A damping coefficient evaluation method for a damping and transmission free switching device

Abstract

The present invention belongs to the technical field of mechanical transmission, and provides a method for evaluating the damping coefficient of a damping and transmission free switching device. Through electromagnetic interaction, a non-contact design is adopted in the transmission mode. By using the electromagnetic force between a permanent magnet and a damping disk with high electrical conductivity, efficient transmission is achieved, reducing mechanical friction and energy loss. In the damping mode, the damping disk is fixed by inserting a pin shaft to generate an induced magnetic field to provide a damping function, adapting to load changes and achieving smooth control. It has the characteristics of high adaptability, low maintenance, and low energy consumption. In addition, the damping coefficient evaluation method calculates by considering power consumption and angular velocity, simplifies the traditional finite element analysis process, improves the system efficiency and accuracy, and avoids complex modeling and high computational load. The present invention has good practical application performance in actual engineering applications, with simple operation and small computational amount.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical transmission, and particularly relates to a method for evaluating the damping coefficient of a damping and transmission free switching device. Background Art

[0002] In the fields of automobiles and modern industries, the application of transmission and damping devices is very extensive. The transmission device is responsible for efficiently transmitting the energy generated by the power device to the actuator and the load to ensure the normal operation of mechanical equipment, while the damping device plays an important role in occasions where deceleration or smooth stopping is required, such as controlling vibration and avoiding impact. Traditional transmission devices mainly achieve power transmission through mechanical connection forms such as couplings and gears. However, due to reasons such as friction and vibration, the wear between mechanical components is relatively large, and it is difficult to adapt to the requirements under different working conditions. The damping system usually relies on hydraulic, pneumatic or friction braking. Although these systems can effectively provide damping effects, their control methods are limited, and the damping effect cannot be flexibly adjusted according to real-time requirements. In the prior art, the transmission and damping functions are usually realized separately. In the face of complex and changeable working conditions, they often cannot be flexibly switched to meet different transmission and damping requirements, resulting in difficulties in ensuring the efficiency and reliability of the system. Therefore, the present invention provides a device that realizes free switching between transmission and damping through a damping automatic pin shaft, which can achieve the conversion of efficient transmission and damping functions through simple mechanical operations under different working conditions. At the same time, a simple method for evaluating the damping coefficient is proposed, providing a more flexible solution for the mechanical transmission system. In addition, in the research on damping coefficient evaluation, the finite element analysis method is usually adopted. However, in the actual modeling process, factors such as material properties, boundary conditions, and external loads need to be considered, which makes the calculation time long, the hardware performance requirements high, the calculation process complex, and the efficiency extremely low. This severely restricts the structural design and performance optimization of the damping device. Therefore, inventing a damping coefficient evaluation method that can take into account both calculation accuracy and efficiency has irreplaceable value and significance for improving the performance of the damping device and realizing the diversification of damping devices used in the industrial machinery field.

[0003] Regarding the torque transmission device, Lin Sanying proposed in the patent "A Damping Device for Transmission Shaft" (CN202321427030.1) to connect the attached damping device on the linkage shaft to the power output member, thereby greatly reducing the external force transmitted from the power output end to the linkage shaft. Although the buffering function can be achieved, effective braking cannot be achieved when facing large impact loads. Regarding the damping coefficient evaluation and calculation method, Yang Deyou constructed a linear equation about the electromechanical parameters (inertia and damping coefficient) and system characteristics (eigenvalue and eigenvector) based on dynamic mode decomposition in the article "Evaluation Method of Generator Inertia and Damping Coefficient Based on Dynamic Mode Decomposition", and then realized the evaluation of the damping coefficient by solving the linear equation. However, this method involves too many parameters and their mutual coupling effects, resulting in great difficulty in the analytical calculation of the linear equation and a complex decoupling process. Therefore, proposing a damping and transmission free switching device and a damping coefficient evaluation method is of great significance for the design and characteristic research of the high-flexibility basic components for the transmission damping function switching in the automotive and modern industrial fields. Summary of the Invention

[0004] In order to make up for the defects of the prior art, the present invention invented a damping and transmission free switching device. Its purpose is to achieve free switching through the damping brake pin. When the pin is pulled out, the electromagnetic interaction between the permanent magnet in the transmission switching disk and the high-conductivity damping disk is used to realize non-contact transmission, effectively reducing mechanical friction and energy loss; when the pin is inserted, the damping disk is fixed, and an induced magnetic field is generated by cutting the magnetic induction line to provide a damping effect. This device has the advantages of flexible switching between transmission and damping, non-mechanical contact transmission, and low energy loss, and is especially suitable for industrial automation, automotive transmission, wind power generation and other occasions with large load changes. In addition, the innovative design of non-contact transmission realized by magnetic force and the damping of the induced magnetic field improve the adaptability and operating efficiency of the system, simplify the structure and reduce the maintenance cost, and have broad application prospects.

[0005] The technical solution of the present invention is as follows:

[0006] A method for evaluating the damping coefficient of a damping and transmission free switching device, the steps are as follows:

[0007] The first step is to construct a damping and transmission free switching device;

[0008] First, embed the permanent magnet into the groove of the transmission switching disk. One end of the transmission switching disk is connected to the power device through the protruding shaft. Secondly, the high-conductivity damping disk and the damping bearing disk are fixed together by bolts. One end of the damping bearing disk is connected to the roller bearing through the protruding shaft. Then, put the high-conductivity damping disk into the inside of the transmission switching disk and align the two ends. A through hole is opened on the roller bearing to cooperate with the damping braking pin shaft, and the switching of the transmission and damping functions is realized in sequence. When the device is operating normally, the driving device drives the transmission switching disk to rotate. When the pin shaft is pulled out, the device realizes non-contact transmission through the electromagnetic interaction between the permanent magnet in the transmission switching disk and the high-conductivity damping disk, effectively reducing mechanical friction and energy loss. When the pin shaft is inserted, the high-conductivity damping disk drives the damping bearing disk and the roller bearing to be fixed. At this time, when the transmission switching disk rotates, the high-conductivity damping disk cuts the magnetic induction line to generate an induced magnetic field, providing a damping effect. The structure of the present invention is compact, can provide non-mechanical contact transmission and high-adaptability damping effect, and has high practicality and engineering application promotion value.

[0009] The damping and transmission free switching device includes a damping braking pin shaft 1, a roller bearing 2, a damping bearing disk 3, a connecting bolt 4, a high-conductivity damping disk 5, a permanent magnet 6, a transmission switching disk 7, a base 8 and a gantry 9;

[0010] The permanent magnet 6 is embedded in the groove of the transmission switching disk 7. One end of the transmission switching disk 7 is connected to the power device through the protruding shaft and is installed on the base 8. The high-conductivity damping disk 5 and the damping bearing disk 3 are fixed together by the connecting bolt 4. One end of the damping bearing disk 3 is connected to the roller bearing 2 through the protruding shaft, and a damping braking pin shaft 1 is installed between them. The roller bearing 2 is fixed on the gantry 9. The high-conductivity damping disk 5 is sleeved into the transmission switching disk 7, and the two sides of the damping disk 5 and the transmission switching disk 7 are ensured to be aligned, that is, the installation is completed;

[0011] Second step, determine the key parameters of the device;

[0012] The angular velocity of the power device during operation is ω. The transmission switching disk 7 is connected to the power device. The angular velocity of the damping and transmission free switching device during operation is provided by the power device and gradually decreases to 0. Therefore, the working angular velocity of the damping and transmission free switching device takes the root mean square value of the angular velocity of the power device, that is The magnetic field strength B between the high-conductivity damping disk 5 and the permanent magnet 6 is determined by the material of the permanent magnet and is affected by the magnetic reluctance of the device structure. The radius of the high-conductivity damping disk 5 is r, and the thickness is h. r3 and r2 are the outer diameter and inner diameter of the transmission switching disk 7 respectively. L is the air gap length between the high-conductivity damping disk 5 and the permanent magnet 6. a, b, and c are the length, width, and height of the permanent magnet 6 respectively;

[0013] Second step, calculate the working frequency and the volume of the high-conductivity damping disk 5

[0014] The operating frequency f of the damping and transmission free switching device is determined by its operating angular velocity ω m To determine, that is:

[0015]

[0016] The high-conductivity damping disk 5 is in the shape of a cylinder with a radius r and a thickness h, so its volume V is:

[0017] V=πr 2 h (2)

[0018] Step 3: Calculate the magnetic field strength;

[0019] The magnetic field strength B is determined by the material of the permanent magnet 6. The magnetic permeability of the back iron material is much greater than that of air. Therefore, in actual calculations, it is necessary to consider the effect of the back iron material's magnetic resistance on the magnetic flux of the magnetic circuit, so that the calculated results are closer to the actual value.

[0020] The magnetic resistance calculation of the damping and transmission free switching device follows the regular magnet calculation formula:

[0021]

[0022] Where, l m is the length in the magnetization direction, μ is the magnetic permeability, A m is the cross-sectional area of the surface through which the magnetic lines of force pass;

[0023] Therefore, the back ferromagnetic resistance of the transmission switching disk 7 is expressed as:

[0024]

[0025] Where, μ1 is the relative magnetic permeability of the back iron material; μ0 is the vacuum magnetic permeability; n is the angle between the center lines of a pair of adjacent magnetic poles, that is, n = 360 / k; k is the number of magnetic pole pairs;

[0026] The internal resistance expression of permanent magnet 6 is:

[0027]

[0028] Where μ pm is the relative magnetic permeability of the permanent magnet;

[0029] The expression of air gap reluctance is:

[0030]

[0031] Where μ a is the relative magnetic permeability of air;

[0032] In addition, the permanent magnet 6 is regarded as a constant and reliable magnetic source, providing a continuous and effective magnetic field, and its magnetomotive force F0 is:

[0033] F0=H pm c (7)

[0034] Where H pm represents the coercive force of the permanent magnet 6;

[0035] The magnetic flux Φ1 of the magnetic circuit after the magnetic resistance correction is:

[0036]

[0037] The corrected expression of magnetic field intensity B is:

[0038] B=B0·λ (9)

[0039] Where λ is the correction coefficient, and its expression is:

[0040]

[0041] Where, B0 is the initial magnetic field strength determined by the material properties of the permanent magnet 6; Φ a is the magnetic flux of the original magnetic circuit, which is determined by the material of the permanent magnet 6. The values of the above two parameters are fixed;

[0042] Step 4: Calculate the eddy current loss power of the smallest element;

[0043] The power loss of the damping and transmission free switching device is mainly due to the eddy current effect caused by the high conductivity damping disk 5 cutting the magnetic flux lines in the magnetic field. The power of this eddy current loss is mainly dissipated in the form of heat. The power of eddy current loss dP m Calculated by the following formula:

[0044] dP m =k·B 2 ·f 2 ·dV (11)

[0045] Where: k is related to the material conductivity and geometric shape, and is taken as 12; B is the magnetic field intensity; f is the operating frequency of the damping and transmission free switching device; dV is the volume element;

[0046] Step 5: Calculate the total eddy current loss power of the high conductivity damping disk 5;

[0047] In order to obtain the total eddy current loss, it is necessary to integrate the high conductivity damping disk 5, usually in the form of:

[0048] P m =∫ V k·B 2 ·f 2 ·dV=k·B 2 ·f 2 ∫V dV(12)

[0049] where: k is related to the material conductivity and geometry, and takes the value of 12; B is the magnetic field strength; f is the operating frequency of the damping and transmission free switching device; V is the volume of the high-conductivity damping disc 5;

[0050] Step 6: Solve the damping coefficient;

[0051] The damping coefficient describes the magnitude of the damping force in the damping and transmission free switching device, and the calculation formula is as follows:

[0052]

[0053] where: P m is the eddy current loss power; ω m is the operating angular velocity of the damping and transmission free switching device;

[0054] So far, a damping and transmission free switching device and the calculation of the damping coefficient are completed.

[0055] The beneficial effects of the present invention are as follows: A damping and transmission free switching device is proposed. Based on the unique principle of electromagnetic interaction, this device combines the dual functions of transmission and damping, and realizes the flexible switching between the transmission and damping modes through simple mechanical operations. In the transmission mode, there is no direct contact between mechanical parts, which greatly reduces friction and wear, extends the service life of the equipment, and significantly reduces energy loss. This non-contact transmission method avoids the noise and vibration generated by friction in conventional gear transmissions or chain transmissions. Therefore, the system operates more quietly and stably. In addition, the damping function of the device can play a role when the load fluctuates or smooth deceleration is required. The damping effect formed by the reverse induced magnetic field generated by electromagnetic induction can quickly respond to load changes, avoiding the hysteresis problem of traditional damping devices during switching, and improving the sensitivity and response speed of the system. This damping mode is based on electromagnetic induction, avoiding the dependence on the external environment (such as temperature, humidity, etc.) of hydraulic or friction damping devices, enabling the device to operate stably under harsh working conditions. The present invention proposes a damping coefficient evaluation calculation method considering eddy current loss and angular velocity. Compared with the finite element analysis method, the calculation process of this method is significantly simplified. When using the finite element method to evaluate the damping coefficient, it is usually necessary to finely model the system and perform a large number of mesh divisions on the model, involving the solution of complex partial differential equations. Although the finite element analysis can provide highly accurate local analysis results, its calculation complexity is high, the calculation time is long, and the requirements for hardware equipment are relatively high, making it difficult to adapt to occasions that require real-time adjustment or rapid response. In contrast, the calculation method based on power and angular velocity does not require complex modeling and mesh division. Only by calculating the power consumption and angular velocity of the system can the damping coefficient be quickly obtained, which can accurately reflect the damping effect of the system under different loads and working conditions, and is particularly suitable for real-time monitoring and adjustment in industrial production. In summary, the damping and transmission free switching device and the damping coefficient evaluation method proposed by the present invention provide a simple and accurate calculation means for the design optimization and performance improvement of similar devices, are applicable to a wide range of engineering applications, and effectively improve the flexibility and stability of the device. Description of the Drawings

[0056] Figure 1 It is a schematic diagram of a damping and transmission free switching device;

[0057] Figure 2 It is a flowchart of a damping and transmission free switching device and a damping coefficient evaluation method;

[0058] Figure 1 In the figure: 1 - damping brake pin, 2 - roller bearing, 3 - damping bearing disc, 4 - connecting bolt, 5 - high conductivity damping disc, 6 - permanent magnet, 7 - transmission switching disc, 8 - base, 9 - gantry. Detailed Implementation Manner

[0059] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings and technical solutions.

[0060] In this embodiment, a damping and transmission free switching device with 6 pairs of magnetic poles is selected and its damping coefficient is evaluated and calculated.

[0061] Among them, the length of the damping brake pin 1 is 20 mm, the diameter is 1.5 mm, the roller bearing 2 is a GB283-94 roller bearing with a shaft diameter of 15 mm, the damping bearing plate 3 has a diameter of 48 mm and a thickness of 8 mm, the connecting bolts 4 are 4 M5×10 socket head cap screws, the high-conductivity damping plate 5 has a diameter of 48 mm and a thickness of 24 mm, the permanent magnet 6 has a thickness of 5 mm and a height of 5 mm, and the transmission switching plate 7 has a diameter of 70 mm and a thickness of 30 mm

[0062] The installation steps of the damping and transmission free switching device are as follows:

[0063] The permanent magnet 6 is embedded in the groove of the transmission switching plate 7. One end of the transmission switching plate 7 is connected to the power device through a protruding shaft and installed on the base 8; secondly, the high-conductivity damping plate 5 and the damping bearing plate 3 are fixed together by 4 M5×10 socket head cap screws. One end of the damping bearing plate 3 is connected to the roller bearing 2 through a protruding shaft; a damping brake pin 1 is installed between them; the roller bearing 2 is fixed on the gantry 9; then, the high-conductivity damping plate 5 is sleeved into the transmission switching plate 7, and the two side surfaces of the damping plate 5 and the transmission switching plate 7 are ensured to be aligned, and the installation is completed.

[0064] So far, the installation of a damping and transmission free switching device is completed.

[0065] A damping and transmission free switching device and a damping coefficient evaluation and calculation method are as Figure 2 shown. The specific steps for evaluating and calculating the damping coefficient of the damping and transmission free switching device are as follows:

[0066] The first step is to determine the key parameters of the device

[0067] The angular velocity during the operation of the power device is ω = 150 rad / s, and the working angular velocity ω of the damping device m = 75 rad / s; the radius of the high-conductivity damping plate is r = 24 mm, and the thickness is h = 24 mm; the outer diameter of the conversion plate is r3 = 35 mm and the inner diameter is r2 = 29 mm; the air gap length L between the high-conductivity damping plate and the permanent magnet is 5 mm; the length, width and height of the permanent magnet are a = 20 mm, b = 10 mm, c = 5 mm respectively;

[0068] The second step is to calculate the working frequency and the volume of the damping plate. From formula (1), the working frequency f of the damping device is approximately 11.9 Hz

[0069] From formula (2), the volume V of the damping disc is obtained as V = 0.0000434 m 3

[0070] Step 3: Calculate the magnetic field intensity. From formula (4), the back iron reluctance R1 of the drive switching disc is obtained as R1 = 0.45 Ω; from formula (5), the internal resistance Rpm of the permanent magnet is obtained as Rpm = 1.25 Ω; from formula (6), the air-gap reluctance Ra is obtained as Ra = 0.75 Ω; from formula (7), the magnetomotive force F0 of the permanent magnet is obtained as F0 = 448 AT; from formula (8), the magnetic flux Φ1 of the magnetic circuit after correction of the magnetic circuit reluctance is obtained as Φ1 = 246 Wb; the initial magnetic field intensity and the original magnetic flux of the magnetic circuit are both determined by the permanent magnet material, and their values are: B0 == 1.67 T, Φ a = 294 Wb; In summary, from formulas (9) and (10), the corrected magnetic field intensity B = 1.579 T is obtained

[0071] Step 4: Calculate the eddy current loss power of the infinitesimal element

[0072] Substitute the calculation result of the second step into formula (3) to obtain the differential form of the eddy current loss power

[0073] Step 5: Calculate the total eddy current loss power of the damping disc

[0074] Substitute the calculation result of the third step into formula (4) and integrate over the volume of the damping disc to obtain p m = 1.65

[0075] Step 6: Solve for the damping coefficient

[0076] Substitute the eddy current loss power obtained from the above calculations and the operating angular velocity of the device into formula (5) to obtain the damping coefficient D = 0.022

[0077] So far, the calculation of the damping and drive free switching device and the damping coefficient is completed.

[0078] The novel structure damping and drive free switching device realizes the flexible switching of the drive and damping functions through a unique damping braking pin shaft structure. In the drive mode, magnetic coupling is used for non-contact torque transmission, reducing mechanical wear and energy loss; in the damping mode, an induced magnetic field is generated by cutting the magnetic induction line, providing an efficient damping effect, thereby realizing the effective control of the system movement.

[0079] This method proposes a damping coefficient calculation method based on power and angular velocity, simplifies the traditional finite element analysis method, is fast in calculation and easy to implement, is suitable for real-time monitoring and dynamic adjustment, does not rely on complex physical models and computing resources, the device can evaluate the damping effect under different actual working conditions, and has stronger adaptability. At the same time, it overcomes the high computational complexity and long solution process of the finite element method, greatly shortens the evaluation time, and enables the system to be instantaneously optimized during operation.

Claims

1. A damping coefficient evaluation method for a damping and transmission free switching device, characterized in that, The steps are as follows: First step, construct a device for freely switching between damping and transmission; The device for freely switching between damping and transmission includes a damping brake pin shaft (1), a roller bearing (2), a damping bearing plate (3), a connecting bolt (4), a high-conductivity damping disk (5), a permanent magnet (6), a transmission switching disk (7), a base (8), and a gantry (9); The permanent magnet (6) is embedded in the groove of the transmission switching disk (7). One end of the transmission switching disk (7) is connected to the power device through an extension shaft and is installed on the base (8); the high-conductivity damping disk (5) and the damping bearing plate (3) are fixed together by the connecting bolt (4). One end of the damping bearing plate (3) is connected to the roller bearing (2) through an extension shaft, and a damping brake pin shaft (1) is installed between them; the roller bearing (2) is fixed on the gantry (9); the high-conductivity damping disk (5) is sleeved into the transmission switching disk (7), and the two side surfaces of the damping disk (5) and the transmission switching disk (7) are ensured to be aligned, then the installation is completed; Second step, determine the key parameters of the device; When the power device is running, the angular velocity is ω. The transmission switching disk (7) is connected to the power device. The damping and the transmission free switching device operate with an angular velocity provided by the power device, which gradually decreases to 0. Therefore, the operating angular velocity of the damping and the transmission free switching device takes the root mean square value of the angular velocity of the power device, that is The magnetic field strength B between the high-conductivity damping disk (5) and the permanent magnet (6) is determined by the material of the permanent magnet and is affected by the magnetic reluctance of the device structure; the radius of the high-conductivity damping disk (5) is r, and the thickness is h; r3 and r2 are the outer diameter and inner diameter of the transmission switching disk (7) respectively; L is the air gap length between the high-conductivity damping disk (5) and the permanent magnet (6); a, b, and c are the length, width, and height of the permanent magnet (6) respectively; Second step, calculate the working frequency and the volume of the high-conductivity damping disk (5) The operating frequency f of the damping and transmission free switching device is determined according to its operating angular velocity ω m That is: The shape of the high-conductivity damping disk (5) is a cylinder with a radius of r and a thickness of h. Therefore, its volume V is: V = πr 2 h (2) Third step, calculate the magnetic field intensity; The magnetic field intensity B is determined by the material of the permanent magnet (6); the permeability of the back iron material is much larger than that of air. Therefore, in actual calculations, the influence of the magnetic resistance of the back iron material on the magnetic flux of the magnetic circuit needs to be considered, so that the calculation result is closer to the actual value; The magnetic resistance calculation of the device for freely switching between damping and transmission follows the regular magnet calculation formula, that is: where l m is the length in the magnetization direction, μ is the magnetic permeability, and A m is the cross-sectional area through which the magnetic flux lines pass; Therefore, the expression of the back iron magnetic resistance of the transmission switching disk (7) is: In the formula, μ1 is the relative permeability of the back iron material; μ0 is the permeability of vacuum; n is the included angle between the midlines of a pair of adjacent magnetic poles, that is, n = 360 / k; k is the number of magnetic pole pairs; The internal resistance expression of the permanent magnet (6) is: where μ pm is the relative permeability of the permanent magnet; The air gap magnetic resistance expression is: where μ a is the relative magnetic permeability of air; In addition, the permanent magnet (6) is regarded as a constant and reliable magnetic source, providing a continuous and effective magnetic field. Its magnetomotive force F0 is: F0 = H pm c (7) Wherein, H pm represents the coercive force of the permanent magnet (6); The magnetic flux Φ1 of the magnetic circuit after magnetic circuit magnetic resistance correction is: The corrected magnetic field intensity B expression is: B = B0·λ (9) In the formula, λ is the correction coefficient, and its expression is: In the formula, B0 is the initial magnetic field intensity determined by the material properties of the permanent magnet (6); Φ a is the magnetic flux of the original magnetic circuit, which is determined by the material of the permanent magnet (6). The values of the above two parameters are both fixed values; Fourth step, calculate the eddy current loss power of an extremely small element; The power loss of the damping and transmission free switching device is mainly due to the energy loss caused by the eddy current effect generated when the high-conductivity damping disk (5) cuts the magnetic induction lines in the magnetic field; the power of this eddy current loss is mainly dissipated in the form of heat; the power of the eddy current loss dP m is calculated by the following formula: dP m = k·B 2 ·f 2 ·dV (11) In the formula: k is related to the material conductivity and geometric shape, and takes 12; B is the magnetic field intensity; f is the working frequency of the device for freely switching between damping and transmission; dV is the volume element; Fifth step, calculate the total eddy current loss power of the high-conductivity damping disk (5); In order to obtain the total eddy current loss, it is necessary to integrate the high-conductivity damping disk (5), and the form is: P m = ∫ V k·B 2 ·f 2 ·dV = k·B 2 ·f 2 ∫ V dV (12) In the formula: k is related to the material conductivity and geometric shape, and takes 12; B is the magnetic field intensity; f is the working frequency of the device for freely switching between damping and transmission; V is the volume of the high-conductivity damping disk (5); Sixth step, solve the damping coefficient; The damping coefficient describes the magnitude of the damping force in the device for freely switching between damping and transmission. The calculation formula is as follows: Where: P m is the eddy current loss power; ω m is the operating angular velocity of the damping and transmission free switching device; So far, the calculation of a device for freely switching between damping and transmission and the damping coefficient is completed.

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