the principle, the purpose of training is to eliminate the non-uniform structure in the process of martensitic phase transformation, to promote the stable output of the mechanical behavior of shape memory alloys in the working process, to improve the linearity and repeatability of the path of the wire, and to reduce the phase transformation hysteresis. In the actual process, training refers to the reciprocating cycle treatment of shape memory alloy wires under a large strain state, which is often accompanied by permanent elongation of the wire length, diameter reduction, phase transformation temperature rise and other phenomena, and dislocation multiplication phenomenon also occurs at the microscale.

[0046] The training methods in the prior art that help to improve the fatigue performance of shape memory alloy materials are all carried out in the laboratory. The training process generally involves cutting shape memory alloy wires of a fixed length, performing loading and unloading cycles at a set strain on a mechanical tensile machine, until the stress-strain curve specific to the shape memory alloy tends to be stable, which means that the training is complete. However, this training method can only be used to train wires of a fixed length and relatively short length, and there are problems in industrial promotion because actual industrialization requires a continuous and uninterrupted stress / strain loading and unloading cycle process, and timely monitoring and feedback of the evolution of stress or strain data to determine whether the training process meets the requirements. This requires researchers to have a deep understanding of the training and performance stabilization mechanism of shape memory alloy materials, microstructure evolution, evaluation methods and assembly. At present, there is no continuous training process for shape memory alloy wires and related training devices.

[0047] To solve the above problems, the embodiments of the present application provide a training device for shape memory alloy wires, which can realize continuous training of shape memory alloy wires, thereby obtaining continuous shape memory alloy wires of any length while ensuring the mechanical properties of the shape memory alloy wires, and helping to realize industrial promotion of the training method.

[0048] First refer to Figure 1 , as shown in Figure 1 , which is a structural schematic diagram of a training device for shape memory alloy wires provided by the embodiments of the present application. The training device 100 can include a seat body, a wire feeding assembly 20, a wire collecting assembly 30, a pulley assembly 40 and a temperature control assembly 50. The wire feeding assembly 20, the wire collecting assembly 30 and the pulley assembly 40 are respectively installed on the seat body. The wire feeding assembly 20 can include a first winding drum 21, which can be used to wind and store untrained shape memory alloy wires 60, hereinafter referred to as wires. The wire collecting assembly 30 can include a second winding drum 31, which can be used to wind and store trained wires 60. The pulley assembly is arranged between the wire feeding assembly 20 and the wire collecting assembly 30. The wires 60 released from the first winding drum 21 can pass through each pulley of the pulley assembly 40 in turn and be subjected to the tension applied by the pulley assembly 40, and then be wound and collected on the second winding drum 31. In this way, by rotating the first winding drum 21 and the second winding drum 31, the wires 60 on the wire feeding assembly 20 can be continuously transferred to the wire collecting assembly 30 through the pulley assembly 40. The temperature control assembly 50 can be used to control the temperature of the wires 60 in tension around the pulley assembly 40, so as to cause the wires 60 to repeatedly undergo martensitic transformation and reverse transformation, and further cause the length of the wires 60 to change. In combination with the continuous release and collection of the wires 60 by the wire feeding assembly 20 and the wire collecting assembly 30, the training of the wires 60 in continuous form can be realized.

[0049] Figure 2 Figure 1 is a side view of a training device for shape memory alloy wires according to an embodiment of the present application. Figure 2 is a perspective view of the training device for shape memory alloy wires according to an embodiment of the present application. Figure 1 and Figure 2 As shown in Figures 1 and 2, in the embodiment of the present application, the seat body 10 can include a mounting wall 11, which can be approximately cuboid in structure. In actual application, the mounting wall 11 can be placed vertically, and the first winding drum 21, the second winding drum 31 and the pulley assembly 40 can be arranged on the mounting wall 11. In addition, in order to improve the stability of the mounting wall 11, the seat body 10 can further include a base 12, which can also be approximately cuboid in structure. The mounting wall 11 can be arranged on a first face 121 of the base 12. In particular design, the area of the cross section of the base 12 perpendicular to the vertical direction can be greater than the area of the cross section of the mounting wall 11 in the same direction, so as to increase the contact area of the base 12 as a whole with the placement plane, thereby reducing the structural stability of the training device 100.

[0050] In some embodiments, the wire feeding assembly 20 can further include a first winding drum shaft 22, the first winding drum 21 can be sleeved on the first winding drum shaft 22, and the first winding drum 21 can rotate relative to the first winding drum shaft 22, and the first winding drum shaft 22 can be fixed on the mounting wall 11. When the first winding drum 21 rotates around the first winding drum shaft 22 in a certain direction, the untrained wire 60 wound on the first winding drum 21 can be released. For example, if the wire 60 is wound on the first winding drum 21 in a clockwise direction, the wire 60 can be released to the pulley assembly 40 by rotating the first winding drum 21 counterclockwise. Conversely, if the wire 60 is wound on the first winding drum 21 in a counterclockwise direction, the wire 60 can be released to the pulley assembly 40 by rotating the first winding drum 21 clockwise.

[0051] Similarly, the wire collecting assembly 30 can include a second winding drum shaft 32, the second winding drum 31 can be sleeved on the second winding drum shaft 32, and the second winding drum 31 can rotate relative to the second winding drum shaft 32, and the second winding drum shaft 32 can be fixed on the mounting wall 11. When the second winding drum 31 rotates around the second winding drum shaft 32, the trained wire 60 can be wound and collected. For example, the second winding drum 31 can wind and collect the wire 60 by rotating clockwise, or can wind and collect the wire 60 by rotating counterclockwise.

[0052] It can be understood that in other embodiments, the first winding drum 21 and the first winding drum shaft 22 can also be fixedly connected, for example, the first winding drum 21 and the first winding drum shaft 22 can be fixed to each other by interference fit, and the first winding drum shaft 22 can rotate relative to the mounting wall 11. In actual implementation, the mounting wall 11 can be provided with a first mounting hole (not shown in the figure), and the first winding drum shaft 22 can be rotatably connected to the first mounting hole through a bearing. At this time, rotating the first winding drum shaft 22 can drive the first winding drum 21 to rotate synchronously, thereby releasing the untrained wire 60 wound on the first winding drum 21. Similarly, the second winding drum 31 and the second winding drum shaft 32 can also be fixedly connected, and the mounting wall 11 can be provided with a second mounting hole (not shown in the figure), and the second winding drum shaft 32 can be rotatably connected to the second mounting hole through a bearing. Rotating the second winding drum shaft 32 can drive the second winding drum 31 to rotate synchronously, thereby winding and collecting the trained wire 60. The following embodiments will be described with the first winding drum shaft 22 and the second winding drum shaft 32 being rotatably assembled on the mounting wall 11 as an example.

[0053] It should be noted that the axis directions of the first winding drum shaft 22 and the second winding drum shaft 32 can be the same, for example, both can be perpendicular to the mounting wall 11, which can improve the uniformity of the force of the wire 60 on the wire feeding assembly 20 side and the wire collecting assembly 30 side, thereby improving the training effect on the wire 60.

[0054] In addition, in some embodiments, the wire collecting assembly 30 can also include a wire collecting motor, and the output shaft of the wire collecting motor can be in transmission connection with the second winding drum shaft 32 to drive the second winding drum shaft 32 to rotate, thereby driving the second winding drum 31 to rotate synchronously, realizing automatic winding and collecting of the trained wire 60.

[0055] In some other embodiments, the wire feeding assembly 20 can also include a wire feeding motor, and the output shaft of the wire feeding motor can be in driving connection with the first reel shaft 22 to drive the first reel shaft 22 to rotate, thereby driving the first reel 21 to rotate synchronously to realize automatic release of the untrained wire 60. Through cooperation of the wire feeding motor and the wire collecting motor, the risk of force imbalance of the wire 60 at the wire feeding assembly 20 side and the wire collecting assembly 30 side can be reduced, thereby improving the training effect on the wire 60, and further improving the mechanical properties of the trained wire 60. Considering that the trained wire 60 will have a certain degree of pre-deformation, that is, the length of the wire 60 will change before and after training, and in the same time period, there will be a certain difference between the length of the wire 60 released by the wire feeding assembly 20 and the length of the wire 60 collected by the wire collecting assembly 30, therefore, in specific implementation, the wire feeding motor and the wire collecting motor can be set to different rotating speeds to keep the tension of the wire 60 unchanged during the training process, thereby improving the training effect on the wire 60. In actual application, the rotating speeds of the wire feeding motor and the wire collecting motor can be set according to the structure form of the pulley assembly 40, the tension applied to the wire 60 by the pulley assembly 40, and the set temperature of the temperature control assembly 50, and the like, which are not limited in the present application.

[0056] Please continue to refer to Figure 1 and Figure 2 In the embodiments of the present application, the pulley assembly 40 can include a movable pulley 42, and the movable pulley 42 can be located below the first reel 21 and the second reel 31. The number of the movable pulley 42 can be one, and in this case, the wire 60 wound out by the first reel 21 can pass through the movable pulley 42 from below the movable pulley 42, and then be wound on the second reel 31. The movable pulley 42 is carried on the wire 60, and under the gravity of the movable pulley 42, the wire 60 is in a tensioned state, and the movable pulley 42 can automatically adjust to a certain position on the center line between the first reel 21 and the second reel 31, thereby ensuring force balance of the wire 60.

[0057] Please continue to refer to Figure 3 as shown, Figure 3Another structural schematic diagram of the training device for the shape memory alloy wire provided by the embodiment of the present application is shown. In this embodiment, the pulley assembly 40 can further include a fixed pulley 41. In a specific arrangement, the number of fixed pulleys 41 can be one or more. Taking the case of multiple fixed pulleys 41, the multiple fixed pulleys 41 can be arranged at intervals on the mounting wall 11, and the axes of the fixed pulleys 41 can be substantially located on the same horizontal line, that is, the distance between the axes of the fixed pulleys 41 and the first face 121 of the base 12 is substantially equal. In a specific implementation, the multiple fixed pulleys 41 can be arranged at substantially equal intervals, that is, the distance between any two adjacent fixed pulleys 41 can be substantially equal, and a certain difference is allowed as long as the difference is within the error tolerance range. This design is conducive to maintaining the consistency of the force on the wire 60, thereby improving the training effect on the wire 60. The diameter D of the fixed pulley 41 can be in the range of 1-50 cm. For example, the diameter D of the fixed pulley 41 can be 1 cm, 10 cm, 25 cm, 40 cm, 50 cm, etc.

[0058] In some embodiments, the pulley assembly 40 can further include multiple fixed shafts 43 corresponding to the multiple fixed pulleys 41. The fixed shafts 43 can be fixedly arranged on the mounting wall 11, and the fixed pulleys 41 can be sleeved on the corresponding fixed shafts 43 and can rotate relative to the fixed shafts 43. When the wire 60 passes around the fixed pulley 41 and is transmitted toward the wire collecting assembly 30, the fixed pulley 41 can rotate synchronously with the rotation of the wire 60, which can reduce the friction between the wire 60 and the fixed pulley 41, thereby reducing the wear of the wire 60 and the fixed pulley 41, and also reducing the influence of the friction on the tension of the wire 60. For example, the fixed pulley 41 and the fixed shaft 43 can be rotatably connected through a bearing, which can reduce the rotation resistance of the fixed pulley 41 and improve the rotation stability of the fixed pulley 41, thereby avoiding the increase of the friction between the wire 60 and the fixed pulley 41 due to the jamming of the fixed pulley 41.

[0059] Continuing to refer to Figure 3 As shown, when the number of fixed pulleys 41 is multiple, the number of movable pulleys 42 can also be multiple. At this time, the multiple movable pulleys 42 can be located below the fixed pulleys 41, that is, on the side of the fixed pulleys 41 close to the base 12. The multiple movable pulleys 42 can also be arranged at equal intervals. In a specific design, along the first direction of the wire feeding assembly 20 pointing to the wire collecting assembly 30, that is, Figure 1In the x direction shown in the figure, the plurality of movable pulleys 42 and the plurality of fixed pulleys 41 can be staggered, the plurality of movable pulleys 42 can be arranged between the first winding drum 21 and the fixed pulley 41 adjacent to the first winding drum 21, between any two adjacent fixed pulleys 41, and between the second winding drum 31 and the fixed pulley 41 adjacent to the second winding drum 31. The wire 60 can pass through each movable pulley 42 and fixed pulley 41 in the first direction in turn, and the wire can pass through the fixed pulley from above the fixed pulley and pass through the movable pulley from below the movable pulley. The movable pulley 42 is carried on the wire 60, and under the action of the gravity of the movable pulley 42, the wire 60 is in a state of tension. At this time, the movable pulley 42 can automatically adjust to a certain position on the midline of the two adjacent fixed pulleys 41, thereby ensuring the force balance of the wire 60. Alternatively, after the wire 60 passes through the pulley assembly 40, the projections of the plurality of movable pulleys 42 and the plurality of fixed pulleys 41 on the first face 121 of the base 12 are staggered, and the distance between the projection of the movable pulley 42 and the projections of the fixed pulleys 41 on both sides is equal. The movable pulley 42 and the two adjacent fixed pulleys 41 are located at three vertices of an isosceles triangle, and the line connecting the movable pulley 42 and the left fixed pulley 41 is one of the two sides of the isosceles triangle, and the line connecting the movable pulley 42 and the right fixed pulley 41 is the other side of the isosceles triangle. It can be seen that the shape of the wire 60 when passing through the pulley assembly 40 is roughly zigzag.

[0060] Since the movable pulley 42 is carried on the wire 60, when the weight of each movable pulley 42 is consistent, the axis of each movable pulley 42 can be substantially located on the same horizontal line, which can ensure that the force on the wire 60 at each movable pulley 42 is equal, thereby facilitating the improvement of the training effect on the wire 60. In the embodiment of the present application, the material of the movable pulley 42 can be the same as that of the fixed pulley 41, and in addition, the diameter of the movable pulley 42 can be smaller than that of the fixed pulley 41. In specific design, the diameter d of the movable pulley 42 and the diameter D of the fixed pulley 41 satisfy 1 / 10≤d / D≤1 / 3.

[0061] It can be understood that the weight of the movable pulley 42 directly affects the tension of the wire 60, that is, the training load of the wire 60. In the embodiment of the present application, by adjusting the weight of the movable pulley 42 or adding a counterweight on the movable pulley 42, the training load of the wire 60 is adjusted to be greater than the critical stress for inducing the transformation of the martensite multiple variants of the wire 60 to single variants, and less than the stress for causing plastic deformation of the wire 60. In this way, the phase change of the wire 60 will not be affected, and the wire 60 will not produce permanent deformation that cannot be restored.

[0062] It should also be noted that the number of movable pulleys 42 can be equal to the number of fixed pulleys 41, or the number of movable pulleys 42 can be one more than the number of fixed pulleys 41, or the number of fixed pulleys 41 can be one more than the number of fixed pulleys 41. In these three cases, the positions of the first drum 21 and the second drum 31 also differ. For example, in... Figure 1 In the embodiment shown, the number of movable pulleys 42 is one more than the number of fixed pulleys 41. In this case, the two pulleys closest to the first drum 21 and the two pulleys closest to the second drum 31 are both movable pulleys 42. The filament 60 wound from the first drum 21 first passes around the leftmost movable pulley 42, and then passes around each pulley in sequence along the first direction in the manner of movable pulley 42-fixed pulley 41-movable pulley 42, and finally passes around to the rightmost movable pulley 42. The filament 60 wound from the rightmost movable pulley 42 is then wound into the second drum 31. Since the movable pulley 42 is positioned below the fixed pulley 41, when the wire 60 wound from the first spool 21 passes over the leftmost movable pulley 42, the first spool 21 can be positioned above the movable pulley 42 to ensure that the wire 60 is subjected to the pulling force of the movable pulley 42. Similarly, when the wire 60 wound from the rightmost movable pulley 42 is wound into the second spool 31, the second spool 31 is also positioned above the movable pulley 42 to ensure that the wire 60 is subjected to the pulling force of the movable pulley 42. For example, the axes of the first spool 21 and the second spool 31 can be on the same horizontal line as the axes of each fixed pulley 41. This ensures that the force on the wire 60 is consistent across each movable pulley 42, thereby improving the training effect on the wire 60.

[0063] refer to Figure 4 As shown, Figure 4 This is a schematic diagram of a training device for shape memory alloy wire provided in an embodiment of this application. In this embodiment, the number of fixed pulleys 41 is one more than the number of movable pulleys 42. Therefore, the two pulleys closest to the first drum 21 and the two closest to the second drum 31 are both fixed pulleys 41. At this time, the influence of the first drum 21 and the second drum 31 on the force on the wire 60 is relatively small, so the first drum 21 and the second drum 31 can still be set at the same height as each fixed pulley 41. Of course, in some other embodiments, the first drum 21 and the second drum 31 can also be located at a certain height between the movable pulley 42 and the fixed pulley 41, or at the same height as each movable pulley 42.

[0064] refer to Figure 5 As shown, Figure 5Another structural schematic diagram of the training device for the shape memory alloy wire provided in the embodiments of the present application is shown in FIG. 6. In this embodiment, the number of the fixed pulleys 41 is equal to the number of the movable pulleys 42. In this case, among the two pulleys closest to the first winding drum 21 and the second winding drum 31, one is the movable pulley 42 and the other is the fixed pulley 41. Taking the leftmost pulley as the movable pulley 42 and the rightmost pulley as the fixed pulley 41 as an example, in order to enable the wire 60 to be subjected to the pulling force of the movable pulley 42, the first winding drum 21 can be arranged at the same height as each fixed pulley 41. Since the second winding drum 31 has relatively small influence on the force applied to the wire 60, the second winding drum 31 can also be arranged at the same height as each fixed pulley 41, or the second winding drum 31 can be arranged at a height between the movable pulley 42 and the fixed pulley 41, or at the same height as each movable pulley 42.

[0065] It should be noted that in actual applications, the number of the movable pulleys 42 and the fixed pulleys 41 can be set according to the training requirements of the wire 60, Figure 3 、 Figure 4 and Figure 5 the number of the movable pulleys 42 and the fixed pulleys 41 in the above embodiments is only illustrative and does not limit the present application.

[0066] Please continue to refer to Figure 5 In the embodiments of the present application, the temperature control assembly 50 can be used to control the temperature of the wire 60 by using the water bath method. Specifically, the temperature control assembly 50 can include a heater 51 and a box 52 for containing water. One end of the box 52 is an open end, and the heater 51 can be used to heat the water contained in the box 52. Illustratively, the heater 51 can be a heating tube, an electric heating wire, etc. In this case, the heater 51 can be directly placed in the water in the box 52, and the water can be heated after being electrified. Alternatively, the heater 51 can be a non-contact heater such as an induction cooker or a stove. In this case, the heater 51 can be arranged below the box 52, i.e., at the end opposite to the open end of the box 52, and the water in the box 52 can be heated after being electrified or aerated. Of course, in other embodiments, the temperature control assembly 50 can also be used to control the temperature of the wire 60 by using the oil bath method. In this case, only the heat-conducting liquid in the box 52 needs to be replaced with oil such as soybean oil or cottonseed oil. The following embodiments are described in detail by using the water bath method.

[0067] The temperature control assembly 50 can be located below the movable pulley 42. Exemplarily, the temperature control assembly 50 can be arranged on the base 12. In this case, the movable pulley 42 can be fully or partially immersed in water, and thus the partial wire 60 wound around the movable pulley 42 is also immersed in water. The phase transition of the wire 60 can be induced by the water bath temperature. It should be noted that the height of the movable pulley 42 immersed in water will affect the water immersion length of the wire 60. Therefore, the heating phase transition length of the wire 60 can be controlled by adjusting the height of the water bath liquid level. In the embodiment, the height of the water bath liquid level can be designed according to the actual training requirements, and the present application does not limit this. In addition, it should be understood that the water bath temperature is related to the phase transition temperature of the wire 60. If the temperature is too low, the training efficiency will be affected, and if the temperature is too high, the overall energy consumption of the training device 100 will be increased. Based on this, in the embodiment of the present application, the water bath temperature can be designed as A f + T, wherein A f is the final temperature at which the wire 60 is transformed from martensite to austenite, that is, the temperature at which the wire 60 is completely transformed from martensite to austenite, and T has a value in the range of 5-20 K. At this water bath temperature, the strain amplitude of the wire 60 is approximately 4%-8%.

[0068] In some embodiments, the training device 100 can further include a displacement detection module (not shown in the figure). Exemplarily, the displacement detection module can be an infrared displacement sensor, a potentiometer type displacement sensor, an inductive displacement sensor, a capacitive displacement sensor, an eddy current displacement sensor or a Hall displacement sensor, etc. The displacement detection module can be arranged on the mounting wall, and is used to detect the position change of the movable pulley 42 in the vertical direction during the phase transition of the wire 60, so as to determine the length expansion and contraction of the wire 60 and determine whether the wire reaches the expected training effect.

[0069] The training process of the wire 60 will be described below with reference to the training device shown in Figure 5 . First, the wire 60 wound out of the first reel 21 is wound through each fixed pulley 41 and the movable pulley 42 in turn, and the end of the wire 60 is fixed to the second reel 31. Then, the weight of the movable pulley 42 is adjusted, and the training load of the wire 60 is adjusted to a set value. It can be understood that, since the water bath will generate a certain buoyancy on the movable pulley 42, the buoyancy of the water bath on the movable pulley 42 needs to be considered when setting the training load, so as to improve the training accuracy.

[0070] The wire feeding motor and the wire collecting motor are started to drive the wire 60 between the first reel 21 and the second reel 31. The wire 60 wound out of the first reel 21 is in the martensite state before the leftmost movable pulley 42. After being wound into the leftmost movable pulley 42 and immersed in water, the wire 60 is heated to change phase from the martensite state to the austenite state. The length of the wire 60 between the first reel 21 and the second reel 31 is shortened, and the height of the movable pulley 42 is raised, so the length of the wire 60 immersed in water is shortened. Then, the wire 60 in the austenite state is raised to the water surface due to the driving of the first reel 21 and the second reel 31. The wire 60 is cooled by the low temperature of the air after being taken out of the water, and the austenite state of the wire 60 is reversed to the martensite state. Then, the wire 60 is wound around the upper fixed pulley 41 and wound into the next movable pulley 42 again, so that the wire 60 is trained again in the process of martensite-austenite-martensite. In this way, the wire 60 is trained until it is wound around the last movable pulley 42 and collected on the second reel 31, that is, the training is completed.

[0071] During the process of transferring the wire on the first reel 21 to the second reel 31, the wire 60 is trained completely at any position except the two ends of the wire 60, that is, the wire 60 between the leftmost movable pulley 42 and the end of the wire 60 fixed on the second reel 31 at the beginning of the training, and the wire 60 between the rightmost movable pulley 42 and the end of the wire 60 fixed on the first reel 21 at the end of the training. Therefore, the trained wire 60 can be continuous and complete, that is, the wire 60 in the continuous state can be trained, and the training method using the training device 100 can be industrialized and popularized.

[0072] It can be understood that the number of movable pulleys 42 in the embodiment of the present application is the number of training times of the wire 60. In actual application, the number of movable pulleys 42 can be set according to the training requirements of the wire 60. Figure 1 Figure 3 Figure 4 The number of movable pulleys 42 and fixed pulleys 41 in the above embodiment is only illustrative and does not limit the present application.

[0073] For example, in the embodiment, the number of movable pulleys 42 can be 45, the wire 60 can be a micro-wire with a diameter of about 25 microns, the training load of the wire 60 can be set to 500 MPa by adjusting the weight of the movable pulley 42, and then the wire 60 is continuously trained by using the above training method. After the training is completed, the phase change behavior of the wire 60 before and after the training is tested. The test can be performed on a dynamic thermomechanical analysis (DMA) device, the test load is 200 MPa, and the measured items include the initial temperature A s ​​the end temperature of the martensite transformation to austenite A f the initial temperature of the austenite transformation to martensite M s and the end temperature of the austenite transformation to martensite M f . Wherein, the initial temperature of the martensite transformation to austenite A s i.e. the temperature at which the wire 60 starts to transform from martensite to austenite, the initial temperature of the austenite transformation to martensite M s i.e. the temperature at which the wire 60 starts to transform from austenite to martensite, and the end temperature of the austenite transformation to martensite M f i.e. the temperature at which the wire 60 completely transforms from austenite to martensite through reverse transformation. The specific test results can be seen in Table 1.

[0074] Table 1

[0075] Filament sample M s (°C) M f (°C) A s (°C) A f (°C) H(A f -M s )(°C) Temperature 65 58 75 84 19

[0076] According to the data in Table 1, the phase transformation hysteresis temperature H (A f -M s ) of the trained wire 60 can be reduced to within 20℃, thus proving that the training of the wire using the training device 100 provided in the embodiments of the present application has a significant effect on improving the mechanical stability of the wire 60.

[0077] Further, the fatigue life of the trained wire 60 was tested using a dynamic thermal mechanical analysis device, with a load of 400MPa, an amplitude of 4%, and a frequency of 1Hz. The test results can be seen in Table 2.

[0078] Table 2

[0079] Structural fatigue life (kilo cycles) Decay rate (%) Filament sample after training 205.7 29.3 Filament sample without training 15.3 38.9

[0080] Wherein, the attenuation rate can be understood as the difference between the strain amplitude before the wire 60 breaks and the initial strain amplitude, expressed as a percentage of the initial strain amount. According to the data in Table 2, the structural fatigue life of the trained wire 60 can reach more than 2 million times, which is much greater than the structural fatigue life of the conventional wire 60 without training, and the attenuation rate is also greatly reduced. Thus, it can also be verified that the stable martensite obtained through appropriate training in the embodiments of the present application can inhibit crack propagation, thereby improving the fatigue performance of the shape memory alloy wire 60.

[0081] From the above test results, it can be seen that the training device 100 provided by the embodiment of the present application is used to train the wire 60, and the phase transition hysteresis temperature of the wire 60 can be reduced to within 20°C, which is very critical for the control accuracy of the driving device using the shape memory alloy wire 60. Under large load and large strain, the service life of the wire 60 can reach more than one million times, and the attenuation rate can be greatly reduced. Therefore, the embodiment of the present application can achieve the purpose of continuous training through simple and controllable process means, while reducing the phase transition hysteresis of the shape memory alloy, the fatigue life of the wire 60 can be greatly improved, and a reasonable technical and equipment idea is provided for industrial training.

[0082] Reference Figure 6 As shown in the figure, Figure 6 The structure of another training device for shape memory alloy wire provided by the embodiment of the present application is shown in the figure. The training device 100 can also include a seat body 10, a wire feeding assembly 20, a wire collecting assembly 30, a pulley assembly 40, a temperature control assembly 50 and a displacement detection module. The structure and relative position relationship of the seat body 10, the wire feeding assembly 20, the wire collecting assembly 30, the pulley assembly 40 and the displacement detection module can refer to the setting mode in the foregoing embodiment, which will not be described here. The difference is that the temperature control assembly 50 in the present embodiment no longer uses water bath or oil bath method to control the temperature of the wire 60, but changes the temperature of the wire 60 by passing current through the wire 60.

[0083] In the embodiment of the present application, the first winding drum 21 and the second winding drum 31 can be made of conductive material, for example, metal materials with good heat dissipation and conductivity such as stainless steel, aluminum alloy or copper alloy. When the wire 60 is in contact with the first winding drum 21 and the second winding drum 31, an electrical connection is formed. The temperature control assembly 50 can include a power supply module 53 and a connecting wire 54, and the first electrode end and the second electrode end of the power supply module 53 can be electrically connected to the first winding drum 21 and the second winding drum 31 through the connecting wire 54, so as to connect the wire 60 in the power supply loop. For example, the first electrode end can be the positive electrode of the power supply module 53, and the second electrode end can be the negative electrode of the power supply module 53. When the power supply module 53 is turned on and current is passed through the wire 60, the wire 60 will be heated, and the tension applied to the wire 60 by the pulley assembly 40 can induce the wire 60 to undergo phase transition.

[0084] In specific implementation, the temperature control assembly 50 can pass pulse current into the wire 60. In a cycle of the pulse current, the current has different sizes at different time periods. When the current is large, the temperature of the wire 60 is also relatively high, and when the current is small, the temperature of the wire 60 is relatively low. Based on this, the size of the pulse current can be designed according to the phase transition temperature of the wire 60. Assuming that the initial temperature A sThe corresponding current is the first current threshold, which is related to the initial temperature M at which the wire 60 transforms from austenite to martensite. s The corresponding current is the second current threshold. Therefore, within one cycle of the pulsed current, there is at least a first time period where the current value is greater than or equal to the first current threshold, and a second time period where the current value is less than or equal to the second current threshold. This allows the wire 60 to transform from martensite to austenite during the first time period and from austenite to martensite during the second time period. Under the action of continuous pulsed current, the wire 60 repeatedly undergoes the martensite-austenite-martensite transformation process until it is collected on the second spool 31, thus completing the training. Furthermore, in this embodiment, a reasonable pulsed current intensity can be set so that the strain amplitude of the wire 60 is approximately between 4% and 8%. Exemplarily, the pulsed current in this embodiment can be a triangular wave, a sine wave, or a square wave, etc.

[0085] The following explains in detail the use of Figure 5 The training device 100 in this embodiment trains the filament 60. In this embodiment, the filament 60 can be a microfilament with a diameter of approximately 30 micrometers. The filament 60 wound from the first spool 21 is sequentially passed around each fixed pulley 41 and movable pulley 42, and the end of the filament 60 is fixed to the second spool 31. Then, the weight of the movable pulley 42 is adjusted to adjust the training load of the filament 60 to a set value. For example, the training load can be set to 450 MPa.

[0086] The feed motor and take-up motor are turned on, causing the wire 60 to move between the first spool 21 and the second spool 31. Simultaneously, a pulsed current is supplied to the wire 60 by the temperature control component. When the pulsed current value is less than a first current threshold, the wire 60 is in a martensitic state. When the pulsed current value exceeds the first current threshold, the wire wound around the pulley assembly 40 begins to transform from martensite to austenite, the length of the wire 60 between the first spool 21 and the second spool 31 shortens, and the height of the movable pulley 42 increases. When the pulsed current value drops below the second current threshold, the wire 60 wound around the pulley assembly 40 begins to transform from austenite to martensite. As the pulsed current continuously circulates, the wire between the first spool 21 and the second spool 31 continuously undergoes a martensitic-austenitic-martensitic cyclic transformation. In this embodiment, the training time of the filament 60 is the transmission time of the filament 60 between the first drum 21 and the second drum 31. This transmission time is related to the number of movable pulleys 42 and fixed pulleys 41. The more movable pulleys 42 and fixed pulleys 41 there are, the longer the training time of the filament, and the cycle period of the pulse current can also be increased accordingly, thereby increasing the number of training cycles of the filament 60. Experiments show that under a training load of 450 MPa, the number of training cycles required to achieve qualified training is approximately 80.

[0087] During the transfer of the filament 60 on the first spool 21 to the second spool 31, any segment of the filament 60 can undergo the complete training described above. Therefore, a continuous and complete trained filament 60 can be obtained, enabling the training of filament 60 with a continuous form. This allows for the industrial-scale promotion of the training method implemented using the training device 100. Furthermore, this embodiment utilizes electrical pulses to control the temperature of the filament 60, which improves the temperature control response speed, resulting in relatively high training efficiency.

[0088] In addition, tests have shown that using Figure 5 The training device 100 shown can achieve the same effect as the aforementioned embodiment after training the wire 60. Therefore, it can achieve the purpose of continuous training through simple and controllable process means. While reducing the phase transformation hysteresis of shape memory alloy, it can significantly improve the fatigue life of wire 60, providing a reasonable technical and equipment idea for industrial training.

[0089] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A training device for a shape memory alloy wire, characterized by The device comprises a seat, a wire feeding assembly, a pulley assembly, a wire collecting assembly and a temperature control assembly, wherein: The seat comprises a mounting wall which is vertically arranged; The wire feeding assembly comprises a first reel which is mounted on the mounting wall and can rotate relative to the mounting wall, and is used for winding the shape memory alloy wire; the wire feeding assembly continuously releases the shape memory alloy wire through the first reel; The pulley assembly comprises a movable pulley which is located below the first reel, and the shape memory alloy wire wound from the first reel can pass through the movable pulley from below, and the movable pulley is carried on the shape memory alloy wire; The wire collecting assembly comprises a second reel which is mounted on the mounting wall and can rotate relative to the mounting wall, and is located above the movable pulley, and is used for winding the shape memory alloy wire wound by the pulley assembly; the wire collecting assembly continuously collects the shape memory alloy wire through the second reel; The temperature control assembly is used for controlling the temperature of the shape memory alloy wire between the first reel and the second reel, and inducing the phase change of the shape memory alloy wire.

2. The exercise device of claim 1, wherein, The number of the movable pulleys is one, and the movable pulley is located between the first reel and the second reel.

3. The exercise device of claim 1, wherein, The pulley assembly further comprises at least one fixed pulley which is mounted on the mounting wall and can rotate relative to the mounting wall; The at least one fixed pulley is located above the movable pulley, and is arranged between the first reel and the second reel in an interval manner; The number of the movable pulleys is at least two, wherein two movable pulleys are respectively located between the first reel and the fixed pulley adjacent to the first reel, and between the second reel and the fixed pulley adjacent to the second reel, and other movable pulleys are respectively located between any two adjacent fixed pulleys; or, at least two movable pulleys are respectively located between any two adjacent fixed pulleys; In the direction from the first reel to the second reel, the shape memory alloy wire wound from the first reel passes through the fixed pulleys and the movable pulleys in an up-and-down staggered manner, and passes through the fixed pulleys from above.

4. The exercise device of claim 3, wherein, The first reel, the second reel and the at least one fixed pulley are arranged in an equal height manner on the mounting wall.

5. The exercise device of claim 3, wherein, The weights of the movable pulleys are equal.

6. The exercise device of claim 3, wherein, The number of the fixed pulleys is equal to the number of the movable pulleys; or, the number of the fixed pulleys is one more than the number of the movable pulleys; or, the number of the fixed pulleys is one less than the number of the movable pulleys.

7. Training device according to any of claims 1-6, characterized in that The temperature control assembly comprises a heater and a box which contains a heat-conducting liquid, and the heater is used for heating the heat-conducting liquid in the box; The box is arranged below the pulley assembly, one end of the box towards the pulley assembly is an open end, and the movable pulley is immersed in the heat-conducting liquid in the box.

8. The exercise device of claim 7, wherein, The temperature of the heat conducting liquid is A f + T, where A f is the end temperature of the transformation of the shape memory alloy wire from martensite to austenite, 5 K ≤ T ≤ 20 K.

9. Training device according to any of claims 1-6, characterized in that The temperature control assembly comprises a power module and a connecting wire, the power module comprises a first electrode end and a second electrode end, the first electrode end is electrically connected with one end of the shape memory alloy wire wound around the first reel through the connecting wire, and the second electrode end is electrically connected with the other end of the shape memory alloy wire wound around the second reel through the connecting wire.

10. The exercise device of claim 9, wherein, The first reel and the second reel are made of conductive material, and the first reel and the second reel are electrically connected with the two ends of the shape memory alloy wire respectively. The first electrode end is electrically connected with the first reel through the connecting wire, and the second electrode end is electrically connected with the second reel through the connecting wire.

11. The exercise device of claim 9, wherein, The output current of the power module is pulse current.

12. The exercise apparatus of any one of claims 1-6, wherein, The wire collecting assembly further comprises a wire collecting motor, an output shaft of the wire collecting motor is in transmission connection with the second reel, and the wire collecting motor is used to drive the second reel to rotate towards the direction of winding the shape memory alloy wire.

13. The exercise apparatus of any one of claims 1-6, wherein, The wire feeding assembly further comprises a wire feeding motor, an output shaft of the wire feeding motor is in transmission connection with the first reel, and the wire feeding motor is used to drive the first reel to rotate towards the direction of releasing the shape memory alloy wire.

14. Training apparatus according to any of claims 3-6, characterized in that The diameter d of the movable pulley and the diameter D of the fixed pulley satisfy: 1 / 10≤d / D≤1 / 3.

15. The exercise apparatus of any one of claims 1-6, wherein, The training device further comprises a displacement detection module, which is used to detect the displacement change of the movable pulley in the vertical direction in the process of phase change of the shape memory alloy wire.

16. A training process for a training device applied to the shape memory alloy wire according to any one of claims 1 to 15, characterized by, Comprise: Winding the shape memory alloy wire to be trained on the first reel, and fixing one end of the shape memory alloy wire wound out of the first reel on the second reel after passing through the pulley assembly; Rotating the first reel and the second reel to drive the shape memory alloy wire from the first reel to the second reel; the wire feeding assembly continuously releases the shape memory alloy wire through the first reel, and the wire collecting assembly continuously collects the shape memory alloy wire through the second reel; The temperature control assembly controls the temperature of the shape memory alloy wire between the first reel and the second reel, so that the shape memory alloy wire changes from martensite to austenite when the temperature rises, and changes from austenite to martensite when the temperature decreases, until the shape memory alloy wire is collected on the second reel.

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