Double-coil multi-disc magnetorheological clutch and assembling method thereof

Abstract

The invention relates to a double-coil multi-disc type magneto-rheological clutch and an assembling method thereof, the double-coil multi-disc type magneto-rheological clutch comprises a driving disc coaxially and fixedly connected with a driving shaft to form a driving disc group and a driven disc coaxially and fixedly connected with a driven shaft to form a driven disc group, and a gap for magneto-rheological fluid to flow is reserved between the driving disc and the driven disc. An inner coil set is arranged between the end, away from the end connected with the driving disc, of the driving shaft and the driving disc, the driven disc and the driving disc are coaxially arranged and located on the outer side of the driving disc, the driven disc is covered with a shell, and an outer coil set is arranged between the outer side of the driven disc and the shell. The state change of the magnetorheological fluid is adjusted through power-on and power-off of the outer coil set and the inner coil set. The double-coil multi-disc type magnetorheological clutch is simple in structure, small in size, large in transmission torque and high in magnetic field utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of clutches, in particular to a double-coil multi-plate magnetorheological clutch and an assembling method thereof. BACKGROUND

[0002] In the robot joint driving system, the traditional clutch device relies on the dry friction between mechanical parts to realize torque transmission and interruption, which has problems such as fast wear, limited service life, obvious noise, and is difficult to meet the transmission requirements of high precision, high smoothness and fast controllability. As a kind of low-energy, environmentally friendly intelligent material, magnetorheological fluid is composed of magnetic particles, carrier liquid and additives. Under the action of external magnetic field, magnetorheological fluid can change from fluid state to solid-like state in milliseconds, realizing rapid and continuous adjustment of shear stress, so it is very suitable for clutch application in robot joints with high dynamic performance.

[0003] At present, the common magnetorheological clutch structure mostly adopts multi-plate or multi-cylinder layout to increase the action area of magnetorheological fluid, so as to improve the transmission torque. However, such design often leads to the increase of the volume of the clutch device and the decrease of the energy efficiency ratio, which is difficult to meet the requirements of compactness and light weight of the robot joint. In addition, some studies try to introduce deformable mechanisms to enhance the performance of the clutch device, but the complex structure will lead to the decrease of the reliability of the clutch device, which is not conducive to stable operation in the robot system.

[0004] Through patent research, it is found that Chinese invention patent (publication number CN106884898A) designs an extrusion type torque increasing magnetorheological clutch, which is provided with magnetorheological fluid and an output sleeve in the shell, and the output sleeve is provided with a piston. The output shaft sleeve is extruded by the spring between the piston and the output shaft sleeve. The side wall of the output sleeve between the piston and the electromagnetic coil is provided with a flow outlet, so that the magnetorheological clutch works under the combined extrusion action of the piston and the steel ball, and the transmission torque of the magnetorheological clutch is enhanced. However, due to the relatively large volume of the magnetorheological clutch, its integration application in the robot joint is limited. Another patent (publication number CN104723354A) proposes a multi-excitation coil magnetorheological clutch. The patent generates a working magnetic field by simultaneously energizing multiple excitation coils, reduces the current stabilization time of the excitation coil, and has faster response speed. At the same time, the arrangement form of multiple coils can replace the fixed magnetic shell of the traditional magnetorheological clutch, effectively reducing the magnetic hysteresis and eddy current phenomenon, accelerating the response speed of the working gap magnetic field of the magnetorheological fluid, and better meeting the requirements of fast transmission occasions. However, due to the increase of multiple excitation coils, the structure is relatively complex, and the problem of resistance heating of the coil is more serious, which is difficult to ensure the working stability. Therefore, there is an urgent need for a magnetorheological brake with small volume, large transmission torque and simple structure, which can ensure its working stability. SUMMARY

[0005] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is to provide a double-coil multi-disc magneto-rheological clutch with small volume, large torque transmission and high magnetic field utilization rate. The multi-disc structure is adopted, and compared with the single-disc structure, the torque that can be transmitted is larger. At the same time, the structure of the inner and outer double coils is arranged in the shell, so that the torque output of the magneto-rheological clutch is more stable. The coil arranged inside the brake disc can constrain the magnetic field of the external outer coil, so that the magnetic field of the outer coil is concentrated in the master and slave disc group position, effectively improving the utilization efficiency of the magnetic field. The arrangement mode of the double coils makes the space inside the clutch be utilized, so that the structure of the clutch is more compact, the transmission torque is larger and the structure is relatively simple.

[0006] In order to solve the above technical problems, the technical scheme of the present application is: a double-coil multi-disc magneto-rheological clutch, comprising a driving disc coaxially connected with a driving shaft to form a driving disc group, a driven disc coaxially connected with a driven shaft to form a driven disc group, a gap is provided between the driving disc and the driven disc for the flow of magneto-rheological fluid, an inner coil group is arranged between the end of the driving shaft away from the driving disc and the driving disc, the driven disc is coaxially arranged outside the driving disc, the driven disc is covered with a shell, an outer coil group is arranged between the driven disc and the shell, and the state change of the magneto-rheological fluid is adjusted by the on-off electricity of the outer coil group and the inner coil group.

[0007] Further, the shell is composed of an outer magnetic sleeve and a driving disc side shell and a driven disc side shell connected to the two ends of the outer magnetic sleeve respectively by screws.

[0008] Further, the inner coil group comprises an inner coil support sleeve coaxially sleeved and rotationally connected on the driving shaft, the inner coil support sleeve is externally wound with an inner coil, the outer side of the inner coil is sleeved and closed by an inner coil magnetic shielding ring, and the inner coil magnetic shielding ring and the inner coil support sleeve are connected with the driving disc side shell by screws.

[0009] Further, the inner wall of the inner coil support sleeve is respectively connected with the driving shaft and the pan seal on both sides by the driving shaft bearing, the driving shaft bearing is installed on the driving shaft in interference fit, the driving shaft is sleeved with a driving disc bearing limiting ring to prevent the driving shaft bearing from falling out, and the pan seal is used to prevent the magneto-rheological fluid from seeping out through the gap between the driving shaft and the inner coil support sleeve.

[0010] Further, the outer coil group comprises an outer coil magnetic shielding ring coaxially sleeved outside the driven disc, the outer coil magnetic shielding ring is externally wound with an outer coil, the outer coil is externally sleeved and closed by an outer magnetic sleeve, and the outer coil magnetic shielding ring and the outer magnetic sleeve are connected with the driving disc side shell and the driven disc side shell respectively by screws.

[0011] Further, the driven disc is divided into two halves to be connected to the driving disc, the inner ends of the two halves of the driven disc are connected to the driven shaft, and the driven disc magnetic isolation ring is embedded on the end face of the driven disc side shell.

[0012] Further, the driving disc is provided with a plurality of ring grooves in the length direction, and the driven disc is provided with annular protrusions corresponding to the ring grooves.

[0013] Further, the driven disc side shell is coaxially connected to the driven disc sleeve, the driven shaft is connected to the driven disc sleeve through the driven shaft bearing, and the driven disc bearing limiting ring is sleeved on the driving shaft to prevent the driven shaft bearing from falling out.

[0014] Further, the driving disc side shell is provided with a liquid injection hole for injecting the magneto-rheological fluid, and the inner coil magnetic isolation ring and the driving disc side shell are provided with an inner coil sealing ring for sealing the magneto-rheological fluid.

[0015] A double-coil multi-disc magneto-rheological clutch assembly method is provided, which is performed according to the following steps: S1: the driving shaft and the driving disc are matched to form a driving disc group through a countersunk screw; S2: the inner coil is wound on the inner coil support sleeve, the driving shaft bearing and the seal are installed on the inner coil support sleeve, and then the driving disc group and the driving disc bearing are assembled through interference fit; S3: the inner coil magnetic isolation ring and the inner coil support sleeve are assembled, the inner coil sealing ring and the outer coil sealing ring are installed on the driving disc side shell, and then the driving disc side shell, the inner coil magnetic isolation ring and the inner coil support sleeve are assembled; S4: the two halves of the driven disc are assembled and matched with the driven shaft through a countersunk screw to form a driven disc group, and the driven disc magnetic isolation ring is installed; S5: the outer coil is wound on the outer coil magnetic isolation ring, and the outer coil magnetic isolation ring and the outer magnetic sleeve are fixed on the driving disc side shell; then the outer coil sealing ring and the seal are installed on the driven disc side shell and matched with the outer coil magnetic isolation ring and the outer magnetic sleeve; S6: the driven shaft bearing is installed on the driven disc bearing, and then the driven disc sleeve is fixed with the driven disc side shell, and the assembly is completed.

[0016] Compared with the prior art, the present application has the following beneficial effects: by transforming and reusing the internal space of the ordinary multi-disc magneto-rheological clutch, an inner coil is arranged in the clutch to generate a magnetic field repelling the outer coil. The arrangement mode of the inner and outer double coils restricts the magnetic field to concentrate in the effective magnetic gap, the internal space of the magneto-rheological clutch is reutilized, and the performance of the magneto-rheological clutch is effectively improved, and specific advantages are as follows: 1) Compared with the single-disc structure, the multiple-disc structure connected by a single handle is adopted, the mass of the driving and driven disc sets is reduced, the maximum part of the force arm of the driving and driven disc sets is ensured, a larger torque is transmitted, and the transmission is relatively more stable.

[0017] 2) The magnetic field of the outer coil is restricted by arranging the coil inside the clutch. The inner coil can concentrate the magnetic field of the outer coil in the effective gap, the area of the magnetic flux lines in the gap vertically penetrating the magneto-rheological fluid is increased, and the transmission torque of the magneto-rheological clutch is greatly improved.

[0018] 3) The double-limiting ring is introduced to limit the displacement of the driving and driven discs of the clutch, the axial deviation of the clutch is avoided, the torque output is more stable, the volume of the clutch is reduced, and the structure is more compact.

[0019] 4) The thin magnetic separation ring is added outside the driven disc to further optimize the magnetic circuit distribution of the clutch, the magnetic field of the outer coil avoids the connecting part of the driven disc, is more concentrated in the effective gap part, and the adjustable proportion of the torque of the clutch is increased.

[0020] The application will be further described in detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a cut structure schematic diagram of the embodiment of the application; Figure 2 It is an explosion schematic diagram of the embodiment of the application; Figure 3 It is a structure schematic diagram of the embodiment of the application; Figure 4 It is a structure schematic diagram of the inner coil set in the embodiment of the application; Figure 5 It is a cooperation structure schematic diagram of the driving and driven disc sets in the embodiment of the application; Figure 6 It is a structure schematic diagram of the outer coil set in the embodiment of the application.

[0022] In the diagram: 1-Drive shaft, 2-Drive disk bearing limiting ring, 3-Drive shaft bearing, 4-Inner coil support sleeve, 5-Inner coil sealing ring, 6-Inner coil magnetic shielding ring, 7-Drive disk side housing, 8-Outer coil sealing ring, 9-Outer magnetic sleeve, 10-Outer coil, 11-Driven disk magnetic shielding ring, 12-Driven disk, 13-Driven disk, 14-Driven disk side housing, 15-Driven disk bushing, 16-Plug seal, 17-Driven disk bearing limiting ring, 18-Driven shaft, 19-Driven shaft bearing, 20-Inner coil, 21-Magnetorheological fluid, 22-Outer coil magnetic shielding ring, 23-Gap, 24-Outer shell, 25-Annular groove, 26-Annular protrusion, 27-Infusion port. Detailed Implementation

[0023] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation.

[0024] like Figures 1-6 As shown, a dual-coil multi-disc magnetorheological clutch includes an active disc 13 coaxially fixed to an active shaft 1 to form an active disc assembly, and a driven disc 12 coaxially fixed to a driven shaft 18 to form a driven disc assembly. A gap 23 is provided between the active disc and the driven disc for the flow of magnetorheological fluid 21. An inner coil assembly is provided between the active shaft and the active disc at the end away from the active disc. The driven disc is coaxially arranged with the active disc and located outside it. The driven disc is covered by a housing 24. An outer coil assembly is provided between the driven disc and the housing. The state change of the magnetorheological fluid is adjusted by switching the outer coil assembly and the inner coil assembly on and off.

[0025] This magnetorheological clutch transmits torque through the driving plate assembly, the driven plate assembly, and the magnetorheological fluid between them. When the clutch is not engaged, the magnetorheological fluid in the gap is in liquid form, and the driving and driven plate assemblies move independently. When the clutch is engaged, the coil is energized to generate a magnetic field. This magnetic field causes the magnetorheological fluid in the gap to undergo a magnetorheological effect, transforming it from a liquid state into a Bingham plastic fluid with solid properties, thereby enabling the clutch to transmit torque.

[0026] In this embodiment of the invention, the outer shell is composed of an outer magnetic sleeve 9 and an active disk-side housing 7 and a driven disk-side housing 14 that are respectively connected to the two ends of the outer magnetic sleeve by screws.

[0027] The connecting part of the driving disc extends to the inside, close to the driven disc group, so that the magneto-rheological clutch saves a large amount of internal space, and the internal coil can be arranged. And because the external structure of the driving disc and the driven disc is reserved, the torque size is less affected. The driven disc is composed of two parts, which are matched into an integral barrel structure when assembled and fixed by the driven disc magnetic ring. The driving disc is fixed by the screw hole matched with the driving shaft, and the driven disc is fixed by the screw hole matched with the driven shaft.

[0028] In the embodiment of the present application, the inner coil group includes an inner coil support sleeve 4 coaxially sleeved and rotationally connected on the driving shaft, an inner coil 20 wound outside the inner coil support sleeve, and the inner coil is closed by an inner coil magnetic ring 6. The inner coil support sleeve and the inner coil magnetic ring are connected to the driving disc side housing by screws. The inner coil group is arranged in the internal space, thereby restricting the magnetic field of the outer coil to concentrate in the effective gap part, so that the magnetic field utilization efficiency of the main coil is higher. The inner coil group is injected with magneto-rheological fluid through the infusion hole, and the magneto-rheological fluid is sealed by the inner coil sealing ring. The opening and closing of the infusion hole is a conventional technology, and will not be described in detail here.

[0029] In the embodiment of the present application, the inner wall of the inner coil support sleeve is respectively connected to the driving shaft through the driving shaft bearing 3 and the generic seal 16 on both sides. The driving shaft bearing is interference-fitted on the driving shaft, and the driving disc bearing limiting ring 2 is sleeved on the driving shaft to prevent the driving shaft bearing from falling out. The generic seal is used to prevent the magneto-rheological fluid from seeping out through the gap between the driving shaft and the inner coil support sleeve.

[0030] In the embodiment of the present application, the outer coil group includes an outer coil magnetic ring 22 coaxially sleeved outside the driven disc, and an outer coil 10 wound outside the outer coil magnetic ring. The outer coil is closed by an outer magnetic sleeve 9, and the outer coil magnetic ring and the outer magnetic sleeve are connected to the driving disc side housing and the driven disc side housing by screws at both ends, respectively.

[0031] The outer coil group mainly includes an outer magnetic sleeve 9, an outer coil 10, an outer coil magnetic ring 22, a driving disc side housing 7, and a driven disc side housing 14, forming a complete magnetic circuit. The outer coil group is the main magnetic field generating device of the clutch. The coil wound on the magnetic ring generates a magnetic field, so that the magneto-rheological fluid in the effective gap between the driving disc group and the driven disc group produces a magneto-rheological phenomenon, thereby making the clutch output torque.

[0032] In the embodiment of the present application, the driven disc is divided into two halves from the middle part to face each other and abut against the driving disc, the inner ends of the two halves of the driven disc are connected with the driven shaft, the driven disc magnetic isolation ring 11 is embedded on the end surface of the driven disc near the side shell of the driven disc, the two halves of the driven disc are clamped by the driven disc magnetic isolation ring, and further positioning is achieved, and the clamping is locked on the driven disc by screws, and the magnetic flow liquid overflow seal is arranged between the driven shaft and the side shell of the driven disc.

[0033] In the embodiment of the present application, the driving disc is recessed with a plurality of ring grooves 25 in the length direction, the driven disc is correspondingly provided with annular protrusions 26 inserted into the ring grooves, and the gaps between the end portions of the driving shaft and the driven shaft and the gaps between the driving disc and the driven disc are consistent.

[0034] In the embodiment of the present application, the driven disc side shell is coaxially connected with the driven disc sleeve 15, the driven shaft is connected with the driven disc sleeve through the driven shaft bearing 19, and the driven disc bearing limiting ring 17 is arranged on the driving shaft to prevent the driven shaft bearing from falling out.

[0035] In the embodiment of the present application, the infusion hole 27 for injecting the magnetic flow liquid is arranged on the side shell of the driving disc, the inner coil magnetic isolation ring and the side shell of the driving disc are provided with the inner coil sealing ring 5 for sealing the magnetic flow liquid, and the outer coil magnetic isolation ring is provided with the outer coil sealing ring 8 for sealing the magnetic flow liquid between the two ends of the outer coil magnetic isolation ring and the side shell of the driving disc and the side shell of the driven disc, thereby effectively preventing the magnetic flow liquid from leaking.

[0036] The working principle of the embodiment of the present application is as follows: The driving disc set and the driven disc set are immersed in the shell sealed with the magnetic flow liquid, and the magnetic field is generated by energizing the exciting coil. The magnetic field causes the magnetic particles in the effective gap to be polarized, so that the particles attract each other and form a chain structure along the distribution direction of the magnetic field magnetic force line. The structure can enhance the shear resistance of the magnetic flow liquid, so that it presents a solid-like characteristic. When the driving disc set rotates, the chain structure formed by the magnetic particles will make the driven disc set rotate at the same time. Under the action of the magnetic field, the magnetic flow liquid presents strong controllable rheological characteristics, and the torque output from the driving disc set to the driven disc set is controlled by controlling the current size of the coil. Since the driving disc set and the driven disc set are non-contact connection, the flexible and stable transmission of the torque can be realized.

[0037] The assembly process of the double-coil multi-disc magnetic flow coupling is as follows: S1, the driving shaft and the driving disc are matched to form a driving disc set by means of a countersunk screw.

[0038] S2, the inner coil is wound on the inner coil support sleeve, the driving shaft bearing and the overflow seal are installed on the inner coil support sleeve, and then the driving disc set and the driving disc bearing are interference fitted.

[0039] S3, the inner coil magnetic ring is assembled with the inner coil support sleeve, the inner coil sealing ring and the outer coil sealing ring are installed on the driving disc side shell, then the driving disc side shell is assembled with the inner coil magnetic ring and the inner coil support sleeve.

[0040] S4, the driven disc assembled in two halves is assembled and matched with the driven shaft through a countersunk screw to form a driven disc set, and the driven disc magnetic ring is installed.

[0041] S5, the outer coil is wound on the outer coil magnetic ring, and the outer coil magnetic ring and the outer magnetic sleeve are fixed on the driving disc side shell. Then the outer coil sealing ring and the grease seal are installed on the driven disc side shell and matched with the outer coil magnetic ring and the outer magnetic sleeve.

[0042] S6, the driven shaft bearing is installed on the driven disc bearing, then the driven disc shaft sleeve is fixed with the driven disc side shell, and the assembly is completed.

[0043] The application is not limited to the above-mentioned best embodiment, and anyone can derive other various forms of double-coil multi-disc magnetorheological clutch and its assembly method under the inspiration of the application. Any equivalent changes and modifications made within the scope of the application should be included in the scope of the application.

Claims

1. A dual-coil multi-disc magnetorheological clutch, characterized in that: The device includes an active disk coaxially fixed to the active shaft to form an active disk assembly, and a driven disk coaxially fixed to the driven shaft to form a driven disk assembly. A gap is provided between the active disk and the driven disk for the flow of magnetorheological fluid. An inner coil assembly is provided between the active shaft and the active disk. The driven disk is coaxially arranged with the active disk and located outside it. The driven disk is covered by a shell. An outer coil assembly is provided between the driven disk and the shell. The state change of the magnetorheological fluid is adjusted by switching the outer coil assembly and the inner coil assembly on and off.

2. The dual-coil multi-disc magnetorheological clutch according to claim 1, characterized in that: The outer casing consists of an outer magnetic sleeve and a driving disk side shell and a driven disk side shell that are respectively connected to the two ends of the outer magnetic sleeve by screws.

3. A dual-coil multi-disc magnetorheological clutch according to claim 2, characterized in that: The inner coil assembly includes an inner coil support sleeve coaxially sleeved and rotatably connected to the drive shaft. An inner coil is wound around the outer side of the inner coil support sleeve. The inner coil is enclosed by an inner coil magnetic isolation ring. Both the inner coil magnetic isolation ring and the inner coil support sleeve are connected to the drive disk side housing by screws.

4. A dual-coil multi-disc magnetorheological clutch according to claim 3, characterized in that: The inner coil support sleeve has its inner walls connected to the drive shaft via drive shaft bearings and plug seals on both sides. The drive shaft bearings are interference-fitted onto the drive shaft, and a drive disc bearing limiting ring is fitted on the drive shaft to prevent the drive shaft bearings from coming off.

5. A dual-coil multi-disc magnetorheological clutch according to claim 2, characterized in that: The outer coil assembly includes an outer coil magnetic isolation ring coaxially sleeved outside the driven disc. An outer coil is wound around the outer coil magnetic isolation ring. The outer coil is sealed by an outer magnetic sleeve. Both ends of the outer coil magnetic isolation ring and the outer magnetic sleeve are connected to the driving disc side housing and the driven disc side housing respectively by screws.

6. A dual-coil multi-disc magnetorheological clutch according to claim 2, characterized in that: The driven disk is divided into two halves that are mated with the driving disk in opposite directions. The inner ends of both halves of the driven disk are connected to the driven shaft. A magnetic isolation ring of the driven disk is embedded on the end face of the housing near the driven disk side. A plug seal is provided between the driven shaft and the housing of the driven disk side.

7. A dual-coil multi-disc magnetorheological clutch according to claim 2, characterized in that: The active disk has several annular grooves recessed inward along its length, and the driven disk has corresponding annular protrusions that can be inserted into the annular grooves.

8. A dual-coil multi-disc magnetorheological clutch according to claim 2, characterized in that: A driven disk bushing is coaxially fixed to the outer side of the driven disk housing. The driven shaft and the driven disk bushing are connected via a driven shaft bearing. A driven disk bearing limiting ring is fitted on the drive shaft to prevent the driven shaft bearing from coming off.

9. A dual-coil multi-disc magnetorheological clutch according to claim 1, characterized in that: The active disk side housing has an infusion hole for injecting magnetorheological fluid. An inner coil sealing ring for sealing the magnetorheological fluid is provided between the inner coil magnetic isolation ring and the active disk side housing. Both ends of the outer coil magnetic isolation ring are respectively provided with outer coil sealing rings for sealing the magnetorheological fluid between the active disk side housing and the driven disk side housing.

10. An assembly method for a dual-coil multi-disc magnetorheological clutch, characterized in that, The method employs a dual-coil multi-disc magnetorheological clutch as described in any one of claims 1-9, and proceeds according to the following steps: S1: The drive shaft and drive disc are fitted together with countersunk screws to form a drive disc assembly; S2: The inner coil is wound onto the inner coil support sleeve, and the drive shaft bearing and sealing plug are installed on the inner coil support sleeve, followed by an interference fit between the drive disc assembly and the drive disc bearing; S3: The inner coil magnetic isolation ring is assembled with the inner coil support sleeve, and the inner coil sealing ring and outer coil sealing ring are installed on the drive disc side housing, followed by an interference fit between the drive disc side housing and the inner coil... S4: Assemble the magnetic shielding ring and inner coil support sleeve; S5: Assemble the driven disk divided into two halves and mate it with the driven shaft using countersunk screws to form a driven disk assembly, and install the driven disk magnetic shielding ring; S6: Wind the outer coil around the outer coil magnetic shielding ring, and fix the outer coil magnetic shielding ring and outer magnetic sleeve to the driving disk side housing; then install the outer coil sealing ring and plug seal on the driven disk side housing, and mate them with the outer coil magnetic shielding ring and outer magnetic sleeve; S7: Install the driven shaft bearing on the driven disk bearing, and then fix the driven disk bushing to the driven disk side housing, completing the assembly.

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