CN116336103A - Low-power consumption self-locking magneto-rheological coupler - Google Patents

Abstract

The invention discloses a low-power-consumption self-locking magnetorheological coupler which comprises magnetorheological fluid, a box body, a transmission disc, a neodymium-iron-boron permanent magnet matrix, a stepping motor, a turbine worm reducer, a Hall sensor and the like. The inside of the shell is filled with magnetorheological fluid, the inside of the transmission disc is provided with a neodymium iron boron permanent magnet matrix, the matrix can rotate around a circular shaft at one end of the matrix, and the torque adjusting function is realized by changing the distance between the matrix and the magnetorheological fluid. The stepping motor is connected with the worm and gear reducer, the winding drum is installed on the output shaft, and the winding drum rotates to drive the permanent magnet matrix to rotate. The invention can still maintain torque after power failure, has the capability of stepless torque adjustment, low power consumption, small heat generation, low cost and simple structure.

Description

Low-power consumption self-locking magneto-rheological coupler

Technical Field

The invention relates to an energy-saving self-locking type coupling transmission device, in particular to a low-power-consumption self-locking type magnetorheological coupling using neodymium-iron-boron permanent magnets, which can solve the problems of heating, high power consumption and the like of the magnetorheological coupling.

Background

The coupling is widely applied to aspects of production and living, and the coupling is generally divided into a rigid coupling and a flexible coupling. The rigid coupling has simple structure, but has no compensation function, has higher requirement on coaxiality and is easy to generate additional stress. The flexible coupling has compensation effect, can compensate certain eccentric transmission and plays a role in damping. Among them, the magnetofluid coupling is receiving more and more attention from people due to its advantages of stepless regulation, smooth connection without impact, rapid responsiveness, etc.

However, the conventional magnetic fluid coupling is to change the viscosity of the magnetic fluid by means of an electromagnetic field generated by an electromagnet so as to achieve the purpose of changing the torque effect. However, the electromagnet needs continuous current input during working, generates a large amount of heat, further influences the viscosity of the magnetic fluid, and negatively influences the accurate adjustment of the transmission torque performance; and the potential safety hazard can be generated due to heat, so that higher requirements are put forward on the heat dissipation module of the coupler.

Sun Hui et al in patent 202010428754.2 describe a high-power torque-adjustable disk magnetorheological fluid coupling, wherein torque is adjusted by a magnetic field generated by an external electromagnetic coil, and the scheme realizes the transmission effect of the high torque by superposition of multiple disks, but cannot solve the problems of power consumption and heat dissipation. Hu Hongsheng et al in patent 201919401081.3 describe a hybrid magnetorheological fluid coupling in which permanent magnets are used in place of electromagnetic coils to save energy but not regulate torque.

Therefore, an energy-saving and environment-friendly magnetorheological coupler is needed, and the function of stepless adjustment of the torque transmission characteristic is realized by providing a magnetic field through the NdFeB permanent magnet; meanwhile, the permanent magnet has a self-locking function, namely, the permanent magnet can keep the position under the condition of no external energy input, and a stable magnetic field is provided.

Disclosure of Invention

Aiming at the defects of the existing magnetorheological coupler, the invention aims to design the self-locking magnetorheological coupler device with low power consumption, small heating and adjustable torque.

In order to realize the invention, the device comprises a stepping motor, a worm and gear reducer, a permanent magnet array adopting a halbach array, a Kevlar knitting line, magnetorheological fluid, a winding drum, a shell, a Hall sensor, a transmission shaft, a sealing ring, an outer cover plate, an inner cover plate, a conjugated iron sheet and the like. The casing is used as a main body, and an input valve and an output valve which play a role in transmitting torque and a sealing ring which play a role in sealing and supporting are arranged in the casing; the inside of the input valve is of a hollow structure, a stepping motor and a turbine worm reducer are arranged, and a winding drum is fixed on an output shaft of the turbine worm reducer; a Hall sensor for monitoring the rotation angle of the winding drum is arranged in the winding drum, a Kevlar braided wire is wound on the winding drum, and the other end of the Kevlar braided wire is fixed at the free end of the permanent magnet matrix; the other end of the sector permanent magnet matrix is drilled with a through hole, and a positioning shaft capable of rotating the permanent magnet is penetrated into the through hole; and sealing rings for preventing leakage of magnetorheological fluid are arranged between the input shaft and the output shaft and between the input shaft and the shell.

Further, the stepping motor is used for adjusting the rotation angle of the NdFeB permanent magnet, so that the torque is changed, and the purpose of stepless adjustment is achieved. The stepping motor has self-locking moment after power failure, and the rotation angle of the stepping motor can be kept unchanged.

Furthermore, the speed reducer is a turbine worm speed reducer, the speed reduction ratio is 50:1, and the self-locking characteristic is achieved. And the brass material is adopted, so that the service life is long, the friction is resisted, and the reliability of equipment is improved.

Further, the winding drum is made of aluminum alloy, is light in weight, cannot be magnetized by the neodymium-iron-boron permanent magnet to cause difficult rotation, and cannot influence the magnetic field distribution of the neodymium-iron-boron permanent magnet array.

Further, the Kevlar braided wire is a two-core six-strand braided wire, the diameter of the wire is 0.98mm, the wire can bear more than 250 pounds of tensile force, and the wire does not generate elastic deformation and has good wear resistance. The Kevlar braided wire is used for connecting the aluminum alloy winding drum and the end part of the permanent magnet array, and the position of the permanent magnet is adjusted through the rotation of the winding drum, so that the torque is changed.

Furthermore, the matrix of the neodymium iron boron permanent magnets is arranged in an array mode by adopting the halbach principle, and the matrix has the advantage of enhancing the magnetic induction intensity under the condition that the mass and the volume of the permanent magnets are not increased. The back of the permanent magnet array is provided with a beam magnet sheet, which plays roles of converging magnetic induction lines and reducing magnetic leakage.

Furthermore, the magnetorheological fluid is oil-based magnetorheological fluid, has good lubricity and is not easy to be viscous. Magnetorheological fluid forms the primary transmission material of the coupling.

Further, the Hall sensor is arranged inside the winding drum and used for accurately monitoring the rotation angle of the winding drum, so that the permanent magnet is ensured to be kept in a proper position.

Furthermore, the input valve is hollow, and parts such as a permanent magnet matrix, a winding drum, a speed reducer, a stepping motor and the like are arranged in the input valve. The side surfaces of the input valve and the output valve are provided with sinking grooves for transmitting torque, so that the torque can be increased.

Further, the input shaft is hollow, and a power supply line and a control line of the stepping motor are connected to the conductive slip ring of the input shaft.

In general, the following beneficial effects can be achieved by the above technical solutions contemplated by the present invention:

(1) The invention can maintain the required torque without depending on continuous power input, so that the power consumption is greatly reduced, and the heating condition is greatly improved;

(2) The invention realizes stepless adjustment of torque by changing the rotation angle of the permanent magnet, has simple control algorithm and low manufacturing and installation cost, and is suitable for mass production;

(3) The permanent magnet array based on the halbach principle is used, so that the magnetic induction intensity can be greatly improved under the condition that the volume and the mass of the permanent magnet are unchanged, and the torque upper limit is improved.

(4) The response curve of torque with respect to speed after the traditional magnetic fluid coupler is powered off is a straight line with small slope, and almost no torque transmission effect exists; the torque adjusting mechanism has self-locking performance, can keep the transmitted torque unchanged after power failure, has resistance to external impact vibration, and can keep stable transmission of the torque in a severe environment.

Drawings

FIG. 1 is a general semi-sectional view;

FIG. 2 is a perspective view in general semi-section;

FIG. 3 is an overall appearance;

FIG. 4 is an internal cross-sectional view of a maximum torque condition;

FIG. 5 is an internal cross-sectional view of a minimum torque condition;

FIG. 6 is a perspective view of a permanent magnet matrix in a minimum torque state;

FIG. 7 is a control flow diagram of the torque adjustment of the present invention.

The same reference numbers are used throughout the drawings to reference like elements or structures, wherein:

the magnetic rheological fluid device comprises an input shaft 1, an electrically conductive slip ring 2, a rotating shaft shell 3, a shell 4, a bearing 5, a sealing ring 6, an input lobe 7, a permanent magnet 8, a conjugated iron sheet 9, a positioning shaft 10, a stepping motor 11, a worm and gear reducer 12, a winding drum 13, an inner cover plate 14, an output lobe 15, an output shaft 16, an outer cover plate 17, a flat head screw 18, a countersunk screw 19, a Kevlar braided wire 20 and a magnetorheological fluid 21. For economy of description, the necessary common accessories such as power supplies, wires, etc. are not shown.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

The interrelationship or manner of installation of the components of the present invention are set forth below:

as shown in fig. 1, one end of an input shaft 1 is freely suspended and is used for connecting power input equipment; the other end is fixed with the lower end plane of the input flap 7 by a grub screw 18 for transmitting torque. The middle part of the input shaft 1 is provided with a conductive slip ring 2 for supplying power to the stepping motor 11 and outputting control signals. The middle part of the input shaft 1 is also provided with a sealing ring 6 which plays a role in sealing and sound insulation. The outer circumference of the sealing ring 6 is tightly connected with the rotating shaft shell 3, and the inner circumference of the rotating shaft shell 3 is connected with the outer circumference of the input shaft 1 through a bearing 5. A sealing ring 6 is installed between the housing 4 and the input shaft 1 to prevent leakage of the magnetorheological fluid 21 inside. The upper end surface of the shell 4 is fixed with the outer cover plate 17 through a countersunk screw 19. The inside of the input valve 7 is provided with a stepping motor 11, a worm gear reducer 12 and a winding drum 13 along the central shaft from bottom to top. The Kevlar braided wire 20 is wound in the wire slot of the winding drum 13, and the other ends of the Kevlar braided wire 20 are respectively connected with 6 conjugated iron sheets 9. Two permanent magnets 8 with opposite polarities are arranged in parallel, and a conjugated iron sheet 9 is arranged on the back surface. One end of the permanent magnet 8 is drilled with a through hole, and the inside of the permanent magnet passes through the positioning shaft 10. One end of the positioning shaft 10 is fixed on the input flap 7, and the other end is fixed on the inner cover plate 14, so that the permanent magnet 8 can rotate around the positioning shaft 10. The upper end surface of the output flap 15 is fixed with the output shaft 16 by a flat head screw 18. A sealing ring 6 is arranged between the output shaft 16 and the outer cover plate 17. A bearing 5 and a sealing ring 6 are arranged between the output shaft 16 and the rotating shaft shell 3. Fig. 2 is a perspective view in total semi-section.

Fig. 3 is an overall external view. As shown in fig. 3, the input shaft 1, the conductive slip ring 2, the rotating shaft housing 3, the shell 4, the outer cover 17, the countersunk slot screw 19 and the output shaft 16 are arranged in sequence from bottom to top.

Fig. 4 is an internal cross-sectional view of the maximum torque state. As shown in fig. 4, the input lobes 7 and the output lobes 17 are alternately arranged, and square protrusions are formed inside the input lobes to increase friction. The magnetorheological fluid 21 fills the space between the input and output lobes 7, 17. The permanent magnet 8 can rotate around the positioning shaft 10, the other end of the permanent magnet 8 is fixed with a Kevlar braided wire 20, and the other end of the Kevlar braided wire 20 is fixed on the winding drum 13.

Fig. 5 is an internal cross-sectional view of a minimum torque condition. As shown in fig. 5, the stepping motor 11 drives the worm and gear reducer 12 to rotate, further drives the winding drum 13 to rotate, tightens the kevlar braided wire 20, pulls the permanent magnet 8 to shrink, reduces the intensity of the magnetic field received by the magnetorheological fluid 21, and reduces the torque.

Fig. 6 is a perspective view of a permanent magnet matrix in a minimum torque state. As shown in FIG. 6, the permanent magnet matrix is composed of 2 tile-shaped neodymium iron boron permanent magnets 8, and is characterized in that the two tile-shaped neodymium iron boron permanent magnets are magnetized along the radial direction, but the magnetizing directions are completely opposite, one outer circular surface is an S pole, and the other outer circular surface is an N pole. The conjugate iron sheet 9 is arranged on the inner circle surface of the permanent magnet matrix, and has the functions of reducing magnetic resistance, converging magnetic induction lines, reducing magnetic leakage and improving the magnetic induction intensity of the magnetorheological fluid 21. In the contracted state of the kevlar braid 20, the permanent magnet 8 is contracted.

The torque adjustment control flow of the present invention is shown in fig. 7. Through a large number of simulation calculations and analyses, the mathematical relationship between the rotation angle x and the torque y of the winding drum of the invention satisfies the following formula:

wherein: x-spool rotation angle (°),

y-torque (N).

The coupling receives the coupling force y input by the operator or the sensor, and then calculates the rotation angle of the spool 13, and rotates. Whether the reel 13 rotates in place or not is judged by a Hall sensor inside the reel 13, and calibration is performed. The temperature sensor inside the drum 13 plays a role in temperature control.

Preferably, the shell 4 is made of steel, has the advantages of high pressure resistance, firmness and reliability, and plays a role in supporting and protecting as a main body structure in the invention.

Preferably, the stepping motor is used for adjusting the rotation angle of the NdFeB permanent magnet, so as to change the torque and achieve the purpose of stepless adjustment. The stepping motor has self-locking moment after power failure, and the rotation angle of the stepping motor can be kept unchanged.

Preferably, the speed reducer is a turbine worm speed reducer, the speed reduction ratio is 50:1, and the self-locking characteristic is achieved. And the brass material is adopted, so that the service life is long, the friction is resisted, and the reliability of equipment is improved.

Preferably, the winding drum is made of aluminum alloy, is light in weight, cannot be magnetized by the neodymium-iron-boron permanent magnet to cause difficult rotation, and cannot influence the magnetic field distribution of the neodymium-iron-boron permanent magnet array.

Preferably, the Kevlar braided wire is a two-core six-strand braided wire with the wire diameter of 0.98mm, can bear more than 250 pounds of tensile force, does not generate elastic deformation, and has good wear resistance. The Kevlar braided wire is used for connecting the aluminum alloy winding drum and the end part of the permanent magnet array, and the position of the permanent magnet is adjusted through the rotation of the winding drum, so that the torque is changed.

Preferably, the matrix of the neodymium iron boron permanent magnets is arranged in an array by adopting the halbach principle, and the matrix has the advantage of enhancing the magnetic induction intensity under the condition of not increasing the mass and the volume of the permanent magnets. The back of the permanent magnet array is provided with a beam magnet sheet, which plays roles of converging magnetic induction lines and reducing magnetic leakage.

Preferably, the magnetorheological fluid is oil-based magnetorheological fluid, has good lubricity and is not easy to be viscous. Magnetorheological fluid forms the primary damping material of the coupling.

Preferably, the hall sensor is arranged inside the winding drum and is used for accurately monitoring the rotation angle of the winding drum, so as to ensure that the permanent magnet is kept in a proper position.

Preferably, the input valve is hollow, and parts such as a permanent magnet array, a winding drum, a speed reducer, a stepping motor and the like are arranged in the input valve.

Preferably, the sealing ring is arranged between the shell and the inner part of the shell, and is used for sealing the magnetorheological fluid and keeping the components stable.

Specific examples of the system are as follows:

(1) The upper computer receives torque demand parameters from staff or sensors and calculates the angle to which the winding drum needs to rotate;

(2) The stepping motor starts to rotate, and a Hall sensor in the winding drum monitors whether the rotating angle is in place or not in real time;

(3) After the winding drum rotates in place, the stepping motor can be powered off, so that energy sources are saved, heating is reduced, and locking is realized under the self-locking effect of the worm and gear reducer of the winding drum;

(4) And (3) if the torque needs to be regulated, repeating the steps (1) - (3).

As can be seen from the above steps, the invention uses a stepper motor to drive the reel to rotate to control the torque. When the winding drum is released, the Kevlar braided wire naturally stretches, the permanent magnet matrix clings to the outer circumference under the action of magnetic attraction, at the moment, the magnetic induction intensity of magnetorheological fluid is maximum, and the torque also reaches the maximum; when the winding drum is tightened, the Kevlar braided wire is tensioned, the permanent magnet matrix is pulled away from the magnetorheological fluid under the action of the pulling force of the Kevlar braided wire, and at the moment, the magnetic induction intensity of the magnetorheological fluid is minimum and the torque is also minimum. Therefore, the permanent magnet matrix can be adjusted steplessly between two extreme positions to obtain continuous torque; after power failure, the permanent magnet locks the position under the self-locking characteristic of the worm and gear reducer and can continuously output torque.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (9)

1. The low-power-consumption self-locking magnetorheological coupler comprises a shell, an outer cover plate, an inner cover plate, a sealing ring, magnetorheological fluid, a stepping motor, a speed reducer, a permanent magnet matrix, a winding drum, a Kevlar braided wire and a conjugated iron sheet, and is characterized in that the shell is used as a main body, and an input flap and an output flap which play a role in transmitting torque and a sealing ring which play a role in sealing and supporting are arranged in the shell; the inside of the input valve is of a hollow structure, a stepping motor and a speed reducer are arranged, and a winding drum is fixed on an output shaft of the speed reducer; a Hall sensor for monitoring the rotation angle of the winding drum is arranged in the winding drum, a Kevlar braided wire is wound on the winding drum, and the other end of the Kevlar braided wire is fixed at the free end of the NdFeB permanent magnet matrix; the other end of the fan-shaped NdFeB permanent magnet matrix is drilled with a through hole, and a positioning shaft capable of enabling the permanent magnet to rotate is penetrated into the through hole; and sealing rings for preventing leakage of magnetorheological fluid are arranged between the input shaft and the output shaft and between the input shaft and the shell.

2. The low-power consumption self-locking magnetorheological coupler according to claim 1, wherein the permanent magnet matrix is composed of two tile-shaped neodymium iron boron permanent magnets, wherein the two tile-shaped neodymium iron boron permanent magnets are magnetized in the radial direction, but the magnetizing directions are completely opposite, one outer circular surface is an S pole, and the other outer circular surface is an N pole; the inner circular surface of the permanent magnet matrix is provided with conjugated iron sheets which play a role of beam magnetism.

3. The low-power self-locking magnetorheological coupling of claim 1, wherein the speed reducer is a worm and gear speed reducer made of brass material and has a speed reduction ratio of 50:1.

4. The low power self-locking magnetorheological coupling of claim 1, wherein the spool is fabricated from an aluminum alloy.

5. The low power self-locking magnetorheological coupling of claim 1, wherein the hall sensor is disposed inside a spool; the interior of the winding drum is also provided with a temperature sensor.

6. The low-power-consumption self-locking magnetorheological coupler according to claim 1, wherein the Kevlar stay wire is a two-core six-strand braided wire, the Kevlar stay wire is connected to the ends of the aluminum alloy winding drum and the permanent magnet array, and the position of the permanent magnet is adjusted through the rotation of the winding drum.

7. The low-power self-locking magnetorheological coupling of claim 1, wherein the matrix of neodymium-iron-boron permanent magnets is arranged in an array using halbach principle.

8. The low-power consumption self-locking magnetorheological coupler according to claim 1, wherein the input valve is of a hollow structure, and a permanent magnet, a winding drum, a speed reducer and a stepping motor are arranged in the input valve; the power supply and control wires of the stepper motor are connected to the conductive slip ring of the input shaft.

9. The low power consumption self-locking magnetorheological coupling of claim 1, wherein the input and output lobes are laterally disposedHas the following componentsSink grooves for increasing torque.

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