A large-torque and low-speed compliant transmission device based on magnetorheological fluid

Abstract

The present invention discloses a large-torque and low-speed compliant transmission device based on magnetorheological fluid, which comprises a fixed base, a housing, a rotating shaft, an upper swing frame and a lower swing frame; the housing is connected to the upper swing frame and moves synchronously with the upper swing frame. An upper magnetic isolation ring is fixed inside the housing, and a main excitation coil is evenly wound in the annular space inside the upper magnetic isolation ring; a driven wheel is fixedly sleeved on the upper part of the rotating shaft, and two sealing rings are rotatably connected inside the housing, and an upper sealing cavity is formed between the two sealing rings, the inner ring of the upper magnetic isolation ring and the outer ring of the driven wheel; a lower magnetic isolation ring is fixed at the middle position of the lower swing frame, and a secondary excitation coil is evenly wound in the annular space inside the lower magnetic isolation ring; two sealing plates are welded and fixed at the lower end of the rotating shaft at intervals up and down, and a lower sealing cavity is formed between the two sealing plates, the inner ring of the lower magnetic isolation ring and the outer wall of the rotating shaft; the upper sealing cavity and the lower sealing cavity are respectively filled with magnetorheological fluid. The present invention can achieve the compliant start and stepless speed regulation functions of the transmission system.

Description

Technical Field

[0001] The present invention relates to the field of transmission devices, and particularly to a large-torque and low-speed compliant transmission device based on magnetorheological fluid. Background Art

[0002] Fermenters are large in volume and the materials to be stirred have a high viscosity, so a large torque is required. Since high-power motor drives are large in volume, high in energy consumption, high in failure rate, and multiple-stage reduction is required to reach the required speed. The traditional ratchet and pawl transmission structure is an intermittent transmission. At the moment of starting and stopping, the key contact between the ratchet and the pawl will generate a strong contact stress, and there will be a strong sense of jerk between the forward and return strokes of the hydraulic cylinder. Under long-term working conditions, the transmission components and the stirring blades are prone to failure, thus affecting the service life of the equipment. Therefore, according to the advantages and disadvantages of the existing equipment, designing a system with excellent performance, simple structure, and longer service life has become an inevitable trend in the development of large-torque transmission systems. Summary of the Invention

[0003] To overcome the deficiencies in the prior art, the purpose of the present invention is to provide a large-torque and low-speed compliant transmission device based on magnetorheological fluid.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A large-torque and low-speed compliant transmission device based on magnetorheological fluid, comprising a fixed base, a housing, a rotating shaft, an upper swing frame, and a lower swing frame;

[0006] The middle part of the rotating shaft is rotatably connected to the fixed base;

[0007] The upper swing frame is driven by a main driver to rotate along the central axis of the rotating shaft;

[0008] The housing is connected to the upper swing frame and moves synchronously with the upper swing frame. An upper magnetic isolation ring is fixed inside the housing, and a main excitation coil is evenly wound in the annular space inside the upper magnetic isolation ring;

[0009] The upper part of the rotating shaft is fixedly sleeved with a driven wheel. Sealing rings are welded and fixed to the upper and lower ends of the driven wheel respectively. The two sealing rings are rotatably connected inside the housing, and an upper sealing cavity is formed between the two sealing rings, the inner ring of the upper magnetic isolation ring, and the outer ring of the driven wheel;

[0010] The lower swing frame is driven by a secondary driver to rotate along the central axis of the rotating shaft. A lower magnetic isolation ring is fixed at the middle position of the lower swing frame, and a secondary excitation coil is evenly wound in the annular space inside the lower magnetic isolation ring; Two sealing plates are welded and fixed to the lower end of the rotating shaft at intervals up and down. The free ends of the two sealing plates are rotatably matched with the inner ring of the lower magnetic isolation ring, and a lower sealing cavity is formed between the two sealing plates, the inner ring of the lower magnetic isolation ring, and the outer wall of the rotating shaft;

[0011] The upper sealing cavity and the lower sealing cavity are respectively filled with magnetorheological fluid.

[0012] Furthermore, positioning grooves are respectively arranged on both sides of the upper swing frame, and positioning blocks are respectively arranged on both sides of the bottom of the housing. The two positioning blocks are respectively and adaptively connected to the corresponding positioning grooves.

[0013] Furthermore, the housing includes an upper housing and a lower housing, and the upper housing and the lower housing are fixedly connected by bolts in a locked manner.

[0014] Furthermore, a first roller is connected between the upper swing frame and the fixed base, and a second roller is connected between the two sealing rings and the inner wall of the housing.

[0015] Furthermore, the middle part of the rotating shaft is connected to the fixed base through a thrust roller bearing.

[0016] Furthermore, the main drive rotator and the auxiliary drive rotator are respectively hydraulic cylinders.

[0017] Furthermore, an upper sealing ring is connected between the free ends of the two sealing rings and the connection surface of the inner circle of the upper magnetic isolation ring to achieve dynamic sealing.

[0018] Furthermore, a lower sealing ring is connected between the free ends of the two sealing plates and the connection surface of the inner circle of the lower magnetic isolation ring to achieve dynamic sealing.

[0019] Furthermore, block-shaped strips are respectively arranged on the inner circle of the upper magnetic isolation ring, the outer circle of the driven wheel, and the inner circle of the lower magnetic isolation ring.

[0020] Furthermore, an end cover is threadedly connected to the bottom of the rotating shaft, and a third roller is connected between the lower swing frame and the end cover.

[0021] Adopting the above technical solution, the beneficial effects are as follows:

[0022] 1. The transmission device of the present invention fills magnetorheological fluid between the inner and outer rings (the main and driven components). On the one hand, it avoids the direct contact between the traditional main and driven components. On the other hand, based on the special properties of magnetorheological fluid, it can achieve the compliant start and stepless speed regulation functions of the transmission system;

[0023] 2. The transmission device of the present invention creatively designs two sets of active parts. By controlling the magnitude and duration of the current applied to the excitation coil, the magnetorheological fluid can be switched between the magnetized state and the Newtonian fluid state. It is ensured that when the main drive rotates forward, the magnetorheological fluid presents the magnetized state, and this state can greatly enhance its shearing effect and has the function of transmitting torque. When the main drive pauses and returns, the magnetorheological fluid presents the Newtonian fluid state, and the torque transmitted by the viscosity of the magnetorheological fluid in this state is very small and is not sufficient to drive the rotating shaft (driven part) to move. At this time, the auxiliary drive is started to repeat the above operations, thereby ensuring that the driven part continues to move at a low speed and waits for the main hydraulic cylinder to transmit force in the next process. Since the rotating shaft has a certain initial speed when the main drive rotates forward in the second round, the effect of compliant transmission with large torque and low speed is achieved. On the other hand, the magnetorheological fluid can also play a lubricating effect at this stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments;

[0025] Figure 1 is the structural diagram of the present invention;

[0026] Figure 2 is the cross-sectional view of the present invention;

[0027] Figure 3 is the structural diagram of the upper magnetic isolation ring;

[0028] Figure 4 is the structural diagram of the driven wheel;

[0029] Figure 5 is the current diagram of the main excitation coil energization;

[0030] Figure 6 is the current diagram of the auxiliary magnetic coil energization. SPECIFIC EMBODIMENTS

[0031] As Figure 1-4 shown, a compliant transmission device with large torque and low speed based on magnetorheological fluid of the present invention includes a fixed base 1, a housing, a rotating shaft 4, an upper swing frame 5 and a lower swing frame 6;

[0032] The middle part of the rotating shaft 4 is rotatably connected to the fixed base 1, and the middle part of the rotating shaft 4 is connected to the fixed base 1 through a thrust roller bearing 7. The middle part of the rotating shaft 4 is designed as a stepped shaft and cooperates with the thrust roller bearing 7. The thrust roller bearing 7 can bear axial loads and can also bear part of the radial loads. The thrust roller bearing 7 is designed with a sealing cover to prevent the lubricating oil inside the thrust roller bearing 7 from being contaminated. The uppermost part of the rotating shaft 4 is designed as a stepped shaft and is connected to the coupling 25 through a key, and this design can facilitate the installation and transportation of the rotating shaft 4.

[0033] The upper swing frame 5 is driven by the main drive rotator 8 to rotate along the central axis of the rotating shaft 4. A first roller 9 is connected between the upper swing frame 5 and the fixed base 1 to support the rotation of the upper swing frame 5 through the first roller 9. The housing is connected to the upper swing frame 5 and moves synchronously with the upper swing frame 5. An upper magnetic isolation ring 10 is fixed inside the housing. A main excitation coil 11 is evenly wound in the annular space inside the upper magnetic isolation ring 10; the upper swing frame 5, the housing, the upper magnetic isolation ring 10 and the main drive rotator 8 together form the first set of active parts of the transmission device of the present invention.

[0034] A driven wheel 12 is fixedly sleeved on the upper part of the rotating shaft 4. Sealing rings 13 are welded and fixed to the upper end and the lower end of the driven wheel 12 respectively. The two sealing rings 13 are rotatably connected inside the housing. A second roller 14 is connected between the two sealing rings 13 and the inner wall of the housing to support the rotation of the driven wheel 12 through the upper and lower second rollers 14. An upper sealing cavity 23 is formed between the two sealing rings 13, the inner ring of the upper magnetic isolation ring 10 and the outer ring of the driven wheel 12. An upper sealing ring 15 is connected between the free ends of the two sealing rings 13 and the connecting surface of the inner ring of the upper magnetic isolation ring 10 to achieve dynamic sealing.

[0035] The lower swing frame 6 is driven by the auxiliary drive rotator 18 to rotate along the central axis of the rotating shaft 4. An end cover 16 is threadedly connected to the bottom of the rotating shaft 4. A third roller 17 is connected between the lower swing frame 6 and the end cover 16 to support the rotation of the lower swing frame 6 through the end cover 16 and the third roller 17; a lower magnetic isolation ring 19 is fixed at the middle position of the lower swing frame 6. An auxiliary excitation coil 20 is evenly wound in the annular space inside the lower magnetic isolation ring 19; two sealing plates 21 are welded and fixed to the lower end of the rotating shaft 4 at upper and lower intervals. The free ends of the two sealing plates 21 are rotatably matched with the inner ring of the lower magnetic isolation ring 19. A lower sealing cavity 24 is formed between the two sealing plates 21, the inner ring of the lower magnetic isolation ring 19 and the outer wall of the rotating shaft 4. A lower sealing ring 22 is connected between the free ends of the two sealing plates 21 and the connecting surface of the inner ring of the lower magnetic isolation ring 19 to achieve dynamic sealing. The lower swing frame 6 and the lower magnetic isolation ring 19 form the second set of active parts of the transmission device of the present invention through the power input of the auxiliary drive rotator 18. The two sealing plates 21, the driven wheel 12 and the rotating shaft 4 form the driven part of the transmission device of the present invention.

[0036] Magnetorheological fluids are respectively filled in the upper sealing cavity 23 and the lower sealing cavity 24. The upper magnetic isolation ring 10 and the lower magnetic isolation ring 19 in the present invention are anti-interference components commonly used in electronic circuits, which can shield a large amount of electromagnetic interference and improve the magnetization effect of the coil on the magnetorheological fluid.

[0037] The main drive rotator 8 and the auxiliary drive rotator 18 are respectively hydraulic cylinders.

[0038] Specifically, in the present invention, the housing includes an upper housing 2 and a lower housing 3, and the upper housing 2 and the lower housing 3 are fixedly connected by bolts in a locked manner. Positioning grooves 51 are respectively provided on both sides of the upper swing frame 5, and positioning blocks 31 are respectively provided on both sides of the bottom of the lower housing 3. The two positioning blocks 31 are respectively adapted to be connected in the corresponding positioning grooves 51.

[0039] The magnetorheological fluid is mainly composed of magnetic particles, a base fluid, and additives. Block-shaped racks 101, 121, and 191 are respectively provided on the inner ring of the upper magnetic isolation ring 10, the outer ring of the driven wheel 12, and the inner ring of the lower magnetic isolation ring 19. The purpose is to increase the shear force during magnetization. When the hydraulic cylinder advances, the coil is energized. At this time, the shear ability of the magnetorheological fluid increases. By arranging racks on the inner and outer rings of the magnetization region to increase the shear ability of the magnetorheological fluid, the rotation shaft 4 is driven to move.

[0040] The present invention can be applied to the stirring structure of a fermenter. The specific working principle is as follows: When the main drive rotator 8 advances, the main excitation coil 11 is energized, and the energization situation is as Figure 5 , where the period from 0 to t0 is a gradually rising straight line. The purpose is to ensure the uniform start of the rotation system and prevent the destruction of the fermentation environment in the fermenter. When the main drive rotator 8 finishes advancing and pauses and is about to return, the main excitation coil 11 is de-energized, and the magnetorheological fluid quickly converts into the Newton fluid state. At this time, the transmitted torque is very small. Under the action of the magnetorheological fluid, the return of the main drive rotator 8, the housing, and the upper magnetic isolation ring 10 is not sufficient to drive the driven parts (the driven wheel 12 and the rotation shaft 4) to return. At this time, the secondary excitation coil 20 is energized, and the energization situation is as Figure 6 shown. Due to the special properties of the magnetorheological fluid, the rotation shaft 4 will continue to rotate at a low speed at the cut-off speed of the previous process. When the secondary drive rotator 18 finishes advancing and is about to return, the main excitation coil 11 continues to be energized. The suspended particles in the magnetorheological fluid are magnetized under the action of the magnetic field, and the shear force increases rapidly, continuing to drive the rotation shaft 4 to rotate at the same speed. Thus, the soft start of the stirring device is realized, the aerobic bacteria group in the fermenter is protected, and to a great extent, the generation of large contact stresses is avoided, and the service life of the device is extended.

[0041] On the other hand, since the shear ability of the magnetorheological fluid changes with the change of the magnetic flux, the transmission device of the present invention can adjust the output torque ability of the magnetorheological fluid by adjusting the magnitude of the current applied to the excitation coil, that is, the rotation speed of the rotation shaft 4 can be adjusted in real time and conveniently. And because the magnetorheological fluid is filled between two relatively moving devices, when the magnetorheological fluid presents the Newton fluid state, it also has the function of lubricating oil.

[0042] The present invention has certain practical significance for the large-torque transmission of large-scale fermentation equipment and can be specifically applied to:

[0043] 1. The multi-stage gear-chain drive system of large fermentation equipment and the ratchet-pawl alternative drive system prone to fatigue damage;

[0044] 2. Research on the design of compliant joints of robots;

[0045] 3. Research on magnetorheological fluid shock absorbers;

[0046] 4. The rotation speed of the stirring shaft of this drive system is stable and easy to control, and it can be used in fermentation occasions where the fermenting bacteria are relatively sensitive.

[0047] 5. This drive device has a simple structure, is easy to process and manufacture, can achieve stepless speed regulation, and can be used in livestock and poultry waste treatment plants with various volume requirements.

[0048] The above describes the implementation of the present invention in conjunction with the accompanying drawings. However, the present invention is not limited to the above specific implementation manners. The above specific implementation manners are illustrative rather than restrictive of the present invention. Those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and the description of the present invention.

Claims

1. A large-torque and low-speed compliant transmission device based on magnetorheological fluid, characterized in that: It includes a fixed base, a housing, a rotating shaft, an upper swing frame and a lower swing frame; The middle part of the rotating shaft is rotatably connected to the fixed base; The upper swing frame is driven by a main drive rotator to rotate along the central axis of the rotating shaft; The housing is connected to the upper swing frame and moves synchronously with the upper swing frame. An upper magnetic isolation ring is fixed inside the housing, and a main excitation coil is evenly wound in the annular space inside the upper magnetic isolation ring; A driven wheel is fixedly sleeved on the upper part of the rotating shaft. Sealing rings are welded and fixed to the upper end and the lower end of the driven wheel respectively. The two sealing rings are rotatably connected inside the housing, and an upper sealing cavity is formed between the two sealing rings, the inner ring of the upper magnetic isolation ring and the outer ring of the driven wheel; The lower swing frame is driven by a secondary drive rotator to rotate along the central axis of the rotating shaft. A lower magnetic isolation ring is fixed at the middle position of the lower swing frame, and a secondary excitation coil is evenly wound in the annular space inside the lower magnetic isolation ring; Two sealing plates are welded and fixed to the lower end of the rotating shaft at intervals up and down. The free ends of the two sealing plates are rotationally matched with the inner ring of the lower magnetic isolation ring, and a lower sealing cavity is formed between the two sealing plates, the inner ring of the lower magnetic isolation ring and the outer wall of the rotating shaft; Magnetorheological fluid is filled in the upper sealing cavity and the lower sealing cavity respectively; When the main drive rotator advances, the main excitation coil is energized. When the main drive rotator finishes advancing and pauses and is about to return, the main excitation coil is powered off, and the magnetorheological fluid quickly converts into a Newtonian fluid state. At this time, the secondary excitation coil is energized, and the rotating shaft continues to rotate at a low speed at the cut-off speed of the previous process; When the secondary drive rotator finishes advancing and is about to return, the main excitation coil continues to be energized, and the suspended particles in the magnetorheological fluid are magnetized under the action of the magnetic field, and the shear force increases rapidly, continuing to drive the rotating shaft to rotate at the same speed, thereby realizing the soft start of the rotating shaft.

2. The compliant transmission device with large torque and low speed based on magnetorheological fluid according to claim 1, wherein: Positioning grooves are respectively arranged on both sides of the upper swing frame, and positioning blocks are respectively arranged on both sides of the bottom of the housing. The two positioning blocks are respectively fitted and connected to the corresponding positioning grooves.

3. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1 or 2, characterized in that: The housing includes an upper housing and a lower housing, and the upper housing and the lower housing are fixedly connected by bolts.

4. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: A first roller is connected between the upper swing frame and the fixed base, and a second roller is connected between the two sealing rings and the inner wall of the housing.

5. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: The middle part of the rotating shaft is connected to the fixed base through a thrust roller bearing.

6. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: The main drive rotator and the secondary drive rotator are respectively hydraulic cylinders.

7. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: An upper sealing ring is connected between the free ends of the two sealing rings and the connecting surface of the inner ring of the upper magnetic isolation ring to achieve dynamic sealing.

8. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: A lower sealing ring is connected between the free ends of the two sealing plates and the connecting surface of the inner ring of the lower magnetic isolation ring to achieve dynamic sealing.

9. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: Block-shaped strips are respectively arranged on the inner ring of the upper magnetic isolation ring, the outer ring of the driven wheel and the inner ring of the lower magnetic isolation ring.

10. A large-torque and low-speed compliant transmission device based on magnetorheological fluid according to claim 1, characterized in that: An end cover is threadedly connected to the bottom of the rotating shaft, and a third roller is connected between the lower swing frame and the end cover.

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