An adjustable synchronous and asynchronous torque transmission device and an effective transmission efficiency calculation method

Abstract

The present invention belongs to the field of mechanical transmission technology and provides a method for calculating the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device. The device realizes flexible switching between synchronous and asynchronous transmission modes through a connecting bolt structure. The power disc and the load disc are rigidly connected to realize non-slip transmission in the synchronous transmission mode. In the asynchronous transmission mode, the embedded magnetic structure is used to realize contactless magnetic transmission, which can adapt to the load requirements under different working conditions. The transmission efficiency calculation method is based on the meshing power method. By measuring the input power and output power and combining the friction loss factor, the transmission efficiency of the device is evaluated. This method greatly simplifies the calculation process while ensuring the calculation accuracy. It is suitable for a variety of engineering application scenarios and can effectively reflect the changes in the transmission efficiency of the device in synchronous and asynchronous modes. The present invention has high engineering application value, novel structural design, convenient operation, and small calculation amount, which significantly improves the performance stability and service life of the transmission device.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical transmission, and in particular relates to an adjustable synchronous and asynchronous torque transmission device and an effective transmission efficiency calculation method. Background Art

[0002] Torque transmission devices are essential for efficiently and smoothly transferring the torque generated by a power unit to the actuator and load. They are widely used in transmission systems, gearboxes, and other areas of automotive and industrial machinery. Traditional torque transmission devices are primarily categorized as synchronous and asynchronous, employing a combination of couplings, gears, chains, and belts. Synchronous transmissions utilize mechanical linkage to ensure transmission accuracy. While simple in structure and easy to maintain, they inevitably generate mechanical friction, vibration, and noise during operation. They are also unsuitable for operating conditions with wide load variations and are prone to damage under overload conditions. In contrast, asynchronous transmissions can accommodate larger load variations and flexibly adapt to varying loads and speeds. However, most asynchronous transmissions rely on asynchronous motors. Due to the lack of mechanical contact, asynchronous transmissions have lower precision and cannot guarantee strict position control. Furthermore, they suffer from certain energy losses, and their effective transmission efficiency is inferior to that of synchronous transmissions. This is particularly true under long-term continuous operation in industrial production, where effective transmission efficiency and accuracy cannot be guaranteed. Furthermore, in the study of the effective transmission efficiency of transmission devices, finite element analysis is typically used to solve for torque, thereby using formulas to determine the specific effective transmission efficiency. This calculation process is complex and inefficient, and the effective transmission efficiency cannot be directly derived. This severely restricts the structural design and performance optimization of torque transmission devices. Therefore, the invention of an adjustable synchronous and asynchronous torque transmission device that combines the advantages of both synchronous and asynchronous torque transmission devices and a method for calculating its effective transmission efficiency are of irreplaceable value and significance for improving the performance of torque transmission devices and achieving diversification of torque transmission devices used in the field of industrial machinery.

[0003] Regarding torque transmission devices, He Haichao's patent, "Roller Synchronous Transmission Device" (CN207131801U), proposes a method for achieving transmission through meshing gears on two rollers mounted on bearing blocks. A screw elevator is also provided to allow the sliding bearing blocks at each end of the rollers to slide on linear guides, thereby adjusting the gap between the two rollers. This device ensures synchronization between the two rollers and transmission accuracy, resulting in more stable transmission. However, due to the traditional mechanical contact of gear meshing, it is limited by gear strength and is not suitable for applications with wide load variations. Regarding a method for calculating the effective transmission efficiency of torque transmission devices, Miao Xinglong, in his article "Torque Transmission Device and Average Transmission Efficiency Calculation Method," analyzes coupling friction losses to calculate the average transmission efficiency. The calculated results are then matched with statistical time series to obtain the average transmission efficiency for a specific tripod-type universal joint. However, this method relies on an empirical formula that requires subsequent correction using statistical time series, making it unsuitable for calculating the average transmission efficiency of various coupling types. Therefore, proposing an adjustable synchronous and asynchronous torque transmission device and an effective transmission efficiency calculation method is of great significance for the design and characteristic research of basic parts with strong load adaptability and high transmission precision in the fields of automobiles and industrial machinery. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention invents an adjustable synchronous / asynchronous torque transmission device. Its purpose is to achieve conversion between synchronous and asynchronous torque transmission using hexagonal bolts. Synchronous torque transmission utilizes a mechanically rigid connection via the hexagonal bolts, while asynchronous torque transmission utilizes a non-contact magnetic connection between the synchronous magnets embedded in the power disc and the synchronous disc. This allows for flexible adaptation to a wide range of load variations while also ensuring high-precision transmission.

[0005] The technical solution adopted in the present invention is:

[0006] An adjustable synchronous and asynchronous torque transmission device. First, a synchronous magnet is embedded in the slot of a power disc, and one end of the power disc is connected to the power device via an extended shaft. Second, the asynchronous disc and the synchronous disc are fixed together to form a load disc, and one end of the load disc is connected to the load device via a ventilated extended shaft. After that, a hexagonal bolt is used in conjunction with a thin nut to separate the power disc from the load disc and adjust the spacing to a suitable level. The power disc is then driven to rotate by a driving device, and under the rigid connection of the hexagonal bolt, the load disc rotates synchronously. This device is suitable for applications requiring high transmission accuracy. The axial magnetic force between the synchronous magnet and the asynchronous disc can also resist axial vibration, effectively preventing the torque transmission device from being damaged by large axial impacts. In addition, the hexagonal bolt is removed, and non-contact asynchronous transmission is achieved under the magnetic force between the synchronous magnet and the asynchronous disc of the power disc. This device is suitable for applications with large load variations. The present invention has a compact structure, asynchronous non-mechanical contact transmission, and synchronous high-precision transmission. It has high practicality and engineering application promotion value in torque transmission devices.

[0007] A method for calculating the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device comprises the following steps:

[0008] The first step is to build an adjustable synchronous and asynchronous torque transmission device;

[0009] The adjustable synchronous and asynchronous torque transmission device includes a power disc 1, a thin nut 2, a synchronous magnetic steel 3, an asynchronous disc 4, a synchronous disc 5, a connecting bolt 6, a load disc 7, a load device 8 and a power device 9;

[0010] The synchronous magnet 3 is embedded in the groove of the power disk 1. One end of the power disk 1 is connected to the power device 9 via an extended shaft. The asynchronous disk 4 and the synchronous disk 5 are fixed together to form the load disk 7. One end of the load disk 7 is connected to the load device 8 via an extended shaft. The connecting bolts 6 cooperate with the thin nuts 2 to separate the power disk 1 and the load disk 7 and adjust them to a certain distance.

[0011] Step 2: Calculate the load end torque;

[0012] The two surfaces interacting with the synchronous magnet 3 and the asynchronous disk 4 are equivalent to the interaction between several magnetic charges on the surfaces. The magnetic charge Q m (u) and magnetic charge Q m (v) Interaction force F m for:

[0013]

[0014] Where μ0 is the vacuum magnetic permeability; u and v are the codes for different magnetic charges respectively;

[0015] The surface magnetic charge is:

[0016] Q m =σ m ΔA (2)

[0017] Where ΔA is the area element and the corresponding surface magnetic charge density is σ m ;

[0018] Since the magnetization direction is uniform and constant, the relative permeability μ r =1, so the volume charge density is 0, that is, The magnetic charge distributed on the magnetic pole can replace the magnetization, and its surface magnetic charge density σ m for:

[0019]

[0020] Where M is the magnetization vector; n is the unit vector pointing out of the surface; Br is the residual magnetic flux density; μ0 is the vacuum permeability;

[0021] Two magnetic charges Q on the equivalent surface m (u) and Qm The interaction force dF between (v) is as follows:

[0022]

[0023] Where Br1 and Br2 are the residual magnetic flux densities of the synchronous magnetic steel 3 and the asynchronous disk 4, respectively, r 12 is the position vector between the point sources; M1 and M2 are the magnetization vectors of the magnetic charge; μ0 is the vacuum permeability;

[0024] Finally, the integration gives the expressions of interaction force and torque:

[0025]

[0026] Where a, b, and c are the length, width, and thickness of the synchronous magnetic steel 3, respectively; R1 is the radius of the asynchronous disk 4; Br1 and Br2 are the residual magnetic flux densities of the synchronous magnetic steel 3 and the asynchronous disk 4, respectively; μ0 is the vacuum permeability;

[0027] Step 3: Determine the input and output power;

[0028] The power disk 1 is connected to the drive device, and the input power is transmitted from the drive device to the adjustable synchronous and asynchronous torque transmission device. The input power P is calculated based on the specific parameters of the drive device. in :

[0029]

[0030] Where, T in is the input torque; n in is the input speed;

[0031] The load disc 7 is connected to the load device 8, so the output power P is calculated by the torque and speed of the load end 7. out :

[0032]

[0033] Where, T out is the input torque; n out is the input speed;

[0034] Step 4: Calculation of friction loss in efficiency loss coefficient;

[0035] The efficiency loss of the adjustable synchronous and asynchronous torque transmission device is affected by the mechanical contact friction during bolt connection. The friction efficiency loss coefficient is calculated according to the following formula:

[0036]

[0037] Where Z1-Z n is the number of bolts for different connection types; fm Take 0.06~0.10;

[0038] Step 5: Calculate the vibration frequency of the adjustable synchronous and asynchronous torque transmission device;

[0039] Since the vibration frequency of the adjustable synchronous and asynchronous torque transmission device is affected by the power device 9, the load device 8 and the structural parameters, for the load disk 7:

[0040]

[0041] Where K is stiffness and M is mass. The specific calculation formula is as follows:

[0042]

[0043] M=ρ·πR2 2 t (12)

[0044] Where, E is the elastic modulus of the material; t is the thickness of the load plate 7; v is the Poisson's ratio of the material; R2 is the radius of the load plate 7; ρ is the density of the material;

[0045] Step 6: Calculation of material damping loss in efficiency loss coefficient;

[0046] The efficiency loss of the adjustable synchronous-asynchronous torque transmission device is also affected by the damping coefficient of the material itself. Since the damping coefficient is related to the vibration frequency, the damping coefficient c is obtained by differentiation:

[0047] dc(f)=c0·α·nf n-1 df (13)

[0048] Where df is the small change in frequency;

[0049] Finally, the damping coefficient c of the adjustable synchronous and asynchronous torque transmission device is obtained through differential calculation:

[0050] c=∑c0·α·nf n-1 df=c0·(1+α·nf n ) (14)

[0051] Where f is the vibration frequency of the system; c0, α, and n are all constants;

[0052] Step 7: Calculate the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device;

[0053] The efficiency loss coefficient G is:

[0054] G=c·ψ m (15)

[0055] The effective transmission efficiency η of the adjustable synchronous and asynchronous torque transmission device is:

[0056]

[0057] At this point, the calculation of the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device is completed.

[0058] The present invention provides an adjustable synchronous-asynchronous torque transmission device that achieves efficient transmission under different operating conditions through an adjustable transmission structure. In synchronous transmission mode, the inner and outer rotors rotate synchronously, ensuring efficient, slip-free power transmission. In asynchronous transmission mode, a certain amount of slip is permitted to accommodate load fluctuations or dynamic operating conditions. This device utilizes an innovative design that precisely adjusts the relative motion between the inner and outer rotors to achieve flexible switching between the two transmission modes, adapting to transmission requirements under varying operating conditions. To optimize the design and application of transmission devices, the present invention proposes a transmission efficiency calculation method based on the meshing power method. The meshing power method measures the device's input and output power and calculates the ratio between the two to obtain the transmission efficiency. This method is simple and convenient, quickly and accurately reflecting changes in the device's efficiency under different operating modes and providing a theoretical basis for optimizing the device's structure. Compared to complex numerical simulations or finite element analysis, the meshing power method has the advantage of effectively evaluating transmission performance by simply measuring rotor torque and speed. Furthermore, this method accounts for power losses due to friction in both synchronous and asynchronous transmission modes, allowing for a more accurate assessment of the device's operating status under actual operating conditions. In summary, the adjustable synchronous and asynchronous transmission device and the effective transmission efficiency calculation method proposed in the present invention provide a simple and accurate calculation means for the design optimization and performance improvement of the device, are suitable for a wide range of engineering applications, and effectively improve the transmission efficiency and operational stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of an adjustable synchronous and asynchronous torque transmission device;

[0060] Figure 2 This is a flow chart of a method for calculating the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device;

[0061] Figure 1 Middle: 1-power disc, 2-thin nut, 3-synchronous magnet, 4-asynchronous disc, 5-synchronous disc, 6-connecting bolt, 7-load disc; 8-load device; 9-power device DETAILED DESCRIPTION

[0062] The embodiments of the present invention are further described below in conjunction with the accompanying drawings and technical solutions.

[0063] This embodiment uses an adjustable synchronous and asynchronous torque transmission device with 8 pairs of magnetic poles and calculates its effective transmission efficiency.

[0064] Among them, the power disc 1 has a diameter of 50mm and a thickness of 10mm, the thin nuts 2 use four M5×3 external hexagon nuts, the synchronous magnet 3 has a thickness of 5mm, and a length and width of 5mm, the asynchronous disc 4 has a diameter of 50mm and a thickness of 6mm, the synchronous disc 5 has a diameter of 50mm and a thickness of 8mm, and the connecting bolts 6 use four M5×30 external hexagon bolts. The installation steps of the adjustable synchronous and asynchronous torque transmission device are as follows:

[0065] The synchronous magnet 3 is embedded in the slot of the power disk 1, one end of which is connected to the power device 9 via an extended shaft. The asynchronous disk 4 and the synchronous disk 5 are fixed together to form the load disk 7, and the load disk 7 has a ventilated extended shaft at one end to connect to the load device 8. Four M5×30 external hexagonal bolts 6 and M5×3 thin nuts 2 separate the power disk 1 and the load disk 7, and adjust them to the appropriate spacing of 5mm.

[0066] At this point, an adjustable synchronous and asynchronous torque transmission device has been installed.

[0067] A method for calculating the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device is as follows: Figure 2 The specific steps for calculating the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device are as follows:

[0068] Step 1: Calculate the load end torque

[0069] The residual magnetic flux density of the synchronous magnet is Br1 = 1.43T, and the residual magnetic flux density of the asynchronous disk is Br2 = 0.85T. According to formulas (5) and (6), T out =95N·m;

[0070] Step 2: Determine the input and output power

[0071] Set the input torque to 100N·m and the speed to 1500rpm; the output torque is calculated to be 95N·m and the speed is 1500rpm according to the first step. From formulas (1) and (2), we can get P in =15.71KW; P out =14.92KW.

[0072] Step 3: Calculation of friction loss in efficiency loss coefficient

[0073] Since there is only one set of bolt connections, there is only Z1=4. Under common working conditions, f m Taking 0.075, we can get ψ using formula (3) m ≈0.86.

[0074] Step 4: Calculate the vibration frequency of the system

[0075] The material is 45# steel, elastic modulus E=2.1×109 pa; disk thickness t = 29 mm; Poisson's ratio v is 0.28; disk diameter R = 50 mm; density ρ = 7850 kg / m 3 Substituting the above parameters into formulas (5) and (6), and then substituting the calculated results into formula (4), we can get the vibration frequency of the system f≈225.44Hz

[0076] Step 5: Calculation of material damping loss in efficiency loss coefficient

[0077] The three constants c0, α, and n are taken as 0.25, 0.1, and 0.57 respectively according to the actual working conditions. Substituting the vibration frequency calculated above into formula (8) can obtain the damping coefficient c = 0.05.

[0078] Step 6: Calculate the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device

[0079] Substituting the friction loss and damping loss obtained in the second and fourth steps into formulas (9) and (10), we can obtain the effective transmission efficiency η = 87.37%

[0080] At this point, the calculation of the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device is completed.

[0081] This novel adjustable synchronous-asynchronous torque transmission device primarily consists of a disc, a load disc, and alternating synchronous magnets. Through a bolted connection structure, the device achieves transmission functionality in both synchronous and asynchronous modes. In synchronous mode, the power disc and the synchronous disc operate at the same speed, achieving slip-free and efficient transmission. In asynchronous mode, a certain amount of slip is permitted to accommodate varying load demands. Since there is no mechanical contact between the power disc and the asynchronous disc, the device effectively avoids mechanical wear and energy loss. This structural design also significantly reduces vibration and noise during operation, further improving transmission performance stability and equipment reliability.

[0082] This method analytically calculates the effective transmission efficiency of adjustable synchronous and asynchronous torque transmission devices based on the meshing power method. The transmission efficiency is evaluated by calculating the efficiency loss coefficient and combining it with measured input and output power. Compared to finite element simulation, this method offers the advantages of simple and convenient calculations, accurately reflecting the transmission efficiency under different operating conditions. This method is suitable for efficiency analysis of both synchronous and asynchronous transmission modes and can effectively assess energy consumption caused by friction loss and slip, helping to optimize the structural design of the device. It is highly adaptable in practical applications, simple to calculate, and time-efficient, making it a highly applicable calculation method.

Claims

1. A method for calculating the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device, characterized in that: Here are the steps: The first step is to build an adjustable synchronous and asynchronous torque transmission device; The adjustable synchronous and asynchronous torque transmission device comprises a power disc (1), a thin nut (2), a synchronous magnetic steel (3), an asynchronous disc (4), a synchronous disc (5), a connecting bolt (6), a load disc (7), a load device (8) and a power device (9); The synchronous magnetic steel (3) is embedded in the slot of the power disk (1), and one end of the power disk (1) is connected to the power device (9) via an extended shaft; the asynchronous disk (4) and the synchronous disk (5) are fixed together to form a load disk (7), and one end of the load disk (7) is connected to the load device (8) via an extended shaft; the connecting bolt (6) cooperates with the thin nut (2) to separate the power disk (1) and the load disk (7), and adjusts them to a certain distance; Step 2: Calculate the load end torque; The two surfaces interacting with the synchronous magnet (3) and the asynchronous disk (4) are equivalent to the interaction between several magnetic charges on the surfaces. The magnetic charge Q m (u) and magnetic charge Q m (v) Interaction force F m for: Where μ0 is the vacuum magnetic permeability; u and v are the codes for different magnetic charges respectively; The surface magnetic charge is: Q m =s m A (2) Where ΔA is the area element and the corresponding surface magnetic charge density is σ m ; Since the magnetization direction is uniform and constant, the relative permeability μ r =1, so the volume charge density is 0, that is, The magnetic charge distributed on the magnetic pole can replace the magnetization, and its surface magnetic charge density σ m for: Where M is the magnetization vector; n is the unit vector pointing out of the surface; Br is the residual magnetic flux density; μ0 is the vacuum permeability; Two magnetic charges Q on the equivalent surface m (u) and Q m The interaction force dF between (v) is as follows: Where Br1 and Br2 are the residual magnetic flux densities of the synchronous magnet (3) and the asynchronous disk (4), respectively, r 12 is the position vector between the point sources; M1 and M2 are the magnetization vectors of the magnetic charge; μ0 is the vacuum permeability; Finally, the integration gives the expressions of interaction force and torque: T out =F×R1 (6) Wherein, a, b, c are the length, width and thickness of the synchronous magnetic steel (3) respectively; R1 is the radius of the asynchronous disk (4); Br1 and Br2 are the residual magnetic flux densities of the synchronous magnetic steel (3) and the asynchronous disk (4) respectively; μ0 is the vacuum permeability; Step 3: Determine the input and output power; The power disk (1) is connected to the drive device, and the input power is transmitted from the drive device to the adjustable synchronous and asynchronous torque transmission device. The input power P is calculated based on the specific parameters of the drive device. in : Where, T in is the input torque; n in is the input speed; The load plate (7) is connected to the load device (8), so the output power P is calculated by the torque and speed of the load end (7). out : Where, T out is the input torque; n out is the input speed; Step 4: Calculation of friction loss in efficiency loss coefficient; The efficiency loss of the adjustable synchronous and asynchronous torque transmission device is affected by the mechanical contact friction during bolt connection. The friction efficiency loss coefficient is calculated according to the following formula: Where Z1-Z n is the number of bolts for different connection types; f m Take 0.06~0.10; Step 5: Calculate the vibration frequency of the adjustable synchronous and asynchronous torque transmission device; Since the vibration frequency of the adjustable synchronous and asynchronous torque transmission device is affected by the power device (9), the load device (8) and the structural parameters, for the load plate (7): Where K is stiffness and M is mass. The specific calculation formula is as follows: M=ρ·πR2 2 t (12) Where E is the elastic modulus of the material; t is the thickness of the load plate (7); v is the Poisson's ratio of the material; R2 is the radius of the load plate (7); ρ is the density of the material; Step 6: Calculation of material damping loss in efficiency loss coefficient; The efficiency loss of the adjustable synchronous-asynchronous torque transmission device is also affected by the damping coefficient of the material itself. Since the damping coefficient is related to the vibration frequency, the damping coefficient c is obtained by differentiation: dc(f)=c0·α·nf n-1 df (13) Where df is the small change in frequency; Finally, the damping coefficient c of the adjustable synchronous and asynchronous torque transmission device is obtained through differential calculation: c=∑c0·α·nf n-1 df=c0·(1+α·nf n ) (14) Where f is the vibration frequency of the system; c0, α, and n are all constants; Step 7: Calculate the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device; The efficiency loss coefficient G is: G=c·ψ m (15) The effective transmission efficiency η of the adjustable synchronous and asynchronous torque transmission device is: At this point, the calculation of the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device is completed.

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