Magnetorheological fluid mechanical property testing device in extrusion-shearing composite mode

Abstract

The invention discloses a magnetorheological fluid mechanical property testing device in an extrusion-shearing composite mode, which comprises a base, a plurality of support columns are arranged on the upper surface of the base, the plurality of support columns are in sliding fit with a driving plate together, a driven plate is fixedly connected below the driving plate, and a top plate is arranged at the tops of the support columns; an extrusion motor is installed on the top plate, a driving shaft of the extrusion motor is fixedly connected with a lead screw, and a threaded hole matched with the lead screw is formed in the driving plate; a shearing motor is installed on the driving plate, an output shaft of the shearing motor is connected with a torque rotating speed sensor, the torque rotating speed sensor is installed on the driven plate and connected with a transmission shaft, and the bottom of the transmission shaft is connected with a shearing mechanism. Through the synergistic effect of the extrusion motor and the shearing motor, the mechanical property test of the magnetorheological fluid under extrusion-shearing compounding is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetorheological fluid testing equipment, and in particular relates to a device for testing the performance of magnetorheological fluid in an extrusion-shearing composite mode. Background Art

[0002] Magnetorheological fluid is a new type of intelligent material with controllable fluidity. It is mainly composed of magnetic materials, base carrier fluid and additives. In the absence of an external magnetic field, magnetorheological fluid exhibits the characteristics of free-flowing Newtonian fluid. Under the action of an external magnetic field, it instantly transforms from a low-viscosity Newtonian fluid to a semi-solid or solid. The moment the magnetic field is removed, it can quickly return to a low-viscosity Newtonian fluid. This transformation from liquid to solid is characterized by rapid change, controllable degree and reversible process.

[0003] In the shear mode, there are gaps between the particle chains of magnetorheological fluid, and the particle chains are easy to break, resulting in a low yield stress. By introducing the extrusion strengthening effect, the particles of the magnetorheological fluid form a dense microstructure in the extrusion-shear composite mode, which can increase the yield stress of the magnetorheological fluid. Therefore, a device is needed to test the mechanical properties of magnetorheological fluid in the extrusion-shear composite mode. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of low yield stress of magnetorheological fluid in the above-mentioned background technology by adding an extrusion motor and a shearing motor.

[0005] The specific technical solutions of the present invention are as follows: A device for testing the mechanical properties of magnetorheological fluid under an extrusion-shear composite mode comprises a base, wherein a plurality of support columns are provided on the upper surface of the base, wherein the plurality of support columns are slidably matched with an active plate, wherein a driven plate is fixedly connected below the active plate, and a top plate is provided on the top of the support columns; an extrusion motor is mounted on the top plate, wherein a screw rod is fixedly connected to the driving shaft of the extrusion motor, and a threaded hole matched with the screw rod is provided on the active plate; a shearing motor is mounted on the active plate, wherein a torque speed sensor is connected to the output shaft of the shearing motor, wherein the torque speed sensor is mounted on the driven plate, wherein the torque speed sensor is connected to a transmission shaft, and a shearing mechanism is connected to the bottom of the transmission shaft.

[0006] Furthermore, the shearing mechanism includes an upper magnetic core 1, the top of the upper magnetic core 1 is connected to an upper magnetic core 2 by a fastener, a lower magnetic core 1 is provided below the upper magnetic core 1, the bottom of the lower magnetic core 1 is connected to a lower magnetic core 2 by a fastening screw, an external fixing sleeve of the lower magnetic core 1 is provided with a magnetic isolation ring, the outer facade of the magnetic isolation ring is circumferentially connected to a coil bracket, a coil is fixedly provided on the upper surface of the coil bracket, the coil is connected to a programmable power supply and a Hall sensor, and a groove is provided at the bottom of the lower magnetic core 2, a pressure sensor is placed in the groove.

[0007] Furthermore, the output shaft of the shearing motor is connected to the torque speed sensor through a coupling, the torque speed sensor is key-connected to the transmission shaft, and the transmission shaft is connected to the second upper magnetic core.

[0008] Furthermore, the shearing mechanism is provided with a magnetic circuit outer wall, a magnetic circuit upper plate is provided on the top of the magnetic circuit outer wall, and a magnetic circuit bottom plate is provided on the bottom, and the magnetic circuit bottom plate is mounted on the upper surface of the base through fasteners.

[0009] Furthermore, a connection plate is key-connected to the bottom of the transmission shaft, the connection plate is connected to the upper plate of the magnetic circuit through a ball bearing, and the connection plate is connected to the upper magnetic core 2 through a fastener.

[0010] Furthermore, a plurality of limiting grooves are provided on the lower surface of the lower magnetic core 1, and a limiting block matched with the limiting grooves is provided on the upper surface of the lower magnetic core 2.

[0011] Furthermore, a positioning groove is provided on the outer facade of the magnetic isolation ring, and a positioning block is provided on the coil support for use with the positioning groove.

[0012] Furthermore, the shear motor is fixedly mounted on the upper surface of the active plate, the torque speed sensor is fixedly mounted on the upper surface of the driven plate, a flange is provided on the lower surface of the driven plate, the flange is connected to the transmission shaft through a combined bearing, and the lower surface of the active plate and the upper surface of the driven plate are commonly connected with several connecting rods.

[0013] Furthermore, a plurality of flange bearings are respectively installed on the active plate and the driven plate, and the flange bearings are sleeved on the support column.

[0014] Furthermore, a hydraulic support rod is connected between the top plate and the driven plate.

[0015] Compared with the prior art, the present invention has the following beneficial effects: During the detection, the magnetorheological fluid is added into the gap between the upper magnetic core 1 and the lower magnetic core 1, and the extrusion motor is turned on. The extrusion motor drives the active plate to descend through the screw rod, and then controls the shear motor to descend slowly. When the pressure measured by the pressure sensor reaches the set value, the extrusion motor stops, the coil is energized, and the magnetic field size is detected by the Hall sensor. When the magnetic field reaches the set value, the programmable power supply controls the current to remain unchanged. At this time, the shear motor is turned on, and the torque speed sensor detects the speed and torque of the shear motor in real time. The device has a simple structure and is easy to operate, and can measure the yield stress of the magnetorheological fluid under the combined action of different extrusion forces, shear rates and currents. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A front view of an embodiment of the present invention; Figure 2 A partial cross-sectional view of an embodiment of the present invention; Figure 3 is a cross-sectional view of a shearing mechanism in an embodiment of the present invention; Figure 4 is a flow chart of the measurement system of the present invention; Reference numerals: 1. Base; 11. Support column; 12. Driven plate; 13. Active plate; 131. Threaded hole; 14. Top plate; 15. Connecting rod; 16. Flange bearing; 17. Flange; 18. Combined bearing; 19. Caster; 2. Extrusion motor; 21. Screw rod; 3. Shearing motor; 31. Torque speed sensor; 32. Transmission shaft; 33. Coupling; 34. Connecting plate; 35. Ball bearing; 4. Shear mechanism; 41. Upper magnetic core 1; 411. Upper magnetic core 2; 42. Lower magnetic core 1; 421. Lower magnetic core 2; 43. Fastening screws; 44. Magnetic isolation ring; 45. Coil bracket; 451. Coil; 46. Pressure sensor; 47. Magnetic circuit outer wall; 48. Magnetic circuit upper plate; 49. Magnetic circuit bottom plate; 5. Hydraulic struts. DETAILED DESCRIPTION

[0017] In order to better understand the purpose, structure and function of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0018] See also Figures 1 to 4The present embodiment discloses a device for testing the mechanical properties of a magnetorheological fluid under an extrusion-shear composite mode, comprising a base 1, the upper surface of the base 1 being rectangular, the upper surface of the base 1 being provided with a plurality of support columns 11, in the present embodiment, there are four support columns 11, which are respectively close to the four corners of the base 1, so that the structure of the entire device is more stable, the active plate 13 is provided with a sliding hole matched with the support column 11, the four support columns 11 are slidably matched with the active plate 13 through the four sliding holes, a driven plate 12 is fixedly connected below the active plate 13, when the active plate 13 moves up and down, it will drive the driven plate 12 to move up and down synchronously, a top plate 14 is provided on the top of the support column 11; an extrusion motor 2 is installed on the top plate 14, the driving shaft of the extrusion motor 2 is fixedly connected with a screw 21, and a screw 21 is provided on the active plate 13 The threaded hole 131 adapted to the screw rod 21, when the driving shaft of the extrusion motor 2 drives the screw rod 21 to rotate, the active plate 13 will move up and down through the threaded connection with the screw rod 21 through the threaded hole 131; a shearing motor 3 is installed on the active plate 13. In this embodiment, the shearing motor 3 is a stepping motor, which can provide high torque at low speed and can achieve high-precision position and speed control. The output shaft of the shearing motor 3 is connected to a torque speed sensor 31, and the torque speed sensor 31 can directly measure the torque of the motor to ensure the accuracy of the test. The torque speed sensor 31 is installed on the driven plate 12, and the torque speed sensor 31 is connected to a transmission shaft 32. The bottom of the transmission shaft 32 is connected to a shear mechanism 4, and the shear yield stress of the magnetorheological fluid is transmitted to the torque speed sensor 31 by the shear mechanism 4.

[0019] The shear mechanism 4 includes an upper magnetic core 41, the top of the upper magnetic core 41 is connected to an upper magnetic core 411 by a fastener, a lower magnetic core 42 is provided below the upper magnetic core 41, the bottom of the lower magnetic core 42 is connected to a lower magnetic core 421 by a fastening screw 43, and an outer fixed sleeve of the lower magnetic core 42 is provided with a magnetic isolation ring 44. In this embodiment, a circular array at the bottom of the magnetic isolation ring 44 has several threaded assembly holes, and a through hole adapted to the threaded assembly hole is provided at the bottom of the lower magnetic core 42. The lower magnetic core 42 is fixed to the magnetic core 42 by a fastening screw 43. The magnetic isolation ring 44 is fixedly installed together by the cooperation of threaded fasteners and threaded assembly holes. The outer facade of the magnetic isolation ring 44 is circumferentially connected to a coil bracket 45. A coil 451 is fixedly provided on the upper surface of the coil bracket 45. The coil 451 is connected to a programmable power supply and a Hall sensor. The current is slowly increased by the programmable power supply, and the Hall sensor detects the size of the magnetic field. After the magnetic field meets the set value, the programmable power supply controls the current to remain unchanged. A groove is provided at the bottom of the lower magnetic core 421, and a pressure sensor 46 is placed in the groove.

[0020] The output shaft of the shearing motor 3 is connected to the torque speed sensor 31 through a coupling 33. The coupling 33 can compensate for the centering error and can efficiently transmit the torque. The torque speed sensor 31 is key-connected to the transmission shaft 32. The key connection can effectively transmit a larger torque and is easy to install and disassemble. The transmission shaft 32 is fixedly connected to the upper magnetic core 411.

[0021] The shearing mechanism 4 is provided with a magnetic circuit outer wall 47, the top of the magnetic circuit outer wall 47 is provided with a magnetic circuit upper plate 48, and the bottom is provided with a magnetic circuit bottom plate 49, and the magnetic circuit bottom plate 49 is installed on the upper surface of the base 1 through fasteners. When the extrusion motor 2 applies an extrusion force to the upper magnetic core 1 41, the extrusion force is applied to the magnetorheological fluid and transmitted to the lower magnetic core 1 42 through the magnetorheological fluid. The lower magnetic core 1 42 transmits the extrusion force to the pressure sensor 46 through the lower magnetic core 2 421. The pressure sensor 46 is squeezed from the lower surface of the lower magnetic core 2 421 and the upper surface of the magnetic circuit bottom plate 49, thereby detecting the extrusion force applied by the extrusion motor 2 on the magnetorheological fluid.

[0022] The transmission shaft 32 is keyed at the bottom with a connecting plate 34, which is connected to the magnetic circuit upper plate 48 via a ball bearing 35. The ball bearing 35 can withstand a high rotation speed without generating excessive heat or wear. The connecting plate 34 is connected to the upper magnetic core 2 411 via fasteners, and the rotation of the connecting plate 34 drives the upper magnetic core 2 411 to rotate.

[0023] The lower surface of the lower magnetic core 1 42 is provided with a plurality of limit grooves, and the upper surface of the lower magnetic core 2 421 is provided with limit blocks matched with the limit grooves. Through the cooperation between the limit grooves and the limit blocks, the lower magnetic core 1 42 and the lower magnetic core 2 421 are connected more firmly, avoiding the problem of inaccurate monitoring data caused by the shear force applied by the shear motor 3, which causes the lower magnetic core 1 42 and the lower magnetic core 2 421 to move relative to each other.

[0024] The outer surface of the magnetic isolation ring 44 is provided with a positioning groove, and the coil bracket 45 is provided with a positioning block matched with the positioning groove. Through the cooperation of the positioning groove and the positioning block, the coil bracket 45 is sleeved on the outside of the magnetic isolation ring 44 and connected to the magnetic isolation ring 44, and is easy to disassemble.

[0025] The shearing motor 3 is fixedly mounted on the upper surface of the active plate 13, the torque speed sensor 31 is fixedly mounted on the upper surface of the driven plate 12, a flange 17 is provided on the lower surface of the driven plate 12, the flange 17 is connected to the transmission shaft 32 via a combined bearing 18, the combined bearing 18 can reduce the friction between the transmission shaft 32 and the flange 17, reduce energy loss, improve the efficiency of the shearing motor 3, and ensure the coaxiality of the transmission shaft 32 and the output shaft of the shearing motor 3, the lower surface of the active plate 13 and the upper surface of the driven plate 12 are commonly connected with a plurality of connecting rods 15, and the active plate 13 drives the driven plate 12 to move up and down through the connecting rods 15.

[0026] Several flange bearings 16 are respectively installed on the active plate 13 and the driven plate 12, and the flange bearings 16 are sleeved on the support column 11. Through the sliding cooperation between the flange bearings 16 and the support column 11, the active plate 13 and the driven plate 12 can move more smoothly when moving up and down, and the verticality of the movement is guaranteed, so that the extrusion force applied by the extrusion motor 2 to the magnetorheological fluid is more evenly distributed.

[0027] A hydraulic strut is connected between the top plate and the driven plate, a hydraulic strut 5 is fixedly installed on the lower surface of the top plate 14, a through hole is provided on the active plate 13, the other end of the hydraulic strut 5 passes through the through hole and is fixedly connected to the upper surface of the driven plate 12, the hydraulic strut 5 can effectively absorb external vibrations and reduce the influence of external factors on the test results, and when the extrusion motor 2 drives the driven plate 12 to move up and down, the hydraulic strut 5 can provide damping, making the up and down movement smoother and ensuring the verticality of the movement, further making the extrusion force applied by the extrusion motor 2 to the magnetorheological fluid more evenly distributed, thereby improving the accuracy of the test results.

[0028] The lower surface of the base 1 is provided with a caster 19. In this embodiment, the caster 19 may be a Fomar wheel. As a supporting and moving tool, the Fomar wheel has the characteristics of stability, shock absorption and flexibility.

[0029] Working principle: During detection, the magnetorheological fluid is added into the gap between the upper magnetic core 41 and the lower magnetic core 42, and the extrusion motor 2 is turned on. The extrusion motor 2 drives the active plate 13 to descend through the screw 21, thereby controlling the shear motor 3 to descend slowly, and the upper magnetic core 41 is introduced into the shear mechanism 4, and the magnetorheological fluid in the gap is squeezed through the upper magnetic core 41 and the lower magnetic core 42. When the pressure measured by the pressure sensor 46 reaches the set value, the extrusion motor 2 stops, and the coil 451 is energized to generate a magnetic field, causing the magnetorheological fluid to generate shear yield stress. The size of the magnetic field is detected by the Hall sensor. When the magnetic field reaches the predetermined value, the programmable power supply controls the current to remain unchanged. At this time, the shear motor 3 is turned on to drive the upper magnetic core 41 to rotate relative to the lower magnetic core 42. The speed and torque of the shear motor 3 are monitored in real time through the torque speed sensor 31. The device has a simple structure and is easy to operate, and can measure the yield stress of the magnetorheological fluid under the combined action of different extrusion forces, shear rates and currents.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A device for testing the mechanical properties of magnetorheological fluid under extrusion-shear composite mode, characterized in that: The invention comprises a base (1), wherein a plurality of support columns (11) are provided on the upper surface of the base (1), wherein the plurality of support columns (11) are slidably matched with an active plate (13), wherein a driven plate (12) is fixedly connected to the lower side of the active plate (13), and a top plate (14) is provided on the top of the support column (11); an extrusion motor (2) is mounted on the top plate (14), wherein a screw rod (21) is fixedly connected to the driving shaft of the extrusion motor (2), and a threaded hole (131) adapted to the screw rod (21) is provided on the active plate (13); a shearing motor (3) is mounted on the active plate (13), wherein the output shaft of the shearing motor (3) is connected to a torque speed sensor (31), wherein the torque speed sensor (31) is mounted on the driven plate (12), wherein the torque speed sensor (31) is connected to a transmission shaft (32), and wherein a shearing mechanism (4) is connected to the bottom of the transmission shaft (32).

2. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 1 is characterized in that: The shearing mechanism (4) comprises an upper magnetic core (41), the top of the upper magnetic core (41) is connected to an upper magnetic core (411) via a fastening bolt, a lower magnetic core (42) is provided below the upper magnetic core (41), the bottom of the lower magnetic core (42) is connected to a lower magnetic core (421) via a fastening bolt, a magnetic isolation ring (44) is provided on an external fixing sleeve of the lower magnetic core (42), a coil bracket (45) is connected to the outer facade of the magnetic isolation ring (44), a coil (451) is fixedly provided on the upper surface of the coil bracket (45), the coil (451) is connected to a programmable power supply and a Hall sensor, and a groove is provided at the bottom of the lower magnetic core (421), a pressure sensor (46) is placed in the groove.

3. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 2 is characterized in that: The output shaft of the shearing motor (3) is connected to the torque speed sensor (31) via a coupling (33), the torque speed sensor (31) is connected to the transmission shaft (32), and the transmission shaft (32) is connected to the second upper magnetic core (411).

4. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 3 is characterized in that: The shearing mechanism (4) is provided with a magnetic circuit outer wall (47), the top of the magnetic circuit outer wall (47) is provided with a magnetic circuit upper plate (48), and the bottom is provided with a magnetic circuit bottom plate (49), and the magnetic circuit bottom plate (49) is mounted on the upper surface of the base (1) by fastening bolts.

5. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 4, characterized in that: The bottom of the transmission shaft (32) is keyed to a connecting plate (34), the connecting plate (34) is connected to the magnetic circuit upper plate (48) via a ball bearing (35), and the connecting plate (34) is connected to the second upper magnetic core (411) via a fastening bolt.

6. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 2, characterized in that: The lower surface of the lower magnetic core 1 (42) is provided with a plurality of limit grooves, and the upper surface of the lower magnetic core 2 (421) is provided with limit blocks matched with the limit grooves.

7. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 2, characterized in that: The outer surface of the magnetic isolation ring (44) is provided with a positioning groove, and the coil support (45) is provided with a positioning block matched with the positioning groove.

8. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 1, characterized in that: The shear motor (3) is fixedly mounted on the upper surface of the active plate (13), the torque speed sensor (31) is fixedly mounted on the upper surface of the driven plate (12), the lower surface of the driven plate (12) is provided with a flange (17), the flange (17) is connected to the transmission shaft (32) via a combined bearing (18), and the lower surface of the active plate (13) and the upper surface of the driven plate (12) are commonly connected with a plurality of connecting rods (15).

9. The magnetorheological fluid mechanical properties testing device under the extrusion-shear composite mode according to claim 1, characterized in that: A plurality of flange bearings (16) are respectively mounted on the active plate (13) and the driven plate (12), and the flange bearings (16) are sleeved on the support column (11).

10. The magnetorheological fluid mechanical property testing device under the extrusion-shear composite mode according to claim 1, characterized in that: A hydraulic support rod (5) is connected between the top plate (14) and the driven plate (12).

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