Magnetorheological clutch excited by double-layer rotary control type Halbach array permanent magnet

Abstract

The invention discloses a double-layer rotary control type Halbach array permanent magnet excitation magnetorheological clutch which comprises a control shaft, a cup-shaped rotor, a main shaft and an inner and outer annular circulation channel composed of an outer sleeve, an inner sleeve and the cup-shaped rotor, the channel is filled with magnetorheological fluid, and Halbach permanent magnet arrays are arranged on the inner side and the outer side of the inner and outer annular circulation channel respectively. During working, the double-layer Halbach array forms a strong magnetic field in the channel, so that the viscosity of the magnetorheological fluid is increased, and the transmission torque is increased; the control shaft is driven by the motor to rotate the inner layer array, the magnetic field intensity and direction synthesized in the channel can be dynamically changed, and therefore torque stepless regulation and clutch state switching are achieved. Compared with a traditional electromagnetic excitation mode, by means of the efficient magnetism gathering characteristic of the Halbach array, heating of the excitation device can be remarkably reduced, temperature rise of the magnetorheological fluid is reduced, and the Halbach array excitation device is particularly suitable for the working condition needing long-time stable operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of magnetorheological transmission, and particularly relates to a double-layer rotary control type Halbach array permanent magnet excited magnetorheological clutch. BACKGROUND

[0002] As a transmission device based on intelligent materials, the magnetorheological fluid clutch (MRFC) realizes torque control by adjusting the magnetic field to change the rheological properties of the magnetorheological fluid. Under the action of the magnetic field, the ferromagnetic particles in the magnetorheological fluid form a chain structure along the magnetic field direction in the flow passage. When the magnetic field direction is distributed along the radial direction of the rotor, the rotor can transmit torque, and at this time, the magnetorheological clutch is in the engaged state. When there is no magnetic field or the magnetic field direction is distributed along the tangential direction of the rotor, the rotor does not transmit torque, and at this time, the magnetorheological clutch is in the disengaged state. Therefore, by controlling the magnetic field distribution in the flow passage, the torque and rotational speed of the magnetorheological clutch can be steplessly adjusted. The magnetorheological clutch is one of the commonly used devices in the transmission field, and is commonly used in the fields of medical instruments, artificial joints and mechanical arms. Because of the characteristics of the magnetorheological fluid itself, the magnetorheological clutch has a fault self-protection function. When a mechanical system fails, the traditional clutch is damaged because the connecting part is stuck due to the sudden increase in torque, while the magnetorheological clutch has the function of overload safety protection because the ferromagnetic particles in the magnetorheological fluid can break and recombine continuously.

[0003] Chinese patent CN 114439863B discloses a high-stability large-torque magnetorheological fluid clutch. The patent increases the excitation magnetic field by connecting the permanent magnet and the electromagnet in series, and uses an electric push rod to push the input disc to make the magnetorheological fluid work in the shear-extrusion mode, thereby improving the maximum transmission torque of the magnetorheological fluid clutch. However, under the current thermal effect, the magnetic field excitation mode of the electromagnet used in the patent will continuously increase the temperature of the magnetorheological fluid in the flow passage, reduce the shear yield stress of the magnetorheological fluid, and further reduce the performance of the magnetorheological clutch.

[0004] Chinese patent CN202080078661X discloses a programmable magnetorheological fluid clutch device. The patent uses multiple coils as the magnetic field excitation device of the magnetorheological clutch, changes the amount of transmitted torque by changing at least one electromagnetic coil, and adjusts the torque transmission of the magnetorheological clutch by setting the desired residual magnetization level in the magnetic components of the magnetorheological clutch. However, the invention uses electromagnetic coils as the magnetic field excitation device, which will generate a large amount of heat under long-term operation, thereby reducing the working performance of the magnetorheological clutch. At the same time, setting the desired magnetization level to adjust the torque transmission cannot achieve large-range stepless adjustment of the transmitted torque.

[0005] A double-shear magnetorheological clutch under permanent magnetic excitation is disclosed in Chinese patent CN 2022100873267. The patent uses magnetorheological glue as a force transmission medium and permanent magnets based on Halbach arrays as the magnetic field excitation device of the clutch. A spring is connected to the permanent magnet sleeve in the inner cavity to control the relative position of the permanent magnet and the magnetorheological glue working channel to control the transmission torque of the magnetorheological clutch. The invention generates an excitation magnetic field through permanent magnets, effectively avoiding the thermal effect of the magnetorheological clutch during operation. However, the method of pushing the permanent magnet to control the transmission torque creates a large cavity in the inner cavity of the magnetorheological clutch, making the structure of the magnetorheological clutch not compact. This control method also makes the transmission torque and the relative position highly nonlinear, making it difficult to achieve stable control of the torque output of the magnetorheological clutch. SUMMARY

[0006] To solve the above problems, the purpose of the present application is to provide a double-layer rotary control Halbach array permanent magnet excitation magnetorheological clutch.

[0007] The present application uses inner and outer double-layer permanent magnets as magnet excitation for the flow channel, avoiding the current thermal effect under long-term operation. Based on the Halbach array, the magnetic field is concentrated in the flow channel, enhancing the transmission torque of the magnetorheological clutch. By rotating the inner permanent magnet, the direction of the magnetic field inside the flow channel is adjusted to achieve stepless adjustment of the transmission torque of the magnetorheological clutch and switching of the clutch state.

[0008] The specific technical solutions are as follows: A double-layer rotary control Halbach array permanent magnet excitation magnetorheological clutch, comprising a control shaft, an inner magnet support, and an inner annular permanent magnet. The keyway of the control shaft is connected to the inner magnet support, and the inner annular permanent magnet is clamped into the inner magnet support for fixation. An inner sleeve is sleeved on the outer side of the inner magnet support, and an outer sleeve is sleeved on the outer side of the inner sleeve. A cup-shaped rotor is arranged between the inner sleeve and the outer sleeve. The ends of the inner sleeve and the outer sleeve are respectively inserted into the annular grooves of the positioning plate located on the outer side of the control shaft for positioning. An annular inner flow channel is formed between the outer wall of the inner sleeve and the inner wall of the cup-shaped rotor, and an annular outer flow channel is formed between the inner wall of the outer sleeve and the outer wall of the cup-shaped rotor. An outer magnet support is arranged on the outer side of the outer sleeve, and an outer annular permanent magnet is clamped into the outer magnet support for fixation.

[0009] Further, one end of the cup-shaped rotor is connected to the main shaft through a screw, and the other end extends to the positioning plate and touches the inner wall of the positioning plate. Sealing elements are respectively arranged between the cup-shaped rotor and the inner sleeve, and between the cup-shaped rotor and the outer sleeve.

[0010] Further, a liquid inlet is formed on the outer sleeve, which communicates with the annular outer flow channel. A backflow port is formed on the cup-shaped rotor for communicating the annular inner flow channel and the annular outer flow channel.

[0011] Further, the inner sleeve end is provided with an inner locking ring, the inner wall of the inner locking ring is in contact with the inner magnet support, the outer wall of the inner locking ring is fixedly connected with the positioning plate through a screw, the outer sleeve end is provided with an outer locking ring, and the outer locking ring is fixedly connected with the outer magnet support through a screw.

[0012] Further, the outer side of the outer magnet support is provided with a cylinder for limiting the outer magnet support, the positioning plate is fixedly connected with the end cover through a screw, the control shaft passes through the center through hole of the end cover and is connected with the end cover through a bearing.

[0013] Further, the inner annular permanent magnet concentrates the magnetic field to the annular inner flow passage through a Halbach array permanent magnet arrangement mode, and the outer annular permanent magnet concentrates the magnetic field to the annular outer flow passage through a Halbach array permanent magnet arrangement mode.

[0014] Further, the width of the annular inner flow passage and the annular outer flow passage is 0.5mm-3mm respectively.

[0015] Further, the annular groove is provided with a sealing ring.

[0016] The beneficial effects of the present application are: 1) large transmission torque: the Halbach array permanent magnet arrangement arranged on the inner and outer magnets concentrates the magnetic field of the permanent magnet on the flow passage, greatly increases the shear stress of the magneto-rheological fluid, and improves the transmission torque of the magneto-rheological clutch.

[0017] 2) low temperature rise efficiency: by using permanent magnets instead of electromagnetic coils, the heat effect generated by the current is removed, so that the temperature rise of the magneto-rheological clutch is stable, and the transmission torque remains constant under long-time work.

[0018] 3) stepless adjustment of torque: the inner magnet is rotated by the rotating shaft, the magnetic field distribution applied to the flow passage is changed, the radial magnetic field applied to the magneto-rheological fluid is adjusted, and stepless adjustment of the transmission torque of the magneto-rheological clutch is realized.

[0019] 4) the structure and assembly of the present magneto-rheological clutch are simple, the magnetic field utilization efficiency is high, the magneto-rheological clutch has a fault self-protection function, and is suitable for the transmission field of long-time work. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a cross-sectional view of the present application; Figure 2 is an enlarged view of the details at A; Figure 3 is an enlarged view of the details at B; Figure 4The schematic diagram of the magnet arrangement of the inner and outer magnets in the combined state of the application; Figure 5 The schematic diagram of the magnet arrangement of the inner and outer magnets in the separated state of the application; Figure 6 The schematic diagram of the average radial magnetic flux density and the average tangential magnetic flux density of the flow channel of the application.

[0021] In the figure: 1, control shaft; 2, inner magnet support; 3, inner annular permanent magnet; 4, inner sleeve; 5, outer sleeve; 6, cup-shaped rotor; 7, positioning plate; 8, annular inner flow channel; 9, annular outer flow channel; 10, outer magnet support; 11, outer annular permanent magnet; 12, main shaft; 13, infusion port; 14, backflow port; 15, inner locking ring; 16, outer locking ring; 17, cylinder; 18, end cover. DETAILED DESCRIPTION

[0022] The application will be further described below in conjunction with the drawings of the specification, but the protection scope of the application is not limited to this.

[0023] As Figures 1 to 3As shown, a double-layer rotary control type Halbach array permanent magnet excited magneto-rheological clutch includes a control shaft 1, an inner magnet support 2, an inner annular permanent magnet 3, an inner sleeve 4, an outer sleeve 5, a cup-shaped rotor 6, a positioning plate 7, an outer magnet support 10, an outer annular permanent magnet 11, a main shaft 12, an inner locking ring 15, an outer locking ring 16, a cylinder 17 and an end cover 18. The key groove on the outer surface of the control shaft 1 is connected with the inner magnet support 2, the inner annular permanent magnet 3 is fixed in the inner magnet support 2, the outer side of the inner magnet support 2 is sleeved with the inner sleeve 4, the outer side of the inner sleeve 4 is sleeved with the outer sleeve 5, the cup-shaped rotor 6 is arranged between the inner sleeve 4 and the outer sleeve 5, one end of the cup-shaped rotor 6 is connected with the main shaft 12 through a screw, and the other end extends to the positioning plate 7 and touches the inner wall of the positioning plate 7, sealing elements are arranged between the cup-shaped rotor 6 and the inner sleeve 4 and between the cup-shaped rotor 6 and the outer sleeve 5, a bearing is arranged between the outer sleeve 5 and the main shaft 12, a bearing is arranged between the main shaft 12 and the cup-shaped rotor 6 and the inner sleeve 4, the ends of the inner sleeve 4 and the outer sleeve 5 are respectively inserted into the annular groove of the positioning plate 7 on the outer side of the control shaft 1 for positioning, a sealing ring is arranged in the annular groove, the inner locking ring 15 is arranged on the inner side of the end of the inner sleeve 4, the inner wall of the inner locking ring 15 touches the inner magnet support 2, the outer wall of the inner locking ring 15 is fixedly connected with the positioning plate 7 through a screw, the outer locking ring 16 is arranged on the outer side of the end of the outer sleeve 5, the outer locking ring 16 is fixedly connected with the outer magnet support 10 through a screw, and the outer annular permanent magnet 11 is prevented from rotating with the inner annular permanent magnet 3. The outer wall of the inner sleeve 4 and the inner wall of the cup-shaped rotor 6 form an annular inner flow channel 8, the inner wall of the outer sleeve 5 and the outer wall of the cup-shaped rotor 6 form an annular outer flow channel 9, the inner annular permanent magnet 3 concentrates the magnetic field to the annular inner flow channel 8 through the Halbach array permanent magnet arrangement mode, and the outer annular permanent magnet 11 concentrates the magnetic field to the annular outer flow channel 9 through the Halbach array permanent magnet arrangement mode. The outer sleeve 5 is provided with a liquid inlet 13, the liquid inlet 13 communicates with the annular outer flow channel 9, the cup-shaped rotor 6 is provided with four reflux inlets 14 which are uniformly distributed in the circumferential direction and are used for communicating the annular inner flow channel 8 and the annular outer flow channel 9, so as to ensure the flow of the magneto-rheological fluid in the annular inner flow channel 8 and the annular outer flow channel 9. The outer side of the outer sleeve 5 is provided with the outer magnet support 10, and the outer annular permanent magnet 11 is fixed in the outer magnet support 10. The outer side of the outer magnet support 10 is provided with the cylinder 17 for limiting the outer magnet support 10, the positioning plate 7 is fixedly connected with the end cover 18 through a screw, the control shaft 1 passes through the center through hole of the end cover 18 and is connected with the end cover 18 through a bearing.

[0024] The inner sleeve 4, the outer sleeve 5 and the cup-shaped rotor 6 are all made of aluminum alloy, so as to ensure that the magnetic induction lines of the annular inner flow passage 8 and the annular outer flow passage 9 can smoothly pass through without changing the direction of the magnetic field. The inner magnet support 2 and the outer magnet support 10 are made of plastic material by 3D printing, so as to avoid affecting the magnetic field distribution. The widths of the annular inner flow passage 8 and the annular outer flow passage 9 are respectively 0.5mm-3mm.

[0025] The working principle is as follows: The magnetorheological fluid enters the annular inner flow passage 8 and the annular outer flow passage 9 through the infusion port 13. The main shaft 12 is connected with the cup-shaped rotor 6 through a screw. The key groove of the main shaft 12 is used to connect the rotating workpiece. When the magnetorheological clutch needs to work with a specific transmission torque, the main shaft 12 drives the cup-shaped rotor 6 to rotate. The magnetorheological fluid in the annular inner flow passage 8 and the annular outer flow passage 9 forms a chain structure under the influence of the magnetic field applied by the inner annular permanent magnet 3 and the outer annular permanent magnet 11, thereby generating a yield stress. Therefore, the magnetorheological clutch generates a transmission torque. The inner magnet support 2 and the control shaft 1 are connected through a key. The inner annular permanent magnet 3 is inlaid in the inner magnet support 2. The control shaft 1 is connected with the rotating workpiece. When the magnetorheological clutch needs to perform stepless speed regulation and clutch state switching, the control shaft 1 drives the inner magnet support 2 to rotate, thereby driving the inner annular permanent magnet 3 to rotate. At this time, the direction of the magnetic field inside the annular inner flow passage 8 and the annular outer flow passage 9 changes from the circumferential radial direction to the tangential direction. At this time, the direction of the chain structure formed by the ferromagnetic particles of the magnetorheological fluid inside the annular inner flow passage 8 and the annular outer flow passage 9 also changes. The transmission torque of the magnetorheological clutch decreases, and the switching from the engaged state Figure 4 to the disengaged state Figure 5 is completed. The permanent magnet is used as the excitation device of the magnetorheological clutch, which avoids the heat effect generated by the electromagnetic coil, greatly reduces the temperature rise of the flow passage, and realizes the long-time stable working effect of the magnetorheological clutch.

[0026] As Figure 6As shown, in this embodiment, the magnetic field in the annular inner flow channel 8 and the annular outer flow channel 9 is simulated and analyzed by using COMSOL finite element simulation software, and the inner annular permanent magnet 3 and the outer annular permanent magnet 11 are respectively arranged in the form of 4 groups of Halbach array, when the magneto-rheological clutch needs to be steplessly adjusted in transmission torque and switched in clutching state, the inner annular permanent magnet 3 is rotated by the control shaft 1, at this time, the direction of the magnetic field in the annular inner flow channel 8 and the annular outer flow channel 9 is changed from the radial direction along the circumference of the annular inner flow channel 8 and the annular outer flow channel 9 to the tangential direction, at this time, the direction of the chain-like structure formed by the ferromagnetic particles of the magneto-rheological fluid in the annular inner flow channel 8 and the annular outer flow channel 9 is also changed, the switching from the engaged state to the disengaged state of the magneto-rheological clutch is completed, and the control shaft 1 only needs to be rotated by 45 degrees to complete the switching of the clutching state.

Claims

1. A dual layer, spin-controlled Halbach array, permanent magnet excited magneto-rheological clutch, characterized in that, It includes control shaft (1), inner magnet support (2) and inner annular permanent magnet (3), the key groove of control shaft (1) is connected with inner magnet support (2), inner annular permanent magnet (3) is fixed by being inserted into inner magnet support (2), the outside of inner magnet support (2) is equipped with inner sleeve (4), the outside of inner sleeve (4) is equipped with outer sleeve (5), cup-shaped rotor (6) is arranged between inner sleeve (4) and outer sleeve (5), the end of inner sleeve (4) and outer sleeve (5) is inserted into annular groove of positioning plate (7) located at the outside of control shaft (1) to be positioned, annular inner flow passage (8) is formed between the outer wall of inner sleeve (4) and the inner wall of cup-shaped rotor (6), annular outer flow passage (9) is formed between the inner wall of outer sleeve (5) and the outer wall of cup-shaped rotor (6), outer magnet support (10) is arranged at the outside of outer sleeve (5), outer annular permanent magnet (11) is fixed by being inserted into outer magnet support (10).

2. A dual layer spin control Halbach array permanent magnet excited magneto-rheological clutch as claimed in claim 1, wherein, One end of cup-shaped rotor (6) is connected with main shaft (12) through screw, the other end extends to positioning plate (7) and touches the inner wall of positioning plate (7), sealing element is arranged between cup-shaped rotor (6) and inner sleeve (4) and between cup-shaped rotor (6) and outer sleeve (5) respectively.

3. A dual layer spin control Halbach array permanent magnet excited magneto-rheological clutch as claimed in claim 1, wherein, Infusion port (13) is formed on outer sleeve (5) and communicates with annular outer flow passage (9), reflux port (14) is formed on cup-shaped rotor (6) and is used for communicating annular inner flow passage (8) and annular outer flow passage (9).

4. A dual layer spin control Halbach array permanent magnet excited magneto-rheological clutch as claimed in claim 1 wherein, Inner lock ring (15) is arranged at the inside of the end of inner sleeve (4), the inner wall of inner lock ring (15) touches inner magnet support (2), the outer wall of inner lock ring (15) is fixedly connected with positioning plate (7) through screw, outer lock ring (16) is arranged at the outside of the end of outer sleeve (5) and is fixedly connected with outer magnet support (10) through screw.

5. A dual layer, spin-controlled Halbach array, magnetorheological clutch as claimed in claim 4, wherein, Cylinder (17) is arranged at the outside of outer magnet support (10) and is used for limiting outer magnet support (10), positioning plate (7) is fixedly connected with end cover (18) through screw, control shaft (1) passes through the center through hole of end cover (18) and is connected with end cover (18) through bearing.

6. A dual layer spin control Halbach array permanent magnet energized magneto-rheological clutch as claimed in claim 1, wherein, Inner annular permanent magnet (3) concentrates magnetic field at annular inner flow passage (8) through Halbach array permanent magnet arrangement, outer annular permanent magnet (11) concentrates magnetic field at annular outer flow passage (9) through Halbach array permanent magnet arrangement.

7. A dual layer spin control Halbach array permanent magnet energized magneto-rheological clutch as claimed in claim 1 wherein, The width of annular inner flow passage (8) and annular outer flow passage (9) is 0.5mm-3mm respectively.

8. A dual layer spin control Halbach array permanent magnet energized magneto-rheological clutch as claimed in claim 1, wherein, Sealing ring is arranged in annular groove.

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