Magneto-rheological brake with piezoelectric-thermotropic shape memory regulation and control function

Abstract

The utility model discloses a magneto-rheological brake with a piezoelectric-thermotropic shape memory regulation function, which comprises a driving shaft and a brake shell, the brake shell comprises a left shell and a right shell, and a magnet exciting coil is arranged at the joint of the left shell and the right shell; one end of the driving shaft extends into the brake shell and is fixedly connected with a driving disc; an aluminum ring is arranged on the right side of the driving disc; a polytetrafluoroethylene ring is arranged on the inner side of the right shell, and a magnetostrictive rod is arranged on the right shell; a friction column and a shape memory alloy spring are arranged in the middle of the driving disc, and a copper wire is wound on the shape memory alloy spring; one end of the copper wire is connected with the aluminum ring, and the other end is connected with the polytetrafluoroethylene ring; and the brake shell is filled with magnetorheological fluid. According to the utility model, electricity is generated through friction, so that the energy utilization rate of the braking device is improved; and the braking capacity of the brake is improved, the performance stability of the device is ensured, extrusion on the magnetorheological fluid is achieved, and the shearing stress of the magnetorheological fluid is increased.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission technology, and in particular to a magnetorheological brake with piezoelectric-thermoelectric shape memory control function. Background Technology

[0002] Magnetorheological fluid (MRF) is a smart material composed of soft magnetic particles, a carrier fluid, and surfactants. It exhibits good fluidity in the absence of an external magnetic field; under an applied magnetic field, it displays high viscosity and low fluidity, a state described as solid-like. Furthermore, its shear strength can be continuously controlled by varying the magnetic field strength. Shape memory alloys are a novel type of functional material. Due to their inherent deformation under temperature influence, the shape memory effect of these alloys can be achieved by controlling the external temperature. Triboelectricity arises from the fact that aluminum sheets easily lose electrons and become positively charged after friction, while polytetrafluoroethylene (PTFE) disks easily gain electrons and become negatively charged. When these two come into contact, electron transfer occurs, generating an electric current. Based on these material properties, they are widely used in the field of mechanical transmission.

[0003] For example, CN113431850B discloses a magnetorheological and shape memory alloy friction composite brake based on electromagnetic extrusion. When the temperature of the environment where the shape memory alloy is located rises, the shape memory alloy spring will generate a large elastic force to push the magnetorheological fluid wall to extrude and extrude the magnetorheological fluid, thereby increasing the performance of the magnetorheological fluid. For example, CN118309739A discloses an eccentric extrusion enhanced magnetorheological clutch. It uses a wedge-shaped reinforcing groove to extrude the magnetorheological fluid as it flows from the small end to the large end, which also improves the performance of the magnetorheological fluid. For example, CN116517976A discloses a temperature-controlled magnetorheological intelligent transmission device based on thermal energy reuse. This device inserts a shape memory alloy sheet into the active cylinder of a cylindrical magnetorheological fluid transmission structure. As the transmission proceeds, when the temperature rises, the shape memory alloy changes shape and then generates frictional transmission with the driven cylinder.

[0004] The aforementioned studies have all contributed to the field of magnetorheological fluid (MRF) transmission. However, when utilizing the performance of MRF, only its compression strengthening effect and temperature are often considered, without fully leveraging the performance and energy harvesting capabilities of MRF transmission devices. For MRF brakes, only the braking effect—the conversion of mechanical energy into internal energy—needs to be considered. Traditional shape memory alloy springs or other components cannot convert heat. As the device continuously brakes, the resulting slip heat will raise the temperature of the MRF, thus affecting its transmission performance. Therefore, maximizing energy utilization and overcoming the temperature dependence of shape memory alloys within the existing conditions of the MRF device are crucial for the transmission performance of MRF braking devices. Utility Model Content

[0005] To address the aforementioned shortcomings of existing technologies, the purpose of this invention is to solve the problems of limited shear yield stress of magnetorheological fluids, decreased performance with increasing temperature, poor stability, excessive temperature dependence of shape memory alloys, low energy utilization, and significant energy waste. The invention provides a magnetorheological brake with piezoelectric-thermal shape memory control function.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a magnetorheological brake with piezoelectric-thermal shape memory control function includes a drive shaft and a brake housing. The brake housing includes a left housing and a right housing connected together. A coil groove is provided at the connection between the left housing and the right housing, and an excitation coil is wound in the coil groove. One end of the drive shaft passes through the right housing and extends into the brake housing, and is rotatably connected to the right housing. The end of the drive shaft extending into the brake housing is fixedly connected to a drive disc, and the drive shaft... There is a gap between the moving disc and the inner side of the brake housing; characterized in that: near the edge of the right side of the moving disc, there is an aluminum ring that surrounds the moving disc; on the inner side of the right housing, there is a polytetrafluoroethylene ring opposite the aluminum ring, and on the right housing, there are several grooves corresponding to the position of the polytetrafluoroethylene ring, and a magnetostrictive rod is provided in each groove. The magnetostrictive rod is in clearance fit with the groove, and one end of the rod near the polytetrafluoroethylene ring is fixedly connected to the polytetrafluoroethylene ring, and the other end is fixedly connected to the bottom of the groove. In the initial state, there is a gap between the polytetrafluoroethylene ring and the aluminum ring.

[0007] A receiving groove is provided in the middle of the active disk, and a friction post is slidably fitted in the receiving groove. A shape memory alloy spring is provided between the friction post and the bottom of the receiving groove, and a copper wire is wound on the shape memory alloy spring. In the initial state, there is a gap between the end of the friction post near the left housing and the left housing. One end of the copper wire is connected to an aluminum ring, and the other end is connected to a polytetrafluoroethylene ring.

[0008] A first sealing ring is provided between the side wall of the drive disc and the side wall of the brake housing. A second sealing ring and a third sealing ring, coaxial with the drive shaft, are provided between the drive disc and the right housing. The second sealing ring is close to the drive shaft, and the third sealing ring is close to the aluminum ring and the polytetrafluoroethylene ring. The gap between the first sealing ring and the left housing, and the gap between the second sealing ring and the third sealing ring, are filled with magnetorheological fluid.

[0009] Furthermore, the active disk has several through holes, which connect the gap between the first sealing ring and the left housing with the gap between the second sealing ring and the third sealing ring.

[0010] Furthermore, there is a gap between the right housing and the drive shaft, and a brush slip ring is installed in the gap. The brush of the brush slip ring is connected to a copper wire, and the slip ring of the brush slip ring is connected to a polytetrafluoroethylene ring through a wire. The aluminum ring is directly connected to the copper wire through a wire.

[0011] Furthermore, the active disk has a number of radially distributed protrusions evenly distributed around one side of the left housing. The length direction of the protrusions is consistent with the radial direction of the active disk, and the cross-section of the protrusions is semi-circular.

[0012] Furthermore, a bearing is also provided between the right housing and the drive shaft.

[0013] Furthermore, the end face of the friction post near the left housing is a friction surface and is spherical; correspondingly, the inner side of the left housing has a spherical groove at the position of the friction post.

[0014] Furthermore, a liquid injection hole is provided on the left shell, and a liquid injection plug is fitted inside the liquid injection hole.

[0015] Furthermore, at corresponding positions on the surfaces where the left and right shells fit together, an annular groove is provided. After the two shells are closed, the two annular grooves form the coil groove. A magnetic isolation ring is provided inside the excitation coil, and the excitation coil is enclosed in the coil groove by the magnetic isolation ring.

[0016] Furthermore, a through cover is provided on the outside of the right housing. The through cover is fitted onto the drive shaft and fixedly connected to the right housing, and a fourth sealing ring is provided between the through cover and the drive shaft.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. Under the influence of a magnetic field, the magnetostrictive rod pushes the polytetrafluoroethylene disc to generate friction with the aluminum ring riveted to the drive disc. On the one hand, the friction realizes the braking function of the brake, and on the other hand, the friction generates electricity, which improves the energy utilization rate of the braking device.

[0019] 2. A shape memory alloy spring is used and placed in the center of the active disc. Copper wire is wound around the spring, with the two poles of the copper wire connected to the brush and the aluminum ring, respectively. The temperature is increased by the electricity generated by friction. As the temperature rises, the shape memory alloy spring pushes the push column, which in turn squeezes the magnetorheological fluid. The magnetorheological fluid is squeezed from the center to the circumference, making the concentration of the magnetorheological fluid at the circumference greater. When the side of the push column contacts the right side of the housing, friction is generated, which further increases the braking capacity of the brake and ensures the performance stability of the device during long-term braking.

[0020] 3. The semi-circular rollers on the active disk are arranged in a circular array. There is less magnetorheological fluid near the axis and more magnetorheological fluid near the circumference. Therefore, the lever arm that generates torque at the circumference is larger. At the same time, during the rotation, the magnetorheological fluid is squeezed to a certain extent. Due to the squeezing strengthening effect, the shear stress of the magnetorheological fluid is increased. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2 This is a structural diagram of one side of the active plate.

[0023] Figure 3 This is a schematic diagram of the structure on the other side of the active plate.

[0024] In the diagram: 1—drive shaft, 2—left housing, 3—right housing, 4—excitation coil, 5—drive disc, 6—aluminum ring, 7—PTFE ring, 8—magnetostrictive rod, 9—friction column, 10—shape memory alloy spring, 11—first sealing ring, 12—second sealing ring, 13—third sealing ring, 14—magnetorheological fluid, 15—through hole, 16—protrusion, 17—bearing, 18—through cover. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0027] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. In addition, the terms "horizontal," "vertical," etc., do not indicate that the component is required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Example: See Figure 1 , Figure 2 as well as Figure 3 A magnetorheological brake with piezoelectric-thermal shape memory control function includes a drive shaft 1 and a brake housing. The brake housing includes a left housing 2 and a right housing 3 connected together, wherein the inner surfaces of the left housing 2 and the right housing 3 are friction surfaces; the left housing 2 is also fixedly connected to a base. A coil groove is provided at the connection between the left housing 2 and the right housing 3, which winds around the brake housing, and an excitation coil 4 is wound in the coil groove. In implementation, an annular groove is provided at the corresponding position of the mating surfaces of the left housing 2 and the right housing 3. After the two housings are closed, the two annular grooves form the coil groove; a magnetic isolation ring is provided inside the excitation coil 4 groove, and the excitation coil 4 is enclosed in the coil groove by the magnetic isolation ring.

[0029] One end of the drive shaft 1 passes through the right housing 3 and extends into the brake housing, where it is rotatably connected. A bearing 17 is also provided between the right housing 3 and the drive shaft 1. To facilitate power supply to the excitation coil 4, a conductive slip ring is fitted onto the portion of the drive shaft 1 located outside the brake housing, and both ends of the excitation coil 4 are connected to this conductive slip ring. A through cover 18 is also provided on the outside of the right housing 3. This through cover 18 is fitted onto the drive shaft 1 and fixedly connected to the right housing 3, and a fourth sealing ring is provided between the through cover 18 and the drive shaft 1. One end of the drive shaft 1 extending into the brake housing is fixedly connected to a drive disc 5, and there is a gap between the drive disc 5 and the inner side of the brake housing.

[0030] Near the edge of the right side of the drive disc 5, an aluminum ring 6 is provided, encircling the drive disc 5. In actual manufacturing, the aluminum ring 6 is fixedly connected to the drive disc 5 by rivets or bolts. On the inner side of the right housing 3, opposite the aluminum ring 6, a polytetrafluoroethylene (PTFE) ring 7 is provided. On the right housing 3, several grooves are evenly distributed around the right housing 3 corresponding to the position of the PTFE ring 7. A magnetostrictive rod 8 is provided in each groove. The magnetostrictive rod 8 is clearance-fitted with the groove. One end of the magnetostrictive rod 8 is fixedly connected to the PTFE ring 7, and the other end (by bonding or other means) is fixedly connected to the bottom of the groove. In the initial state, there is a gap between the PTFE ring 7 and the aluminum ring 6. In actual assembly, the side of the PTFE ring 7 near the magnetostrictive rod 8 has a T-shaped connecting groove. Correspondingly, the end of the magnetostrictive rod 8 connected to the PTFE ring 7 has a T-shaped connector. The magnetostrictive rod 8 is connected to the PTFE ring 7 through the fit between the connector and the connecting groove.

[0031] A receiving groove is provided in the middle of the active disk 5. A friction post 9 is slidably fitted in the receiving groove. A shape memory alloy spring 10 is provided between the friction post 9 and the bottom of the receiving groove, and a copper wire is wound on the shape memory alloy spring 10. In the initial state, there is a gap between the end of the friction post 9 near the left housing 2 and the left housing 2. One end of the copper wire is connected to the aluminum ring 6, and the other end is connected to the polytetrafluoroethylene ring 7. In implementation, there is a gap between the right housing 3 and the active shaft 1. A brush slip ring is installed in this gap. The brush of the brush slip ring is connected to the copper wire, and the slip ring of the brush slip ring is connected to the polytetrafluoroethylene ring 7 through a wire. The aluminum ring 6 is directly connected to the copper wire through a wire.

[0032] As an optimization, the active disk 5 has a plurality of radially distributed protrusions 16 evenly distributed around its side near the left housing 2. The length direction of the protrusions 16 is consistent with the radial direction of the active disk 5, and the cross-section of the protrusions 16 is semi-circular. As an optimization, the cross-section of the protrusions 16 is a regular semi-circle, and the height of each protrusion 16 is consistent. This results in a distribution of less magnetorheological fluid 14 in the middle and more around the circumference, which can improve the extrusion effect. The end face of the friction column 9 near the left housing 2 is a friction surface and is spherical; correspondingly, the inner side of the left housing 2 has a spherical groove at the position of the friction column 9.

[0033] A first sealing ring 11 is provided between the side wall of the drive disc 5 and the side wall of the brake housing. A second sealing ring 12 and a third sealing ring 13, coaxial with the drive shaft 1, are provided between the drive disc 5 and the right housing 3. The second sealing ring 12 is close to the drive shaft 1, and the third sealing ring 13 is close to the aluminum ring 6 and the polytetrafluoroethylene ring 7. The gaps between the first sealing ring 11 and the left housing 2, and between the second sealing ring 12 and the third sealing ring 13, are filled with magnetorheological fluid 14. The drive disc 5 has at least one through hole 15, which connects the gap between the first sealing ring 11 and the left housing 2 with the gap between the second sealing ring 12 and the third sealing ring 13.

[0034] A liquid injection hole is also provided on the left shell 2, and a liquid injection plug is installed in the liquid injection hole for injecting and replacing the magnetorheological fluid 14.

[0035] In this design, when a magnetic field is present, the magnetostrictive rod 8 located on the right side of the PTFE disk will extend and push the PTFE disk to the left, bringing it into contact with the aluminum ring 6 and generating friction. The formula for the current generated by this friction is:

[0036]

[0037] In the formula: I is the current, k0 is a material-related coefficient representing the fundamental influence of the material on the triboelectric effect without compressive force, α is the force-affecting factor of the material, F is the compressive force between the two disks, ∈0 is the vacuum permittivity, ∈ r Let be the relative permittivity, R be the outer radius of the disk, r be the inner radius of the disk, and ω be the angular velocity.

[0038] During the work process:

[0039] 1. In the initial state, the excitation coil 4 is not energized, the drive shaft 1 rotates, and the magnetorheological fluid 14 is in a liquid state. The torque generated by the zero magnetic field viscosity of the magnetorheological fluid 14 alone cannot make the driven disk rotate, and no frictional electricity is generated.

[0040] 2. When the excitation coil 4 is energized, the magnetic lines of force generated by the excitation coil 4 penetrate the working gap of the magnetorheological fluid 14, causing the magnetorheological fluid 14 to change from a liquid state to a near-solid state. In addition, the magnetostrictive rod 8 extends along the direction of the magnetic field and pushes the polytetrafluoroethylene disk to the left, contacting the aluminum ring 6 riveted to the active disk 5, generating frictional transmission and electricity. The generated electricity is transmitted through wires and brushes to the copper wire on the shape memory alloy spring 10 located on the active disk 5. The copper wire consumes electrical energy and generates heat, heating the shape memory alloy spring 10. As the temperature rises, the shape memory alloy spring 10 extends to the left, pushing the friction column 9 to squeeze the magnetorheological fluid 14, continuously moving to the left, and finally contacting the inner surface of the shell, generating frictional transmission.

[0041] 3. After the excitation coil 4 is de-energized, the magnetorheological fluid 14 returns to a liquid state, the magnetostrictive rod 8 retracts into the sleeve, the aluminum ring 6 separates from the polytetrafluoroethylene ring 7, and no longer generates friction or electricity. The shape memory alloy spring 10 gradually retracts as the temperature drops, and no longer generates friction. The brake no longer applies.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of this utility model that do not depart from the spirit and scope of this technical solution should be covered within the scope of the claims of this utility model.

Claims

1. A magnetorheological brake with piezoelectric-thermal shape memory control function, comprising a drive shaft and a brake housing, the brake housing comprising a left housing and a right housing connected together, a coil groove with one revolution around the brake housing provided at the connection between the left housing and the right housing, and an excitation coil wound in the coil groove; one end of the drive shaft passes through the right housing and extends into the brake housing, and is rotatably connected to the right housing, the end of the drive shaft extending into the brake housing being fixedly connected to a drive disc, and there is a gap between the drive disc and the inner side of the brake housing; characterized in that: Near the edge on the right side of the active disk, there is an aluminum ring that wraps around the active disk. On the inner side of the right housing, opposite the aluminum ring, there is a polytetrafluoroethylene (PTFE) ring. On the right housing, there are several grooves corresponding to the position of the PTFE ring. In each groove, there is a magnetostrictive rod. The magnetostrictive rod is fitted with the groove with a gap. One end of the rod near the PTFE ring is fixedly connected to the PTFE ring, and the other end is fixedly connected to the bottom of the groove. In the initial state, there is a gap between the PTFE ring and the aluminum ring. A receiving groove is provided in the middle of the active disk, and a friction post is slidably fitted in the receiving groove. A shape memory alloy spring is provided between the friction post and the bottom of the receiving groove, and a copper wire is wound on the shape memory alloy spring. In the initial state, there is a gap between the end of the friction post near the left housing and the left housing. One end of the copper wire is connected to an aluminum ring, and the other end is connected to a polytetrafluoroethylene ring. A first sealing ring is provided between the side wall of the drive disc and the side wall of the brake housing. A second sealing ring and a third sealing ring, coaxial with the drive shaft, are provided between the drive disc and the right housing. The second sealing ring is close to the drive shaft, and the third sealing ring is close to the aluminum ring and the polytetrafluoroethylene ring. The gap between the first sealing ring and the left housing, and the gap between the second sealing ring and the third sealing ring, are filled with magnetorheological fluid.

2. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: The active disk has several through holes, which connect the gap between the first sealing ring and the left housing with the gap between the second sealing ring and the third sealing ring.

3. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: There is a gap between the right housing and the drive shaft, and a brush slip ring is installed in the gap. The brush of the brush slip ring is connected to a copper wire, and the slip ring of the brush slip ring is connected to a polytetrafluoroethylene ring through a wire. The aluminum ring is directly connected to the copper wire through a wire.

4. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1 or 3, characterized in that: A bearing is also provided between the right housing and the drive shaft.

5. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: The active disk has several radially distributed protrusions evenly distributed around one side of the left housing. The length direction of the protrusions is consistent with the radial direction of the active disk, and the cross-section of the protrusions is semi-circular.

6. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: The end face of the friction post near the left housing is a friction surface and is spherical; correspondingly, the inner side of the left housing has a spherical groove at the position of the friction post.

7. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: A liquid injection hole is also provided on the left housing, and a liquid injection plug is fitted inside the liquid injection hole.

8. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: At corresponding positions on the surfaces where the left and right shells meet, an annular groove is provided. When the two shells are closed, the two annular grooves form the coil groove. A magnetic isolation ring is provided inside the excitation coil, and the excitation coil is enclosed in the coil groove by the magnetic isolation ring.

9. A magnetorheological brake with piezoelectric-thermal shape memory control function according to claim 1, characterized in that: A through cover is provided on the outside of the right housing. The through cover is fitted onto the drive shaft and fixedly connected to the right housing. A fourth sealing ring is provided between the through cover and the drive shaft.

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