CN113007242A - Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device - Google Patents

Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device Download PDF

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CN113007242A
CN113007242A CN202110290662.7A CN202110290662A CN113007242A CN 113007242 A CN113007242 A CN 113007242A CN 202110290662 A CN202110290662 A CN 202110290662A CN 113007242 A CN113007242 A CN 113007242A
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driven
transmission
cylinder
spring
shape memory
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黄金
熊洋
邱锐
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Chongqing University of Technology
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Chongqing University of Technology
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Priority to CN202110290662.7A priority Critical patent/CN113007242A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D57/00—Liquid-resistance brakes; Brakes using the internal friction of fluids or fluid-like media, e.g. powders
    • F16D57/002—Liquid-resistance brakes; Brakes using the internal friction of fluids or fluid-like media, e.g. powders comprising a medium with electrically or magnetically controlled internal friction, e.g. electrorheological fluid, magnetic powder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00—Parts or details
    • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2121/00—Type of actuator operation force
    • F16D2121/18—Electric or magnetic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D2129/00—Type of operation source for auxiliary mechanisms
    • F16D2129/14—Shape memory or other thermo-mechanical elements

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Springs (AREA)

Abstract

The invention discloses a shape memory alloy controlled single-change double-cylinder type magnetorheological automatic heat dissipation device, which comprises a driving shaft, a driven shell and a driven shaft, wherein a driven inner cylinder is coaxially arranged in the driven cylinder, a driving disc is sleeved on the driving shaft, a plurality of arc-shaped transmission shaft tiles are distributed around the outer side of the driven inner cylinder, a return spring is arranged on the left side of the transmission disc, the outer end of the return spring is connected with a spring pull rod, one end of the spring pull rod is fixedly connected with the return spring, and the other end of the spring pull rod is fixedly connected with a bent part of the transmission shaft tile after penetrating through a strip-shaped hole; a spring groove is arranged on the driven inner cylinder, and a shape memory alloy spring is arranged in the spring groove; the middle part of the driven inner cylinder is wound with an excitation coil; magnetorheological fluid is filled in a gap between the transmission shaft tile and the driven outer cylinder. The magnetorheological fluid automatic heat dissipation device has the advantages that the transmission performance of the magnetorheological fluid automatic heat dissipation device is obviously improved, and meanwhile, the lower idle load torque and the transmission performance at high temperature can be obviously enhanced.

Description

Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device
Technical Field
The invention relates to the field of automatic heat dissipation devices, in particular to a shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device.
Background
The magnetic rheological liquid is a magnetic intelligent material, mainly comprises magnetic particles and base liquid (usually silicon oil), is controlled by an external magnetic field, and shows the property of Newtonian fluid in the absence of the external magnetic field; after the magnetic field is added, the viscosity of the magnetorheological fluid changes by several orders of magnitude, and the property of the Bingham plastic fluid is shown; the whole change process is rapid and reversible, and the operation is simple and convenient. Shape Memory Alloy (SMA) is a novel intelligent material, after the shape memory alloy with a certain initial shape is deformed to a certain degree under a certain condition, the shape memory alloy can be deformed reversely by properly changing the temperature, so that the material is restored to the initial shape, and in the process of shape restoration, the shape memory alloy can generate great restoring force if being restrained, and the restoring force can be utilized to do work outwards.
The intelligent materials such as the shape memory alloy and the magnetorheological fluid have unique characteristics and excellent performance, so that the intelligent materials have wide application prospect in the mechanical field. For example, the "multi-plate magnetorheological fluid electromagnetic clutch" disclosed in CN103603891A, it adopts a multi-plate structure, and utilizes magnetorheological fluid as a medium to fill the gap between multiple driving and driven friction plates of the electromagnetic clutch, forming multiple working ring surfaces of magnetorheological fluid, the gap magnetic field intensity is large, the distribution is reasonable, and the transmission torque is large. For example, the device is a wedge-shaped extrusion soft start device based on magnetorheological fluid and shape memory alloy, which is disclosed in CN103591234A, and utilizes the extrusion strengthening effect of the magnetorheological fluid, so that the transmission power of the soft start device is improved; meanwhile, the memory alloy assists in transmitting torque, so that the transmission performance of the soft start device is more reliable. For example, CN105288876A discloses a "permanent magnet length variable magnetorheological fluid and friction composite soft landing device", which utilizes a permanent magnet to generate a magnetic field to excite the magnetorheological fluid to generate a magnetorheological effect, thereby controlling the braking torque of the soft landing device, and simultaneously utilizes the friction torque between a spring and a friction disk to assist deceleration landing. For example, CN105650148A discloses a "wheel initial deceleration brake based on magnetorheological fluid", which is a brake system that is provided with magnetorheological fluid in a brake working chamber and applies a driving magnetic field to the magnetorheological fluid through an electromagnetic wire coil to change the viscosity of the magnetorheological fluid, so that the magnetorheological fluid causes resistance to a brake wheel, and the brake system performs abrasion-free braking deceleration at the initial braking stage in a high-speed state. For another example, CN102562874A discloses a "double-disc type extrusion magnetorheological brake", 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 normal stress generated by the magnetorheological fluid in the direction of the magnetic field, and greatly increasing the braking torque. Also, as "a temperature control variable surface magnetorheological transmission device" disclosed in CN107763109A, the driving disk is pushed by the shape memory alloy spring to change one magnetorheological working surface into two, so as to transmit a larger torque, automatically adjust the transmitted torque according to the real-time temperature, and ensure the stability of the transmission process.
Researchers have developed wide application in the aspect of transmission aiming at the magnetorheological fluid, but the magnetorheological fluid also has the following defects in the aspect of transmission: the yield stress of the magnetorheological fluid is small under the common conditions, the requirement of transmitting high-power cannot be met, the shear yield stress of the magnetorheological fluid can be remarkably improved by improving the volume fraction of the magnetic particles in the magnetorheological fluid, but the no-load torque of a transmission device is large due to the fact that the volume fraction of the magnetic particles in the magnetorheological fluid is too high, and the controllable range of the torque under the action of a magnetic field is reduced, so that the problem that how to improve the braking performance of a magnetorheological fluid brake and reduce the no-load torque are to be solved urgently in the existing magnetorheological transmission is solved; the performance of the magnetorheological fluid is reduced along with the rise of the environmental temperature, the working requirements under different temperature environments cannot be met, the shape memory effect of the shape memory alloy can be used for making up the defects of the magnetorheological fluid in the aspect of transmission, and although researchers have studied the shape memory alloy and the magnetorheological fluid independently in the field of transmission engineering, the research on the combined application of the shape memory alloy and the magnetorheological fluid in a transmission device, particularly the research on the invention of exciting the shape memory effect of the shape memory alloy by utilizing the heating of the coil is less.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to solve the problems of small torque transmission, low transmission efficiency and poor high-temperature transmission stability of the existing magnetorheological automatic heat dissipation device, and provides the shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device.
In order to solve the technical problem, the technical scheme adopted by the invention is as follows: a shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device comprises a driving shaft, a driven shell and a driven shaft, wherein the driven shell comprises a left end cover, a driven outer cylinder and a right end cover, the left end cover, the driven outer cylinder and the right end cover are sequentially and fixedly connected, and the driven shaft is fixedly connected with the right end cover; the method is 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 with a right end cover, and a space is formed between the driven inner cylinder and the driven outer cylinder; the driving shaft penetrates through the left end cover and then extends into the driven inner cylinder, and is connected with the driven inner cylinder through a bearing; the driving shaft is sleeved with a driving disc, the driving disc is fixedly connected with the driving shaft and can synchronously rotate along with the driving shaft, and the driving disc is connected with 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 with the driven inner cylinder and is tightly attached to the transmission disc, so that a gap is formed between the driven inner cylinder and the transmission disc; a plurality of arc-shaped transmission shaft tiles are distributed around the outer side of the driven inner cylinder, and when the transmission shaft tiles are attached to the driven inner cylinder, the transmission shaft tiles can be sequentially connected to form a shaft tile cylinder; a gap is formed between the right end of the transmission bearing bush and the right end cover, the left end of the transmission bearing bush is bent towards the inner side direction of the driven inner cylinder, extends and is attached to the end face of the driven inner cylinder, and the bent part of the transmission bearing bush is wedge-shaped; an annular groove is formed in the left side of the transmission disc, a return spring is arranged in the annular groove corresponding to each transmission shaft tile respectively, the axial direction of the return spring is consistent with the radial direction of the transmission disc, and the inner end of the return spring is fixedly connected with the transmission disc; a strip-shaped hole is formed in the transmission disc along the radial direction of the transmission disc corresponding to the position of the return spring; the outer end of the reset spring is connected with a spring pull rod, one end of the spring pull rod is fixedly connected with the reset spring, the other end of the spring pull rod penetrates through the strip-shaped hole and is fixedly connected with the bending part of the transmission bearing bush, and the transmission bearing bush is attached to the driven inner cylinder under the action of the reset spring;
a spring groove is respectively arranged on the driven inner cylinder close to the two ends of the driven inner cylinder and corresponding to each transmission shaft tile, 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 arranged in the spring groove, 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 with the groove bottom of the spring groove, the other end of the shape memory alloy spring is fixedly connected with a sliding block, and the sliding block is connected with the side wall of the spring groove in a sliding fit manner;
a coil groove is arranged around the middle part of the driven inner cylinder, and an excitation coil is arranged in the coil groove in a winding way; the section of the middle part of the transmission bearing bush, which corresponds to the excitation coil, is a low-permeability material block, the two ends of the transmission bearing bush are high-permeability material blocks, and the low-permeability material block and the two high-permeability material blocks are welded and connected into a whole; magnetorheological fluid is filled in a gap between the transmission shaft tile and the driven outer cylinder.
Furthermore, a limiting ring surrounding the driven outer cylinder in a circle is arranged in the middle of the inner side of the driven outer cylinder, the outer side of the limiting ring is fixedly connected with the driven outer cylinder, and a gap is formed between the inner side of the limiting ring and the transmission shaft tile.
Further, a heat conduction hole is provided between the coil groove and the spring groove.
Furthermore, a heat insulation sleeve is further sleeved on the outer side of the magnet exciting coil, and the heat conduction hole penetrates through the heat insulation sleeve.
Furthermore, the transmission disc comprises a shaft sleeve and a disc body, the disc body is positioned on the inner side of the driven shell, and a sealing ring is arranged between the outer edge of the disc body and the inner side of the driven outer cylinder; the shaft sleeve is sleeved on the driving shaft and is connected with the left end cover through a bearing.
Furthermore, a transparent cover is arranged on the outer side of the left end cover and sleeved on the shaft sleeve; a felt ring is arranged between the transparent cover and the shaft sleeve.
Furthermore, a transmission block is arranged between the bending part of the transmission bearing bush and the transmission disc, a sliding groove is arranged on the transmission disc corresponding to the transmission block, the sliding groove is arranged along the radial direction of the transmission disc, and the transmission block is embedded into the sliding groove and is connected with the sliding groove in a sliding fit manner; and two sides of the transmission block are respectively fixedly connected with the spring pull rod and the bent part of the transmission bearing bush.
And furthermore, a conductive slip ring is arranged on the outer side of the right end cover and is connected with the excitation coil through a lead.
Furthermore, the middle part of the right end cover protrudes outwards to form a mounting seat, and the conductive sliding ring is sleeved on the mounting seat and is fixedly connected with the right end cover.
Furthermore, a liquid injection hole is formed in the driven outer cylinder, and a liquid injection screw plug is arranged in the liquid injection hole in a matched mode.
Compared with the prior art, the invention has the following advantages: the shape memory alloy spring is used for pushing the transmission bearing bush, so that the working clearance of the magnetorheological fluid in the device is changed from one to two, no-load torque is reduced, when the temperature of the device is increased to a certain temperature, the transmitted torque reaches the maximum value, the rotating speed of the driven shaft also reaches the maximum value, and the heat dissipation effect of the heat dissipation device driven by the driven shaft is most obvious; with the further rise of the temperature, the transmitted torque and the rotating speed of the driven shaft are also in a higher range; meanwhile, the heat generated by the coil is conducted to the shape memory alloy, and the friction torque is generated through the shape memory alloy spring, so that the transmission torque is further increased; thereby ensuring that the transmission performance at low idle load torque and high temperature can be obviously enhanced.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a state diagram of the driven inner cylinder and the transmission bearing bush when the single cylinder of the present invention works.
Fig. 3 is a state diagram of the driven inner cylinder and the transmission bearing bush when the double cylinders work.
FIG. 4 is a cloud chart of the magnetic induction intensity distribution in the single cylinder of the present invention.
Fig. 5 is a cloud of internal magnetic induction distribution when the invention is changed into double cylinders.
Fig. 6 is a graph of the braking torque of the present invention at various temperatures.
FIG. 7 is a graph of the limiting rotation speed of the present invention at different temperatures.
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-driving disc, 8-convex ring, 9-driving bearing bush, 10-return spring, 11-spring pull rod, 12-shape memory alloy spring, 13-sliding block, 14-excitation coil, 15-magnetorheological fluid, 16-limit ring, 17-heat conduction hole, 18-heat insulation sleeve, 19-transparent cover, 20-driving block, 21-conductive slip ring and 22-liquid injection plug screw.
Detailed Description
The invention will be further explained with reference to the drawings and the embodiments.
Example (b): referring to fig. 1 to 7, a shape memory alloy controlled single-change double-cylinder type magnetorheological automatic heat dissipation device comprises a driving shaft 1, a driven shell and a driven shaft 5; the driven shell comprises a left end cover 2, a driven outer barrel 3 and a right end cover 4, the left end cover 2, the driven outer barrel 3 and the right end cover 4 are fixedly connected in sequence, and the driven shaft 5 is fixedly connected with the right end cover 4. A driven inner cylinder 6 is coaxially arranged in the driven cylinder, and the driven inner cylinder 6 is provided with a shaft hole; the right end of the driven inner cylinder 6 is fixedly connected with the right end cover 4, a space is reserved between the driven inner cylinder 6 and the driven outer cylinder 3, and a space is reserved between the left end of the driven inner cylinder and the left end cover 2. The driving shaft 1 penetrates through the left end cover 2 and then extends into the driven inner cylinder 6, extends into a shaft hole of the driven inner cylinder 6 and is connected with the driven inner cylinder 6 through a bearing. The driving shaft 1 is sleeved with a transmission disc 7, the transmission disc 7 is fixedly connected with the driving shaft 1 and can synchronously rotate along with the driving shaft 1, and the transmission disc 7 is connected with the left end cover 2 through a bearing. In specific implementation, the transmission disc 7 comprises a shaft sleeve and a disc body, the disc body is positioned on the inner side of the driven shell and positioned between the left end of the driven inner cylinder 6 and the left end cover 2, and a sealing ring is arranged between the outer edge of the disc body and the inner side of the driven outer cylinder 3; the shaft sleeve is sleeved on the driving shaft 1 and is connected with the left end cover 2 through a bearing; wherein, the shaft sleeve is connected with the driving shaft 1 through keys, so that the transmission disc 7 can synchronously rotate along with the driving shaft 1. In order to ensure that the sealing effect of the whole driven shell is better, a transparent cover 19 is arranged on the outer side of the left end cover 2, and the transparent cover 19 is sleeved on the shaft sleeve; a felt ring is also arranged between the transparent cover 19 and the shaft sleeve.
A convex ring 8 is coaxially arranged at the left end of the driven inner cylinder 6, the convex ring 8 is fixedly connected with the driven inner cylinder 6 and is tightly attached to the transmission disc 7, so that a gap is formed between the driven inner cylinder 6 and the transmission disc 7, and a sealing ring is arranged between the convex ring 8 and the transmission disc 7. A plurality of transmission shaft tiles 9 with arc-shaped sections are distributed around the outer side of the driven inner cylinder 6, and when the transmission shaft tiles 9 are attached to the driven inner cylinder 6, the transmission shaft tiles 9 can be sequentially connected to form a bearing tile cylinder. A gap is formed between the right end of the transmission bearing bush 9 and the right end cover 4, the left end of the transmission bearing bush is bent towards the inner side of the driven inner cylinder 6, extends and is attached to 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 portions when the driving bearing bush 9 is attached to the driven inner cylinder 6. An annular groove is formed in the left side of the transmission disc 7, a return spring 10 is arranged in the annular groove corresponding to each transmission shaft tile 9 respectively, the axial direction of the return spring 10 is consistent with the radial direction of the transmission disc 7, and the inner end of the return spring is fixedly connected with the transmission disc 7. On the transmission disc 7, a strip-shaped hole is arranged along the radial direction corresponding to the position of the return spring 10. The outer end of the reset spring 10 is connected with a spring pull rod 11, one end of the spring pull rod 11 is fixedly connected with the reset spring 10, the other end of the spring pull rod 11 penetrates through the strip-shaped hole and then is fixedly connected with the bent part of the transmission shaft tile 9, and the transmission shaft tile 9 is attached to the driven inner cylinder 6 under the action of the reset spring 10; when the transmission disc 7 rotates along with the driving shaft 1, the transmission bearing bush 9 can be driven to synchronously rotate by the spring pull rod 11. During actual manufacturing, a transmission block 20 is arranged between the bending part of the transmission bearing bush 9 and the transmission disc 7, a sliding groove is arranged on the transmission disc 7 corresponding to the transmission block 20, the sliding groove is arranged along the radial direction of the transmission disc 7, and the transmission block 20 is embedded into the sliding groove and is connected with the sliding groove in a sliding fit mode. In practice, the transverse section of the transmission block 20 is wedge-shaped; correspondingly, the section of the sliding groove is also wedge-shaped, so that the matching stability of the transmission block and the sliding groove is better. Two sides of the driving block 20 are respectively fixedly connected with the spring pull rod 11 and the bent part of the transmission shaft tile 9. Thus, the transmission disk 7 can transmit the torque to the transmission shaft bushing 9 through the transmission block 20 in the rotating process, so that the transmission shaft bushing 9 is driven to synchronously rotate, and the torque can be transmitted more stably. During processing, the driving block 20 and the spring pull rod 11 are of an integral structure, so that the connection stability of the spring pull rod 11 and the driving block 20 can be better improved.
A spring groove is respectively arranged on the driven inner cylinder 6 close to the two ends of the driven inner cylinder and corresponding to each transmission shaft tile 9, and the depth direction of the spring groove is consistent with the radial direction of the driven inner cylinder 6; the spring groove is internally provided with a shape memory alloy spring 12, the axial direction of the shape memory alloy spring 12 is consistent with the depth direction of the spring groove, one end of the shape memory alloy spring is fixedly connected with the groove bottom of the spring groove, the other end of the shape memory alloy spring is fixedly connected with a sliding block 13, the sliding block 13 is connected with the side wall of the spring groove in a sliding fit manner, and a sealing ring is arranged between the sliding block 13 and the side wall of the spring groove. A limiting ring 16 which surrounds the driven outer cylinder 3 in a circle is arranged in the middle of the inner side of the driven outer cylinder 3, the outer side of the limiting ring 16 is fixedly connected with the driven outer cylinder 3, and a gap is formed between the inner side of the limiting ring and the transmission shaft tile 9; therefore, the drive bearing bush 9 is prevented from being attached to the inner wall of the driven outer cylinder 3, and the stability of the double-cylinder mode during working is ensured.
A coil groove is arranged around the middle part of the driven inner cylinder 6, and an excitation coil 14 is arranged in the coil groove; the section of the middle part of the transmission bearing bush 9 corresponding to the excitation coil 14 is a low magnetic conductive material block, the two ends of the transmission bearing bush 9 are high magnetic conductive material blocks, and the low magnetic conductive material block and the two high magnetic conductive material blocks are welded and connected into a whole. The outer side of the coil is also sleeved with a heat insulation sleeve 18, so that heat generated in the working process of the magnet exciting coil 14 is reduced from being transferred to the magnetorheological fluid 15, and the stability of the magnetorheological fluid 15 is improved. A heat conduction hole 17 is arranged between the coil groove and the spring groove, and the heat conduction hole 17 penetrates through the heat insulation sleeve 18; so that the heat generated by the exciting coil 14 is quickly transferred to the shape memory alloy spring 12, and the shape memory alloy spring 12 is quickly actuated. And a conductive slip ring 21 is arranged outside the right end cover 4, and the conductive slip ring 21 is connected with the excitation coil 14 through a lead. One end of the lead is connected with the excitation coil 14, and the other end of the lead passes through the right end cover 4, the inner hole of the driven inner cylinder 6 and the bottom of the coil slot and then is connected with the excitation coil 14. During manufacturing, the middle part of the right end cover 4 protrudes outwards to form a mounting seat, and the conductive sliding ring 21 is sleeved on the mounting seat and is fixedly connected with the right end cover 4, so that the conductive sliding ring 21 is more convenient to mount.
Magnetorheological fluid 15 is filled in a gap between the transmission bearing bush 9 and the driven outer cylinder 3. A liquid injection hole is formed in the driven outer cylinder 3, and a liquid injection screw plug 22 is arranged in the liquid injection hole in a matching manner, so that the magnetorheological fluid 15 can be conveniently injected.
In the working process:
1. in an initial state, the magnetorheological fluid 15 is only contacted with the transmission shaft tile 9 and the driven outer cylinder 3 in a working gap between the transmission shaft tile 9 and the driven outer cylinder 3; when the driving shaft 1 rotates, the driving shaft 1 drives the transmission bearing bush 9 to rotate through the transmission disc 7 and the spring pull rod 11; however, when the temperature is lower than a certain temperature (50 ℃), the shape memory alloy spring 12 is in the original position, and cannot push the slide block 13, and further cannot push the transmission bearing bush 9, and due to the initial tension of the return spring 10, the centrifugal force generated when the transmission bearing bush 9 rotates cannot overcome the initial tension of the return spring 10, a single-cylinder magnetorheological fluid 15 working gap is formed between the transmission bearing bush 9 and the driven outer cylinder 3, and the thickness of the gap is about 2 mm; meanwhile, the excitation coil 14 is not electrified, and the driving shaft 1 cannot transmit the torque and the power to the driven shaft 5 by means of the torque transmitted by the viscous force of the zero magnetic field of the magnetorheological fluid 15.
2. The excitation coil 14 is electrified, a magnetic field penetrates through the magnetorheological fluid 15 between the transmission bearing bush 9 and the driven outer cylinder 3, and the shear stress generated by the magnetorheological fluid 15 under the action of the magnetic field enables the transmission bearing bush 9 and the driven outer cylinder 3 to act to drive the driven outer cylinder 3 to rotate, so that the driven shaft 5 is driven to start rotating.
3. When the whole heat dissipation device participates in a transmission process for a long time, the temperature in the device can be increased by Joule heat generated by electrifying the exciting coil 14, the heat generated by the exciting coil 14 due to the existence of the heat insulation sleeve 18 is restrained in the accommodating groove of the exciting coil 14, the heat is conducted to the shape memory alloy spring 12 through the heat conduction hole 17, and after the temperature of the shape memory alloy spring 12 is increased to austenite transformation temperature (50 ℃), the shape memory alloy spring 12 extends and pushes the transmission bearing bush 9 through the slide block 13; at the moment, the driving bearing bush 9 overcomes the pulling force of the reset spring 10 under the action of the centrifugal force and the pushing force generated by the shape memory alloy spring 12, the driving bearing bush 9 slides outwards along the driven inner cylinder 6, when the driving bearing bush 9 is in contact with the limiting ring 16, the working gap of the magnetorheological fluid 15 is changed from a single cylinder type to a double cylinder type (the thickness of the working gap is 1 mm), and magnetic induction intensity distribution cloud charts of the working gap of the magnetorheological fluid 15 between the single cylinder type and the double cylinder type are shown in fig. 4 and 5; the transmission performance of the device can be doubled by the working gap of the two cylindrical magnetorheological fluids 15 formed by the transmission bearing bush 9, the driven outer cylinder 3 and the driven inner cylinder 6, and the performance attenuation of the magnetorheological fluids 15 at high temperature is effectively compensated.
4. With the continuous rise of the temperature, 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 bush 9 and the limit ring 16 is continuously increased, the performance attenuation of the magnetorheological fluid 15 at the high temperature is further compensated by the friction torque, the maximum input rotating speed of the driving shaft 1 of the device is assumed to be =4000r/min, and simultaneously, the resistance torque and the fan running speed of the fan connected with the driven shaft 5 of the device during working can be expressed by an empirical formula: = 29.2N · m, the maximum operating torque of the device obtained by analysis, the maximum torque that can be transmitted by the device during a change in the temperature of the device, the maximum rotational speed that can be transmitted by the heat sink at different temperatures being shown in fig. 7, the limit rotational speed increasing significantly as a result of the temperature increase changing a single cylinder to multiple cylinders. When the temperature reaches 60 ℃, the device reaches the limit rotating speed 3680 r/min. The transmission performance of the magnetorheological fluid 15 is reduced at high temperature due to continuous temperature rise, when the temperature reaches 100 ℃, the transmission speed of the device is 3420 r/min, but the limit speed is in a more stable range (3420 + 3680 r/min) in the whole temperature rise process, the transmission speed is reduced by 7.06 percent, and the transmission stability of the device in the full working temperature range is ensured.
The driving bearing bush 9 is pushed by the shape memory alloy spring 12, so that the working gaps of the magnetorheological fluid 15 in the device are changed from one to two, no-load torque is reduced, when the temperature of the device rises to a certain temperature, the transmitted torque reaches the maximum value, the rotating speed of the driven shaft 5 also reaches the maximum value, and the heat dissipation effect of the heat dissipation device driven by the driven shaft 5 is most obvious; as the temperature further increases, the transmitted torque and the rotation speed of the driven shaft 5 are also in a higher range; meanwhile, the heat generated by the coil is conducted to the shape memory alloy, and the friction torque is generated through the shape memory alloy spring 12, so that the transmission torque is further increased; thereby ensuring that the transmission performance at low idle load torque and high temperature can be obviously enhanced.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the technical solutions, and those skilled in the art should understand that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all that should be covered by the claims of the present invention.

Claims (10)

1. A shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device comprises a driving shaft, a driven shell and a driven shaft, wherein the driven shell comprises a left end cover, a driven outer cylinder and a right end cover, the left end cover, the driven outer cylinder and the right end cover are sequentially and fixedly connected, and the driven shaft is fixedly connected with the right end cover; the method is 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 with a right end cover, and a space is formed between the driven inner cylinder and the driven outer cylinder; the driving shaft penetrates through the left end cover and then extends into the driven inner cylinder, and is connected with the driven inner cylinder through a bearing; the driving shaft is sleeved with a driving disc, the driving disc is fixedly connected with the driving shaft and can synchronously rotate along with the driving shaft, and the driving disc is connected with 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 with the driven inner cylinder and is tightly attached to the transmission disc, so that a gap is formed between the driven inner cylinder and the transmission disc; a plurality of arc-shaped transmission shaft tiles are distributed around the outer side of the driven inner cylinder, and when the transmission shaft tiles are attached to the driven inner cylinder, the transmission shaft tiles can be sequentially connected to form a shaft tile cylinder; a gap is formed between the right end of the transmission bearing bush and the right end cover, the left end of the transmission bearing bush is bent towards the inner side direction of the driven inner cylinder, extends and is attached to the end face of the driven inner cylinder, and the bent part of the transmission bearing bush is wedge-shaped; an annular groove is formed in the left side of the transmission disc, a return spring is arranged in the annular groove corresponding to each transmission shaft tile respectively, the axial direction of the return spring is consistent with the radial direction of the transmission disc, and the inner end of the return spring is fixedly connected with the transmission disc; a strip-shaped hole is formed in the transmission disc along the radial direction of the transmission disc corresponding to the position of the return spring; the outer end of the reset spring is connected with a spring pull rod, one end of the spring pull rod is fixedly connected with the reset spring, the other end of the spring pull rod penetrates through the strip-shaped hole and is fixedly connected with the bending part of the transmission bearing bush, and the transmission bearing bush is attached to the driven inner cylinder under the action of the reset spring;
a spring groove is respectively arranged on the driven inner cylinder close to the two ends of the driven inner cylinder and corresponding to each transmission shaft tile, 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 arranged in the spring groove, 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 with the groove bottom of the spring groove, the other end of the shape memory alloy spring is fixedly connected with a sliding block, and the sliding block is connected with the side wall of the spring groove in a sliding fit manner;
a coil groove is arranged around the middle part of the driven inner cylinder, and an excitation coil is arranged in the coil groove in a winding way; the section of the middle part of the transmission bearing bush, which corresponds to the excitation coil, is a low-permeability material block, the two ends of the transmission bearing bush are high-permeability material blocks, and the low-permeability material block and the two high-permeability material blocks are welded and connected into a whole; magnetorheological fluid is filled in a gap between the transmission shaft tile and the driven outer cylinder.
2. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: the middle part of the inner side of the driven outer cylinder is provided with a limiting ring which surrounds the driven outer cylinder for a circle, the outer side of the limiting ring is fixedly connected with the driven outer cylinder, and a gap is arranged between the inner side of the limiting ring and the transmission shaft tile.
3. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: and a heat conduction hole is arranged between the coil groove and the spring groove.
4. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 3, wherein: the outside of the magnet exciting coil is also sleeved with a heat insulation sleeve, and the heat conduction hole penetrates through the heat insulation sleeve.
5. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: the transmission disc comprises a shaft sleeve and a disc body, the disc body is positioned on the inner side of the driven shell, and a sealing ring is arranged between the outer edge of the disc body and the inner side of the driven outer cylinder; the shaft sleeve is sleeved on the driving shaft and is connected with the left end cover through a bearing.
6. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 5, wherein: a transparent cover is arranged on the outer side of the left end cover and sleeved on the shaft sleeve; a felt ring is arranged between the transparent cover and the shaft sleeve.
7. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: a transmission block is arranged between the bent part of the transmission shaft tile and the transmission disc, a sliding groove is arranged on the transmission disc corresponding to the transmission block, the sliding groove is arranged along the radial direction of the transmission disc, and the transmission block is embedded into the sliding groove and is connected with the sliding groove in a sliding fit manner; and two sides of the transmission block are respectively fixedly connected with the spring pull rod and the bent part of the transmission bearing bush.
8. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: and a conductive slip ring is arranged on the outer side of the right end cover and is connected with the excitation coil through a lead.
9. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 8, wherein: the middle part of the right end cover protrudes outwards to form a mounting seat, and the conductive sliding ring is sleeved on the mounting seat and is fixedly connected with the right end cover.
10. The shape memory alloy controlled single-variable dual-cylinder magnetorheological automatic heat sink according to claim 1, wherein: a liquid injection hole is formed in the driven outer cylinder, and a liquid injection screw plug is arranged in the liquid injection hole in a matched mode.
CN202110290662.7A 2021-03-18 2021-03-18 Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device Pending CN113007242A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110290662.7A CN113007242A (en) 2021-03-18 2021-03-18 Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110290662.7A CN113007242A (en) 2021-03-18 2021-03-18 Shape memory alloy controlled single-variable double-cylinder type magnetorheological automatic heat dissipation device

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CN113007242A true CN113007242A (en) 2021-06-22

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113431850A (en) * 2021-07-23 2021-09-24 重庆理工大学 Electromagnetic extrusion magnetorheological and shape memory alloy friction composite brake

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113431850A (en) * 2021-07-23 2021-09-24 重庆理工大学 Electromagnetic extrusion magnetorheological and shape memory alloy friction composite brake
CN113431850B (en) * 2021-07-23 2022-03-08 重庆理工大学 Electromagnetic extrusion magnetorheological and shape memory alloy friction composite brake

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