Clutch and power gear shifting device

Abstract

The invention belongs to the technical field of magnetorheological transmission control, and particularly relates to a clutch and a power gear shifting device.The clutch comprises a shell, an input rotating shaft, an output rotating shaft and a connecting unit, and the input rotating shaft and the output rotating shaft are inserted into the two opposite side walls of the shell in a penetrating mode correspondingly; the connecting unit comprises an input connecting part, an output connecting part, magnetorheological fluid and a magnet exciting coil. The input connecting part comprises a rotating disc and a barrel, the rotating disc is fixedly arranged on the input rotating shaft in a sleeving mode, and the barrel is fixedly connected to the rotating disc. The output connecting part comprises a transmission seat, the transmission seat is fixedly connected with the output rotating shaft, an annular guide groove is formed in the side, facing the rotating disc, of the transmission seat, the barrel is inserted into the annular guide groove, and a fit clearance used for being filled with magnetorheological fluid is reserved between the barrel and the annular guide groove; the magnet exciting coil is wound on the transmission seat and used for being matched with the magnetorheological fluid through a magnetic field to achieve fixation and separation of the input rotating shaft and the output rotating shaft. According to the device, the response time is greatly shortened in the gear shifting and speed changing process, and the response lag phenomenon is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetorheological drive control, and particularly relates to a clutch and a power shift device. Background Art

[0002] At present, most non-road vehicles or construction machinery use traditional wet clutches for shift adjustment. In order to adapt to various working conditions during operation, frequent reverse shifting is required. For traditional wet clutches, a hydraulic control system usually needs to be equipped with a rotary joint and proportional valve components. Through the pressure action of the oil, the friction plates in the clutch are pressed against each other, thereby achieving power transmission. At the same time, by controlling the pressure of the oil, the engagement and separation of the clutch and the change in the magnitude of the transmitted power can be achieved. However, since the wet clutch mainly relies on mechanical transmission, in applications, if the return spring of the wet clutch is too soft, the pedal stroke is too large, the return oil hole of the clutch oil pump is blocked, and the clutch disc, pressure plate, and release bearing are worn, it will all cause the clutch to be sluggish, with a slow response speed and easy to produce a lag phenomenon. Moreover, this lag phenomenon is particularly obvious in high-speed rotating equipment.

[0003] In order to reduce the clutch response time and reduce the occurrence of lag phenomenon, magnetic powder clutches for non-road vehicles or construction machinery have emerged. The medium of the magnetic powder clutch is magnetic powder, and its working principle is based on the electromagnetic principle. When there is no current passing through the exciting coil, the magnetic powder in the working chamber is in a loose state. Under the action of the centrifugal force generated by the driving rotor, the magnetic powder is evenly thrown on the inner wall of the driving rotor, and there is no mutual force between the driving and driven rotors. The magnetic powder clutch is in a disengaged state and no torque is transmitted. When there is current passing through the exciting coil, a working magnetic flux is generated in the magnetic yoke, and the magnetic powder in the working chamber is connected in a chain shape along the magnetic flux direction (forming a magnetic powder chain). The magnetic powder clutch transmits torque by the friction force between the magnetic powder and the magnetic powder, and between the magnetic powder and the working surface, and the shear resistance between the magnetic powder chains. The magnetic powder clutch is in an engaged state. By controlling the current of the exciting coil, the state of the magnetic powder is changed, thereby achieving the transmission or cut-off of torque. Although the response speed is improved compared with traditional wet clutches, due to the fact that it takes a certain amount of time for the magnetic powder to form a magnetic chain and transmit torque, in the harsh working conditions of frequent shifting, the clutch will still be sluggish and produce a shift response lag phenomenon. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a clutch and a power shift device, which have excellent dynamic response and control performance, can effectively improve the reaction sensitivity of the clutch during the shift and speed change process, greatly shorten the response time, reduce the occurrence of response lag phenomenon, optimize the shift effect, and are convenient for adapting to the harsh working conditions of frequent shifting.

[0005] The technical solution of the present invention is as follows: A clutch includes a housing, an input rotating shaft, an output rotating shaft, and a connecting unit. The input rotating shaft and the output rotating shaft are respectively inserted through opposite side walls of the housing and are coaxial. The connecting unit is arranged inside the housing and is used to realize the fixation and separation of the input rotating shaft and the output rotating shaft; The connecting unit includes: An input connecting part, including a rotating disk and a cylinder body. The rotating disk is sleeved and fixed on the input rotating shaft, and the cylinder body is fixedly connected to the side of the rotating disk away from the input rotating shaft; An output connecting part, including a transmission seat. The transmission seat is fixedly connected to the output rotating shaft. An annular guide groove is formed on the side of the transmission seat facing the rotating disk. The cylinder body is inserted into the annular guide groove, and a fitting gap is reserved between the cylinder body and the annular guide groove; Magnetorheological fluid, filled in the fitting gap reserved between the cylinder body and the annular guide groove; An excitation coil, wound around the transmission seat. The excitation coil is used to apply the generated magnetic field to the magnetorheological fluid after applying current, so that the magnetorheological fluid undergoes the magnetorheological effect of solid-liquid conversion under the action of the magnetic field to realize the fixation and separation of the input rotating shaft and the output rotating shaft.

[0006] Preferably, the magnetorheological fluid is a suspension composed of magnetic particles and a carrier liquid, and the volume concentration of the magnetic particles is 20vol%-40vol%. The magnetic particles are composed of a composite of ferromagnetic particles and aerogel particles. The magnetic particles are composed of a composite of 6μm-10μm hollow iron oxide particles and aerogel particles filled in the hollow iron oxide particles.

[0007] Preferably, a plurality of the cylinder bodies and the annular guide grooves are provided in one-to-one correspondence. The plurality of cylinder bodies are all coaxial with the input rotating shaft, and the plurality of cylinder bodies are sleeved together. One end of the cylinder body is fixedly connected to the rotating disk, and the other end is respectively inserted into the corresponding annular guide groove on the transmission seat, and the fitting gaps reserved between adjacent two cylinder bodies and the annular guide grooves are communicated.

[0008] Preferably, a groove is further formed on the side of the transmission seat facing the rotating disk. The annular guide grooves are all formed on the bottom wall of the groove. The rotating disk is placed in the groove. A first filling gap is reserved between the side of the rotating disk facing the groove and the bottom wall of the groove. A left end cover is provided on the side of the rotating disk away from the groove. The left end cover is sleeved on the input rotating shaft and a second filling gap is provided between the left end cover and the rotating disk. The first filling gap, the second filling gap, and the fitting gaps between each cylinder body and the annular guide groove are communicated with each other to realize that the magnetorheological fluid surrounds the circumferences of the rotating disk and each cylinder body.

[0009] Preferably, a right end cover is further arranged inside the housing. The right end cover is sleeved at the connection part of the transmission seat and the output rotating shaft. The right end cover is attached to the side wall of the transmission seat and the two are detachably connected. An annular slot for placing an exciting coil is formed on one side of the transmission seat facing the right end cover, and the exciting coil is placed in the annular slot.

[0010] Preferably, the outside of the exciting coil is wrapped with a magnetic isolation coil frame composed of a left coil frame and a right coil frame. The magnetic isolation coil frame is an annular cavity structure embedded in the annular slot. The exciting coil is composed of copper wires wound on the left coil frame, and the exciting coil is located in the cavity of the magnetic isolation coil frame. Channels for the copper wires to pass through and be connected to an external power supply are successively formed on the left coil frame, the transmission shaft and the output rotating shaft.

[0011] Preferably, a thermal expansion compensation assembly is further arranged between the rotating disc and the transmission seat. The thermal expansion compensation assembly includes a sliding disc and a return spring. A sliding slot is formed on the bottom wall of the groove. The sliding slot communicates with the first filling gap. The sliding slot is a cylindrical structure coinciding with the axis of the output rotating shaft. The sliding disc is slidably connected in the sliding slot, and the sliding direction of the sliding disc is parallel to the axis of the output rotating shaft. The return spring is placed between the sliding disc and the bottom wall of the sliding slot, and a sealed setting is arranged between the sliding disc and the side wall of the sliding slot.

[0012] Preferably, a placing hole is formed on the bottom wall of the annular slot. The placing hole is located in the side wall between any two adjacent annular guide grooves, and a temperature sensor is installed in the placing hole.

[0013] Preferably, a cooling flow channel is arranged between the circumferences of the rotating disc and the transmission seat and the inner wall of the housing. The cooling flow channel is filled with a coolant. A coolant inlet and a coolant outlet are respectively formed on the housing for connecting with a pump body to realize the flow rate regulation of the coolant in the cooling flow channel.

[0014] Preferably, a power shift device includes a clutch as described in any one of the above, and further includes a motor and a shift gearbox. A single gear, a double gear, a reverse gear and a shift control assembly are arranged in the shift gearbox. The shift control assembly includes a clutch one and a clutch two. The clutch one is used to realize the transmission and separation between the motor and the double gear or the reverse gear, and the clutch two is used to realize the transmission and separation between the motor and the single gear.

[0015] Compared with the prior art, a clutch and a power shift device of the present invention have the following beneficial effects: The clutch of this device uses magnetorheological fluid as the transmission medium. Under the action of a magnetic field, the magnetorheological fluid can quickly transform between a liquid state and a quasi-solid state in milliseconds, with a fast response. Moreover, the energizing current required for the magnetorheological fluid is very small, usually between 0 and 3 A. The magnetorheological fluid can generate a large shear yield stress and output a large torque. Therefore, during the gear shifting process, by applying a current to the excitation coil, the magnetorheological fluid quickly changes from a liquid state to a quasi-solid state to realize the clamping of the transmission seat and the cylinder body, that is, to realize the connection between the output connecting part and the input connecting part. And by controlling the magnitude of the energizing current of the excitation coil, the torque of the magnetorheological fluid can be adjusted to realize the adjustment of the output torque, and then the gear shift is carried out. The adjustment range is wide, and the torque magnitude changes rapidly with the change of the current applied to the excitation coil, with a rapid response. When the current is removed, the magnetorheological fluid will quickly return to the liquid state, separating the input connecting part and the output connecting part. Therefore, in the above manner, it has excellent dynamic response and control performance, can effectively improve the reaction sensitivity of the clutch during the gear shifting and speed changing process, greatly shorten the response speed, reduce the generation of response lag phenomenon, optimize the gear shifting effect, and is convenient for adapting to the harsh working conditions of frequent gear shifting. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the transmission principle of the power shift transmission in the embodiment of the present invention; Figure 2 is a transmission principle diagram of clutch one or clutch two in the embodiment of the present invention; Figure 3 is a schematic structural diagram of clutch one or clutch two in the embodiment of the present invention; Figure 4 is a comparison diagram of the clutch temperature rise situations of cooling and natural cooling in the embodiment of the present invention; Figure 5 is a comparison schematic diagram of the structural forms of the excitation coil layout in the embodiment of the present invention, where 5(a) is an external type, 5(b) is an internal type, and 5(c) is a side-mounted type; Figure 6 is a schematic structural diagram of the thermal expansion compensation component in the embodiment of the present invention; Figure 7 is a schematic structural diagram of the input connecting part in the embodiment of the present invention; Figure 8 is a schematic structural diagram of the output connecting part in the embodiment of the present invention; Figure 9 is a schematic structural diagram of the magnetic induction intensity distribution and the magnetic field line direction in the embodiment of the present invention; Figure 10 is a comparison diagram of the output angular velocities of the liquid viscous speed regulation and the magnetorheological fluid speed regulation in the embodiment of the present invention; Figure 11 is a schematic system diagram of the magnetorheological fluid speed regulation in the embodiment of the present invention; Figure 12 In the embodiments of the present invention I-ω 2 Flow chart of relationship establishment

[0017] Explanation of reference numerals in the drawings: 1. Single gear position; 2. Double gear position; 3. Reverse gear; 4. Clutch one; 5. Clutch two; 6. Housing; 7. Input connection part; 71. Input rotating shaft; 72. Rotating disk; 73. Cylinder body; 8. Output connection part; 81. Output rotating shaft; 82. Driving seat; 83. Annular guide groove; 84. Excitation coil; 9. Magnetorheological fluid; 10. Driving shaft one; 11. Driving shaft two; 12. First filling gap; 13. Cooling flow channel; 14. Coolant inlet; 15. Coolant outlet; 16. Groove; 17. Left end cover; 18. Second filling gap; 19. Magnetorheological fluid input port; 20. Right end cover; 21. Annular slot hole; 22. Left coil holder; 23. Right coil holder; 24. Channel; 25. Thermal expansion compensation component; 251. Sliding disk; 252. Return spring; 26. Placing hole; 27. Temperature sensor Detailed implementation manners

[0018] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention

[0019] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the protection scope of the present invention

[0020] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention

[0021] See Figures 2 to 8As shown, in order to have excellent dynamic response and control performance, effectively improve the reaction sensitivity of the clutch during the gear shifting process, greatly shorten the response speed, reduce the occurrence of response lag, optimize the shifting effect, and facilitate adaptation to the harsh working conditions of frequent shifting. This embodiment provides a clutch. Specifically, the clutch includes a housing 6, an input rotating shaft 71, an output rotating shaft 81, and a connecting unit. The input rotating shaft 71 and the output rotating shaft 81 are coaxially arranged and respectively penetrate and are inserted on opposite side walls of the housing 6, and both the input rotating shaft 71 and the output rotating shaft 81 are rotatably connected to the side wall of the housing 6. The connecting unit is arranged inside the housing 6 and is used to realize the fixation and separation of the input rotating shaft 71 and the output rotating shaft 81. The connecting unit includes an input connecting part 7, an output connecting part 8, a magnetorheological fluid 9, and an excitation coil 84. The input connecting part 7 includes a rotating disk 72 and a cylinder body 73. The rotating disk 72 is sleeved and fixed on the input rotating shaft 71. Preferably, the rotating disk 72 is integrally formed with the input rotating shaft 71. The cylinder body 73 is fixedly connected to the side of the rotating disk 72 facing away from the input rotating shaft 71. Furthermore, the output connecting part 8 mainly includes a transmission seat 82. The transmission seat 82 is fixedly connected to the end of the output rotating shaft 81 facing the rotating disk 72, and a ring-shaped guide groove 83 for inserting and mating with the cylinder body 73 is formed on the side of the transmission seat 82 facing the rotating disk 72. The cylinder body 73 is inserted into the ring-shaped guide groove 83, and a fitting gap is reserved between the cylinder body 73 and the ring-shaped guide groove 83. The magnetorheological fluid 9 is filled in the fitting gap reserved between the cylinder body 73 and the ring-shaped guide groove 83, and the excitation coil 84 is wound around the transmission seat 82. The excitation coil 84 is used to apply the generated magnetic field to the magnetorheological fluid 9 after applying current, so that the magnetorheological fluid 9 undergoes the magnetorheological effect of solid-liquid conversion under the action of the magnetic field, that is, the liquid-state magnetorheological fluid 9 is converted into a quasi-solid state, so that the cylinder body 73 and the ring-shaped guide groove 83 present an interference fit state, realizing the clamping of the cylinder body 73 and the transmission seat 82, so as to realize the fixation of the input rotating shaft 71 and the output rotating shaft 81. When the current of the excitation coil 84 is withdrawn, the magnetorheological fluid 9 immediately changes from a quasi-solid state to a liquid state, so that the cylinder body 73 and the transmission seat 82 rotate relative to each other, that is, indirectly realize the separation of the input rotating shaft 71 and the output rotating shaft 81. And in order to ensure uniform power transmission when the input rotating shaft 71 and the output rotating shaft 81 are fixed, the input rotating shaft 71, the cylinder body 73, the transmission seat 82, the ring-shaped guide groove 83, and the output rotating shaft 81 are all coaxially arranged.

[0022] Furthermore, in order to effectively shorten the response time of the solid-liquid conversion of the magnetorheological fluid 9 under the magnetic field of the excitation coil 84, the magnetorheological fluid 9 is a suspension composed of magnetic particles and a carrier liquid. And in order to maintain good magnetism, the volume concentration of the magnetic particles is 20 vol% - 40 vol%. Specifically, the magnetic particles are preferably composed of a composite of ferromagnetic particles and aerogel particles. The ferromagnetic particles are preferably hollow iron oxide particles with a micron scale (6 μm - 10 μm), and the aerogel particles are filled inside the hollow iron oxide particles. The ferromagnetic particles themselves have significant magnetic properties. When these particles are combined with the aerogel particles, the high porosity and low density characteristics of the aerogel can enhance the distribution and intensity of the magnetic field to a certain extent, thereby improving the overall magnetic performance. And the porous structure of the aerogel particles endows the composite material with excellent mechanical stability and chemical stability. This structure can not only effectively prevent the aggregation and sedimentation of the magnetic particles, but also improve the ability of the composite material to resist the influence of the external environment, such as temperature changes, humidity changes, etc. Thus, after an electric current is introduced into the excitation coil 84 to generate a magnetic field, under the action of the magnetic field, the magnetorheological fluid 9 can quickly transform between the liquid state and the quasi-solid state, with a time of milliseconds and a fast response.

[0023] See Figure 7 and Figure 8Furthermore, in order to enable the magnetorheological fluid 9 to respond quickly to complete the solid-liquid conversion under the magnetic field of the excitation coil 84, and to effectively ensure the transmission stability of the output shaft 81 and the input shaft 71, a plurality of cylinders 73 are provided one by one corresponding to the annular guide groove 83, and the plurality of cylinders 73 are coaxial with the input shaft 71, and the plurality of cylinders 73 are mutually fitted together, one end of the cylinder 73 is fixedly connected to the rotating disk 72, and the other end is respectively inserted into the corresponding annular guide groove 83 on the transmission seat 82, and the matching gaps reserved for two adjacent cylinders 73 and the annular guide groove 83 are communicated. In addition, a groove 16 is provided on the side of the transmission seat 82 facing the rotating disk 72, and the annular guide grooves 83 are all provided on the bottom wall of the groove 16. The rotating disk 72 is placed in the groove 16, and a first filling gap 12 is reserved between the side of the rotating disk 72 facing the groove 16 and the bottom wall of the groove 16. A left end cover 17 is provided on the side of the rotating disk 72 away from the groove 16. The left end cover 17 is mounted on the input shaft 71 and a second filling gap 18 is provided between the rotating disk 72. The edge of the left end cover 17 is also sealed with the transmission seat 82 and the two are detachably connected by bolts. The first filling gap 12, the second filling gap 18 and the matching gaps between each cylinder 73 and the annular guide groove 83 are connected to each other, so that the magnetorheological fluid 9 surrounds the rotating disk 72 and the peripheral side of each cylinder 73, and a magnetorheological fluid input port 19 is provided on the left end cover 17, which is opened when the magnetorheological fluid 9 needs to be filled and sealed after the filling is completed. Therefore, by increasing the number of cylinders 73 and annular guide grooves 83 and the cooperation of the first filling gap 12 and the second filling gap 18, the distribution area of ​​the magnetorheological fluid 9 can be greatly increased, so that the clamping effect between the transmission seat 82 and the cylinder 73 can be effectively increased in the magnetic field, and the torque is increased, thereby realizing stable transmission of the input shaft 71 and the output shaft 81.

[0024] See also Figure 3 and Figure 8, Further, in order to effectively shorten the response time of the solid-liquid conversion of the magnetorheological fluid under the magnetic field of the excitation coil 84, the excitation coil 84 is designed as follows: First, a right end cover 20 is arranged inside the housing 6. The right end cover 20 is sleeved at the connection of the transmission seat 82 and the output rotating shaft 81. The right end cover 20 is attached to the side wall of the transmission seat 82 and the two are detachably connected by bolts. A circular groove hole 21 for placing the excitation coil 84 is opened on one side of the transmission seat 82 facing the right end cover 20, and the excitation coil 84 is placed in the circular groove hole 21. The outside of the excitation coil 84 is wrapped with a magnetic isolation coil frame composed of a left coil frame 22 and a right coil frame 23. The magnetic isolation coil frame is an annular cavity structure embedded in the circular groove hole 21. The excitation coil 84 is integrally composed of copper wires wound on the left coil frame 22, and the excitation coil 84 is located in the cavity of the magnetic isolation coil frame. Channels 24 for the copper wires to pass through and connect to an external power supply are successively opened on the left coil frame 22, the transmission seat 82, and the output rotating shaft 81. A placement hole 26 is opened on the bottom wall of the circular groove hole 21. The placement hole 26 is located in the side wall between any two adjacent circular guide grooves 83. A temperature sensor 27 is installed in the placement hole 26 for real-time monitoring of the temperature in the working area of the magnetorheological fluid 9. As Figure 9 shown, the magnetic induction intensity distribution state of the excitation coil 84 under the action of the magnetorheological fluid 9 in practical applications.

[0025] Through the above design, the excitation coil 84 of this device adopts a side-mounted structure. Compared with the external and internal mounting methods, it can effectively improve the transmission efficiency, make the magnetic field act on the magnetorheological fluid to the greatest extent, and facilitate the rapid response of the magnetorheological fluid.

[0026] Refer to Figure 5 and Figure 9 shown, for the selection of the setting form of the excitation coil 84, the analysis is as follows: (1) For the external mounting method as Figure 5 shown in (a), the coil is in a stationary state, with a simple structure and easy replacement. It is far from the working space, which ensures reliability and is also conducive to heat dissipation in a timely manner. However, due to the existence of the air gap, the external mounting of the coil increases the magnetic resistance of the magnetic circuit, reduces the magnetic field strength in the working area, and results in low transmission efficiency.

[0027] (2) For the internal mounting method as Figure 5 shown in (b), the excitation coil 84 is installed inside the device, which can effectively save space and the device has little magnetic leakage. However, the compact layout is not conducive to heat dissipation, and it is not easy to troubleshoot when the coil fails.

[0028] (3) For the side-mounted method as Figure 5 shown in (c), the coil is located on one side of the transmission device. This layout makes the structure relatively compact and has high transmission efficiency.

[0029] The excitation coil 84 designed in this study is arranged in a side-mounted manner. The coil and the magnetic isolation coil holder are fixed on the drive seat 82, that is, connected to the output rotating shaft 81. As the output rotating shaft 81 rotates, power is supplied through a conductive slip ring, effectively improving the utilization rate of the coil.

[0030] During the working process, when a large amount of heat is generated by the magnetorheological fluid 9, the carrier liquid inside the magnetorheological fluid 9 undergoes thermal expansion, further forming local high pressure, damaging the seal of the magnetorheological fluid 9, causing leakage, and affecting the transmission performance of the clutch. See Figure 3 As shown, in order to ensure the normal solid-liquid conversion of the magnetorheological fluid under the action of the magnetic field and achieve the transmission performance between the input rotating shaft 71 and the output rotating shaft 81. A thermal expansion compensation component 25 is also provided between the rotating disc 72 and the drive seat 82. The thermal expansion compensation component 25 includes a sliding disc 251 and a return spring 252. A sliding groove is opened on the bottom wall of the groove 16, and the sliding groove communicates with the first filling gap 12. The sliding groove is a cylindrical structure coinciding with the axis of the output rotating shaft 81. The sliding disc 251 is slidably connected in the sliding groove, and the sliding direction of the sliding disc 251 is parallel to the axis of the output rotating shaft 81. The return spring 252 is placed between the sliding disc 251 and the bottom wall of the sliding groove, and a seal is provided between the sliding disc 251 and the side wall of the sliding groove. Therefore, a simple thermal expansion compensation component 25 is designed in this study as the thermal expansion compensation system of the magnetorheological fluid 9. When the magnetorheological fluid 9 undergoes thermal expansion, it squeezes the sliding disc 251 to compensate for the expansion space of the magnetorheological fluid 9. When the temperature is relatively low, the elastic force of the return spring 252 drives the sliding disc 251 to reset, ensuring the normal operation of the clutch. At the same time, in order to control the temperature of the working area of the magnetorheological fluid, a cooling channel 13 is provided between the circumferences of the rotating disc 72 and the drive seat 82 and the inner wall of the housing 6. The cooling channel 13 is hermetically arranged with the filling area of the magnetorheological fluid 9 and the installation part of the excitation coil 84. The cooling channel 13 is filled with a coolant. A coolant inlet 14 and a coolant outlet 15 are respectively opened on the housing 6 for connecting with a pump body to realize the flow regulation of the coolant in the cooling channel 13.

[0031] Based on the above clutch, its practical application in a power shift device is as follows: See Figures 1 to 8As shown in the figure, the power shift device includes a motor, a shift transmission, and an electronic control system. The electronic control system is the main integrator for jointly controlling the electrical appliances of the device. Inside the shift transmission, there are odd gears 1, even gears 2, reverse gear 3, and a shift control component. The shift control component is used to achieve the power switching between the motor and the odd gears 1, even gears 2, and reverse gear 3 respectively. The shift control component includes drive shaft 1 10, drive shaft 2 11, and two clutches (clutch 1 4, clutch 2 5). Specifically, one end of drive shaft 1 10 is used to connect to the odd gears 1, and the other end is connected to the output rotating shaft 81 of clutch 1 4; one end of drive shaft 2 11 is used to connect to the even gears 2 and reverse gear 3, and the other end is connected to the output rotating shaft 81 of clutch 2 5; the input rotating shafts 71 of clutch 1 4 and clutch 2 5 are both connected to the motor. Clutch 1 4 is used to achieve the transmission and separation between the motor and the even gears 2 or reverse gear 3; clutch 2 5 is used to achieve the transmission and separation between the motor and the odd gears 1.

[0032] In actual operation, clutch 1 4 and clutch 2 5 use magnetorheological fluid 9 as the transmission medium. Magnetorheological fluid 9 is a suspension formed by mixing magnetic particles and a carrier fluid. Under the action of a magnetic field, it can quickly transform between a liquid state and a quasi-solid state in milliseconds, with a fast response. Moreover, the energizing current of the clutch is very small, usually between 0 and 3 A. Then, magnetorheological fluid 9 can generate a large shear yield stress and output a large torque. Therefore, during the shift process, by applying a current to the excitation coil 84 arranged inside clutch 1 4 or clutch 2 5, magnetorheological fluid 9 quickly changes from a liquid state to a quasi-solid state, causing the transmission seat 82 to tightly hold the cylinder body 73, so as to achieve the fixed connection between the output rotating shaft 81 and the input rotating shaft 71. And by controlling the magnitude of the energizing current of the excitation coil 84, the torque of magnetorheological fluid 9 can be regulated to achieve the regulation of the output torque. Subsequently, under the combined action of the motor, input rotating shaft 71, and output rotating shaft 81, drive shaft 1 10 or drive shaft 2 11 is controlled to move, realizing the switching between the odd gears 1, even gears 2, and reverse gear 3. And the torque magnitude changes rapidly with the change of the current applied to the excitation coil 84. When the current is removed, magnetorheological fluid 9 will quickly return to the liquid state, separating the input part and the output part of the shaft, with a rapid response time. Therefore, through the above method, it has excellent dynamic response and control performance, can effectively improve the reaction sensitivity of the clutch during the shift speed change process, greatly shorten the response speed, reduce the generation of response lag phenomenon, optimize the shift effect, and is convenient to adapt to the harsh working conditions of frequent shifting.

[0033] The specific shift working principle is described as follows: Specifically, when applying a current I (the current I is between 0 amperes and 3 amperes) to the excitation coil 84, a magnetic field is generated. In the magnetic circuit, a magnetic induction intensity will be generated at the position of magnetorheological fluid 9 B ,B and I There is a linear correspondence, and the magnetorheological fluid 9 will exhibit a magnetorheological effect under the action of a magnetic field, manifested in that its viscosity and shear yield stress increase with the increase of B until saturation. The shear yield stress of the magnetorheological fluid 9 is proportional to the torque it can transmit. Therefore, to adjust the shifting torque, it can be achieved by adjusting the current of the excitation coil 84.

[0034] Since the magnetorheological fluid 9 is a suspension composed of magnetic particles and a carrier liquid, there is no mechanical friction during use, and the wear of transmission components is small. Under the action of a magnetic field, it can quickly transform between a liquid state and a quasi-solid state (the time is in the millisecond level, with fast response), and the process is controllable and reversible. The required energizing current is very small, usually between 0 and 3 A (low energy consumption), and the magnetorheological fluid 9 can generate a large shear yield stress, thereby outputting a large torque (wide adjustment range), and the torque size changes rapidly with the change of the applied current (simple control). When the current is removed, the magnetorheological fluid 9 will quickly return to the liquid state, separating the input and output shafts.

[0035] During the application process, according to the gear adjustment object, by applying current to the excitation coil 84 in the first clutch 4 or the second clutch 5, the magnetorheological fluid 9 quickly changes from the liquid state to the quasi-solid state to realize the connection of the output rotating shaft 81 and the input rotating shaft 71, and the torque size of the magnetorheological fluid 9 can be regulated by using the magnitude of the energizing current of the excitation coil 84 to realize the regulation of the output torque. Then, under the combined action of the motor, the input connection part 7, the output connection part 8, the input rotating shaft 71 and the output rotating shaft 81, the first drive shaft 10 or the second drive shaft 11 is controlled to move for gear shifting. When the current is removed, the magnetorheological fluid 9 will quickly return to the liquid state, enabling the cylinder body 73 and the annular guide groove 83 to rotate relative to each other, that is, realizing the separation of the input rotating shaft 71 and the output rotating shaft 82. Thus, the above method has excellent dynamic response and control performance, can effectively improve the reaction sensitivity of the clutch during the gear shifting process, greatly shorten the response speed, reduce the generation of response lag phenomenon, optimize the gear shifting effect, and is convenient for adapting to the harsh working conditions of frequent gear shifting.

[0036] See Figure 3 As shown, considering that the coolant has a large magnetic resistance and a low magnetic permeability, if there is an intersection with the magnetic circuit, it will seriously affect the magnitude of the magnetic induction intensity in the working area of the magnetorheological fluid 9. Therefore, the cooling channel 13 is arranged between the housing 6, the rotating disk 72 and the transmission seat 82, which can effectively isolate the influence of the coolant on the magnetic induction intensity in the working area of the magnetorheological fluid 9. Compared with the existing water-cooled structure, the cooling channel 13 designed in this study is simpler, does not interfere with the magnitude of the magnetic induction intensity in the working area of the magnetorheological fluid 9, and has a significantly improved cooling effect.

[0037] See Figure 4As shown, this study compares the temperature rise of the clutch with cooling and natural heat dissipation. As time goes by, the heat generated by the magnetorheological fluid 9 is transferred to the cooling channel 13 through various components for cooling and heat dissipation, and its heat generation and heat dissipation gradually reach equilibrium. In addition, temperature sensors 27 are attached to the working areas of clutch one 4 and clutch two 5 of this device, which can detect the temperature of the working area of the magnetorheological fluid 9 in real time. The flow rate of the coolant is controlled by a pump to forcibly cool the temperature of the magnetorheological fluid 9 to improve the working stability and reliability of the clutch.

[0038] See Figure 3 and Figure 6 As shown, further, a thermal expansion compensation component 25 is also provided between the rotating disk 72 and the transmission seat 82. The thermal expansion compensation component 25 serves as a thermal expansion compensation system for the magnetorheological fluid 9. When the magnetorheological fluid 9 undergoes thermal expansion, it squeezes the sliding disk 251 to compensate for the expansion space of the magnetorheological fluid 9. When the temperature is low, the elastic force of the return spring 252 drives the sliding disk 251 to reset to ensure the normal operation of the clutch.

[0039] To further clarify the advantages of the speed regulation of the magnetorheological fluid 9, the following verification analysis is carried out: As Figure 11 is the system schematic diagram for the speed regulation verification of the magnetorheological fluid 9. Its main part consists of a motor, a torque and speed sensor, a magnetorheological fluid clutch (i.e., clutch one 4 or clutch two 5 in this application), a working machine, an inverter, and a programmable current source. The motor provides the torque for the entire system, and the torque is transmitted to the working machine through the torque and speed sensor and the magnetorheological fluid 9 clutch to drive the working machine to work. Let the transmitted torque provided by the motor (the total input torque of the system) be T 1, the total frictional torque of the entire system be T f , the input and output angular velocities be ω 1 、ω 2 , and the load torque of the working machine be T L . From the system dynamics equation, it can be obtained that:

[0040] , (1) In the formula, J is the total rotational inertia at the output end of the system kg·m 2 (the sum of the rotational inertias of the output end of the magnetorheological fluid clutch, the coupling, and the input end of the working machine); = dω:dt is the output acceleration of the system rad / s 2 .

[0041] In Figure 11 , the total input torque TThe available torque can be measured by a torque speed sensor, and the excitation current can be displayed by a programmable current source. The input angular velocity ω is controlled by a frequency converter, while the output angular velocity ω is measured by a speed sensor.

[0042] According to Equation (1), if the total system output moment of inertia J , the input angular velocity ω 1, the total system friction torque T f and the working machine load torque T L are known, changing the excitation current I can change the transmitted torque T 1 input to the magnetorheological fluid clutch, thereby changing the system output acceleration dω:dt to achieve output angular velocity regulation.

[0043] If T 1 > T f + T L , then dω:dt > 0, and the system output is accelerating; If T 1 = T f + T L , then dω:dt = 0, and the system output is uniform; If T 1 < T f + T L , then dω:dt < 0, and the system output is decelerating.

[0044] I. Establishment of the Magnetorheological Fluid Speed Regulation Model and Analysis of Load Characteristics Establishment of the Magnetorheological Fluid Speed Regulation Model When discussing the speed regulation of magnetorheological fluids, the primary task is to establish an output angular velocity control model. Since the speed regulation of magnetorheological fluids uses the current passing through the excitation coil as the control variable, it is necessary to construct a relationship model of I-ω2 (excitation current - output angular velocity), and its basic construction model process is as Figure 12 shown.

[0045] (1) Magnetic Circuit Electromagnetics Calculation Kirchhoff's second law of the magnetic circuit expresses the relationship between the magnetic induction intensity B and the excitation current I as: , (2) In the formula, N is the number of turns of the excitation coil; S is the working area of the magnetorheological fluid, m 2 ; is the total magnetic reluctance of the magnetic circuit, H -1 .

[0046] It can be seen from Equation (2) that when other parameters remain unchanged, the magnetic induction intensity B is proportional to the excitation current I .

[0047] , (3) In the formula, τ magnetorheological fluid shear stress, kPa; τ B is the magneto-induced yield stress, kPa; is the shear strain rate of the magnetorheological fluid, s -1 ; η is the dynamic viscosity of the magnetorheological fluid, Pa·s.

[0048] According to Equation (3), we can get , (4) In the formula, L is the width (working length, m) of the housing in the magnetorheological fluid clutch along the axis of the input rotating shaft; r 1 、r 2 are the inner radius and outer radius (m) of the cylindrical housing respectively.

[0049] Before the soft magnetic particles of the magnetorheological fluid are completely magnetically saturated, its magneto-induced yield stress is expressed as: , (5) In the formula, B is the magnetic induction intensity; k , c are material parameters depending on the material properties of the magnetorheological fluid.

[0050] (2) Calculation of the shear strain rate of the magnetorheological fluid: , (6) In the formula, h is the thickness of the magnetorheological fluid (width of the first filling gap or the second filling gap), m; r is the gap radius (radius of the first filling gap or the second filling gap) of the filling area corresponding to the magnetorheological fluid in the housing, m.

[0051] By combining Equation (3) and Equation (5), the relationship between the magnetorheological fluid shear stress τ and the magnetic induction intensity B can be expressed as: , (7) (3) Transmission torque calculation model , (8) In the formula,[[]] n is the number of working areas,[[]] I is the exciting current (A) of the exciting coil,[[]] t is between 0 and 1.

[0052] By combining equations (5), (6), and (7) and substituting them into equation (8), the exciting current I and the output angular velocity ω 2 The relationship expression between them is:[[]] , (9) In the formula n is the number of working areas, taking n= 11.16. In equation (9), let

[0053] , (10) Equation (9) can be expressed as:[[]] , (11) Taking the Laplace transform of equation (11) gives:[[]] , (12) In the formula,[[]] s is the complex variable after Laplace transform, representing the complex frequency of the function,[[]] s = 0, 1, 2...

[0054] Set the initial condition ω 2(0) = 0, substituting it into equation (12) gives:[[]] , (13) (4) Establish the system dynamics equation, that is, the specific speed regulation model Furthermore, analyze the clutch speed regulation performance Constant torque load is a common load. Therefore, studying the clutch speed regulation performance under this load has important practical significance.

[0055] For this reason, evaluate the designed clutch and obtain the following parameters through normalization:[[]] r 1 = 61mm, r 2 = 62.5mm, L = 40mm, the thickness of the magnetorheological fluid h = 1.5mm, the number of working areas n = 11.16; The material parameters of the magnetorheological fluid are respectivelyc = 1.35 and k = 140 kPa, zero-field apparent viscosity η = 1.2 Pa·s; number of turns of the excitation coil N = 1200, total magnetic reluctance of the magnetic circuit = 45043.9 H -1 ; total moment of inertia is J = 0.12 kg·m 2 ; total frictional torque of the system is T f = 10 N·m, load torque of the working machine T L = 40 N·m.

[0056] Substitute the above given parameters into Equation (10), we get: , (14) Substitute Equation (14) into Equation (13), we can get: , (15) It is known that the total frictional torque of the system is T f = 10 N·m, load torque of the working machine T L = 40 N·m, respectively with the input angular velocity ω 1 = 800 r / min, the current of the excitation coil is 1 A, 1.5 A and 2 A. Taking several working conditions as the research objects, the output angular velocity response characteristics are explored. Since the input angular velocity of the magnetorheological fluid clutch is always greater than its output angular velocity, so when the input angular velocity is ω 1 = 800 r / min, the speed regulation models of the output angular velocity under three excitation currents are respectively:

[0057] I When 1 = 1.0 A, , (16) I 2 = When 1.5 A , (17) I When 3 = 2.0 A , (18) Similarly, it is known that the total frictional torque of the system is T f = 10 N·m, load torque of the working machine T L = 40 N·m, respectively and the current of the excitation coil is kept constant at I= 1.5 A, input angular velocity ω 1 is 500 r / min, 800 r / min and 1000 r / min. Taking several working conditions as the research objects, the output angular velocity response characteristics are explored. When the current I = 1.5 A, the speed regulation models of the output angular velocity corresponding to the three input angular velocities are respectively:

[0058] n 1 = 500 r / min , (19) n 2 = 800 r / min , (20) n 3 = 1000 r / min , (21) To sum up, since the speed regulation of magnetorheological fluid is realized based on its transmission principle, that is, the excitation current of the excitation coil controls the external magnetic field of the magnetorheological fluid to change the shear yield stress of the magnetorheological fluid, and then realizes the regulation of the output angular velocity. Compared with other speed regulation methods, magnetorheological fluid speed regulation has the following advantages:

[0059] (1) High speed regulation sensitivity and reversibility When the excitation current changes, the output angular velocity is immediately changed through the magnetorheological fluid. The response time is on the order of milliseconds. Compared with the response of liquid-viscous speed regulation, the speed regulation sensitivity of magnetorheological fluid is very high. Due to the reversibility of the magnetorheological effect, the application prospect of magnetorheological fluid speed regulation is wider.

[0060] (2) Approximate linear speed output After setting the output angular velocity as a fixed value, the comparison of the output characteristics of liquid-viscous speed regulation and magnetorheological fluid speed regulation is as Figure 10 shown. Under a constant torque load, as the output angular velocity increases, the torque of liquid-viscous speed regulation decreases, so the speed change rate decreases until it becomes zero and reaches the set speed; during the magnetorheological fluid speed regulation process, the torque is basically constant, so the acceleration is also basically unchanged, and the output angular velocity increases approximately linearly with time.

[0061] (3) Easy to control and low power consumption Magnetorheological fluid speed regulation is achieved by changing the excitation current. The excitation current is a control quantity provided by a steady current source. The steady current source is controlled by an external power supply, which is easy to implement and has low power consumption. Therefore, magnetorheological fluid speed regulation is a typical example of regulating high power with low power.

[0062] (4) Small wear of the speed regulation mechanism, stable and reliable The magnetorheological fluid works between the transmission surfaces, and realizes the speed setting by utilizing the characteristics of the magnetorheological fluid to change the shear yield stress. There is no direct contact between the components for speed regulation, and the wear is small; since the shear yield stress of the magnetorheological fluid is continuous, the speed regulation process is continuous, stable and reliable.

[0063] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A clutch, comprising a housing (6), an input rotating shaft (71), an output rotating shaft (81), and a connecting unit, wherein the input rotating shaft (71) and the output rotating shaft (81) are coaxial and respectively penetrate and are inserted into opposite side walls of the housing (6), and the connecting unit is arranged in the housing (6) for achieving the fixing and separation of the input rotating shaft (71) and the output rotating shaft (81), characterized in that: The connecting unit comprises: An input connection portion (7) comprises a rotating disk (72) and a cylinder (73), wherein the rotating disk (72) is sleeved and fixed on the input rotating shaft (71), and the cylinder (73) is fixedly connected to a side of the rotating disk (72) facing away from the input rotating shaft (71); The output connection portion (8) comprises a transmission seat (82), the transmission seat (82) being fixedly connected to the output rotating shaft (81), an annular guide groove (83) being formed on a side of the transmission seat (82) facing the rotating disk (72), the cylinder (73) being inserted into the annular guide groove (83), and a matching clearance being reserved between the cylinder (73) and the annular guide groove (83); A magnetorheological fluid (9) is filled in a matching gap reserved between the cylinder (73) and the annular guide groove (83); An excitation coil (84) is wound around the transmission seat (82). The excitation coil (84) is used to generate a magnetic field to act on the magnetorheological fluid (9) after applying current, so that the magnetorheological fluid (9) produces a magnetorheological effect of solid-liquid conversion under the action of the magnetic field, thereby achieving the fixing and separation of the input rotating shaft (71) and the output rotating shaft (81).

2. A clutch according to claim 1, characterized in that, The magnetorheological fluid (9) is a suspension formed by mixing magnetic particles and a carrier fluid, wherein the volume concentration of the magnetic particles is 20 vol%-40 vol%, and the magnetic particles are composited from 6 μm-10 μm ferroferric oxide hollow particles and aerogel particles filled in the ferroferric oxide hollow particles.

3. A clutch according to claim 1, wherein, A plurality of the cylinders (73) are arranged in one-to-one correspondence with the annular guide grooves (83), the plurality of the cylinders (73) are coaxial with the input rotating shaft (71), and the plurality of the cylinders (73) are mutually sleeved together, one end of the cylinder (73) is fixedly connected to the rotating disk (72), and the other end is respectively inserted into the corresponding annular guide grooves (83) on the transmission seat (82), and two adjacent cylinders (73) are communicated with the reserved matching gaps of the annular guide grooves (83).

4. A clutch according to claim 3, characterized in that, The transmission seat (82) is further provided with a groove (16) on the side facing the rotating disk (72), and the annular guide grooves (83) are all provided on the bottom wall of the groove (16). The rotating disk (72) is placed in the groove (16), and a first filling gap (12) is reserved between the side of the rotating disk (72) facing the groove (16) and the bottom wall of the groove (16). The rotating disk (72) is provided with a left end cover (17) on the side away from the groove (16). The left end cover (17) is sleeved on the input shaft (71) and a second filling gap (18) is provided between the left end cover (17) and the rotating disk (72). The first filling gap (12), the second filling gap (18) and the matching gaps between each of the cylinders (73) and the annular guide grooves (83) are interconnected, so that the magnetorheological fluid (9) surrounds the rotating disk (72) and the peripheral side of each cylinder (73).

5. A clutch according to claim 4, characterized in that, A right end cover (20) is further provided inside the housing (6). The right end cover (20) is sleeved on the connection between the transmission seat (82) and the output shaft (81). The right end cover (20) is in close contact with the side wall of the transmission seat (82) and the two are detachably connected. The transmission seat (82) is provided with an annular slot (21) for accommodating an excitation coil (84) on a side facing the right end cover (20). The excitation coil (84) is placed in the annular slot (21).

6. A clutch according to claim 5, wherein The excitation coil (84) is wrapped on the outside with a magnetic isolation coil frame composed of a left coil frame (22) and a right coil frame (23); the magnetic isolation coil frame is an annular cavity structure embedded in the annular slot (21); the excitation coil (84) is composed of a copper wire wound on the left coil frame (22); and the excitation coil (84) is located in the cavity of the magnetic isolation coil frame; the left coil frame (22), the transmission shaft and the output shaft (81) are respectively provided with channels (24) for the copper wire to pass through and connect to an external power source.

7. A clutch according to claim 4, wherein, A thermal expansion compensation component (25) is also provided between the rotating disk (72) and the transmission seat (82), and the thermal expansion compensation component (25) includes a sliding disk (251) and a reset spring (252). A sliding groove is provided on the bottom wall of the groove (16), and the sliding groove is connected to the first filling gap (12). The sliding groove is a cylindrical structure that coincides with the axis of the output shaft (81). The sliding disk (251) is slidably connected in the sliding groove, and the sliding direction of the sliding disk (251) is parallel to the axis of the output shaft (81). The reset spring (252) is placed between the sliding disk (251) and the bottom wall of the sliding groove, and a seal is provided between the sliding disk (251) and the side wall of the sliding groove.

8. A clutch according to claim 5, characterized in that, A placement hole (26) is provided on the bottom wall of the annular groove hole (21); the placement hole (26) is located in the side wall between any two adjacent annular guide grooves (83); and a temperature sensor (27) is installed in the placement hole (26).

9. A clutch according to claim 4, characterized in that, A cooling channel (13) is provided between the circumferences of the rotating disk (72) and the transmission seat (82) and the inner wall of the housing (6). The cooling channel (13) is filled with a coolant. A coolant inlet (14) and a coolant outlet (15) are respectively formed in the housing (6) and are used for connecting to a pump body to realize the flow rate control of the coolant in the cooling channel (13).

10. A power shift device, comprising a clutch according to any one of claims 1-9, characterized in that, It further includes a motor and a shift gearbox. A single gear (1), a double gear (2), a reverse gear (3) and a shift control assembly are arranged in the shift gearbox. The shift control assembly includes a first clutch (4) and a second clutch (5). The first clutch (4) is used to realize the transmission and separation between the motor and the double gear (2) or the reverse gear (3). The second clutch (5) is used to realize the transmission and separation between the motor and the single gear (1).

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