Single-variable double-tube magnetorheological automatic heat dissipation device controlled by shape memory alloy

Abstract

This invention discloses a single-variable double-cylinder magnetorheological automatic heat dissipation device controlled by shape memory alloy, comprising a drive shaft, a driven housing, and a driven shaft. A driven inner cylinder is coaxially arranged inside the driven cylinder. A transmission disc is sleeved on the drive shaft. Several arc-shaped transmission bearings are distributed around the outer side of the driven inner cylinder. A return spring is provided on the left side of the transmission disc. The outer end of the return spring is connected to a spring rod. One end of the spring rod is fixedly connected to the return spring, and the other end passes through a strip hole and is fixedly connected to the bent portion of the transmission bearing. A spring groove is provided on the driven inner cylinder, and a shape memory alloy spring is provided within the spring groove. An excitation coil is wound around the middle of the driven inner cylinder. Magnetorheological fluid is filled in the gap between the transmission bearings and the driven outer cylinder. This invention significantly improves the transmission performance of the magnetorheological fluid automatic heat dissipation device, while ensuring low no-load torque and significantly enhanced transmission performance at high temperatures.

Description

Technical Field

[0001] The invention relates to the field of automatic heat dissipation devices, in particular to a single-variable double-tube magnetorheological automatic heat dissipation device controlled by a shape memory alloy. Background Art

[0002] Magnetorheological fluid is a magnetic intelligent material, which is mainly composed of magnetic particles and base fluid (usually silicone oil). It is controlled by an external magnetic field. In the absence of an external magnetic field, it exhibits the properties of a Newtonian fluid. After adding a magnetic field, the viscosity of the magnetorheological fluid changes by several orders of magnitude, showing the properties of a Bingham plastic fluid. The entire change process is rapid, reversible, and easy to operate. Shape memory alloy (SMA) is a new type of intelligent material. After a certain degree of deformation under certain conditions, a shape memory alloy with a certain initial shape will undergo reverse deformation by appropriately changing the temperature, restoring the material to its initial shape. During the shape recovery process, if the shape memory alloy is constrained, it will generate a large restoring force, which can be used to do external work.

[0003] Due to the unique characteristics and excellent performance of smart materials such as shape memory alloys and magnetorheological fluids, they have broad prospects in the field of machinery. For example, the "multi-plate magnetorheological fluid electromagnetic clutch" disclosed in CN103603891A adopts a multi-plate structure and uses magnetorheological fluid as a medium to fill the gaps between multiple master and slave friction plates of the electromagnetic clutch to form multiple magnetorheological fluid working annular surfaces. The gap magnetic field has a large intensity, reasonable distribution, and large transmission torque. For example, the "wedge extrusion soft start device based on magnetorheological fluid and shape memory alloy" disclosed in CN103591234A uses the extrusion strengthening effect of magnetorheological fluid to improve the transmission power of the soft start device; at the same time, the memory alloy assists in the transmission of torque, making the transmission performance of the soft start device more reliable. For example, the "permanent magnet variable length magnetorheological fluid and friction composite soft landing device" disclosed in CN105288876A uses a permanent magnet to generate a magnetic field to excite the magnetorheological fluid to produce a magnetorheological effect, thereby controlling the braking torque of the soft landing device, and also uses the friction torque between the spring and the friction disk to assist in deceleration and landing. For example, the "wheel initial deceleration brake based on magnetorheological fluid" disclosed in CN105650148A, which sets a magnetorheological fluid in the brake working chamber and applies a driving magnetic field to the magnetorheological fluid through an electromagnetic coil to change the viscosity of the magnetorheological fluid, so that the magnetorheological fluid causes resistance to the brake wheel, and performs wear-free braking and deceleration for the initial braking section under high-speed conditions. Another example is the "double-disc extruded magnetorheological brake" disclosed in CN102562874A, which can not only increase the torque by increasing the current of the excitation coil, but also increase the current of the electromagnet, thereby increasing the positive stress generated by the magnetorheological fluid in the direction of the magnetic field, greatly improving the braking torque. Another example is the “temperature-controlled variable-surface magnetorheological transmission device” disclosed in CN107763109A, which uses a shape memory alloy spring to push the active disk to change the working surface of the magnetorheological fluid from one to two, can transmit a larger torque, and can automatically adjust the transmitted torque according to the real-time temperature, and ensure the stability of the transmission process.

[0004] Researchers have carried out extensive applications of magnetorheological fluids in transmission, but magnetorheological fluids also have the following defects in transmission: magnetorheological fluids have a small yield stress under normal conditions and cannot meet the needs of transmitting high-power power. By increasing the volume fraction of magnetic particles in the magnetorheological fluid, the shear yield stress of the magnetorheological fluid can be significantly improved, but too high a volume fraction of magnetic particles in the magnetorheological fluid will lead to a large no-load torque of the transmission device, and the controllable range of torque will become smaller under the action of the magnetic field. Therefore, how to improve the braking performance of magnetorheological fluid brakes and reduce no-load torque are urgent problems to be solved in magnetorheological transmission; magnetorheological fluids will decrease in performance as the ambient temperature increases and cannot meet the working requirements under different temperature environments. The shape memory effect of shape memory alloys can be used to make up for the defects of magnetorheological fluids in transmission. Although researchers have done a lot of research on the separate applications of shape memory alloys and magnetorheological fluids in the field of transmission engineering, there is still little research on the combined application of shape memory alloys and magnetorheological fluids in transmission devices, especially on the invention of using coil heating to stimulate the shape memory effect of shape memory alloys. 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 of small torque transmitted by the existing magnetorheological automatic heat dissipation device, low transmission efficiency and poor transmission stability at high temperature, and to provide a single-change double-cylinder magnetorheological automatic heat dissipation device controlled by a shape memory alloy, which can stimulate the shape memory effect of the shape memory alloy spring through coil heating to push the transmission bearing, so that the single-cylinder is transformed into a double-cylinder magnetorheological automatic heat dissipation device, thereby significantly improving the transmission performance of the magnetorheological fluid automatic heat dissipation device, while ensuring a lower no-load torque and significantly enhancing the transmission performance at high temperature.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a single-variable double-cylinder magnetorheological automatic heat dissipation device controlled by a shape memory alloy, comprising a driving shaft, a driven housing and a driven shaft, wherein the driven housing comprises a left end cover, a driven outer cylinder and a right end cover, wherein the left end cover, the driven outer cylinder and the right end cover are fixedly connected in sequence, and the driven shaft is fixedly connected to the right end cover; the characteristic is that: a driven inner cylinder is coaxially arranged in the driven cylinder, the right end of the driven inner cylinder is fixedly connected to the right end cover, and there is a spacing between the driven inner cylinder and the driven outer cylinder; the driving shaft extends into the driven inner cylinder after passing through the left end cover, and is connected to the driven inner cylinder through a bearing; a transmission disc is sleeved on the driving shaft, the transmission disc is fixedly connected to the driving shaft, and can rotate synchronously with the driving shaft, and the transmission disc is connected to the left end cover through a bearing;

[0007] A convex ring is coaxially arranged at the left end of the driven inner cylinder, and the convex ring is fixedly connected to the driven inner cylinder and is tightly attached to the transmission disc, so that there is a gap between the driven inner cylinder and the transmission disc; a plurality of arc-shaped transmission bearing shells are distributed around the outer side of the driven inner cylinder, and when the transmission bearing shells are attached to the driven inner cylinder, they can form a bearing shell cylinder connected in sequence; there is a gap between the right end of the transmission bearing shell and the right end cover, and the left end thereof is bent and extended toward the inner side of the driven inner cylinder and is attached to the end face of the driven inner cylinder, and the bent portion of the transmission bearing shell is wedge-shaped; on the transmission disc An annular groove is provided on the left side of the drive bearing, and a return spring is provided in the annular groove corresponding to each drive bearing, the axial direction of the return spring is consistent with the radial direction of the drive plate, and the inner end thereof is fixedly connected to the drive plate; a strip hole is provided on the drive plate along its radial direction at the position corresponding to the return spring; the outer end of the return spring is connected to a spring pull rod, one end of the spring pull rod is fixedly connected to the return spring, and the other end is fixedly connected to the bent part of the drive bearing after passing through the strip hole, and under the action of the return spring, the drive bearing and the driven inner cylinder are fitted together;

[0008] On the driven inner cylinder, a spring groove is respectively provided near both ends thereof corresponding to each transmission bearing bush, and the depth direction of the spring groove is consistent with the radial direction of the driven inner cylinder; a shape memory alloy spring is provided in the spring groove, and the axial direction of the shape memory alloy spring is consistent with the depth direction of the spring groove, one end of the shape memory alloy spring is fixedly connected to the groove bottom of the spring groove, and the other end is fixedly connected to a slider, and the slider is connected to the side wall of the spring groove in a sliding fit;

[0009] A coil groove is arranged around the middle of the driven inner cylinder, and an excitation coil is wound in the coil groove; a section of the middle of the transmission bearing corresponding to the excitation coil is a low magnetic permeability material block, and the two ends of the transmission bearing are high magnetic permeability material blocks, and the low magnetic permeability material block and the two high magnetic permeability material blocks are welded and connected to form a whole; the gap between the transmission bearing and the driven outer cylinder is filled with magnetorheological fluid.

[0010] Furthermore, a limiting ring is provided in the middle of the inner side of the driven outer cylinder and surrounds the driven outer cylinder. The outer side of the limiting ring is fixedly connected to the driven outer cylinder, and there is a gap between the inner side and the transmission bearing bush.

[0011] Furthermore, a heat conduction hole is provided between the coil slot and the spring slot.

[0012] Furthermore, a heat insulating sleeve is sleeved on the outside of the excitation coil, and the heat conducting hole passes through the heat insulating sleeve.

[0013] Furthermore, the transmission disc includes a sleeve and a disc body, the disc body is located inside the driven housing, and a sealing ring is provided between its outer edge and the inner side of the driven outer cylinder; the sleeve is sleeved on the driving shaft and connected to the left end cover through a bearing.

[0014] Furthermore, a transparent cover is provided on the outer side of the left end cover, and the transparent cover is sleeved on the shaft sleeve; a felt ring is also provided between the transparent cover and the shaft sleeve.

[0015] Furthermore, a transmission block is provided between the bent part of the transmission bearing and the transmission disk. On the transmission disk, a slide groove is provided corresponding to the transmission block. The slide groove is arranged along the radial direction of the transmission disk. The transmission block is embedded in the slide groove and is connected with the slide groove in a sliding manner; the two sides of the transmission block are respectively fixedly connected to the spring pull rod and the bent part of the transmission bearing.

[0016] Furthermore, a conductive slip ring is provided on the outer side of the right end cover, and the conductive slip ring is connected to the excitation coil through a wire.

[0017] Furthermore, the middle portion of the right end cover protrudes outward to form a mounting seat, and the conductive slip ring is sleeved on the mounting seat and fixedly connected to the right end cover.

[0018] Furthermore, a liquid injection hole is provided on the driven outer cylinder, and a liquid injection screw plug is provided in the liquid injection hole.

[0019] Compared with the prior art, the present invention has the following advantages: shape memory alloy springs are used to push the transmission bearing bushes, so that the working gap of the magnetorheological fluid in the device is changed from one to two, thereby reducing the no-load torque; and when the temperature of the device rises to a certain temperature, the transmitted torque reaches a maximum value, the speed of the driven shaft also reaches a maximum value, and the heat dissipation effect of the heat dissipation device driven by the driven shaft is the most significant; as the temperature further rises, the transmitted torque and the speed of the driven shaft are also in a higher range; at the same time, the present invention conducts the heat generated by the coil to the shape memory alloy, generates friction torque through the shape memory alloy spring, and further increases the transmission torque; thereby simultaneously ensuring a lower no-load torque and significantly enhancing the transmission performance at high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 This is a state diagram of the driven inner cylinder and the transmission bearing bush when the single cylinder of the present invention is working.

[0022] Figure 3 This is a state diagram of the driven inner cylinder and the transmission bearing bush when the double cylinder of the present invention is working.

[0023] Figure 4 This is a cloud diagram of the internal magnetic induction intensity distribution of a single cylinder of the present invention.

[0024] Figure 5 It is a cloud diagram of the internal magnetic induction intensity distribution when the present invention is changed into a double-tube.

[0025] Figure 6 This is a diagram showing the relationship between the braking torque of the present invention at different temperatures.

[0026] Figure 7 This is a relationship diagram of the limiting speed of the present invention at different temperatures.

[0027] In the figure: 1-driving shaft, 2-left end cover, 3-driven outer cylinder, 4-right end cover, 5-driven shaft, 6-driven inner cylinder, 7-transmission plate, 8-convex ring, 9-transmission bearing, 10-reset spring, 11-spring pull rod, 12-shape memory alloy spring, 13-slider, 14-excitation coil, 15-magnetorheological fluid, 16-limiting ring, 17-heat conduction hole, 18-thermal insulation sleeve, 19-transparent cover, 20-transmission block, 21-conductive slip ring, 22-liquid injection plug. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] Example: See Figures 1 to 7 A single-variable double-cylinder magnetorheological automatic heat dissipation device controlled by a shape memory alloy comprises a driving shaft 1, a driven housing and a driven shaft 5; the driven housing comprises a left end cover 2, a driven outer cylinder 3 and a right end cover 4, the left end cover 2, the driven outer cylinder 3 and the right end cover 4 are fixedly connected in sequence, and the driven shaft 5 is fixedly connected to the right end cover 4. A driven inner cylinder 6 is coaxially arranged in the driven cylinder, and the driven inner cylinder 6 has an axial hole; the right end of the driven inner cylinder 6 is fixedly connected to the right end cover 4, and there is a distance between the driven inner cylinder 6 and the driven outer cylinder 3, and there is also a distance between the left end and the left end cover 2. The driving shaft 1 passes through the left end cover 2 and then extends into the driven inner cylinder 6, and then into the axial hole of the driven inner cylinder 6, and is connected to the driven inner cylinder 6 through a bearing. A transmission disc 7 is sleeved on the driving shaft 1. The transmission disc 7 is fixedly connected to the driving shaft 1 and can rotate synchronously with the driving shaft 1. The transmission disc 7 is connected to the left end cover 2 through a bearing. In specific implementation, the transmission disc 7 includes a sleeve and a disc body. The disc body is located inside the driven housing and between the left end of the driven inner cylinder 6 and the left end cover 2. A sealing ring is provided between its outer edge and the inner side of the driven outer cylinder 3. The sleeve is sleeved on the driving shaft 1 and connected to the left end cover 2 through a bearing. The sleeve is connected to the driving shaft 1 through a key, so that the transmission disc 7 can rotate synchronously with the driving shaft 1. In order to achieve a better sealing effect of the entire driven housing, a transparent cover 19 is provided on the outer side of the left end cover 2. The transparent cover 19 is sleeved on the sleeve. A felt ring is also provided between the transparent cover 19 and the sleeve.

[0030] A convex ring 8 is coaxially arranged at the left end of the driven inner cylinder 6. The convex ring 8 is fixedly connected to the driven inner cylinder 6 and is in close contact with the transmission disc 7, so that there is a gap between the driven inner cylinder 6 and the transmission disc 7. A sealing ring is arranged between the convex ring 8 and the transmission disc 7. Several transmission bearing bushes 9 with arc-shaped cross sections are distributed around the outer side of the driven inner cylinder 6. When the transmission bearing bushes 9 are attached to the driven inner cylinder 6, they can be connected in sequence to form a bearing bush cylinder. There is a gap between the right end of the transmission bearing bush 9 and the right end cover 4, and its left end is bent and extended toward the inner side of the driven inner cylinder 6 and is in contact with the end face of the driven inner cylinder 6, and the bent part of the transmission bearing bush 9 is wedge-shaped; thereby avoiding interference between the bent parts when the transmission bearing bush 9 is attached to the driven inner cylinder 6. An annular groove is provided on the left side of the transmission disc 7. A return spring 10 is provided in the annular groove corresponding to each transmission bearing bush 9. The axial direction of the return spring 10 is consistent with the radial direction of the transmission disc 7, and the inner end thereof is fixedly connected to the transmission disc 7. A strip hole is provided in the transmission disc 7 along its radial direction at the position corresponding to the return spring 10. The outer end of the return spring 10 is connected to a spring pull rod 11. One end of the spring pull rod 11 is fixedly connected to the return spring 10, and the other end is fixedly connected to the bent part of the transmission bearing bush 9 after passing through the strip hole. Under the action of the return spring 10, the transmission bearing bush 9 and the driven inner cylinder 6 are fitted together; when the transmission disc 7 rotates with the driving shaft 1, the spring pull rod 11 can drive the transmission bearing bush 9 to rotate synchronously. In actual production, a transmission block 20 is provided between the bent part of the transmission bearing bush 9 and the transmission disc 7. On the transmission disc 7, a slide groove is provided corresponding to the transmission block 20. The slide groove is arranged along the radial direction of the transmission disc 7. The transmission block 20 is embedded in the slide groove and is connected with the slide groove in a sliding manner. During implementation, the transverse section of the transmission block 20 is wedge-shaped; correspondingly, the section of the slideway is also wedge-shaped, so that the matching stability between the transmission block and the slideway is better. The two sides of the transmission block 20 are fixedly connected to the spring pull rod 11 and the bent part of the transmission bearing 9 respectively. In this way, the transmission disc 7 can transfer the torque to the transmission bearing 9 through the transmission block 20 during the rotation process, thereby driving the transmission bearing 9 to rotate synchronously, and the torque can be transferred more stably. During processing, the transmission block 20 and the spring pull rod 11 are an integrated structure, so that the connection stability of the spring pull rod 11 and the transmission block 20 can be better improved.

[0031] On the driven inner cylinder 6, a spring groove is provided near both ends thereof corresponding to each transmission bearing 9, and the depth direction of the spring groove is consistent with the radial direction of the driven inner cylinder 6; a shape memory alloy spring 12 is provided in the spring groove, and the axial direction of the shape memory alloy spring 12 is consistent with the depth direction of the spring groove, one end of which is fixedly connected to the bottom of the spring groove, and the other end is fixedly connected to a slider 13, and the slider 13 is connected to the side wall of the spring groove by sliding fit, and a sealing ring is provided between the slider 13 and the side wall of the spring groove. In the middle of the inner side of the driven outer cylinder 3, a limiting ring 16 is provided around it, and the outer side of the limiting ring 16 is fixedly connected to the driven outer cylinder 3, and there is a gap between the inner side and the transmission bearing 9; thereby avoiding the transmission bearing 9 from fitting with the inner wall of the driven outer cylinder 3, ensuring the stability when the double cylinder mode is working.

[0032] In the middle of the driven inner cylinder 6, a coil groove is arranged around it, and an excitation coil 14 is wound in the coil groove; a section of the middle of the transmission bearing 9 corresponding to the excitation coil 14 is a low magnetic conductivity material block, and the two ends of the transmission bearing 9 are high magnetic conductivity material blocks, and the low magnetic conductivity material block and the two high magnetic conductivity material blocks are welded and connected to form a whole. A heat insulation sleeve 18 is also sleeved on the outside of the coil, so as to reduce the heat generated during the operation of the excitation coil 14 and transfer to the magnetorheological fluid 15, thereby improving the stability of the magnetorheological fluid 15. A heat conduction hole 17 is provided between the coil groove and the spring groove, and the heat conduction hole 17 passes through the heat insulation sleeve 18; so that the heat generated by the excitation coil 14 is quickly transferred to the shape memory alloy spring 12, so that the shape memory alloy spring 12 can quickly generate an action. A conductive slip ring 21 is provided on the outside of the right end cover 4, and the conductive slip ring 21 is connected to the excitation coil 14 through a wire. One end of the wire is connected to the excitation coil 14, and the other end passes through the right end cover 4, the inner hole of the driven inner cylinder 6 and the bottom of the coil slot and is connected to the excitation coil 14. During manufacturing, the middle part of the right end cover 4 protrudes outward to form a mounting seat, and the conductive slip ring 21 is sleeved on the mounting seat and fixedly connected to the right end cover 4, so that it is easier to install the conductive slip ring 21.

[0033] The gap between the transmission bearing bush 9 and the driven outer cylinder 3 is filled with a magnetorheological fluid 15. The driven outer cylinder 3 is provided with a liquid injection hole, and a liquid injection screw plug 22 is provided in the liquid injection hole, so as to facilitate the filling of the magnetorheological fluid 15.

[0034] During work:

[0035] 1. In the initial state, the magnetorheological fluid 15 is in the working gap between the transmission bearing 9 and the driven outer cylinder 3, and only contacts with the transmission bearing 9 and the driven outer cylinder 3; when the driving shaft 1 rotates, the driving shaft 1 drives the transmission bearing 9 to rotate through the transmission plate 7 and the spring pull rod 11; but when the temperature is lower than a certain temperature (50°C), the shape memory alloy spring 12 is in place and cannot push the slider 13, and thus cannot push the transmission bearing 9, and due to the initial tension of the reset spring 10, the centrifugal force generated by the transmission bearing 9 during rotation cannot overcome the initial tension of the reset spring 10, and a single-tube magnetorheological fluid 15 working gap is formed between the transmission bearing 9 and the driven outer cylinder 3, and the thickness of the gap is about 2 mm; at the same time, the excitation coil 14 is not energized, and the torque transmitted by the viscous force of the zero magnetic field of the magnetorheological fluid 15, the driving shaft 1 cannot transfer the torque and power to the driven shaft 5.

[0036] 2. When the excitation coil 14 is energized, the magnetic field passes through the magnetorheological fluid 15 between the transmission bearing 9 and the driven outer cylinder 3. Relying on the shear stress generated by the magnetorheological fluid 15 under the action of the magnetic field, an effect is generated between the transmission bearing 9 and the driven outer cylinder 3, driving the driven outer cylinder 3 to rotate, and then driving the driven shaft 5 to start rotating.

[0037] 3. When the entire heat dissipation device is involved in the transmission process for a long time, the Joule heat generated by the power supply of the excitation coil 14 will cause the internal temperature of the device to rise. Due to the existence of the heat insulation sleeve 18, the heat generated by the excitation coil 14 is confined in the accommodating groove of the excitation coil 14, and the heat is conducted to the shape memory alloy spring 12 through the heat conduction hole 17. When the temperature of the shape memory alloy spring 12 rises to the austenite transformation temperature (50°C), the shape memory alloy spring 12 stretches and pushes the transmission bearing 9 through the slider 13; at this time, the transmission bearing 9 overcomes the pulling force of the reset spring 10 under the action of centrifugal force and the thrust generated by the shape memory alloy spring 12, and the transmission bearing 9 slides outward along the driven inner cylinder 6. When the transmission bearing 9 contacts the limit ring 16, the working gap of the magnetorheological fluid 15 changes from a single-cylinder type to a double-cylinder type (the working gap thickness is 1mm). The distribution cloud diagram of the magnetic induction intensity of the working gap of the single-cylinder and double-cylinder magnetorheological fluid 15 is shown as follows: Figure 4 and Figure 5 The working gap between the two cylindrical magnetorheological fluids 15 formed by the transmission bearing 9 and the driven outer cylinder 3 and the driven inner cylinder 6 can double the transmission performance of the device, effectively compensating for the attenuation of the magnetorheological fluid 15 at high temperatures.

[0038] 4. As the temperature continues to rise, the shape memory alloy spring 12 generates the maximum extrusion force. At this time, the friction torque generated by the friction between the transmission bearing 9 and the limit ring 16 continues to increase. The friction torque further compensates for the performance attenuation of the magnetorheological fluid 15 at high temperature. Assuming that the maximum input speed of the device driving shaft 1 is =4000r / min, at the same time, the resistance torque and the fan running speed of the fan connected to the device driven shaft 5 can be expressed by the empirical formula: =, the maximum working torque of the device obtained by analysis is =29.2 N·m. During the temperature change of the device, the maximum torque that the device can transmit is changing. Among them, the maximum speed that the heat dissipation device can transmit at different temperatures is as follows: Figure 7 As shown in the figure, the limit speed increases significantly due to the temperature rise, which changes the single cylinder into multiple cylinders. When the temperature reaches 60℃, the device reaches a limit speed of 3680 r / min. As the temperature continues to rise, the transmission performance of the magnetorheological fluid 15 decreases at high temperatures. When the temperature reaches 100℃, the speed transmitted by the device is 3420 r / min, but during the entire temperature rise process, the limit speed is in a relatively stable range (3420-3680 r / min), and the transmitted speed only decreases by 7.06%, ensuring the transmission stability of the device within the full operating temperature range.

[0039] The present invention utilizes the shape memory alloy spring 12 to push the transmission bearing 9, so that the working gap of the magnetorheological fluid 15 in the device is changed from one to two, thereby reducing the no-load torque. When the temperature of the device rises to a certain temperature, the transmitted torque reaches a maximum value, the speed of the driven shaft 5 also reaches a maximum value, and the heat dissipation effect of the heat dissipation device driven by the driven shaft 5 is the most significant. As the temperature further increases, the transmitted torque and the speed of the driven shaft 5 are also in a higher range. At the same time, the present invention conducts the heat generated by the coil to the shape memory alloy, generates friction torque through the shape memory alloy spring 12, and further increases the transmission torque. Thereby, a lower no-load torque is ensured and the transmission performance at high temperature can be significantly enhanced.

[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 single-variable double-tube magnetorheological automatic heat dissipation device controlled by a shape memory alloy, comprising a driving shaft, a driven housing and a driven shaft, wherein the driven housing comprises a left end cover, a driven outer cylinder and a right end cover, wherein the left end cover, the driven outer cylinder and the right end cover are fixedly connected in sequence, and the driven shaft is fixedly connected to the right end cover; characterized in that: A driven inner cylinder is coaxially arranged in the driven cylinder, the right end of the driven inner cylinder is fixedly connected to the right end cover, and there is a distance between the driven inner cylinder and the driven outer cylinder; the driving shaft passes through the left end cover and then extends into the driven inner cylinder, and is connected to the driven inner cylinder through a bearing; a transmission disc is sleeved on the driving shaft, the transmission disc is fixedly connected to the driving shaft and can rotate synchronously with the driving shaft, and the transmission disc is connected to the left end cover through a bearing; A convex ring is coaxially arranged at the left end of the driven inner cylinder, and the convex ring is fixedly connected to the driven inner cylinder and is tightly attached to the transmission disc, so that there is a gap between the driven inner cylinder and the transmission disc; a plurality of arc-shaped transmission bearing shells are distributed around the outer side of the driven inner cylinder, and when the transmission bearing shells are attached to the driven inner cylinder, they can form a bearing shell cylinder connected in sequence; there is a gap between the right end of the transmission bearing shell and the right end cover, and the left end thereof is bent and extended toward the inner side of the driven inner cylinder and is attached to the end face of the driven inner cylinder, and the bent portion of the transmission bearing shell is wedge-shaped; on the transmission disc An annular groove is provided on the left side of the drive bearing, and a return spring is provided in the annular groove corresponding to each drive bearing, the axial direction of the return spring is consistent with the radial direction of the drive plate, and the inner end thereof is fixedly connected to the drive plate; a strip hole is provided on the drive plate along its radial direction at the position corresponding to the return spring; the outer end of the return spring is connected to a spring pull rod, one end of the spring pull rod is fixedly connected to the return spring, and the other end is fixedly connected to the bent part of the drive bearing after passing through the strip hole, and under the action of the return spring, the drive bearing and the driven inner cylinder are fitted together; On the driven inner cylinder, a spring groove is respectively provided near both ends thereof corresponding to each transmission bearing bush, and the depth direction of the spring groove is consistent with the radial direction of the driven inner cylinder; a shape memory alloy spring is provided in the spring groove, and the axial direction of the shape memory alloy spring is consistent with the depth direction of the spring groove, one end of the shape memory alloy spring is fixedly connected to the groove bottom of the spring groove, and the other end is fixedly connected to a slider, and the slider is connected to the side wall of the spring groove in a sliding fit; A coil groove is arranged around the middle of the driven inner cylinder, and an excitation coil is arranged in the coil groove; a section of the middle of the transmission bearing bush corresponding to the excitation coil is a low magnetic conductivity material block, and the two ends of the transmission bearing bush are high magnetic conductivity material blocks, and the low magnetic conductivity material block and the two high magnetic conductivity material blocks are welded and connected to form a whole; the gap between the transmission bearing bush and the driven outer cylinder is filled with magnetorheological fluid; a limit ring is arranged around the middle of the inner side of the driven outer cylinder, and the outer side of the limit ring is fixedly connected to the driven outer cylinder, and there is a gap between the inner side and the transmission bearing bush; a heat conduction hole is arranged between the coil groove and the spring groove; a heat insulation sleeve is also arranged on the outer side of the excitation coil, and the heat conduction hole runs through the heat insulation sleeve; A transmission block is provided between the bent part of the transmission bearing and the transmission disk. On the transmission disk, a slide groove is provided corresponding to the transmission block. The slide groove is arranged along the radial direction of the transmission disk. The transmission block is embedded in the slide groove and is connected with the slide groove in a sliding manner. The two sides of the transmission block are respectively fixedly connected to the spring pull rod and the bent part of the transmission bearing.

2. The shape memory alloy controlled single-variable double-tube magnetorheological automatic heat dissipation device according to claim 1, characterized in that: The transmission disc includes a shaft sleeve and a disc body. The disc body is located inside the driven housing, and a sealing ring is provided between its outer edge and the inner side of the driven outer cylinder. The shaft sleeve is sleeved on the driving shaft and connected to the left end cover through a bearing.

3. The shape memory alloy controlled single-variable double-tube magnetorheological automatic heat dissipation device according to claim 2, characterized in that: A transparent cover is arranged on the outer side of the left end cover, and the transparent cover is sleeved on the shaft sleeve; a felt ring is also arranged between the transparent cover and the shaft sleeve.

4. The shape memory alloy controlled single-variable double-tube magnetorheological automatic heat dissipation device according to claim 1, characterized in that: A conductive slip ring is arranged on the outer side of the right end cover, and the conductive slip ring is connected to the excitation coil through a wire.

5. The shape memory alloy controlled single-variable double-tube magnetorheological automatic heat dissipation device according to claim 4, characterized in that: The middle part of the right end cover protrudes outward to form a mounting seat, and the conductive slip ring is sleeved on the mounting seat and fixedly connected to the right end cover.

6. The shape memory alloy controlled single-variable double-tube magnetorheological automatic heat dissipation device according to claim 1, characterized in that: A liquid injection hole is provided on the driven outer cylinder, and a liquid injection screw plug is matched in the liquid injection hole.

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