Adjustable synchronous and asynchronous torque transmission device and effective transmission efficiency calculation method

Abstract

The invention belongs to the technical field of mechanical transmission, and provides an effective transmission efficiency calculation method of an adjustable synchronous and asynchronous torque transmission device. According to the device, flexible switching between a synchronous transmission mode and an asynchronous transmission mode is achieved through a connecting bolt structure, non-sliding transmission between the power disc and the load disc in the synchronous transmission mode is achieved through rigid connection, non-contact magnetic transmission is achieved through an embedded magnetic structure in the asynchronous transmission mode, and the device adapts to load requirements under different working conditions. The transmission efficiency calculation method is based on a meshing power method, and the transmission efficiency of the device is evaluated by measuring input power and output power in combination with a friction loss factor. According to the method, the calculation process is greatly simplified while the calculation precision is guaranteed, the method is suitable for various engineering application scenes, and transmission efficiency changes of the device in synchronous and asynchronous modes can be effectively reflected. The method has high engineering application value, is novel in structural design, convenient to operate and small in calculation amount, and remarkably improves the performance stability and the service life of the transmission device.

Description

Technical Field

[0001] The 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] The torque transmission device is a necessary device that efficiently and smoothly transmits the torque generated by the power unit to the actuator and the load. It is widely used in the fields of automobiles and industrial machinery such as transmission systems and gearboxes. Traditional torque transmission devices are mainly divided into synchronous and asynchronous types, using a combination of couplings, gears, chains and conveyor belts. The synchronous transmission device ensures the accuracy of the transmission device through mechanical linkage. Although the structure is simple and maintenance is convenient, it will inevitably produce problems such as mechanical friction, vibration and noise during operation and is not suitable for large-scale load change conditions. It is easy to be damaged under overload conditions. In contrast, the asynchronous transmission device can adapt to larger load changes and flexibly adapt to respective variable load and speed occasions. However, most asynchronous transmissions need to rely on asynchronous motor drive. Due to the lack of mechanical contact, the accuracy of asynchronous transmission is low and strict posture control cannot be guaranteed. In addition, there is a certain amount of energy loss, and its effective transmission efficiency is not as good as that of the synchronous transmission device. Especially under the condition of long-term continuous operation of industrial production, its effective transmission efficiency and transmission accuracy cannot be guaranteed. In addition, in the study of the effective transmission efficiency of the transmission device, the finite element analysis method is usually used to solve the torque, so that the specific effective transmission efficiency is solved with the help of the formula. The calculation time is long, the hardware performance requirements are high, and the effective transmission efficiency cannot be directly derived. The calculation process is complicated and the efficiency is extremely low. Therefore, the structural design and performance optimization of the torque transmission device are seriously restricted. Therefore, the invention of an adjustable synchronous and asynchronous torque transmission device that can take into account the advantages of synchronous and asynchronous torque transmission devices and its effective transmission efficiency calculation method has irreplaceable value and significance for improving the performance of the torque transmission device and realizing the diversification of the torque transmission devices used in the field of industrial machinery.

[0003] Regarding the torque transmission device, He Haichao proposed in his patent "Roller Synchronous Transmission Device" (CN207131801U) that the transmission is achieved by meshing the gears on the two rollers installed on the bearing seat, and a screw lift is provided to make the sliding bearing seats at both ends of the roller slide on the linear guide rail, thereby adjusting the gap between the two rollers. This device can ensure the synchronization of the two rollers and the accuracy of the transmission, and the transmission is more stable, but because it adopts the traditional gear meshing mechanical contact, it is restricted by the strength of the gear and cannot be applied to occasions with a large range of load changes. Regarding the calculation method of the effective transmission efficiency of the torque transmission device, Miao Xinglong calculated its average transmission efficiency by analyzing the friction loss of the coupling in the article "Torque Transmission Device and Average Transmission Efficiency Calculation Method". The calculation results are matched with the statistical time series to obtain the average transmission efficiency for the specific three-prong universal coupling. However, this method is based on the empirical formula for calculation, and it needs to be corrected by the statistical time series later, and it cannot be adapted to the calculation of the average transmission efficiency of various types of couplings. 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] In order to make up for the defects of the prior art, the present invention invents an adjustable synchronous and asynchronous torque transmission device. Its purpose is to realize the conversion between synchronous torque transmission and asynchronous torque transmission by hexagonal bolts. Synchronous torque transmission is a mechanical rigid connection through hexagonal bolts, while asynchronous torque transmission is a non-contact magnetic connection between the synchronous magnetic steel embedded in the power disk and the synchronous disk, so that it can not only flexibly adapt to the occasions of large-scale load changes, but also ensure high-precision transmission.

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

[0006] An adjustable synchronous and asynchronous torque transmission device, first, the synchronous magnetic steel is embedded in the power disk slot, and one end of the power disk is connected to the power device through an extended shaft; secondly, the asynchronous disk and the synchronous disk are fixed together to form a load disk, and one end of the load disk is ventilated and extended to connect the load device; then, the hexagonal bolt cooperates with the thin nut to separate the power disk from the load disk, and adjusts to a suitable spacing; then the driving device is used to drive the power disk to rotate, and under the rigid connection of the hexagonal bolt, the load disk rotates synchronously, which is suitable for occasions with high transmission accuracy. The axial magnetic force between the synchronous magnetic block and the asynchronous disk can also resist axial vibration, effectively avoiding damage to the torque transmission device after a large axial impact. In addition, the hexagonal bolt is removed, and non-contact asynchronous transmission is realized under the magnetic force between the synchronous magnetic steel of the power disk and the asynchronous disk; it is suitable for occasions with large load changes. The present invention has a compact structure, asynchronous non-mechanical contact transmission, and synchronous high-precision transmission, and 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, the steps are as follows:

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

[0009] 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;

[0010] The synchronous magnetic steel 3 is embedded in the groove of the power disk 1, and one end of the power disk 1 is connected to the power device 9 through 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 through an extended shaft; the connecting bolt 6 cooperates with the thin nut 2 to separate the power disk 1 from the load disk 7, and adjusts them to a certain distance;

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

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

[0013]

[0014] In the formula, 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 magnetic permeability μ r =1, so the volume charge density is 0, that is, The magnetic charge distributed on the magnetic poles can replace 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. 12 is the position vector between the point sources; M1 and M2 are the magnetization vectors of the magnetic charge; μ0 is the magnetic permeability of vacuum;

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

[0025]

[0026] 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;

[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 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 :

[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] In the formula, 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] In the formula, K is stiffness; M is mass; the specific calculation formula is as follows:

[0042]

[0043] M=ρ·πR2 2 t (12)

[0044] Wherein, 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 asynchronous torque transmission device is obtained by 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 beneficial effect of the present invention is that an adjustable synchronous asynchronous torque transmission device is proposed, and the device realizes efficient transmission under different working conditions through an adjustable transmission structure. In the synchronous transmission mode, the inner and outer rotors keep rotating synchronously to ensure efficient and non-slip power transmission; while in the asynchronous transmission mode, a certain slip is allowed to cope with load fluctuations or dynamic working conditions. The device adopts an innovative design, and realizes flexible switching of the two transmission modes by accurately adjusting the relative movement between the inner and outer rotors to adapt to the transmission requirements under different working conditions. In order to optimize the design and application of the transmission device, the present invention proposes a transmission efficiency calculation method based on the meshing power method. The meshing power method measures the input power and output power of the device and calculates the ratio of the two to obtain the transmission efficiency. The method is simple and convenient, can quickly and accurately reflect the efficiency changes of the device under different working modes, and provides a theoretical basis for the optimization of the device structure. Compared with complex numerical simulation or finite element analysis, the advantage of the meshing power method is that the transmission performance can be effectively evaluated by measuring the rotor torque and speed. At the same time, the method takes into account the power loss caused by friction loss in the synchronous and asynchronous transmission modes, so as to more accurately evaluate the working state of the device under actual working 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 operating 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 It is a flow chart of the calculation method of the effective transmission efficiency of an adjustable synchronous and asynchronous torque transmission device;

[0061] Figure 1 Middle: 1-power disk, 2-thin nut, 3-synchronous magnet, 4-asynchronous disk, 5-synchronous disk, 6-connecting bolt, 7-load disk; 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 selects 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 disk 1 has a diameter of 50mm and a thickness of 10mm, the thin nut 2 uses 4 M5×3 external hexagon nuts, the thickness of the synchronous magnetic steel 3 is 5mm, the length and width are 5mm, the asynchronous disk 4 has a diameter of 50mm and a thickness of 6mm, the synchronous disk 5 has a diameter of 50mm and a thickness of 8mm, the connecting bolt 6 uses 4 M5×30 external hexagon bolts, and the installation steps of the adjustable synchronous and asynchronous torque transmission device are as follows:

[0065] The synchronous magnetic steel 3 is embedded in the groove of the power disk 1, and one end of the power disk 1 is connected to the power device 9 through 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 through a ventilated extended shaft. Four M5×30 hexagonal bolts 6 are matched with M5×3 thin nuts 2 to separate the power disk 1 from the load disk 7, and are adjusted to a suitable 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 magnetic steel is Br1 = 1.43T, and the residual magnetic flux density of the asynchronous disk is Br2 = 0.85T. From formulas (5) and (6), we can get T out =95N·m;

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

[0071] Set the input torque to 100 N·m and the speed to 1500 rpm; the output torque is 95 N·m and the speed is 1500 rpm calculated in 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 obtain ψ using formula (3) m ≈0.86.

[0074] Step 4: Find 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 obtain 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) yields the damping coefficient c = 0.05.

[0078] Step 6: Determine 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] The adjustable synchronous asynchronous torque transmission device of this new structure is mainly composed of a disc, a load disc and alternatingly distributed synchronous magnets. The device realizes the transmission function in both synchronous and asynchronous modes through the connecting bolt structure. In synchronous mode, the power disc and the synchronous disc run at the same speed to achieve non-slip and efficient transmission; in asynchronous mode, a certain slip is allowed to adapt to the changing requirements of the load. Since there is no mechanical contact between the power disc and the asynchronous disc, the device effectively avoids mechanical wear and energy loss. The structural design also significantly reduces the vibration and noise during operation, further improving the stability of the transmission performance and the reliability of the equipment.

[0082] This method is based on the meshing power method to analyze and calculate the effective transmission efficiency of the adjustable synchronous and asynchronous torque transmission device. The transmission efficiency is evaluated by calculating the efficiency loss coefficient and combining the measured input power and output power. Compared with finite element simulation, this method has the advantages of simple and convenient calculation, and can accurately reflect the transmission efficiency under different working conditions. This method is suitable for efficiency analysis of synchronous and asynchronous transmission modes, and can effectively evaluate the energy consumption caused by friction loss and slip, and help optimize the structural design of the device. It has strong adaptability in practical applications, simple calculation, and low time cost. It is 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 groove of the power disk (1), and one end of the power disk (1) is connected to the power device (9) through 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) through 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 magnetic steel (3) and the asynchronous disk (4) are equivalent to the interaction between a number of magnetic charges on the surfaces. The magnetic charge Q m (u) and magnetic charge Q m (v) The interaction force F m for: In the formula, 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 magnetic permeability μ r =1, so the volume charge density is 0, that is, The magnetic charge distributed on the magnetic poles can replace 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 magnetic steel (3) and the asynchronous disk (4), respectively. 12 is the position vector between the point sources; M1 and M2 are the magnetization vectors of the magnetic charge; μ0 is the magnetic permeability of vacuum; Finally, the integration gives the expressions of interaction force and torque: T out =F×R1 (6) Wherein, a, b, c are respectively the length, width and thickness of the synchronous magnetic steel (3); R1 is the radius of the asynchronous disk (4); Br1 and Br2 are respectively the residual magnetic flux densities of the synchronous magnetic steel (3) and the asynchronous disk (4); μ0 is the vacuum magnetic 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: In the formula, 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): In the formula, K is stiffness; 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 asynchronous torque transmission device is obtained by 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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