Magneto-rheological shock absorber

Abstract

The utility model provides a magneto-rheological shock absorber which comprises a cylinder barrel and a sliding sleeve movably arranged in the cylinder barrel in a sleeved mode, the sliding sleeve and the cylinder barrel form a sealed cavity, a transmission assembly is installed in the sealed cavity, the transmission assembly drives the sliding sleeve to do reciprocating horizontal movement in the cylinder barrel, and the sliding sleeve is connected with the cylinder barrel. A driver for providing or recovering kinetic energy of the transmission assembly is further arranged in the cylinder barrel, and a connecting line arranged on the driver penetrates through the outside of the cylinder barrel to be connected with a damping regulator and a controller. Kinetic energy can be provided for movement of the sliding sleeve through the built-in driver, part of energy can be generated in the shock absorption process, fuel economy can be improved to a certain degree, the damping characteristic of the device is rapidly adjusted according to actual requirements through the magneto-rheological technology, and the service life of the device is prolonged. And the optimal damping performance can be kept under different road conditions and driving conditions.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle suspension systems, in particular to a magnetorheological shock absorber. Background Art

[0002] In recent years, energy and environmental issues have become increasingly severe, and new energy vehicles and energy-saving technologies have become a global research focus. Vehicle suspension systems are used to attenuate vehicle body vibration and tire deformation caused by road irregularities, ensuring vehicle handling stability while enhancing ride comfort. Currently, oil-based dampers are widely used in vehicle suspension systems, favored by numerous automakers for their simple structure, low cost, and high reliability.

[0003] However, oil dampers have the following two disadvantages:

[0004] ①The damping coefficient is not adjustable, making it difficult to adapt to complex road conditions;

[0005] ② The vibration energy of the vehicle body is converted into heat energy and dissipated through the damper oil. The temperature rise of the oil will reduce the reliability of the damper and also cause the waste of vibration energy. This part of energy accounts for about 17.2% of the vehicle's driving energy.

[0006] Electromagnetic dampers (EMDs) are an effective way to address two shortcomings of traditional hydraulic dampers. Using the principle of electromagnetic induction, EMDs convert the suspension's tensile and compressive motion into motion that cuts through magnetic flux lines, generating an induced potential and converting vibration energy into electrical energy. Furthermore, the damping coefficient can be adjusted based on actual road conditions by adjusting the electromagnetic damper load via a controller. In recent years, numerous researchers have conducted in-depth research on EMDs, proposing various damper structures and control methods. Electromagnetic dampers primarily include magnetorheological and regenerative motor types. Magnetorheological dampers are the most commonly used. While their control is simple, they are limited by the complexities of magnetorheological fluid control and the cost. Using a motor as a damping actuator facilitates energy recovery. The transmission mechanism designed by Maravandi's team based on a rotating motor reduces damper size and improves transmission efficiency. However, reliability is challenging. Utility Model Content

[0007] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a magnetorheological shock absorber.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a magnetorheological shock absorber, comprising: a cylinder, a sliding sleeve movably arranged in the cylinder, the sliding sleeve and the cylinder forming a sealed cavity, a transmission assembly is installed in the sealed cavity, the transmission assembly drives the sliding sleeve to make reciprocating horizontal movements in the cylinder, a driver for providing or recovering kinetic energy of the transmission assembly is also provided in the cylinder, and a connecting line provided on the driver passes through the outside of the cylinder and is connected to a damping adjuster and a controller.

[0009] Furthermore, the transmission assembly includes a ball screw horizontally arranged along the extension direction of the cylinder opening and a screw nut arranged on the ball screw, wherein the ball screw is connected to the cylinder through a rolling bearing, and the ball screw passes through one end of the rolling bearing and is connected to the power output end of the driver, and the side wall of the screw nut is fixed on the inner wall of the sliding sleeve; part of the ball screw can be movably accommodated in the sliding sleeve.

[0010] Furthermore, the inner cavity length of the sliding sleeve is ≤0.5-1 times the length of the ball screw ≤0.5-1 times the length of the inner cavity opening of the cylinder.

[0011] Furthermore, the inner cavity of the cylinder away from the sliding sleeve is composed of a sliding cavity and a limiting cavity, the cross-section of the sliding cavity is larger than the cross-section of the limiting cavity, the transmission assembly and part of the sliding sleeve are accommodated in the sliding cavity, and the driver is accommodated in the limiting cavity.

[0012] As a preferred solution of the present application, the outer wall of the screw nut abuts against the inner wall of the cylinder.

[0013] As a preferred solution of the present application, the resistance of the damping regulator is 1Ω-10Ω.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] The present application not only provides kinetic energy for the movement of the sliding sleeve through the built-in driver, but also generates part of the energy during the recovery and shock absorption process, which can improve fuel economy to a certain extent. In addition, the present application uses magnetorheological technology to quickly adjust its damping characteristics according to actual needs, and can maintain optimal shock absorption performance under different road conditions and driving conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present invention will become more apparent from the detailed description of the non-limiting embodiments with reference to the following drawings:

[0017] Figure 1 It is a schematic diagram of the main structure of the utility model;

[0018] Figure 2 It is a cross-sectional view of the present invention.

[0019] In the figure: 1. Cylinder; 11. Sliding chamber; 12. Limiting chamber; 2. Sliding sleeve; 3. Transmission assembly; 31. Ball screw; 32. Screw nut; 4. Rolling bearing; 5. Driver; 6. Damping adjuster; 7. Controller. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0021] Currently, electromagnetically powered suspension systems using electromagnetic dampers (EMDs) effectively address the two shortcomings of traditional hydraulic dampers. Using the principle of electromagnetic induction, EMDs convert the suspension's tension and compression into motion that cuts through magnetic flux lines, generating an induced potential and converting vibration energy into electrical energy. Furthermore, the damping coefficient can be adjusted based on actual road conditions by adjusting the electromagnetic damper load via controller 7.

[0022] In recent years, electromagnetic dampers mainly include magnetorheological type and energy-feeding motor type. The magnetorheological damper is the most commonly used. Although its control method is simple, it cannot be promoted due to the complex control of magnetorheological fluid and cost issues.

[0023] To address the damping adjustment and energy recovery issues of electromagnetic dampers, this application designs an electromagnetic damping actuator based on a DC motor and ball screw mechanism. A DC-DC converter is used to achieve closed-loop damping adjustment, and a battery pack (connected to controller 7, whose specific parameters are a damping adjustment circuit based on a DC-DC converter, using a DSP to complete current acquisition, PWM signal duty cycle calculation and output, and a MOSFET driver using a 6N136 high-speed optocoupler to significantly improve the response speed of the damping adjustment circuit. The energy storage device is six 18650 batteries) is used for energy storage. The DC-DC converter-based damping adjustment circuit achieves continuous damping adjustment with fast response and low energy consumption.

[0024] like Figure 1-2As shown, its specific technical solution is: a magnetorheological shock absorber, comprising: a cylinder 1 with an open end, a sliding sleeve 2 movably sleeved on the open end of the cylinder 1, the sliding sleeve 2 and the cylinder 1 forming a sealed cavity, a transmission component 3 is installed in the sealed cavity, the transmission component 3 drives the sliding sleeve 2 to move reciprocatingly horizontally in the cylinder 1, and a driver 5 for providing or recovering kinetic energy of the transmission component 3 is also provided in the cylinder 1, and the driver 5 is provided with a connecting line passing through the outside of the cylinder 1 and connected to a damping regulator 6 and a controller 7, wherein the present application realizes damping closed-loop adjustment by using a DC-DC converter, uses a battery pack to complete energy storage, and realizes high-frequency electromagnetic damping adjustment based on the circuit topology of the DC-DC converter, and ultimately can achieve ideal damping coefficient adjustment and vibration attenuation effect. The electromagnetic damper has a response speed of up to 10 Hz and can respond to road inputs of varying frequencies over a wide range. According to ISO 2631-1:1997(E), a widely adopted standard for evaluating vehicle ride comfort, the frequency range of road inputs is generally 0.1 to 12 Hz. This electromagnetic damper has the advantages of fast response speed and a wide response frequency band, and can achieve energy recovery and damping adjustment while maintaining the ride comfort of the suspension system.

[0025] The implementation principle is:

[0026] The damper is used in the actual vehicle. Figure 2 As shown in the figure, the uneven road surface during the driving process of the car will cause the relative movement of the car body and chassis. The damper output force can suppress the relative movement. The damping force F d It can be expressed as

[0027] (1)

[0028] Where: l represents the ball screw lead, m; T em It represents the electromagnetic torque output of the electromagnetic damper, in N·m.

[0029] The differential equation of the suspension system can be expressed as

[0030] (2)

[0031] Where: m s and m u is the vehicle body mass and chassis mass, kg; k1 and k2 are the suspension spring stiffness and wheel stiffness, N / m; x s and x u are the displacements of the body and chassis, m; x g is the road roughness excitation, m. Combining formula (1), we can get

[0032] (3)

[0033] Where: c eq is the linear damping coefficient of the damper, N·s / m; v is the relative motion speed between the vehicle body and chassis, and the relationship between m / s, v and the motor speed ω can be expressed as

[0034] (4)

[0035] Where ω is the motor speed, rad / s. Combining equations (3) and (4), the linear damping coefficient of the damper can be obtained as

[0036] (5)

[0037] Where: c em is the rotational damping coefficient of the DC motor, N·s / m. According to formula (5), when the speed is known, the linear damping coefficient is proportional to the motor torque output.

[0038] According to the characteristics of DC motor, its electromagnetic torque can be expressed as

[0039] (6)

[0040] Where: K t is the torque constant of the motor, N·m / A; K e is the back electromotive force constant of the motor, V / (rad·s -1 );ω is the motor speed, rad / s;R L and R a is the load resistance and the armature equivalent resistance, Ω.

[0041] From formula (6), it is easy to get that the motor torque output is proportional to its speed. After the ball screw pair is driven, the damper output force can be expressed as

[0042] (7)

[0043] Therefore, the linear damping coefficient of the damper can be expressed as

[0044] (8)

[0045] From formula (8), it can be concluded that in the electromagnetic damper based on the DC motor, by adjusting the load resistance value R L The damping coefficient can be adjusted.

[0046] In addition, the DC-DC converter selected in this application has two working modes: continuous conduction (CCM) and discontinuous conduction (DCM), so that in actual operation, when the car encounters an uneven road surface during driving, the frame drives the screw nut 32 on the sliding sleeve 2 to move along the ball screw 31. At this time, the ball screw 31 rotates, thereby driving the linear motor to run. The controller 7 provided in this application is connected to a battery as an energy storage device to realize the storage of vibration energy after conversion into electrical energy. The controller 7 drives the damper to respond, and the driver 5 runs to reset the magnetorheological shock absorber of this application.

[0047] To ensure high efficiency and stability of transmission, the transmission assembly 3 includes a ball screw 31 horizontally arranged along the extension direction of the opening of the cylinder 1 and a screw nut 32 arranged on the ball screw 31, wherein the ball screw 31 is connected to the cylinder 1 through a rolling bearing 4, and the ball screw 31 passes through one end of the rolling bearing 4 and is connected to the power output end of the driver 5, and the side wall of the screw nut 32 is fixed on the inner wall of the sliding sleeve 2; part of the ball screw 31 can be movably accommodated in the sliding sleeve 2, and in actual operation, a motor transmission seat and a coupling are also provided between the motor and the ball screw 31, and the ball screw 31 is supported by the screw nut 32, thereby ensuring the horizontal stability of the screw, and the use of this structure improves the response speed and shock absorption accuracy of the shock absorber, while reducing energy loss and friction wear, and extending the service life.

[0048] To ensure a good structural layout of the shock absorber and make the structure more compact, and to ensure that the screw nut 32 does not suffer excessive fatigue, the inner cavity length of the sliding sleeve 2 is ≤0.5-1 times the length of the ball screw 31 ≤0.5-1 times the inner cavity opening length of the cylinder 1.

[0049] In order to ensure the safety and stability of the driver 5 (i.e., the preferred linear motor in this application) during operation, the inner cavity of the cylinder 1 at the end away from the sliding sleeve 2 is composed of a sliding cavity 11 and a limiting cavity 12. The cross-section of the sliding cavity 11 is larger than the cross-section of the limiting cavity 12. The transmission assembly 3 and part of the sliding sleeve 2 are accommodated in the sliding cavity 11. This structure enables the transmission assembly and part of the sliding sleeve 2 to be smoothly accommodated in the sliding wall, and the driver 5 is accommodated in the limiting cavity 12.

[0050] The outer wall of the screw nut 32 abuts against the inner wall of the cylinder 1 , which can improve the overall stiffness and load-bearing capacity of the shock absorber, thereby enhancing the anti-roll and anti-bump capabilities of the shock absorber, and further improving the vehicle's handling stability and ride comfort.

[0051] To improve the adaptability and flexibility of the shock absorber, the present application preferably sets the resistance of the damping adjuster 6 to 3Ω. To match the energy recovery performance of the existing vehicle-mounted adjustable damping suspension system, the resistance of the damping adjuster 6 is 1Ω-10Ω.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A magnetorheological shock absorber, characterized in that: include: A cylinder (1), a sliding sleeve (2) movable within the cylinder (1), the sliding sleeve (2) and the cylinder (1) forming a sealed cavity, a transmission assembly (3) installed within the sealed cavity, the transmission assembly (3) driving the sliding sleeve (2) to perform reciprocating horizontal movement within the cylinder (1), a driver (5) for providing or recovering kinetic energy of the transmission assembly (3) further provided within the cylinder (1), a connecting line provided on the driver (5) passing through the outside of the cylinder (1) and connected to a damping regulator (6) and a controller (7).

2. A magnetorheological shock absorber according to claim 1, characterized in that: The transmission assembly (3) includes a ball screw (31) horizontally arranged along the extension direction of the opening of the cylinder (1) and a screw nut (32) arranged on the ball screw (31), wherein the ball screw (31) is connected to the cylinder (1) through a rolling bearing (4) provided therein, and one end of the ball screw (31) passes through the rolling bearing (4) and is connected to the power output end of the driver (5), and the side wall of the screw nut (32) is fixed to the inner wall of the sliding sleeve (2); part of the ball screw (31) can be movably accommodated in the sliding sleeve (2).

3. The magnetorheological shock absorber according to claim 2, characterized in that: The inner cavity length of the sliding sleeve (2) is ≤0.5-1 times the length of the ball screw (31) and ≤0.5-1 times the inner cavity opening length of the cylinder (1).

4. A magnetorheological shock absorber according to claim 3, characterized in that: The inner cavity of the cylinder (1) at one end away from the sliding sleeve (2) is composed of a sliding cavity (11) and a limiting cavity (12), the cross section of the sliding cavity (11) is larger than the cross section of the limiting cavity (12), the transmission assembly (3) and part of the sliding sleeve (2) are accommodated in the sliding cavity (11), and the driver (5) is accommodated in the limiting cavity (12).

5. The magnetorheological shock absorber according to claim 4, characterized in that: The outer wall of the screw nut (32) abuts against the inner wall of the cylinder (1).

6. The magnetorheological shock absorber according to claim 1, characterized in that: The resistance of the damping regulator (6) is 1Ω-10Ω.

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