Magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing

Abstract

The invention discloses a magnetorheological transmission device based on coil heating induced shape memory alloy extruded bearing bush, comprising a driving shaft, a driven housing and a driven shaft, a coil groove is provided in the middle of the transmission section, and an excitation coil is provided in the coil groove; a plurality of bearing bushes are provided on both sides of the outer guide plate, a receiving groove is provided on the transmission section, and a top block and a shape memory alloy spring are provided in the receiving groove; a first liquid guide channel is provided between the coil groove and the receiving groove, and a second liquid guide channel is provided on the inner side of the coil groove and the receiving groove; liquid gallium-based alloy is filled in the receiving groove, the coil receiving cavity, the first liquid guide channel, the second liquid guide channel, the third liquid guide channel and the fourth liquid guide channel. The invention not only reduces the influence of coil heating on the performance of the magnetorheological transmission device, but also enhances the transmission performance of the transmission device under high temperature conditions, thereby improving the reliability and stability of the transmission device.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission, and in particular to a magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing bushing. Background Art

[0002] Magnetorheological fluid is a solid-liquid two-phase smart material whose morphology and performance are constrained and controlled by an external magnetic field. Under the action of an external magnetic field, magnetorheological fluid completes a reversible transformation from liquid to viscoplastic in milliseconds. In the process of increasing magnetic induction intensity, the apparent viscosity of these fluids can show a change of several orders of magnitude, have a certain shear yield strength, and can be continuously controlled by an external magnetic field.

[0003] Based on the excellent performance of continuous control, reversible transformation and rapid response of magnetorheological fluid, it has a wide range of application scenarios in the field of transmission devices. For example, the "a stacked high-power magnetorheological fluid clutch" disclosed in CN103161846A uses a multi-layer friction plate group for transmission, effectively disperses the heat source and reduces the difficulty of heat dissipation; at the same time, it uses cooling water for cooling, which significantly improves the transmission power and heat dissipation effect; when the transmission power is insufficient, it can be easily realized by increasing the number of friction plate groups. Controllable operation of power transmission. For example, the "multi-plate magnetorheological fluid electromagnetic clutch" disclosed in CN103603891A adopts a multi-plate structure, uses magnetorheological fluid as a medium to fill the gaps between multiple master and slave friction plates of the electromagnetic clutch, and forms multiple magnetorheological fluid working annular surfaces. The gap magnetic field strength is large, the distribution is reasonable, the transmission torque is large, the structure is compact, the rigidity is relatively good, and the installation and maintenance are convenient; the structure is simple, the reliability is high, the transmission is stable, and it is suitable for various small and medium-sized automation equipment and servo transmission devices.

[0004] However, in order to increase the transmitted torque, most of the above-mentioned magnetorheological fluid transmission devices adopt a structural stacking method to increase the effective working gap of the magnetorheological fluid, so as to enhance the transmission performance of the transmission device. Due to the limitations of magnetorheological fluid materials, if the magnetorheological fluid is in a high-temperature working environment for a long time, the performance will be significantly reduced or even fail, resulting in poor reliability and stability of the transmission device. At present, in order to solve the problem of excessive temperature rise of the transmission device, forced convection methods such as water cooling and air cooling are generally used to discharge heat from the transmission device. Although this method effectively controls the temperature rise of the transmission device, the energy converted from the heat of the transmission device is directly discarded, resulting in energy waste, and at the same time, it will also reduce the transmission efficiency of the transmission device. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to solve the problems that the existing magnetorheological transmission devices are greatly affected by temperature, have poor reliability and stability, suffer from large energy waste and low transmission efficiency, and to provide a magnetorheological transmission device based on a coil-heated shape memory alloy extruded bearing, which can convert the heat energy generated during the operation of the transmission device into mechanical energy, thereby reducing the attenuation of the magnetorheological fluid performance caused by the coil heating and enhancing the transmission performance of the transmission device under high temperature conditions, thereby improving the reliability and stability of the transmission device and, at the same time, reducing energy waste and improving transmission efficiency.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a magnetorheological transmission device based on coil-heat-induced shape memory alloy extruded bearing, comprising a driving shaft, a driven housing and a driven shaft, the driven housing comprising a left end cover, a driven cylinder and a right end cover connected in sequence, the left end of the driving shaft passes through the right end cover and then extends into the driven housing, and is connected to the left end cover and the right end cover through a bearing; the part of the driving shaft located in the driven housing is expanded to form a transmission section, and there is a gap between the transmission section and the inner wall of the driven cylinder, and the gap is filled with magnetorheological fluid; the driven shaft is fixedly connected to the left end cover; The invention is characterized in that: a coil groove is arranged around the middle of the transmission section, an inner guide plate and an outer guide plate are arranged in the coil groove, the inner guide plate is in close contact with the bottom of the coil groove, the outer side of the outer guide plate protrudes from the transmission section, and the inner guide plate and the outer guide plate are both interference-fitted with the coil groove; a coil accommodating cavity is formed between the inner guide plate, the outer guide plate and the side wall of the coil groove, an excitation coil is arranged in the coil accommodating cavity, and there are gaps around the excitation coil and the side wall of the coil groove and between the inner guide plate and the outer guide plate; a conductive slip ring is arranged on the driving shaft, and the excitation coil is connected to the conductive slip ring through a wire;

[0007] Several bearings are arranged on both sides of the outer guide plate. The bearings are distributed around the transmission section. The outer sides of two adjacent bearings are connected by a rubber sheet. Under the action of the rubber sheet, the bearings fit the transmission section, and the two adjacent bearings fit together to form a sleeve. There is a gap between the outer wall of the sleeve and the inner wall of the driven cylinder. On the transmission section, corresponding to the middle position of each bearing, a receiving groove is respectively opened along the radial direction of the transmission section. A top block and a shape memory alloy spring are arranged in the receiving groove. The inner end of the shape memory alloy spring is connected to the bottom of the receiving groove, and the outer end is connected to the top block. When the shape memory alloy spring is heated and elongated, it can push the top block along the radial direction of the transmission section, and push the bearing to move along the radial direction of the transmission section through the top block.

[0008] A first liquid guiding channel is respectively provided between the two side walls of the coil slot and each accommodating slot, one end of the first liquid guiding channel is connected to the coil accommodating chamber, and the other end is connected to the accommodating slot; on the inner side of the coil slot and the accommodating slot, a second liquid guiding channel is respectively provided corresponding to each accommodating slot, the length direction of the second liquid guiding channel is consistent with the axial direction of the transmission section, and is located in the same radial direction as the corresponding accommodating slot; the bottom of each accommodating slot is connected to the second liquid guiding channel at the corresponding position through the third liquid guiding channel; each second liquid guiding channel is connected to the coil accommodating chamber through the fourth liquid guiding channel, wherein one end of the fourth liquid guiding channel is connected to the second liquid guiding channel, and the other end passes through the bottom of the coil slot and the inner guide plate and is connected to the coil accommodating chamber;

[0009] The accommodating groove, the coil accommodating cavity, the first liquid guiding channel, the second liquid guiding channel, the third liquid guiding channel and the fourth liquid guiding channel are filled with liquid gallium-based alloy.

[0010] Furthermore, a section of the first liquid-conducting through hole close to the coil slot is arc-shaped, and a ferrite ceramic sleeve is provided in the arc-shaped section, and the outer wall of the ferrite ceramic sleeve is tightly attached to the inner wall of the arc-shaped section and interference fits together; an electrode plate is provided on both sides of the ferrite ceramic sleeve; the electrode plate is connected to the conductive slip ring through a wire.

[0011] Furthermore, a sealing ring is provided between the top block and the receiving groove, the sealing ring is fixedly connected to the receiving groove, and the sealing ring is always tightly attached to the receiving groove during the movement of the top block.

[0012] Furthermore, on the side where the inner guide plate and the outer guide plate face each other, a boss snap-in is provided at a position corresponding to the excitation coil, and the inner guide plate and the outer guide plate fix the excitation coil via the boss snap-in.

[0013] Furthermore, the inner guide plate and the outer guide plate are both made of polyurethane.

[0014] Furthermore, sealing rings are provided between the left end cover and the transmission section and between the right end cover and the transmission section respectively; one side of the sealing ring is fixedly connected to the left end cover and the right end cover respectively, and the other side is in close contact with the end faces of the transmission section and the bearing shell at the same time.

[0015] Furthermore, a wire hole is opened on the driving shaft along its axial direction, wherein an end of a fourth liquid guiding channel away from the coil slot passes through the second liquid guiding channel and extends to be connected with the wire hole; a sealing block is provided in the part of the fourth liquid guiding channel after passing through the second liquid guiding channel; the wire passes through the sealing block.

[0016] Furthermore, a blind cover is provided on the left side of the left end cover, the blind cover is fixedly connected to the left end cover, and the driven shaft is fixedly connected to the blind cover; a transparent cover is provided on the right side of the right end cover, the transparent cover is sleeved on the driving shaft and fixedly connected to the right end cover, and a felt ring is provided between the transparent cover and the driving shaft.

[0017] Furthermore, a liquid injection screw hole is provided on the driven cylinder, the liquid injection screw hole is communicated with the interior of the driven housing, and a liquid injection screw plug is matched in the liquid injection screw hole.

[0018] Compared with the prior art, the present invention has the following advantages: the excitation coil is isolated between the inner guide plate and the outer guide plate, thereby effectively reducing the influence of the heating of the excitation coil on the magnetorheological fluid; at the same time, the internal fluid guide channel of the transmission section is used to conduct the heat generated by the coil to the shape memory alloy spring, thereby converting the heat energy generated by the coil into mechanical energy using the shape memory alloy, which can not only quickly dissipate the heat of the coil and reduce the attenuation of the magnetorheological fluid performance due to excessive temperature, but also can quickly deform and elongate through the shape memory alloy spring, thereby pushing the top block to extrude the bearing shell, so that the bearing shell extrude the magnetorheological fluid, strengthen the magnetorheological effect, and enhance the transmission performance of the transmission device under high temperature conditions; thereby improving the reliability and stability of the transmission device, and at the same time, reducing energy waste and improving transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention.

[0020] Figure 2 for Figure 1 Cross-sectional view along A-A.

[0021] Figure 3 It is a partial cutaway view of the middle part of the driven cylinder.

[0022] Figure 4 Schematic diagram of fluid acceleration inside a ferrite ceramic sleeve.

[0023] Figure 5 Temperature distribution cloud diagram of heat conduction in the liquid-conducting channel.

[0024] Figure 6 Velocity distribution cloud diagram of the flow field in the liquid-conducting channel.

[0025] Figure 7 Shear yield stress relationship diagram of magnetorheological fluid.

[0026] In the figure: 1—driving shaft, 2—driven shaft, 3—left end cover, 4—driven cylinder, 5—right end cover, 6—transmission section, 7—magnetorheological fluid, 8—inner guide plate, 9—outer guide plate, 10—excitation coil, 11—conductive slip ring, 12—bearing bush, 13—rubber sheet, 14—top block, 15—shape memory alloy spring, 16—first liquid guide channel, 17—second liquid guide channel, 18—third liquid guide channel, 19—fourth liquid guide channel, 20—gallium-based alloy fluid, 21—ferrite ceramic sleeve, 22—electrode plate, 23—sealing block, 24—liquid injection plug. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] Example: See Figures 1 to 7 A magnetorheological transmission device based on coil-heat-induced shape memory alloy extruded bearing comprises a driving shaft 1, a driven housing and a driven shaft 2. The driven housing comprises a left end cover 3, a driven cylinder 4 and a right end cover 5 which are connected in sequence. The left end of the driving shaft 1 extends into the driven housing after passing through the right end cover 5, and is connected to the left end cover 3 and the right end cover 5 through bearings. The part of the driving shaft 1 located in the driven housing is enlarged to form a transmission section 6, and there is a gap between the transmission section 6 and the inner wall of the driven cylinder 4, and the gap is filled with a magnetorheological fluid 7. The driven shaft 2 is fixedly connected to the left end cover 3. In specific implementation, a blind cover is provided on the left side of the left end cover 3, the blind cover is fixedly connected to the left end cover 3, and the driven shaft 2 is fixedly connected to the blind cover; a transparent cover is provided on the right side of the right end cover 5, the transparent cover is sleeved on the driving shaft 1, and is fixedly connected to the right end cover 5, and a felt ring is provided between the transparent cover and the driving shaft 1; this can make the sealing effect of the driven housing better, and the bearing is axially positioned by the blind cover and the transparent cover, which can ensure the stability of the driving shaft 1. A liquid injection screw hole is provided on the driven cylinder 4, the liquid injection screw hole is connected to the inside of the driven housing, and a liquid injection screw plug 24 is provided in the liquid injection screw hole.

[0029] In the middle of the transmission section 6, there is a coil groove around it; an inner guide plate 8 and an outer guide plate 9 are provided in the coil groove; wherein the inner guide plate 8 is in close contact with the bottom of the coil groove, the outer side of the outer guide plate 9 protrudes from the transmission section 6, and the inner guide plate 8 and the outer guide plate 9 are both interference fit with the coil groove. During the manufacturing process, the inner guide plate 8 and the outer guide plate 9 are both made of (hard) polyurethane; this (hard) polyurethane has good thermal insulation performance and low magnetic permeability. Its good thermal insulation performance can prevent the heat generated by the excitation coil 10 from being transferred to the magnetorheological fluid 7, thereby preventing the performance of the magnetorheological fluid 7 from deteriorating at high temperatures. A coil accommodating cavity is formed between the inner guide plate 8, the outer guide plate 9 and the side wall of the coil groove, and an excitation coil 10 is provided in the coil accommodating cavity, and there is a gap around the excitation coil 10 and the side wall of the coil groove and between the inner guide plate 8 and the outer guide plate 9. Among them, the inner guide plate 8 and the outer guide plate 9 are both multi-section splicing structures, which makes assembly more convenient and quick. In specific implementation, the side of the inner guide plate 8 and the outer guide plate 9 facing each other is arc-shaped, so that the gap between the excitation coil 10 and the inner guide plate 8 and the outer guide plate 9 can be effectively increased to facilitate the flow of fluid. On the side of the inner guide plate 8 and the outer guide plate 9 facing each other, a boss bayonet is provided at the position corresponding to the excitation coil 10, and the inner guide plate 8 and the outer guide plate 9 fix the excitation coil 10 through the boss bayonet; thereby, the installation and fixation of the excitation coil 10 can be quickly realized. A conductive slip ring 11 is provided on the driving shaft 1, and the excitation coil 10 is connected to the conductive slip ring 11 through a wire.

[0030] Several bearing bushes 12 are respectively arranged on both sides of the outer guide plate 9. Preferably, the bearing bushes 12 on both sides of the outer guide plate 9 are symmetrically distributed with respect to the outer guide plate 9. The bearing bushes 12 are distributed around the transmission section 6. The outer sides of two adjacent bearing bushes 12 are connected by a rubber sheet 13. Under the action of the rubber sheet 13, the bearing bushes 12 fit with the transmission section 6, and the two adjacent bearing bushes 12 fit together to form a sleeve. There is a gap between the outer wall of the sleeve and the inner wall of the driven cylinder 4. Among them, a fixing groove is arranged on the outer side of the fitting part of the two adjacent bearing bushes 12 corresponding to the position of the rubber sheet 13. The rubber sheet 13 is located in the fixing groove, and its outer side surface is located on the same circumferential surface as the outer side surface of the bearing bush 12. During the processing, sealing rings are respectively provided between the left end cover 3 and the transmission section 6 and between the right end cover 5 and the transmission section 6; one side of the sealing ring is fixedly connected to the left end cover 3 and the right end cover 5, and the other side is tightly attached to the end faces of the transmission section 6 and the bearing 12 at the same time; and the bearing 12 can always be tightly attached to the sealing ring when moving in the radial direction; thereby ensuring the sealing of the working gap of the magnetorheological fluid 7.

[0031] On the transmission section 6, corresponding to the middle position of each bearing 12, a receiving groove is opened along the radial direction of the transmission section 6, and a top block 14 and a shape memory alloy spring 15 are arranged in the receiving groove. The inner end of the shape memory alloy spring 15 is connected to the bottom of the receiving groove, and the outer end is connected to the top block 14. When the shape memory alloy spring 15 is heated and elongated, it can push the top block 14 along the radial direction of the transmission section 6, and push the bearing 12 to move along the radial direction of the transmission section 6 through the top block 14. A sealing ring is arranged between the top block 14 and the receiving groove, and the sealing ring is fixedly connected to the receiving groove, and the sealing ring is always tightly attached during the movement of the top block 14; thereby preventing the magnetorheological fluid 7 from entering the receiving groove and preventing the fluid from flowing out of the receiving groove.

[0032] A first liquid conducting channel 16 is provided between the two side walls of the coil slot and each receiving slot, one end of the first liquid conducting channel 16 is connected to the coil receiving chamber, and the other end is connected to the receiving slot. On the inner side of the coil slot and the receiving slot, a second liquid conducting channel 17 is provided corresponding to each receiving slot, the length direction of the second liquid conducting channel 17 is consistent with the axial direction of the transmission section 6, and is located in the same radial direction as the corresponding receiving slot. The bottom of each receiving slot is connected to the second liquid conducting channel 17 at the corresponding position through the third liquid conducting channel 18; each second liquid conducting channel 17 is connected to the coil receiving chamber through the fourth liquid conducting channel 19, wherein one end of the fourth liquid conducting channel 19 is connected to the second liquid conducting channel 17, and the other end passes through the bottom of the coil slot and the inner guide plate 8 and is connected to the coil receiving chamber. During the processing, the first liquid guiding channel 16 and the second liquid guiding channel 17 are formed by processing from the two ends of the transmission section 6 toward the middle, and a first sealing screw and a second sealing screw are respectively provided at the two ends of the transmission section 6 corresponding to the first liquid guiding channel 16 and the second liquid guiding channel 17, so that the processing is more convenient.

[0033] The accommodating groove, the coil accommodating cavity, the first liquid-conducting channel 16, the second liquid-conducting channel 17, the third liquid-conducting channel 18 and the fourth liquid-conducting channel 19 are filled with liquid gallium-based alloy. Liquid gallium-based alloy is an alloy metal that is liquid at room temperature and has better heat transfer performance. It can quickly transfer heat to the shape memory alloy spring 15, thereby reducing heat loss. In specific implementation, the cross-section of a section of the first liquid-conducting through hole close to the coil groove is arc-shaped, and a ferrite ceramic sleeve 21 is provided in the arc-shaped section. The outer wall of the ferrite ceramic sleeve 21 is tightly attached to the inner wall of the arc-shaped section and interference fits together. An electrode plate 22 is provided on both sides of the ferrite ceramic sleeve 21; the electrode plate 22 is connected to the conductive slip ring 11 through a wire. Among them, the ferrite ceramic sleeve 21 has the characteristics of magnetic conductivity and insulation, so that the current generated by the electrode plate 22 can form a current loop with the gallium-based alloy fluid 20, and it is also conducive to forming a magnetic field loop with good performance. During the manufacturing process, a wire hole is opened on the driving shaft 1 along its axial direction, wherein a fourth liquid conducting channel 19 extends from the end away from the coil slot through the second liquid conducting channel 17 to communicate with the wire hole; a sealing block 23 is provided in the portion after the fourth liquid conducting channel 19 passes through the second liquid conducting channel 17; the wire passes through the sealing block 23; by providing the sealing block 23, fluid leakage can be effectively prevented. Preferably, one end of the wire is connected to the conductive slip ring 11, and the other end passes through the wire hole, the sealing block 23 and the fourth liquid conducting channel 19 and enters the coil accommodating cavity, and then is connected to the excitation coil 10 and the electrode plate 22 in each ferrite ceramic sleeve 21 through the wire.

[0034] During the assembly process, the liquid screw plug is opened, and the magnetorheological fluid 7 is injected into the gap between the bearing bush 12 and the driven cylinder 4 through the injection screw hole. In order to enable the magnetorheological fluid 7 to produce a magnetorheological effect in the working gap, the gap width between the bearing bush 12 and the driven cylinder 4 should be within the effective working gap range of the magnetorheological fluid 7 (for example, when the shear yield stress of the magnetorheological fluid 7 is 58.5 kPa, the viscosity is 0.23 Pa·s, and the controllable transmission ratio is 20, the effective gap is 1.149 mm); at the same time, the gallium-based alloy fluid 20 is injected through any two sealing screws at one end of the transmission section 6, one of which is used as the injection port and the other as the observation port, and the flow channel is sealed when the liquid level is level with the observation port.

[0035] During work:

[0036] 1. In the initial state, the driving shaft 1 rotates under the drag of external power, and when the excitation coil 10 is not energized, the magnetic particles in the magnetorheological fluid 7 are in a free state in the base fluid. The viscous torque of the magnetorheological fluid 7 under zero magnetic field cannot drive the driven shaft 2 to rotate, and the transmission device is in a separated state.

[0037] 2. When the excitation coil 10 is energized, the magnetic flux generated by the coil passes through the working gap of the magnetorheological fluid 7 vertically in the radial direction. The magnetic particles in the magnetorheological fluid 7 are arranged into a chain structure along the direction of the magnetic flux. The torque transmitted by the shear stress of the chain structure can drive the driven rotation, and the torque increases with the increase of the magnetic field intensity. When the magnetorheological fluid 7 reaches magnetic saturation, the torque that can be transmitted by the transmission device reaches the maximum value.

[0038] 3. During the continuous transmission process, the working temperature of the magnetorheological fluid 7 in the transmission device gradually rises. When it rises to a certain temperature (such as 60°C), the stability of the magnetic chain structure composed of magnetic particles in the magnetorheological fluid 7 begins to decrease, and the transmission performance also decreases, and the decrease is more significant as the temperature increases. However, at this time, the heat generated by the excitation coil 10 is heat-conducted through the gallium-based alloy fluid 20. Since the shape memory alloy spring 15 is immersed in the gallium-based alloy fluid 20, and the gallium-based alloy fluid 20 has very excellent thermal conductivity, the heat generated by the magnetorheological fluid 7 is quickly transferred to the shape memory alloy spring 15, so that the shape memory alloy spring 15 is extended under the drive of thermal energy, and the top block 14 is pushed outward, thereby pushing the bearing 12 to move in the radial direction. The movement of the bearing 12 squeezes the magnetorheological fluid 7. Through the extrusion strengthening of the magnetorheological fluid 7, the magnetorheological fluid 7 can overcome the stagnation of the shear yield stress growth caused by magnetic saturation, and can effectively improve the shear yield stress of the magnetorheological fluid 7, thereby further improving the transmission performance of the transmission device. For example, when the temperature of the magnetorheological fluid 7 rises from room temperature 20°C to 100°C, the magnetorheological fluid 7 is subjected to a magnetic field with a magnetic induction intensity of 10 kGs. Figure 7 As shown, the shear yield stress decreases from 68kPa to 42kPa. For the magnetorheological transmission device with a cylindrical working gap, the torque is linearly related to the shear yield stress of the magnetorheological fluid 7. Assuming that all the magnetorheological fluids 7 in the working gap participate in the shear flow, the torque decreases by 38% during the process of the transmission device rising from room temperature 20°C to 100°C. However, at the same time, the shape memory alloy spring 15 gradually generates an extrusion force, pushing the top block 14 to drive the bearing 12 to extrude the magnetorheological fluid 7. When the temperature of the shape memory alloy spring 15 reaches 100°C, the extrusion force generated is the largest. At this time, the maximum extrusion stress on the working gap of the magnetorheological fluid 7 is 21.5kPa. Under the action of this extrusion stress, the magnetorheological fluid 7 has an extrusion strengthening effect. Compared with the unextruded magnetorheological fluid 7, the shear yield stress of the magnetorheological fluid 7 after extrusion is increased by 32%. The shape memory alloy spring 15 drives the bearing 12 to extrude the magnetorheological fluid 7, which can effectively compensate for the performance degradation of the magnetorheological fluid 7 caused by the temperature increase.

[0039] 5. In the process of transferring the coil heat to the shape memory alloy spring 15, if only the stationary gallium-based alloy fluid 20 is used for heat exchange by heat conduction, the heat cannot be quickly transferred to the shape memory alloy. Therefore, the first liquid guide channel 16 near the coil slot is processed into an arc, and a structure that can accelerate the flow of the metal fluid is set in the arc segment; when the excitation coil 10 is energized, the magnetic flux generated by the excitation coil 10 passes vertically through the arc segment, and at the same time, the electrode plate 22 in the ferrite ceramic sleeve 21 is energized, and the electrons in the gallium-based alloy fluid 20 in the arc segment start to move in a directional manner from a free state to form a current. When the electrons move in a directional manner, the current along the moving direction is generated. There is a magnetic field passing through the normal direction, so the moving charge is subject to the Lorentz force, and the direction of the force is along the vector product direction of the current direction and the magnetic field direction; under the action of the Lorentz force, the gallium-based alloy fluid 20 accelerates when passing through the fan-shaped arc segment; through forced convection, the heat generated by the coil can be quickly transferred to the shape memory alloy spring 15, and the Joule heat generated by the coil is conducted to the shape memory alloy spring 15, realizing the use of shape memory alloy to convert the heat energy dissipated by the coil into mechanical energy, reducing the performance attenuation of the magnetorheological fluid 7 due to excessive temperature, enhancing the transmission performance of the transmission device under high temperature conditions, and fully converting and utilizing thermal energy, reducing energy waste. For example: when the potential difference of the electrode plate 22 corresponding to the wall of the fan-shaped arc segment is 10A, the gallium-based alloy fluid 20 in the cross-section of the arc segment is subjected to a Lorentz force of 0.6N. Under the action of this force, the flow velocity of the gallium-based alloy fluid 20 at the outlet of the fan-shaped arc segment is 0.18m / s, and the flow velocity distribution cloud diagram of the gallium-based alloy fluid 20 in the arc segment is as follows: Figure 5 As shown in FIG. 1 , through analysis, it can be known that the flow rate of the gallium-based alloy fluid 20 in the arc segment can be increased by using the Lorentz force, which effectively enhances the heat transfer effect of forced convection. When the power of the excitation coil 10 is 35W, assuming that the Joule heat coefficient is 1 and the initial temperature is 25°C, the temperature rise caused by the heat generated by the excitation coil 10 being transferred to the shape memory alloy spring 15 through the gallium-based alloy fluid 20 is as follows: Figure 6 As shown, since the flow rate of the fluid in the arc segment is increased and the maximum temperature gradient is 12.7°C, the temperature distribution in the arc segment is relatively uniform. When the heat conduction process reaches a steady state, the temperature of the temperature zone of the shape memory alloy spring 15 reaches 101°C, at which temperature the shape memory alloy spring 15 can generate the maximum extrusion force.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing, comprising a driving shaft, a driven housing and a driven shaft, wherein the driven housing comprises a left end cover, a driven cylinder and a right end cover which are connected in sequence, the left end of the driving shaft passes through the right end cover and then extends into the driven housing, and is connected to the left end cover and the right end cover through a bearing; the part of the driving shaft located in the driven housing is expanded to form a transmission section, and there is a gap between the transmission section and the inner wall of the driven cylinder, and the gap is filled with magnetorheological fluid; the driven shaft is fixedly connected to the left end cover; it is characterized in that: In the middle of the transmission section, a coil groove is provided around it, and an inner guide plate and an outer guide plate are provided in the coil groove, the inner guide plate is tightly attached to the bottom of the coil groove, the outer side of the outer guide plate protrudes from the transmission section, and the inner guide plate and the outer guide plate are both interference fit with the coil groove; a coil accommodating cavity is formed between the inner guide plate, the outer guide plate and the side wall of the coil groove, and an excitation coil is provided in the coil accommodating cavity, and there are gaps around the excitation coil and the side wall of the coil groove and between the inner guide plate and the outer guide plate; a conductive slip ring is provided on the driving shaft, and the excitation coil is connected to the conductive slip ring through a wire; on the side where the inner guide plate and the outer guide plate face each other, a boss bayonet is provided at the position corresponding to the excitation coil, and the inner guide plate and the outer guide plate fix the excitation coil through the boss bayonet; Several bearings are provided on both sides of the outer guide plate. The bearings are distributed around the transmission section. The outer sides of two adjacent bearings are connected by a rubber sheet. Under the action of the rubber sheet, the bearings fit the transmission section, and the two adjacent bearings fit together to form a sleeve. There is a gap between the outer wall of the sleeve and the inner wall of the driven cylinder. On the transmission section, corresponding to the middle position of each bearing, a receiving groove is provided along the radial direction of the transmission section. An inner top block and a shape memory alloy spring are provided in the receiving groove. The inner end of the shape memory alloy spring is connected to the bottom of the receiving groove, and the outer end is connected to the top block. When the shape memory alloy spring is heated and elongated, it can push the top block along the radial direction of the transmission section, and push the bearing to move along the radial direction of the transmission section through the top block. A first liquid conducting channel is respectively provided between the two side walls of the coil slot and each accommodating slot, one end of the first liquid conducting channel is connected to the coil accommodating chamber, and the other end is connected to the accommodating slot; on the inner side of the coil slot and the accommodating slot, a second liquid conducting channel is respectively provided for each accommodating slot, the length direction of the second liquid conducting channel is consistent with the axial direction of the transmission section, and is located in the same radial direction as the corresponding accommodating slot; the bottom of each accommodating slot is connected to the second liquid conducting channel at the corresponding position through the third liquid conducting channel; each second liquid conducting channel is connected to the coil accommodating chamber through the fourth liquid conducting channel, wherein one end of the fourth liquid conducting channel is connected to the second liquid conducting channel, and the other end is connected to the coil accommodating chamber after passing through the bottom of the coil slot and the inner guide plate; the cross-section of a section of the first liquid conducting through hole close to the coil slot is arc-shaped, and a ferrite ceramic sleeve is provided in the arc section, and the outer wall of the ferrite ceramic sleeve is tightly attached to the inner wall of the arc section and interference fits together; an electrode plate is respectively provided on both sides of the ferrite ceramic sleeve; the electrode plate is connected to the conductive slip ring through a wire; The accommodating groove, the coil accommodating cavity, the first liquid guiding channel, the second liquid guiding channel, the third liquid guiding channel and the fourth liquid guiding channel are filled with liquid gallium-based alloy.

2. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: A sealing ring is provided between the top block and the accommodating groove. The sealing ring is fixedly connected to the accommodating groove, and the sealing ring is always tightly attached to the accommodating groove during the movement of the top block.

3. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: The inner guide plate and the outer guide plate are both made of polyurethane.

4. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: Sealing rings are provided between the left end cover and the transmission section and between the right end cover and the transmission section respectively; one side of the sealing ring is fixedly connected to the left end cover and the right end cover respectively, and the other side is in close contact with the end surface of the transmission section and the bearing shell at the same time.

5. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: A wire hole is opened on the driving shaft along its axial direction, wherein an end of a fourth liquid guiding channel away from the coil slot passes through the second liquid guiding channel and extends to be connected with the wire hole; a sealing block is provided in the part of the fourth liquid guiding channel after passing through the second liquid guiding channel; the wire passes through the sealing block.

6. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: A blind cover is provided on the left side of the left end cover, the blind cover is fixedly connected to the left end cover, and the driven shaft is fixedly connected to the blind cover; a transparent cover is provided on the right side of the right end cover, the transparent cover is sleeved on the driving shaft and fixedly connected to the right end cover, and a felt ring is provided between the transparent cover and the driving shaft.

7. The magnetorheological transmission device based on coil-heated shape memory alloy extruded bearing according to claim 1 is characterized in that: A liquid injection screw hole is arranged on the driven cylinder, the liquid injection screw hole is communicated with the interior of the driven housing, and a liquid injection screw plug is matched in the liquid injection screw hole.

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