Electromagnetic damper with variable lead based on safety protection

Abstract

The application discloses a variable lead electromagnetic damper based on safety protection, which comprises a frameless torque motor, a screw nut, a guide ring, a three-layer composite screw outer cylinder, a permanent magnet ring and an electromagnetic attractor, etc. The guide ring is linked with the screw nut and is provided with rolling bodies on the outer surface. The inner conductive layer of the three-layer composite screw outer cylinder is provided with variable lead screw grooves matched with the rolling bodies. The permanent magnet ring is nested outside the screw nut and moves with the screw nut. The three-layer composite screw outer cylinder is provided with mounting through holes. When the frameless torque motor fails, the electromagnetic attractor will contact the inner conductive layer through the mounting through holes and form a closed loop. The application reduces the transmission ratio in the middle stroke section through the variable lead screw grooves, reduces the rotational inertia impact under high frequency and low amplitude, reduces the screw wear and realizes the safety protection at the structure level. When the frameless torque motor fails, the electromagnetic attractor makes the inner conductive layer form a closed loop, generates electromagnetic damping and realizes the safety protection at the failure level.

Description

Technical Field

[0001] This invention relates to the field of vibration damper technology, specifically to a variable lead electromagnetic vibration damper based on safety protection, which is particularly suitable for vibration control of vehicle suspension systems. Background Technology

[0002] In existing technologies, ball screw-type electromagnetic vibration dampers rely solely on the lead of the ball screw for operation, resulting in a fixed transmission ratio. This fails to meet the diverse vibration damping requirements under different operating conditions and is prone to mechanical transmission component failure under high-frequency excitation. Current technologies include variable damping and variable stiffness electromagnetic vibration dampers, which can alter the performance of the damper to some extent, but cannot change the transmission ratio by modifying the inherent lead of the ball screw. Furthermore, current technologies lack safety protection in case of frameless torque motor failure.

[0003] A search revealed that relevant existing technologies include:

[0004] 1. CN202410895820.5, A dual-moving-coil variable stiffness electromagnetic vibration damper. This scheme achieves stiffness adjustment through the cooperation of two moving coils, but the structure is complex, the size and weight are large, and the transmission ratio cannot be changed.

[0005] 2. CN202221364514.1, A damping adjustment mechanical device for an electromagnetic vibration damper. This solution uses a single-lead ball screw with a fixed transmission ratio. The damping coefficient can only be changed by adjusting the current of the frameless torque motor, but the transmission ratio cannot be changed. This results in the inability to simultaneously meet the requirements of low-speed high damping and high-speed low damping. Under high-frequency conditions, the large reciprocating rotational inertia will exacerbate the failure of the ball screw.

[0006] Disadvantages of existing technology:

[0007] Main disadvantages: High-frequency reciprocating vibration impact easily causes ball screw failure, and there is a lack of safety protection after failure. Because the ball screw lead is fixed and the transmission ratio is constant, under high-frequency small-amplitude vibration conditions, the vibration damper needs to drive the ball screw to rotate at high frequency, generating a large reciprocating rotational inertia impact, which accelerates the wear and failure of the ball screw in the middle stroke section and shortens its service life; at the same time, existing electromagnetic vibration dampers completely lose damping when the motor fails, lacking a safety protection mechanism in the failure state, which poses a safety hazard.

[0008] Secondary disadvantages:

[0009] 1. Current technologies based on variable damping or variable stiffness of electromagnetic vibration dampers result in electromagnetic vibration dampers having a large mass or volume, making it impossible to achieve lightweight design.

[0010] 2. Current optimization designs based on electromagnetic vibration dampers require significant changes to the original vibration damper design.

[0011] 3. High-speed and high-precision applications require the replacement of lead screws with different lead pitches, resulting in high operating costs and poor versatility.

[0012] Causal reasoning:

[0013] Because the ball screw lead in existing electromagnetic vibration dampers is fixed, the transmission ratio cannot be changed by altering the lead, resulting in fixed performance. Furthermore, existing optimization schemes involving variable damping or stiffness lead to increased size or mass and significant alterations to the original design. In addition, existing electromagnetic vibration dampers do not consider safety issues arising from the failure of mechanical transmission components and frameless torque motors. These combined shortcomings result in poor adaptability of electromagnetic vibration dampers, failing to meet the comprehensive comfort and safety requirements of real-world vehicles. Summary of the Invention

[0014] The technical problem to be solved by this invention is to provide a variable lead electromagnetic vibration damper based on safety protection, which addresses the shortcomings of the prior art. This variable lead electromagnetic vibration damper based on safety protection achieves passive adaptive change of the equivalent lead through the pre-rotation function of the guide ring and the variable lead spiral groove, solving the problem of large reciprocating inertial impact force output by the electromagnetic vibration damper under high-frequency road excitation caused by a single fixed lead transmission ratio, and reducing high-frequency wear of the lead screw. Through the safety damping mechanism composed of a three-layer composite lead screw outer cylinder and a permanent magnet ring, an additional electromagnetic damping force is automatically generated when the frameless torque motor fails, thereby improving safety and reliability.

[0015] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0016] A variable lead electromagnetic vibration damper based on safety protection includes an upper mounting base, a lower mounting base, a frameless torque motor, a hollow piston rod, a lead screw drive assembly, a lead screw nut, a guide ring, a three-layer composite lead screw outer cylinder, a permanent magnet ring, and an electromagnetic attractor.

[0017] The lower mounting base is used to connect the lower lifting lug and is fixedly connected to the lower end of the hollow piston rod through the piston rod nut;

[0018] The upper end of the hollow piston rod is connected to the lead screw nut, which is used to transmit road excitation to the lead screw drive assembly;

[0019] The top of the lead screw drive assembly is connected to the rotor of the frameless torque motor;

[0020] The guide ring is linked with the lead screw nut, and its outer surface is provided with rolling elements. The inner conductive layer of the three-layer composite lead screw outer cylinder is provided with a variable lead spiral groove that cooperates with the rolling elements. When the guide ring moves axially with the lead screw nut, it rotates along the variable lead spiral groove to change the equivalent lead of the lead screw transmission assembly.

[0021] The permanent magnet ring is nested outside the lead screw nut and moves synchronously with the hollow piston rod;

[0022] The three-layer composite screw outer cylinder is composed of an inner conductive layer, a middle insulating layer and an outer metal layer. Its upper end is connected to the housing of the frameless torque motor, and its lower end is connected to the outer cylinder end cap. The outer cylinder end cap is slidably connected to the hollow piston rod.

[0023] The outer cylinder of the three-layer composite screw is provided with a mounting through hole, and part of the inner conductive layer is exposed in the mounting through hole;

[0024] The electromagnetic attractor is connected to the housing of the frameless torque motor, and the moving end of the electromagnetic attractor is used to extend into the mounting through hole and contact the inner conductive layer when the frameless torque motor fails, so that the inner conductive layer forms a closed circuit.

[0025] The upper mounting bracket is connected to the top of the housing of the frameless torque motor and is used to connect the upper lifting lug.

[0026] As a further improvement of the present invention, the inner conductive layer is an integral conductive cylinder structure with a strip-shaped opening penetrating its upper and lower ends, the strip-shaped opening forming a break in the inner conductive layer in the circumferential direction; the inner surface of the intermediate insulating layer is provided with a strip-shaped protrusion for embedding the strip-shaped opening, the surface of the strip-shaped protrusion being flush with the inner surface of the inner conductive layer, the variable lead spiral groove being disposed on the surface of the strip-shaped protrusion and the inner surface of the inner conductive layer, and the variable lead spiral groove extending continuously between the surface of the strip-shaped protrusion and the inner surface of the inner conductive layer; the mounting through hole is opened on the outer cylinder of the three-layer composite screw and penetrates the strip-shaped protrusion.

[0027] As a further improvement of the present invention, the electromagnetic attractor adopts a suction-type cylindrical electromagnet. When working normally, its moving end is in a retracted state. When the frameless torque motor fails, its moving end extends out and enters the mounting through hole and contacts the inner conductive layer on both sides of the strip opening, so that the inner conductive layer on both sides of the strip opening forms an electrical connection through the moving end of the electromagnetic attractor.

[0028] As a further improvement of the present invention, the variable lead spiral groove is a spiral groove whose lead changes continuously along the axial direction. The lead at the middle position of the variable lead spiral groove is smaller than the lead at both sides, and the lead tends to a fixed value at both ends. The rolling element on the outer surface of the guide ring is precisely matched with the variable lead spiral groove of the inner conductive layer, and the rotation direction of the variable lead spiral groove is opposite to the rotation direction of the lead screw drive assembly.

[0029] As a further improvement of the present invention, the inner conductive layer of the three-layer composite screw outer cylinder is provided with multiple through holes for heat dissipation and weight reduction.

[0030] As a further improved technical solution of the present invention, the upper end of the hollow piston rod is fixedly connected to the external thread of the lead screw nut connecting guide block through the internal thread, the internal thread of the lead screw nut connecting guide block is fixedly connected to the external thread of the lead screw nut connecting piece, and the lead screw nut connecting piece and the lead screw nut are fixedly connected by a key; the guide ring is nested on the lead screw nut connecting piece; there are multiple permanent magnet rings, which are respectively nested outside the lead screw nut connecting piece and the lead screw nut connecting guide block.

[0031] As a further improved technical solution of the present invention, the guide ring and the lead screw nut connector are fixedly connected by a cylindrical pin, and the permanent magnet ring is fixedly connected to the lead screw nut connector and the lead screw nut connecting guide block by means of glue injection.

[0032] As a further improved technical solution of the present invention, there are three permanent magnet rings, two of which are fixedly connected to the outside of the lead screw nut connector and are located above and below the guide ring respectively, and one permanent magnet ring is fixedly connected to the outside of the lead screw nut connecting guide block.

[0033] As a further improved technical solution of the present invention, the internal thread at the lower end of the three-layer composite screw outer cylinder is threadedly connected to the external thread of the outer cylinder end cap, and the external thread at the upper end of the three-layer composite screw outer cylinder is threadedly connected to the internal thread of the housing of the frameless torque motor.

[0034] As a further improvement of the present invention, a piston rod protective cover is provided on the outside of the hollow piston rod. The top inner surface of the piston rod protective cover is slidably connected to the outer cylinder of the three-layer composite screw. The bottom of the piston rod protective cover is connected to the piston rod protective base through external threads. The piston rod protective base is snapped into the shoulder of the piston rod nut. A lower spring seat is threadedly connected to the lower outer surface of the piston rod protective cover. A spring is provided between the lower spring seat and the bottom of the housing of the frameless torque motor, and the spring is sleeved on the outside of the piston rod protective cover.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. Reduces high-frequency reciprocating inertial impact, improves shock absorber life, and achieves structural safety protection. This invention achieves passive adaptive change of the equivalent lead with the shock absorber's stroke position through the cooperation of the rolling element on the outer surface of the guide ring and the variable lead helical groove of the inner conductive layer of the three-layer composite screw outer cylinder. When the shock absorber is working near the equilibrium position (middle stroke section), the helical groove lead is small, the pre-rotation angle generated by the guide ring is large, the equivalent lead increases significantly, and the transmission ratio decreases. This reduces the reciprocating rotational inertia impact force of the screw drive assembly under high-frequency, small-amplitude vibration conditions, reducing the risk of wear failure of the screw in the middle stroke section and extending the service life of the shock absorber. When the shock absorber moves to near the compression or tension limit (both sides of the stroke section), the helical groove lead increases, the pre-rotation angle generated by the guide ring decreases, the equivalent lead approaches the inherent lead, and the transmission ratio increases. This ensures sufficient linear damping force under large-amplitude vibration conditions, effectively suppressing large-amplitude vehicle body vibrations. Therefore, this invention achieves passive adaptive suppression of high-frequency reciprocating inertial impacts of the lead screw drive assembly through a purely mechanical structure, thereby improving the operational reliability and service life of the vibration damper from a structural perspective.

[0037] Meanwhile, the control system can adjust the drive current in real time according to the vehicle speed sensor signal. When driving at low speed, it sends a larger drive current command to make the frameless torque motor generate a larger electromagnetic torque and output a larger linear damping force; when driving at high speed, it sends a smaller drive current command to make the frameless torque motor generate a smaller electromagnetic torque and output a smaller linear damping force. This realizes the adaptive adjustment of the damping force to the vehicle speed, taking into account both the handling stability at low speed and the ride comfort at high speed.

[0038] 2. Lightweight design and compact structure. The variable lead structure (i.e., guide ring and variable lead spiral groove) and safety protection structure (i.e., the inner conductive layer of the three-layer composite lead screw outer cylinder, permanent magnet ring, and electromagnetic attractor) of this invention are all integrated inside the lead screw nut and lead screw outer cylinder, eliminating the need for additional independent drive mechanisms and control units. Simultaneously, multiple through holes on the inner conductive layer further enhance heat dissipation and weight reduction. The volume and weight are essentially equivalent to or lighter than traditional electromagnetic vibration dampers, solving the problem of increased mass or volume caused by existing variable damping or variable stiffness technologies.

[0039] 3. Strong compatibility, directly replacing existing products: This invention only improves the lead screw nut and its auxiliary components (i.e., guide ring, permanent magnet ring, etc.) and the three-layer composite lead screw outer cylinder (i.e., integrating the guide ring, permanent magnet ring, etc., replacing the ordinary lead screw outer cylinder with a three-layer composite lead screw outer cylinder). The main structure of the frameless torque motor, the shape and interface of the frameless torque motor housing, the encoder installation method, and the interface dimensions of the upper and lower mounting brackets and lifting lugs remain unchanged. The connection method (threaded) between the upper end of the lead screw outer cylinder and the frameless torque motor housing, and the connection method (threaded) between the lower end and the outer cylinder end cap are consistent with existing products. Therefore, this invention focuses all improvements on the core (lead screw nut and its auxiliary components, lead screw outer cylinder), without touching the outer shell, interface, or external connection method. That is, this invention adopts a compatible design and can directly replace the existing single-lead ball screw electromagnetic shock absorber without any modification to the suspension system's mounting bracket, control unit, or overall vehicle layout, solving the problem that existing optimization designs require significant changes to the original shock absorber structure.

[0040] 4. High versatility, one mechanism covers a variety of working conditions. By designing different lead variation curves of the variable lead helical groove, different equivalent lead variation characteristics with stroke can be obtained. There is no need to replace the lead screw with different lead specifications for different working conditions, which reduces the cost of use and improves the versatility of the product.

[0041] 5. Enhanced Safety and Reliability: This invention provides a purely passive, fail-safe protection mechanism that requires no external power supply, through the combination of a three-layer composite screw outer cylinder and a permanent magnet ring. During normal operation, the strip-shaped opening creates a circumferential break in the inner conductive layer, disconnecting the circuit and preventing the generation of additional damping force. When the frameless torque motor fails, the moving end of the electromagnetic attractor extends into the mounting through-hole, allowing the inner conductive layer to form an electrical connection through the moving end of the electromagnetic attractor, thus creating a closed conductive circuit. As the permanent magnet ring moves up and down with the screw nut, the closed circuit cuts the magnetic field lines generated by the permanent magnet ring, inducing a current according to Lenz's law, which in turn generates an electromagnetic damping force that opposes the movement of the permanent magnet ring. This solves the safety hazard of complete loss of damping in existing electromagnetic dampers when the frameless torque motor fails, ensuring basic vehicle driving safety.

[0042] In summary, this invention achieves an increase in equivalent lead through the cooperation of the guide ring and the variable lead spiral groove. It also provides structural safety protection to reduce lead screw wear and failure safety protection in case of frameless torque motor failure through the cooperation of the variable lead spiral groove, the three-layer composite lead screw outer cylinder, and the permanent magnet ring. Furthermore, its compatible design ensures direct product replaceability. All these technical effects are achieved through a compact structure integrated within the lead screw nut and the three-layer composite lead screw outer cylinder, without adding an independent drive mechanism or control unit. Ultimately, this results in a high-performance, safe, reliable, lightweight, low-cost, and highly compatible electromagnetic vibration damper. Attached Figure Description

[0043] Figure 1 This is a perspective view of the electromagnetic vibration damper of the present invention.

[0044] Figure 2 This is a front view of the electromagnetic vibration damper of the present invention.

[0045] Figure 3 for Figure 2 AA section view.

[0046] Figure 4 This is a schematic diagram of the structure of the three-layer composite screw outer cylinder of the present invention.

[0047] Figure 5 This is an exploded view of the three-layer composite screw outer cylinder of the present invention.

[0048] Figure 6 This is a schematic diagram of the structure of the inner conductive layer of the present invention.

[0049] Figure 7 for Figure 6 BB cross-section diagram.

[0050] Figure 8 This is a schematic diagram of the guide ring structure of the present invention.

[0051] Figure 9 This is a flowchart illustrating the control principle of the present invention. Detailed Implementation

[0052] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0053] like Figure 1-9 As shown, this embodiment provides a variable lead electromagnetic vibration damper based on safety protection, mainly including a lower lifting lug 1, a lower mounting base 2, a piston rod nut 3, a hollow piston rod 4, a piston rod protective base 5, an outer cylinder end cap 6, a lower spring seat 7, a spring rubber pad 8, a three-layer composite screw outer cylinder 9, a piston rod protective cover 10, a screw nut connecting guide block 11, a permanent magnet ring 12, a screw nut 13, a screw nut connector 14, a guide ring 15, a rubber pad 16, a spring 17, a frameless torque motor 18, a frameless torque motor housing 19, an upper mounting base 20, an upper lifting lug 21, a screw transmission assembly 22, and an electromagnetic attractor 23.

[0054] In this embodiment, the lead screw drive assembly 22 preferably uses a ball screw, which is used to convert linear motion into rotational motion. The encoder is a component known in the art and can be optionally mounted on the housing 19 of the frameless torque motor 18. It is used to detect the rotation angle and speed of the lead screw drive assembly 22, and is not separately labeled in the drawings.

[0055] Structural connection relationships:

[0056] like Figure 3 As shown, the lower mounting base 2 is connected to the piston rod nut 3 via threads, and is used to connect the lower lifting lug 1. The piston rod nut 3 is engaged in the piston rod protective base 5 via a shoulder portion, which is used to restrict the lower lifting lug 1 and make it completely fixed. The piston rod nut 3 is screwed into the lower end of the hollow piston rod 4 via external threads. The piston rod protective base 5 is screwed into the bottom of the piston rod protective cover 10 via external threads.

[0057] like Figure 3 As shown, the upper end of the hollow piston rod 4 is fixedly connected to the external thread of the lead screw nut connecting guide block 11 via the internal thread. The internal thread of the lead screw nut connecting guide block 11 is fixedly connected to the external thread of the lead screw nut connecting piece 14. The lead screw nut connecting piece 14 and the lead screw nut 13 are fixedly connected by a key. The lead screw nut 13 is fitted onto the lead screw transmission assembly 22. The two are helically engaged by ball bearings, converting the linear motion of the lead screw nut 13 into the rotational motion of the lead screw transmission assembly 22. A rubber pad 16 is filled between the top of the lead screw nut 13 and the lead screw nut connecting piece 14, and a rubber pad 16 is filled between the bottom of the lead screw nut 13 and the lead screw nut connecting guide block 11.

[0058] like Figure 8 As shown, the guide ring 15 is nested on the lead screw and nut connector 14 and connected by positioning welding via a cylindrical pin. A rolling element 1501 is provided on the outer surface of the guide ring 15. The inner conductive layer 9A of the three-layer composite lead screw outer cylinder 9 is provided with a variable lead spiral groove 904 that precisely matches the rolling element 1501. In this embodiment, the rolling element 1501 is preferably a ball bearing, which is rotatably embedded in a receiving hole on the outer surface of the guide ring 15, with the ball bearing portion protruding from the outer surface of the guide ring, forming a rolling fit with the variable lead spiral groove 904. Three permanent magnet rings 12 are nested on the outside of the lead screw and nut connector 14 and the lead screw and nut connecting guide block 11, respectively. Two permanent magnet rings 12 are fixedly connected to the outside of the lead screw and nut connector 14 and are located above and below the guide ring 15, respectively. One permanent magnet ring 12 is fixedly connected to the outside of the lead screw and nut connecting guide block 11. The permanent magnet rings 12 are fixed by injection molding. The guide ring 15 is made of copper.

[0059] like Figure 7 As shown, the variable lead spiral groove 904 is a spiral groove with a continuously varying lead along the axial direction. The lead at the middle position of the variable lead spiral groove 904 is smaller than the lead at its two sides, and the lead tends to a fixed value at both ends. The rolling element 1501 on the outer surface of the guide ring 15 is precisely fitted with the variable lead spiral groove 904 of the inner conductive layer 9A. The rotation direction of the variable lead spiral groove 904 is opposite to the rotation direction of the lead screw drive assembly 22. When the guide ring 15 moves axially with the lead screw nut 13, it rotates along the variable lead spiral groove 904 to change the equivalent lead of the lead screw drive assembly 22.

[0060] like Figure 4-7 As shown, the three-layer composite lead screw outer cylinder 9 is composed of an inner conductive layer 9A, an intermediate insulating layer 9B, and an outer metal layer 9C. The inner conductive layer 9A is an integral conductive cylinder structure with a strip-shaped opening 902 penetrating its upper and lower ends, creating a circumferential break in the inner conductive layer 9A. The inner surface of the intermediate insulating layer 9B has a strip-shaped protrusion 903 for embedding the strip-shaped opening 902, and the surface of the strip-shaped protrusion 903 is flush with the inner surface of the inner conductive layer 9A. A variable lead spiral groove 904 is provided on the surface of the strip-shaped protrusion 903 and the inner surface of the inner conductive layer 9A, and the variable lead spiral groove 904 extends continuously between the surface of the strip-shaped protrusion 903 and the inner surface of the inner conductive layer 9A. The outer cylinder 9 of the three-layer composite screw has a mounting through hole 901, through which a strip-shaped protrusion 903 passes, and part of the inner conductive layer 9A is exposed inside the mounting through hole 901. The inner conductive layer 9A also has multiple through holes for heat dissipation and weight reduction.

[0061] The internal thread at the lower end of the three-layer composite screw outer cylinder 9 is threadedly connected to the external thread of the outer cylinder end cap 6. The outer cylinder end cap 6 is fitted over the hollow piston rod 4 and is slidably connected to it through a sealing ring. The external thread at the upper end of the three-layer composite screw outer cylinder 9 is threadedly connected to the internal thread of the housing 19 of the frameless torque motor 18. A rubber pad 16 is provided between the top of the three-layer composite screw outer cylinder 9 and the inner step of the housing 19 of the frameless torque motor 18.

[0062] In this embodiment, the electromagnetic attractor 23 is a cylindrical electromagnet designed for suction, which is a de-energized extension type electromagnet, and it has a return spring inside. Under normal energized conditions, the electromagnetic force overcomes the spring force to keep the moving end in the retracted position; when the power is off, the electromagnetic force disappears, and the moving end automatically extends under the action of the return spring.

[0063] The housing of the electromagnetic attractor 23 is threadedly connected to the housing 19 of the frameless torque motor 18, and a slot is provided on the upper spring rubber pad 8 to avoid the electromagnetic attractor 23. The moving end of the electromagnetic attractor 23 is in a retracted state during normal operation. When the frameless torque motor 18 fails, it extends out and enters the mounting through hole 901, contacting the inner conductive layer 9A on both sides of the strip opening 902, so that the inner conductive layer 9A on both sides of the strip opening 902 forms an electrical connection through the moving end of the electromagnetic attractor 23.

[0064] The hollow piston rod 4 is fitted with a piston rod protective cover 10. The top inner surface of the piston rod protective cover 10 is slidably connected to the outer surface of the three-layer composite screw outer cylinder 9 through a sealing ring to prevent external impurities from entering the damper and ensure a clean working environment for the moving parts. The bottom of the piston rod protective cover 10 is connected to the piston rod protective base 5 through an external thread. A lower spring seat 7 is threaded onto the lower outer surface of the piston rod protective cover 10, and a spring rubber pad 8 is provided on the lower spring seat 7. A spring rubber pad 8 is provided at the bottom of the housing 19 of the frameless torque motor 18. A spring 17 is provided between the spring rubber pad 8 on the lower spring seat 7 and the spring rubber pad 8 at the bottom of the housing 19 of the frameless torque motor 18. The spring 17 is fitted onto the outside of the piston rod protective cover 10.

[0065] The upper mounting bracket 20 is screwed into the top of the housing 19 of the frameless torque motor 18 via an external thread for connecting the upper lifting lug 21.

[0066] The frameless torque motor 18 is a frameless torque motor, nested inside the housing 19. The top of the lead screw drive assembly 22 is connected to the rotor of the frameless torque motor 18.

[0067] Optionally, the encoder housing is bolted to the housing 19 of the frameless torque motor 18 via a fixed bracket. Its rotating part is connected to the end of the lead screw drive assembly 22. The encoder is used to detect the rotation angle and speed of the frameless torque motor and feed it back to the control system to achieve closed-loop control.

[0068] Working principle:

[0069] I. Working principle of variable lead:

[0070] This invention employs a variable lead spiral groove to achieve passive adaptive variation of the equivalent lead. The lead of the variable lead spiral groove changes continuously along the axial direction, with the lead at the middle position being smaller than the lead at the two sides, and the lead tending to a fixed value at both ends.

[0071] The variable lead function is achieved through the cooperation of the guide ring and the internal helical groove of the three-layer composite screw outer cylinder, without the need for an additional drive mechanism. The working principle is as follows:

[0072] When the suspension is excited by the road surface and generates relative motion, the hollow piston rod 4 drives the lead screw nut 13 to move up and down. The rolling element 1501 on the outer surface of the guide ring 15 rolls along the variable lead spiral groove of the inner conductive layer 9A of the three-layer composite lead screw outer cylinder 9. Since the rotation direction of the variable lead spiral groove is opposite to the rotation direction of the lead screw drive assembly 22, the guide ring 15 generates a pre-rotation opposite to the rotation direction of the lead screw drive assembly 22, which partially cancels the rotation angle of the lead screw, causing the equivalent lead of the lead screw drive assembly 22 to change.

[0073] Lead of the lead screw : refers to the inherent lead of the lead screw itself, that is, the lead screw's rotation per revolution ( When the radius is radians, the distance the lead screw nut moves axially along the lead screw drive assembly 22 is considered. This value is determined by the geometric parameters of the thread of the lead screw drive assembly 22 and is a fixed value, such as the SFU1610 type ball screw used in the preferred embodiment of the present invention, whose inherent lead is... .

[0074] Screw rotation angle The axial displacement z of the lead screw nut refers to the angle by which the lead screw drive assembly 22 rotates when the lead screw nut moves a certain distance. This is related to the rotation angle of the lead screw. The relationship is as follows:

[0075] ;

[0076] Variable lead spiral groove lead : refers to the lead of the variable lead spiral groove 904 opened on the inner wall of the three-layer composite screw outer cylinder 9 at the axial position z, that is, the guide ring 15 moves axially along the variable lead spiral groove 904. When the distance is measured, it rotates one revolution relative to the outer cylinder. (Radius). Because the spiral groove employs a variable lead design. The lead changes continuously with the axial position z: the lead is small at the middle position and large at the two sides.

[0077] The guide ring rotates relative to the outer cylinder at an angle : The angle of rotation of the guide ring 15 relative to the outer cylinder 9 of the three-layer composite screw when it moves axially along the variable lead spiral groove 904. The relationship is as follows:

[0078] ;

[0079] Because the rotation direction of the variable lead helical groove is opposite to that of the lead screw drive assembly 22, the guide ring 15 generates a pre-rotation opposite to the rotation direction of the lead screw drive assembly 22, partially offsetting the rotation angle of the lead screw. The total rotation angle of the lead screw is as follows:

[0080] ;

[0081] Equivalent lead Equivalent lead refers to the distance the lead screw nut moves when the lead screw drive assembly 22 rotates one revolution during actual operation, after considering the pre-rotation counteracting effect of the guide ring 15. Due to the inherent lead of the lead screw With variable lead spiral groove lead A joint decision. Order The relationship is as follows:

[0082] ;

[0083] in This is the inherent lead of the lead screw. Let z be the lead of the variable lead helical groove at position z, and Greater than .

[0084] Since the lead of the variable lead spiral groove 904 changes continuously along the axial direction, the equivalent lead also changes continuously with the stroke position of the damper.

[0085] As an exemplary numerical embodiment: taking the SFU1610 ball screw as an example, its inherent lead Assume the total stroke of the shock absorber is 120mm (i.e., 60mm on each side of the equilibrium position); the lead of the variable lead helical groove 904 in the middle stroke section (within ±10mm of the equilibrium position) is... Take 12mm as the lead in the stroke range on both sides (within ±10mm to ±60mm of the balance position). The lead gradually increases from 12mm to 40mm. All of the above lead values ​​are greater than the inherent lead of the lead screw. (Right now > To ensure the denominator of the equivalent lead formula is positive, a smaller lead is used in the middle stroke section to reduce the transmission ratio and suppress high-frequency inertial impact, while a larger lead is used in the two side stroke sections to ensure linear damping force under large-amplitude vibration conditions. Substituting into the equivalent lead formula for calculation: In the middle stroke section, when... At that time, equivalent lead The transmission ratio is reduced to ; on both sides of the travel section, when At that time, equivalent lead The transmission ratio is reduced to .

[0086] Therefore, in the middle stroke section, the reciprocating rotation requirement of the lead screw drive assembly is reduced to about 1 / 6 of that of the fixed lead scheme, and the impact force of the reciprocating rotation inertia is reduced proportionally, which significantly reduces the risk of wear failure of the lead screw in the middle stroke section and extends its service life.

[0087] When the vibration damper is in the middle stroke section (near the equilibrium position), the lead of the variable lead spiral groove is small, the pre-rotation angle generated by the guide ring 15 is large, the equivalent lead is significantly increased, the transmission ratio is reduced, and the reciprocating rotational inertia impact force of the screw drive assembly under high-frequency small-amplitude vibration is reduced accordingly (the damping generation mechanism of the vibration damper in passive state (frameless torque motor is driven to rotate by the screw as a generator)). This reduces the risk of wear failure of the screw in the middle stroke section and extends the service life of the vibration damper.

[0088] When the shock absorber moves to near its compression or tension limit (both sides of the travel section), the lead of the variable lead spiral groove increases, the pre-rotation angle generated by the guide ring 15 decreases, the equivalent lead approaches the inherent lead, the transmission ratio increases, the shock absorber exhibits a larger damping force, effectively suppressing large vibrations of the vehicle body and improving handling stability and safety.

[0089] Therefore, this invention eliminates the need for sensors, controllers, and actuators. It achieves passive adaptive suppression of high-frequency reciprocating inertial impacts on the screw drive assembly through a purely mechanical structure of a variable lead spiral groove, thus providing structural safety protection for the vibration damper.

[0090] II. Working principle of active damping in frameless torque motors:

[0091] like Figure 9 As shown, when the frameless torque motor 18 is working normally, the control system calculates the required target damping force based on sensor signals such as vehicle acceleration and suspension deflection (using existing technology, which is not within the scope of protection of this invention), and sends a corresponding current command to the driver of the frameless torque motor 18. After the frameless torque motor 18 is energized, it generates electromagnetic torque, which is converted into axial linear force via the lead screw drive assembly 22 and acts on the suspension system to suppress vehicle vibration. By adjusting the magnitude of the drive current in real time, the damping force can be continuously controlled; optionally, the encoder can detect the rotation angle and speed of the frameless torque motor in real time and feed it back to the control system to achieve closed-loop control. At this time, the inner conductive layer 9A circuit of the three-layer composite lead screw outer cylinder 9 is in an open state, the movement of the permanent magnet ring 12 does not generate additional electromagnetic damping force, and the damping force of the shock absorber is entirely actively controlled by the frameless torque motor 18.

[0092] The passive adaptive characteristics provided by the variable lead spiral groove are superimposed with the damping force generated by the active control of the frameless torque motor 18: the variable lead spiral groove reduces the high-frequency reciprocating inertial impact by reducing the transmission ratio in the middle stroke section, and the active control of the frameless torque motor 18 provides a real-time adjustable dynamic damping force. The two work together to ensure the vibration reduction effect while also protecting the structure of the lead screw drive assembly.

[0093] III. Working principle of safety protection:

[0094] The "safety-based protection" of this invention has two layers of meaning: firstly, structural protection, which involves reducing the transmission ratio under high-frequency, small-amplitude vibration conditions through a variable lead helical groove, thereby reducing the impact of reciprocating rotational inertia, reducing lead screw wear, and extending service life; secondly, failure-level protection, which involves the mechanical conductive layer forming a closed loop when the frameless torque motor fails, superimposing new electromagnetic damping, and improving the failure safety protection capability of the vibration reduction system. These will be explained below with reference to the accompanying drawings.

[0095] During normal operation, the strip-shaped opening 902 on the inner conductive layer 9A of the three-layer composite screw outer cylinder 9 creates a break in the inner conductive layer in the circumferential direction, and the inner conductive layer 9A is in a circuit-disconnected state. At this time, when the permanent magnet ring 12 moves up and down with the screw nut 13, there is no closed conductive circuit, no induced current is generated, and therefore no additional damping force is generated.

[0096] like Figure 9 As shown, when the frameless torque motor 18 malfunctions (such as open circuit, short circuit, controller failure, or system power failure), the safety protection mechanism is triggered in the following manner:

[0097] (1) If the system power supply is normal, the control system will immediately send a trigger signal to the electromagnetic actuator 23 after detecting abnormal current or loss of speed signal of the frameless torque motor.

[0098] (2) If the system is completely de-energized, the electromagnetic actuator 23 will automatically extend in the de-energized state.

[0099] The electromagnetic attractor 23 uses a suction-type cylindrical electromagnet. When the power is off, its moving end extends from the retracted state and enters the mounting through hole 901, contacting the inner conductive layer 9A on both sides of the strip opening 902. This allows the inner conductive layer 9A on both sides of the strip opening 902 to form an electrical connection through the moving end of the electromagnetic attractor 23, thus forming a closed conductive circuit.

[0100] After the closed loop is formed, the permanent magnet ring 12 continues to move up and down with the lead screw nut 13, and the closed loop cuts the axial magnetic field lines generated by the permanent magnet ring 12. According to Lenz's law, an induced current is generated in the closed loop, and the direction of the magnetic field of the induced current always opposes the change in magnetic flux that caused it, that is, it opposes the movement of the permanent magnet ring 12, thereby generating an electromagnetic damping force. The magnitude of this damping force is directly proportional to the movement speed of the permanent magnet ring 12 (i.e., the suspension vibration speed); the greater the speed, the greater the safety damping force generated.

[0101] Therefore, even if the frameless torque motor 18 completely fails and the active damping force is zero, the present invention can still provide sufficient passive electromagnetic damping force for the vehicle, ensuring the basic damping function of the suspension system, avoiding severe vibration of the vehicle due to complete failure of the shock absorber, and significantly improving the vehicle driving safety.

[0102] The scope of protection of this invention includes, but is not limited to, the above embodiments. The scope of protection of this invention is defined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art fall within the scope of protection of this invention.

Claims

1. A variable lead electromagnetic vibration damper based on safety protection, characterized in that, It includes an upper mounting base (20), a lower mounting base (2), a frameless torque motor (18), a hollow piston rod (4), a screw drive assembly (22), a screw nut (13), a guide ring (15), a three-layer composite screw outer cylinder (9), a permanent magnet ring (12), and an electromagnetic attractor (23). The lower mounting base (2) is used to connect the lower lifting lug (1) and is fixedly connected to the lower end of the hollow piston rod (4) through the piston rod nut (3); The upper end of the hollow piston rod (4) is connected to the lead screw nut (13) to transmit road excitation to the lead screw drive assembly (22). The top of the lead screw drive assembly (22) is connected to the rotor of the frameless torque motor (18); The guide ring (15) is linked with the lead screw nut (13), and its outer surface is provided with a rolling element (1501). The inner conductive layer (9A) of the three-layer composite lead screw outer cylinder (9) is provided with a variable lead spiral groove (904) that cooperates with the rolling element (1501). When the guide ring (15) moves axially with the lead screw nut (13), it rotates along the variable lead spiral groove (904) to change the equivalent lead of the lead screw transmission assembly (22). The permanent magnet ring (12) is nested outside the lead screw nut (13) and moves synchronously with the hollow piston rod (4); The three-layer composite screw outer cylinder (9) is composed of an inner conductive layer (9A), a middle insulating layer (9B) and an outer metal layer (9C). Its upper end is connected to the outer shell (19) of the frameless torque motor (18), and its lower end is connected to the outer cylinder end cap (6). The outer cylinder end cap (6) is slidably connected to the hollow piston rod (4). The outer cylinder (9) of the three-layer composite screw is provided with a mounting through hole (901), and the inner conductive layer (9A) is partially exposed in the mounting through hole (901); The electromagnetic attractor (23) is connected to the housing (19) of the frameless torque motor (18), and the moving end of the electromagnetic attractor (23) is used to extend into the mounting through hole (901) and contact the inner conductive layer (9A) when the frameless torque motor (18) fails, so that the inner conductive layer (9A) forms a closed loop. The upper mounting base (20) is connected to the top of the housing (19) of the frameless torque motor (18) for connecting the upper lifting lug (21).

2. The electromagnetic vibration damper with variable lead based on safety protection according to claim 1, characterized in that, The inner conductive layer (9A) has a strip-shaped opening (902) that extends through its upper and lower ends, and the strip-shaped opening (902) forms a break in the inner conductive layer (9A) in the circumferential direction; the inner surface of the intermediate insulating layer (9B) is provided with a strip-shaped protrusion (903) for embedding the strip-shaped opening (902), and the surface of the strip-shaped protrusion (903) is flush with the inner surface of the inner conductive layer (9A); the variable lead spiral groove (904) is provided on the surface of the strip-shaped protrusion (903) and the inner surface of the inner conductive layer (9A), and the variable lead spiral groove (904) extends continuously between the surface of the strip-shaped protrusion (903) and the inner surface of the inner conductive layer (9A); the mounting through hole (901) is opened on the outer cylinder (9) of the three-layer composite screw and extends through the strip-shaped protrusion (903).

3. The electromagnetic vibration damper with variable lead based on safety protection according to claim 2, characterized in that, The electromagnetic attractor (23) is a cylindrical electromagnet with an inlet. When it is working normally, its moving end is in a retracted state. When the frameless torque motor (18) fails, its moving end extends out and enters the mounting through hole (901) and contacts the inner conductive layer (9A) on both sides of the strip opening (902), so that the inner conductive layer (9A) on both sides of the strip opening (902) forms an electrical connection through the moving end of the electromagnetic attractor (23).

4. The electromagnetic vibration damper with variable lead based on safety protection according to claim 1, characterized in that, The variable lead spiral groove (904) is a spiral groove whose lead changes continuously along the axial direction. The lead of the variable lead spiral groove (904) at the middle position is smaller than the lead at both sides, and the lead tends to a fixed value at both ends. The rolling element (1501) on the outer surface of the guide ring (15) is precisely matched with the variable lead spiral groove (904) of the inner conductive layer (9A). The direction of rotation of the variable lead spiral groove (904) is opposite to the direction of rotation of the lead screw drive assembly (22).

5. The electromagnetic vibration damper with variable lead based on safety protection according to claim 1, characterized in that, The inner conductive layer (9A) of the three-layer composite screw outer cylinder (9) is provided with multiple through holes for heat dissipation and weight reduction.

6. The variable lead electromagnetic vibration damper based on safety protection according to claim 1, characterized in that, The upper end of the hollow piston rod (4) is fixedly connected to the external thread of the lead screw nut connecting guide block (11) through the internal thread. The internal thread of the lead screw nut connecting guide block (11) is fixedly connected to the external thread of the lead screw nut connecting piece (14). The lead screw nut connecting piece (14) and the lead screw nut (13) are fixedly connected by a key. The guide ring (15) is nested on the lead screw nut connecting piece (14). There are multiple permanent magnet rings (12), which are nested on the outside of the lead screw nut connecting piece (14) and the lead screw nut connecting guide block (11).

7. The electromagnetic vibration damper with variable lead based on safety protection according to claim 6, characterized in that, The guide ring (15) is fixedly connected to the lead screw nut connector (14) by a cylindrical pin, and the permanent magnet ring (12) is fixedly connected to the lead screw nut connector (14) and the lead screw nut connecting guide block (11) by glue injection.

8. The variable lead electromagnetic vibration damper based on safety protection according to claim 6, characterized in that, There are three permanent magnet rings (12), two of which are fixedly connected to the outside of the lead screw nut connector (14) and are located above and below the guide ring (15) respectively, and one permanent magnet ring (12) is fixedly connected to the outside of the lead screw nut connecting guide block (11).

9. The variable lead electromagnetic vibration damper based on safety protection according to claim 1, characterized in that, The internal thread at the lower end of the three-layer composite screw outer cylinder (9) is threaded to the external thread of the outer cylinder end cap (6), and the external thread at the upper end of the three-layer composite screw outer cylinder (9) is threaded to the internal thread of the outer shell (19) of the frameless torque motor (18).

10. The variable lead electromagnetic vibration damper based on safety protection according to claim 1, characterized in that, The hollow piston rod (4) is fitted with a piston rod protective cover (10). The top inner surface of the piston rod protective cover (10) is sealed and slidably connected to the outer cylinder (9) of the three-layer composite screw. The bottom of the piston rod protective cover (10) is connected to the piston rod protective base (5) through an external thread. The piston rod protective base (5) is snapped into the shoulder of the piston rod nut (3). The lower outer surface of the piston rod protective cover (10) is threaded with a lower spring seat (7). A spring (17) is provided between the lower spring seat (7) and the bottom of the housing (19) of the frameless torque motor (18). The spring (17) is fitted outside the piston rod protective cover (10).

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