An electromagnetic friction and centrifugal extrusion magnetorheological soft starting device

Abstract

The invention discloses an electromagnetic friction and centrifugal extrusion magnetorheological soft starting device, comprising a driving shaft, a driven shaft, a driving inner cylinder, a driven outer cylinder, and a left end cover and a right end cover; an excitation coil is respectively arranged near both ends of the driving inner cylinder; an active friction sleeve, a driven friction shoe and an armature shoe are sleeved on the outer side of the coil slot; a receiving groove is arranged in the driving inner cylinder, an extrusion slider, a first return spring and a centrifugal rheostat are arranged in the receiving groove, and an extrusion shoe is arranged on the outer side of the receiving groove; a magnetorheological fluid is filled between the extrusion shoe and the driven outer cylinder; a brush slip ring is also arranged on the driving shaft, and the brush slip ring connects the centrifugal rheostat and the excitation coil in series through a wire. The invention can effectively improve the torque transmission capacity of the starter, automatically adjust the torque output according to the speed, and improve the torque transmission efficiency, transmission reliability and stability of the starter.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission, and in particular to an electromagnetic friction and centrifugal extrusion magnetorheological soft starting device. Background Art

[0002] Magnetorheological fluid is a new type of material composed of magnetic particles, base fluid and additives. Its rheological properties change dramatically with the change of external magnetic field: under zero magnetic field, it behaves as Newtonian fluid; under the action of external magnetic field, it can change from liquid to solid in an instant (about one thousandth of a second), and its viscosity suddenly increases to several orders of magnitude and even loses fluidity, showing the behavior of Bingham plastic body, with a certain shear yield stress. Its yield stress increases with the increase of external magnetic field intensity, and its performance can be continuously controlled by the external magnetic field. The reaction time of this control is measured in milliseconds. Therefore, it is widely used in machinery, automobiles, aviation, precision machining, construction, medical and other fields.

[0003] Based on the above properties of magnetorheological fluid, it has broad application prospects in the fields of clutch (starter), brake, etc. For example, the "magnetorheological fluid soft start device" disclosed in CN101029664A realizes fan heat dissipation through its own rotation. It has a simple structure, small size, large transmission torque, good heat dissipation performance, high heat dissipation efficiency, long service life, and wide practicality. For example, the "magnetorheological fluid soft start device" disclosed in CN102278446A first transmits torque through the magnetorheological fluid medium when starting, and then smoothly transitions to gear transmission when the start is smooth; it not only solves the impact problem of hard start, especially the problem of starting with load, but also ensures the reliability of transmission after the start is smooth. 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 transmitting torque, making the transmission performance of the soft start device more reliable. Although the above patents use extruded magnetorheological fluid to increase the torque transmitted by the device, or use the friction of the centrifugal slider to increase the torque transmitted by the device; there are still the following shortcomings: 1. The transmitted torque is limited and cannot meet the current large torque transmission needs; 2. It cannot effectively compensate for the problem of decreased transmission torque caused by increased temperature and decreased performance of magnetorheological fluid, and cannot ensure the stability of torque transmission; 3. It cannot automatically and adaptively transmit torque according to the rotational speed, affecting the stability of torque transmission.

[0004] In summary, how to cleverly utilize the characteristics of shape memory alloys and magnetorheological fluids to increase the maximum transmission torque of the starter and improve the transmission efficiency and transmission reliability is a technical problem that technical personnel in this field urgently need to solve. 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 in the prior art that the starter has limited torque transmission, cannot meet the demand for large torque transmission, has low transmission efficiency, cannot adaptively transmit torque according to the speed, and has poor transmission reliability and stability. An electromagnetic friction and centrifugal extrusion magnetorheological soft starting device is provided, which can effectively improve the torque transmission capacity of the starter, automatically adjust the torque output according to the speed, and improve the torque transmission efficiency as well as the transmission reliability and stability of the starter.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: an electromagnetic friction and centrifugal extrusion magnetorheological soft starting device, comprising a driving shaft, a driven shaft, an active inner cylinder, a driven outer cylinder, and a left end cover and a right end cover; the two ends of the driven outer cylinder are respectively fixedly connected to the left end cover and the right end cover to form a driven housing; one end of the active shaft passes through the right end cover and extends into the driven housing, and is connected to the left end cover and the right end cover through a bearing; the active inner cylinder is located in the driven housing and is sleeved on the active shaft, and the active inner cylinder can rotate synchronously with the active shaft; there is a gap between the outer wall of the active inner cylinder and the inner wall of the driven outer cylinder; one end of the driven shaft is fixedly connected to the left end cover; it is characterized in that: coil grooves that surround the active inner cylinder are respectively provided near the two ends of the active inner cylinder, and an excitation coil is respectively provided in the two coil grooves; an active A friction sleeve, wherein the active friction sleeve is fixedly connected to the active inner cylinder and the excitation coil is enclosed in the coil groove; on the outside of the active friction sleeve, a plurality of driven friction shoes are arranged around the active friction sleeve, and an armature shoe is arranged on the outside of the driven friction shoe, and the driven friction shoe is fixedly connected to the corresponding armature shoe; on the inner wall of the driven outer cylinder, a spring groove is arranged at a position corresponding to the middle of each armature shoe, and a shape memory alloy spring is arranged in the spring groove, one end of the shape memory alloy spring is fixedly connected to the bottom of the spring groove, and the other end is fixedly connected to the armature shoe; on the inner wall of the driven outer cylinder, at least one guide column is arranged corresponding to each armature shoe, one end of the guide column is fixedly connected to the driven outer cylinder, and the other end extends radially along the driven outer cylinder; on the armature shoe, a guide hole is arranged at a position corresponding to the guide column, and the armature shoe is sleeved on the guide column through the guide hole and is in clearance fit with the guide column;

[0007] Two receiving grooves are symmetrically provided on opposite sides of the middle part of the active inner cylinder, and an extrusion slider, a first return spring and a centrifugal rheostat are provided in the receiving grooves, the extrusion slider is connected to the receiving groove in a sliding manner, the first return spring is located between the inner end of the extrusion slider and the bottom of the receiving groove, and its two ends are respectively fixedly connected to the inner end of the extrusion slider and the bottom of the receiving groove; a mounting groove is provided at the inner end of the extrusion slider, and the centrifugal rheostat is installed in the mounting groove, wherein the resistance of the centrifugal rheostat decreases with the increase of centrifugal force; an extrusion shoe is respectively provided on the outer side of the two receiving grooves, the extrusion shoe is arc-shaped, the inner side of the extrusion shoe is fixedly connected to the extrusion slider, and there is a gap between the outer side and the driven outer cylinder; in the initial state, under the action of the first return spring, the two extrusion shoes are fitted with the active inner cylinder, and the two ends of the two extrusion shoes are connected to form a circular ring structure, and the gap between the two extrusion shoes and the driven outer cylinder is filled with magnetorheological fluid;

[0008] A brush slip ring is also provided on the driving shaft. The brush slip ring connects a centrifugal resistor and an excitation coil in series through a group of conducting wires, and connects another centrifugal resistor and another excitation coil in series through another group of conducting wires.

[0009] Furthermore, the centrifugal rheostat comprises a cylindrical shell, a sealing cover is provided at one end of the cylindrical shell, and a wiring cover is provided at the other end; a guide cylinder is provided in the cylindrical shell along its axial direction, and the two ends of the guide cylinder are respectively connected to the sealing cover and the wiring cover, a sliding sleeve is sleeved on the guide cylinder, and a second return spring is provided between the sliding sleeve and the wiring cover, and the second return spring is sleeved on the guide cylinder, and the two ends of the second return spring are respectively fixedly connected to the sliding sleeve and the wiring cover; a resistance wire is spirally wound on the inner wall of the cylindrical shell on the side of the sliding sleeve away from the second return spring to form a resistance wire cylinder; A conductive wire is spirally wound on the guide cylinder, and a conductive slide is also provided on the side of the sleeve away from the second return spring. When the sleeve moves into the resistance wire cylinder, the conductive slide can fit the inner wall of the resistance wire cylinder; a first terminal, a second terminal and a third terminal are provided on the wiring cover, wherein the first terminal and the second terminal are respectively connected to the two ends of the resistance wire, the third terminal is connected to one end of the conductive wire away from the sleeve, and the other end of the conductive wire is connected to the conductive slide; the brush slip ring is connected to the first terminal and the third terminal at the same time through a wire, and the second terminal is connected to the excitation coil through a wire.

[0010] Furthermore, a resistance wire holding cylinder is provided on the inner side of the cylindrical shell, the resistance wire is wound on the resistance wire holding cylinder, the sliding sleeve, the conductive sliding piece and the second return spring are all located on the inner side of the resistance wire holding cylinder, and the sliding sleeve is connected to the resistance wire holding cylinder in a sliding manner; on the side wall of the resistance wire holding cylinder, a strip hole is opened along its axial direction at the position corresponding to the conductive sliding piece, and the two ends of the strip hole extend to the outer sides of the two ends of the resistance wire cylinder respectively, and the conductive sliding piece can enter the strip hole and electrically contact with the resistance wire during the movement of the sliding sleeve.

[0011] Furthermore, the conductive sliding piece is arc-shaped and protrudes toward the side wall of the cylindrical shell, and its outer side is used to contact the resistance wire; a retaining frame is also provided on the sliding sleeve, and the conductive sliding piece is fixed on the sliding sleeve through the retaining frame.

[0012] Furthermore, a sealing ring is provided between the extrusion slider and the side wall of the accommodating groove. The sealing ring is sleeved on the extrusion slider and can move with the extrusion slider.

[0013] Furthermore, an oil filling hole is provided on the driven outer cylinder at a position corresponding to the extrusion shoe, and an oil filling screw plug is installed in the oil filling hole.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. Combining electromagnetic friction transmission with magnetorheological shear transmission can transmit greater torque; at high temperatures, the compression force generated by the shape memory alloy spring can also make up for the decrease in the torque transmitted by the device, thereby greatly improving the reliability and stability of torque transmission.

[0016] 2. The magnetic flux generated by the excitation coil can attract the armature shoe, thereby pressing the driven friction shoe against the active friction sleeve, thereby further increasing the friction between the driven friction shoe and the active friction sleeve, thereby further increasing the torque transmission.

[0017] 3. Due to the extrusion strengthening effect, the extrusion shoe squeezes the magnetorheological fluid, reducing the gap between the magnetic particles in the magnetorheological fluid, thereby increasing the shear force of the magnetorheological fluid and significantly improving the transmitted torque.

[0018] 4. The current is automatically controlled by the centrifugal rheostat, and the torque output can be adaptively adjusted according to the speed. The transmitted torque changes with the speed of the driving shaft (active inner cylinder). The faster the speed, the greater the centrifugal force and the greater the current, which can further increase the transmitted torque. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0021] Figure 3 It is a structural schematic diagram of the centrifugal resistor in the present invention.

[0022] In the figure: 1-active shaft, 2-driven shaft, 3-active inner cylinder, 4-driven outer cylinder, 5-excitation coil, 6-active friction sleeve, 7-driven friction shoe, 8-armature shoe, 9-shape memory alloy spring, 10-guide column, 11-extrusion slider, 12-first return spring, 13-centrifugal rheostat, 131-cylindrical shell, 132-sealing cover, 133-wiring cover, 134-guide cylinder, 135-sliding sleeve, 136-second return spring, 137-resistance wire, 138-conductive wire, 139-conductive sliding piece, 14-extrusion shoe, 15-magnetorheological fluid, 16-brush slip ring, 17-resistance wire holding cylinder, 18-cage, 19-oil filling plug. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] Example: See Figure 1 , Figure 2 as well as Figure 3 , an electromagnetic friction and centrifugal extrusion magnetorheological soft starting device, comprising a driving shaft 1, a driven shaft 2, an active inner cylinder 3, a driven outer cylinder 4, and a left end cover and a right end cover. The two ends of the driven outer cylinder 4 are respectively fixedly connected with the left end cover and the right end cover to form a driven housing; one end of the driving shaft 1 passes through the right end cover and extends into the driven housing, and is connected to the left end cover and the right end cover through a bearing. The active inner cylinder 3 is located in the driven housing and is sleeved on the driving shaft 1, and the active inner cylinder 3 can rotate synchronously with the driving shaft 1; in specific implementation, the active inner cylinder 3 and the driving shaft 1 are formed as one body to make the stability better; there is a gap between the outer wall of the active inner cylinder 3 and the inner wall of the driven outer cylinder 4; one end of the driven shaft 2 is fixedly connected with the left end cover; wherein the driving shaft 1, the driven shaft 2, the active inner cylinder 3 and the driven outer cylinder 4 are all arranged coaxially, so that the stability of the entire device can be better during operation.

[0025] Coil grooves are provided near both ends of the active inner cylinder 3, and an excitation coil 5 is provided in each of the two coil grooves. An active friction sleeve 6 is sleeved on the outer side of the coil groove. The active friction sleeve 6 is sleeved on the active inner cylinder 3 and fixedly connected to the active inner cylinder 3, and the excitation coil 5 is enclosed in the coil groove. On the outer side of the active friction sleeve 6, several driven friction shoes 7 are provided around it. When the driven friction shoes 7 are fitted with the active friction sleeve 6, they can be connected in sequence to form a driven friction ring; thereby, the contact area between the driven friction shoes 7 and the active friction sleeve 6 can be increased, and the friction force between the driven friction shoes 7 and the active friction sleeve 6 can be increased, which helps to increase the output torque. An armature shoe 8 is provided on the outer side of the driven friction shoe 7, and the driven friction shoe 7 is fixedly connected to the corresponding armature shoe 8; when the driven friction shoe 7 is fitted with the active friction sleeve 6, the armature shoes 8 can also be connected in sequence to form an armature ring; in this way, the pressing force of the armature ring on the driven friction shoe 7 can be effectively increased. A spring groove is provided on the inner wall of the driven outer cylinder 4 at the position corresponding to the middle of each armature shoe 8, and a shape memory alloy spring 9 is provided in the spring groove, one end of the shape memory alloy spring 9 is fixedly connected to the groove bottom of the spring groove, and the other end is fixedly connected to the armature shoe 8. At least one guide column 10 is provided on the inner wall of the driven outer cylinder 4 at the position corresponding to each armature shoe 8, one end of the guide column 10 is fixedly connected to the driven outer cylinder 4, and the other end extends in the radial direction of the driven outer cylinder 4; a guide hole is provided on the armature shoe 8 at the position corresponding to the guide column 10, and the armature shoe 8 is sleeved on the guide column 10 through the guide hole, and has a clearance fit with the guide column 10; in this way, the armature shoe 8 and the driven friction shoe 7 can be ensured to move in the radial direction of the driven outer cylinder 4, and the stability during the movement can be improved.

[0026] Two receiving grooves are symmetrically arranged on opposite sides of the middle of the active inner cylinder 3, wherein the axial direction of the receiving groove is consistent with the radial direction of the active inner cylinder 3, and an extrusion slider 11, a first return spring 12 and a centrifugal rheostat 13 are arranged in the receiving groove. The extrusion slider 11 is connected to the receiving groove by sliding cooperation, and a sealing ring is also arranged between the extrusion slider 11 and the side wall of the receiving groove. The sealing ring is sleeved on the extrusion slider 11 and can move with the extrusion slider 11; thereby preventing the magnetorheological fluid 15 from entering the receiving groove, causing loss to the magnetorheological fluid 15 and affecting the stability of the entire device. The first return spring 12 is located between the inner end of the extrusion slider 11 and the bottom of the receiving groove, and its two ends are fixedly connected to the inner end of the extrusion slider 11 and the bottom of the receiving groove respectively. An installation groove is arranged at the inner end of the extrusion slider 11, and the axial direction of the installation groove is also consistent with the axial direction of the active inner cylinder 3, and the centrifugal rheostat 13 is installed in the installation groove. Among them, as the centrifugal force increases, the resistance of the centrifugal rheostat 13 decreases. In a specific implementation, the centrifugal rheostat 13 includes a cylindrical housing 131, a sealing cover 132 is provided at one end of the cylindrical housing 131, and a wiring cover 133 is provided at the other end. One end of the cylindrical housing 131 with the sealing cover 132 is received in the mounting groove and fixedly connected to the extrusion slider 11. A guide cylinder 134 is provided in the cylindrical housing 131 along its axial direction, and the two ends of the guide cylinder 134 are respectively connected to the sealing cover 132 and the wiring cover 133. A sliding sleeve 135 is sleeved on the guide cylinder 134, and a second reset spring 136 is provided between the sliding sleeve 135 and the wiring cover 133. The second reset spring 136 is sleeved on the guide cylinder 134, and its two ends are respectively fixedly connected to the sliding sleeve 135 and the wiring cover 133. A resistance wire 137 is spirally wound on the inner wall of the cylindrical housing on the side of the sliding sleeve 135 away from the second reset spring 136 to form a resistance wire cylinder; wherein the outer diameter of the sliding sleeve 135 is smaller than the inner diameter of the resistance wire cylinder, so that the sliding sleeve 135 can slide freely in the resistance wire cylinder. A resistance wire holding cylinder 17 is also provided on the inner side of the cylindrical housing 131, and the resistance wire 137 is wound on the resistance wire holding cylinder 17. Positioning flanges that are wound around the resistance wire holding cylinder 17 are respectively provided on the resistance wire holding cylinder 17 at the positions corresponding to the two ends of the resistance wire cylinder to position the resistance wire cylinder. The sliding sleeve 135, the conductive slide 139 and the second reset spring 136 are all located inside the resistance wire holding cylinder 17, and the sliding sleeve 135 is connected to the resistance wire holding cylinder 17 in a sliding manner. On the side wall of the resistance wire holding cylinder 17, a strip hole is opened along its axial direction corresponding to the position of the conductive sliding piece 139, and the two ends of the strip hole extend to the outside of the two ends of the resistance wire cylinder respectively. During the movement of the conductive sliding piece 139 with the sliding sleeve 135, it can enter the strip hole and contact and electrically connect with the resistance wire 137. Therefore, the installation stability and convenience of the resistance wire 137 can be effectively improved.The cylindrical shell 131 , the guide tube 134 , the sliding sleeve 135 , the resistance wire holding tube 17 , the sealing cover 132 and the wiring cover 133 are all made of insulating materials, so as to avoid short circuit caused by electricity.

[0027] A conductive wire 138 is spirally wound on the guide cylinder 134 on the side of the sliding sleeve 135 away from the second return spring 136, and a conductive slide 139 is also provided on the side of the sliding sleeve 135 away from the second return spring 136. When the sliding sleeve 135 moves into the resistance wire cylinder, the conductive slide 139 can fit with the inner wall of the resistance wire cylinder, thereby being electrically connected to the resistance wire 137. A first terminal, a second terminal and a third terminal are provided on the wiring cover 133, wherein the first terminal and the second terminal are respectively connected to the two ends of the resistance wire 137, the third terminal is connected to one end of the conductive wire 138 away from the sliding sleeve 135, and the other end of the conductive wire 138 is connected to the conductive slide 139. The conductive slide 139 is arc-shaped and protrudes toward the side wall of the cylindrical shell, and its outer side (arc-shaped side) is used to contact with the resistance wire 137, so as to facilitate the movement of the conductive slide 139. A retainer 18 is also provided on the sleeve 135, through which the conductive slide 139 is fixed on the sleeve 135; the conductive slide 139 is positioned by the retainer 18, so as to ensure the stability of the conductive slide 139, thereby ensuring the stability of the conductive slide 139 in contact with the resistance wire 137 during operation. In the specific implementation process, a through hole connected to the guide cylinder 134 is provided on the wiring cover 133, and a wire hole is provided on the side wall of the guide cylinder 134 near the sealing end. The wire enters the guide cylinder 134 through the through hole, and passes through the guide cylinder 134 from the wire hole and is connected to the resistance wire 137 or the conductive wire 138 accordingly. The brush slip ring 16 is connected to the first terminal and the third terminal at the same time through the wire, and the second terminal is connected to the excitation coil 5 through the wire; wherein the first terminal is connected to the end of the resistance wire cylinder near the sleeve 135, and the second terminal is connected to the end of the resistance wire cylinder near the driven outer cylinder 4.

[0028] An extrusion shoe 14 is provided on the outside of each of the two accommodating grooves. The extrusion shoe 14 is arc-shaped, and its inner side is fixedly connected to the extrusion slider 11, and there is a gap between the outer side and the driven outer cylinder 4. In the initial state, under the action of the first return spring 12, the two extrusion shoes 14 fit with the active inner cylinder 3, and the two ends of the two extrusion shoes 14 are connected to form a ring structure, and the gap between the two extrusion shoes 14 and the driven outer cylinder 4 is filled with magnetorheological fluid 15. Among them, when the magnetic flux generated by the two excitation coils 5 passes through the magnetorheological fluid 15 in the working gap, the magnetic flux has the same direction. On the driven outer cylinder 4, an oil filling hole is provided at the position corresponding to the extrusion shoe 14, and an oil filling screw 19 is installed in the oil filling hole to facilitate the injection or replacement of the magnetorheological fluid 15.

[0029] A brush slip ring 16 is also provided on the driving shaft 1. The brush slip ring 16 connects a centrifugal rheostat 13 and an excitation coil 5 in series through a set of wires, and connects another centrifugal rheostat 13 and another excitation coil 5 in series through another set of wires. During the implementation, an axial hole is provided on the driving shaft 1, and a through hole connected to the axial hole is provided on the driving inner cylinder 3 at positions corresponding to the coil slot and the accommodating slot. The wire connected to the brush slip ring 16 is connected to the centrifugal rheostat 13 and the excitation coil 5 through the axial hole and the through hole.

[0030] During work:

[0031] 1. After the power supply of the brush slip ring 16 is turned on, the resistance wire 137 is fully connected to the circuit, and the excitation coil 5 is energized. When the driving shaft 1 rotates slowly, the sliding sleeve 135 in the centrifugal rheostat 13 moves outward under the action of the centrifugal force. However, due to the action of the second reset spring 136, the sliding sleeve 135 cannot drive the conductive sliding piece 139 to contact the resistance wire 137 when it fails to overcome the action of the second reset spring 136. At this time, the resistance wire 137 is fully connected to the circuit, but the resistance value is the largest at this time, the current in the excitation coil 5 is the smallest, the magnetic field intensity generated is the smallest, the torque transmitted by the electromagnetic friction (the suction force received by the armature shoe 8) and the magnetorheological fluid 15 (the shear stress generated) is small, and the driven shaft 2 rotates slowly.

[0032] 2. As the speed of the driving shaft 1 increases, the centrifugal force gradually increases, the centrifugal force on the sliding sleeve 135 increases, and it continues to overcome the pulling force of the second return spring 136, moves toward the driven outer cylinder 4, and drives the conductive sliding piece 139 to move toward the driven outer cylinder 4 and contact the resistance wire 137. As the moving distance increases, the resistance of the centrifugal rheostat 13 connected to the circuit gradually decreases, the current of the excitation coil 5 gradually increases, the intensity of the generated magnetic field gradually increases, the suction force on the armature shoe 8 increases, and then the pressing force between the driven friction shoe 7 and the active friction sleeve 6 increases, the friction force between the driven friction shoe 7 and the active friction sleeve 6 increases, and the shear force generated by the magnetorheological fluid 15 also increases, so that the torque transmitted by the electromagnetic friction and the magnetorheological fluid 15 continues to increase, the speed of the driven shaft 2 continues to increase, and the torque transmitted by the device also increases, so that the size of the transmitted torque can be automatically adjusted according to the speed of the driving shaft 1; when the speed of the driving shaft 1 reaches the required maximum speed, the combined torque transmitted by the electromagnetic friction and the magnetorheological fluid reaches the maximum value.

[0033] 3. At the same time, the extrusion shoe 14 and the extrusion slider 11 slide out of the accommodating groove under the action of centrifugal force and squeeze the magnetorheological fluid 15; due to the extrusion strengthening effect, the torque transmitted by the magnetorheological fluid 15 is greatly increased, thereby greatly improving the torque output.

[0034] 4. When the working time is too long, the friction shoe heats up, the friction coefficient decreases, and the friction torque decreases; the temperature rise also reduces the performance of the magnetorheological fluid 15, so the torque transmitted by the electromagnetic friction will decrease; but at this time, the shape memory alloy spring 9 axially presses the armature shoe 8 at high temperature, increasing the pressing force to compensate for the part of the torque transmitted by the device at high temperature, thereby improving the reliability and stability of the torque transmission of the entire device.

[0035] 5. When the power is turned off, the magnetic flux disappears, and the armature is separated from the driven friction shoe 7 and the active friction sleeve 6 by the action of the shape memory spring; at the same time, the extrusion slider 11 and the sliding sleeve 135 return to their original positions under the action of the first return spring 12 and the second return spring 136 respectively, and the master and slave are separated, and torque transmission is no longer performed.

[0036] 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. An electromagnetic friction and centrifugal extrusion magnetorheological soft starting device, comprising a driving shaft, a driven shaft, a driving inner cylinder, a driven outer cylinder, and a left end cover and a right end cover; the two ends of the driven outer cylinder are respectively fixedly connected with the left end cover and the right end cover to form a driven housing; one end of the driving shaft passes through the right end cover and then extends into the driven housing, and is connected with the left end cover and the right end cover through a bearing; the driving inner cylinder is located in the driven housing and is sleeved on the driving shaft, and the driving inner cylinder can rotate synchronously with the driving shaft; there is a gap between the outer wall of the driving inner cylinder and the inner wall of the driven outer cylinder; one end of the driven shaft is fixedly connected with the left end cover; it is characterized in that: Coil grooves are provided around the active inner cylinder near both ends, and an excitation coil is provided in each of the two coil grooves; an active friction sleeve is sleeved on the outer side of the coil groove, and the active friction sleeve is fixedly connected to the active inner cylinder and seals the excitation coil in the coil groove; a plurality of driven friction shoes are provided around the outer side of the active friction sleeve, and an armature shoe is provided on the outer side of the driven friction shoe, and the driven friction shoe is fixedly connected to the corresponding armature shoe; a spring groove is provided on the inner wall of the driven outer cylinder at a position corresponding to the middle of each armature shoe, and a shape memory alloy spring is provided in the spring groove, one end of the shape memory alloy spring is fixedly connected to the bottom of the spring groove, and the other end is fixedly connected to the armature shoe; at least one guide column is provided on the inner wall of the driven outer cylinder corresponding to each armature shoe, and one end of the guide column is fixedly connected to the driven outer cylinder, and the other end extends in the radial direction of the driven outer cylinder; a guide hole is provided on the armature shoe at a position corresponding to the guide column, and the armature shoe is sleeved on the guide column through the guide hole and is in clearance fit with the guide column; Two receiving grooves are symmetrically arranged on opposite sides of the middle part of the active inner cylinder, and an extrusion slider, a first return spring and a centrifugal rheostat are arranged in the receiving grooves. The extrusion slider is connected to the receiving groove by sliding cooperation, and the first return spring is located between the inner end of the extrusion slider and the bottom of the receiving groove, and its two ends are respectively fixedly connected to the inner end of the extrusion slider and the bottom of the receiving groove; an installation groove is arranged at the inner end of the extrusion slider, and the centrifugal rheostat is installed in the installation groove, wherein the resistance of the centrifugal rheostat decreases with the increase of centrifugal force; The outer side is respectively provided with an extrusion shoe, the extrusion shoe is arc-shaped, the inner side of which is fixedly connected to the extrusion slider, and there is a gap between the outer side and the driven outer cylinder; in the initial state, under the action of the first return spring, the two extrusion shoes are fitted with the active inner cylinder, and the two ends of the two extrusion shoes are connected to form a ring structure, and the gap between the two extrusion shoes and the driven outer cylinder is filled with magnetorheological fluid; the centrifugal rheostat includes a cylindrical shell, a sealing cover is provided at one end of the cylindrical shell, and a wiring cover is provided at the other end; a guide cylinder is provided in the cylindrical shell along its axial direction, and the two ends of the guide cylinder are respectively connected to The sealing cover is connected to the wiring cover, a sliding sleeve is sleeved on the guide cylinder, a second return spring is provided between the sliding sleeve and the wiring cover, the second return spring is sleeved on the guide cylinder, and its two ends are respectively fixedly connected to the sliding sleeve and the wiring cover; a resistance wire is spirally wound on the inner wall of the cylindrical shell on the side of the sliding sleeve away from the second return spring to form a resistance wire cylinder; a conductive wire is spirally wound on the guide cylinder on the side of the sliding sleeve away from the second return spring, and a conductive sliding sheet is also provided on the side of the sliding sleeve away from the second return spring. When the sliding sleeve moves into the resistance wire cylinder, the conductive sliding sheet can contact with the resistance wire cylinder. The inner wall of the resistance wire cylinder is fitted; a first terminal, a second terminal and a third terminal are arranged on the wiring cover, wherein the first terminal and the second terminal are respectively connected to the two ends of the resistance wire, the third terminal is connected to one end of the conductive wire away from the sliding sleeve, and the other end of the conductive wire is connected to the conductive sliding sheet; the brush slip ring is simultaneously connected to the first terminal and the third terminal through a wire, and the second terminal is connected to the excitation coil through a wire; a sealing ring is also arranged between the extrusion slider and the side wall of the accommodating groove, and the sealing ring is sleeved on the extrusion slider and can move with the extrusion slider; A brush slip ring is also provided on the driving shaft. The brush slip ring connects a centrifugal resistor and an excitation coil in series through a group of conducting wires, and connects another centrifugal resistor and another excitation coil in series through another group of conducting wires.

2. The electromagnetic friction and centrifugal extrusion magnetorheological soft starting device according to claim 1 is characterized in that: A resistance wire holding cylinder is also provided on the inner side of the cylindrical shell, and the resistance wire is wound on the resistance wire holding cylinder. The sliding sleeve, the conductive sliding piece and the second return spring are all located on the inner side of the resistance wire holding cylinder, and the sliding sleeve is connected to the resistance wire holding cylinder in a sliding manner. A strip hole is provided on the side wall of the resistance wire holding cylinder at a position corresponding to the conductive sliding piece along its axial direction, and the two ends of the strip hole extend to the outer sides of the two ends of the resistance wire cylinder respectively. The conductive sliding piece can enter the strip hole and electrically contact the resistance wire during the movement of the sliding sleeve.

3. The electromagnetic friction and centrifugal extrusion magnetorheological soft starting device according to claim 1 is characterized in that: The conductive sliding piece is arc-shaped and protrudes toward the side wall of the cylindrical shell, and its outer side is used to contact the resistance wire; a retaining frame is also provided on the sliding sleeve, and the conductive sliding piece is fixed on the sliding sleeve through the retaining frame.

4. The electromagnetic friction and centrifugal extrusion magnetorheological soft starting device according to claim 1 is characterized in that: An oil filling hole is arranged on the driven outer cylinder at a position corresponding to the extrusion shoe, and an oil filling screw plug is installed in the oil filling hole.

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