Method and device for detecting speed regulation range of liquid-viscous clutch based on dynamic solution

Abstract

The present invention specifically discloses a method and device for detecting the speed domain of a liquid-viscous clutch based on dynamic solution, wherein the method obtains the fluid Reynolds equation considering the influence of centrifugal force in a cylindrical coordinate system; introduces a pressure flow factor and a shear flow factor into the fluid Reynolds equation to correct the error generated when solving the lubrication of a rough surface; describes the rough surface profile, establishes an M-B fractal contact model to simulate the contact state between micro-convex peaks, and obtains the friction pair gap flow field characteristic parameters; discretizes the friction pair gap flow field characteristic parameters, constructs a liquid-viscous clutch flat-torsion coupling dynamic model, obtains the friction pair gap oil film viscous torque and power transmission mechanism, proposes a discretized numerical solution method for the friction pair gap flow field characteristic parameters, and obtains the output speed and / or output speed range of the load end. The technical solution is adopted to clarify the contact mechanism between the gap fluid and the micro-convex peaks under discrete distribution, and obtain the dynamic mapping relationship between the load end and the input end speed transmission.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid viscous transmission, and relates to a liquid viscous clutch speed regulation domain detection method and device based on dynamic solution. Background Art

[0002] The performance of the liquid viscous speed control clutch (HVD) is related to many factors, and the transmission friction pair, which is the core of its power transmission, is even more critical. During the speed control process of the liquid viscous clutch, the abrupt change of the friction pair gap flow field characteristics leads to the problem of speed control boundary instability. Under the action of the system oil pressure, the friction pair transitions from fluid lubrication to boundary lubrication. The micro-convex bodies on the friction plate surface are the main carriers of the bearing capacity and transmission torque in the mixed friction stage. The speed control process of the liquid viscous clutch is a complex problem of thermal, fluid and solid coupling. There is a lack of a dynamic mapping transmission relationship between the structural parameters of the liquid viscous friction plate, the gap oil characteristic parameters (oil film bearing capacity, viscous torque), and the actual output speed of the load end. Understanding the friction pair gap flow field characteristics is the key to accurately establish the dynamic model of the liquid viscous clutch system. However, in the existing technology, it is limited to obtaining the speed control domain of the liquid viscous clutch through experimental means, which increases the required cost and cannot accurately and quickly calculate the speed control domain. Summary of the invention

[0003] The object of the present invention is to provide a method and device for detecting the speed regulation range of a liquid-viscous clutch based on dynamic solution, so as to obtain a dynamic mapping relationship between the speed transmission of the load end and the input end, and to accurately and quickly calculate the speed regulation range.

[0004] In order to achieve the above object, the basic scheme of the present invention is: a method for detecting the speed range of a liquid-viscous clutch based on dynamic solution, comprising the following steps:

[0005] Obtaining the axial system force and / or force range of the liquid-viscous clutch;

[0006] Obtain the Reynolds equation of the fluid considering the influence of centrifugal force in the cylindrical coordinate system;

[0007] Based on the mean flow model, the pressure flow factor and shear flow factor are introduced into the fluid Reynolds equation to correct the error generated when solving the rough surface lubrication.

[0008] The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the contact state between micro-convex peaks, and the flow field characteristic parameters of the friction pair gap are obtained.

[0009] A hydroviscous clutch torsional coupling dynamics calculation model is established, and the friction pair clearance flow field characteristic parameters are discretized and substituted into the hydroviscous clutch torsional coupling dynamics model to obtain the output speed and / or output speed range at the load end.

[0010] The working principle and beneficial effects of this basic solution are as follows: the present invention adopts the idea of ​​dynamic solution, and substitutes the characteristics of load-bearing capacity and transmission torque with the friction pair clearance into the flat-torsion coupling dynamic model of the liquid-viscous clutch for discretization processing to obtain the output speed and / or output speed range of the load end. By establishing the dynamic model of the liquid-viscous clutch system, the viscous torque and power transmission mechanism of the friction pair clearance oil film are obtained, and a numerical solution method for the discretization of the characteristic parameters of the friction pair clearance flow field is proposed to obtain the actual output speed of the load end. The contact mechanism between the gap fluid and the micro-convex peak under discrete distribution is clarified, and a calculation model for load-bearing capacity and transmission torque is established. Through the flat-torsion coupling dynamic model of the liquid-viscous clutch system, the dynamic mapping relationship between the speed transmission of the load end and the input end is obtained by coupling solution.

[0011] Further, according to the input speed, the system transmission ratio or the system transmission ratio range is obtained according to the output speed and / or the output speed range. The system transmission ratio range is the speed regulation domain range corresponding to the axial system force range.

[0012] According to the needs, the load end speed value under axial forces of different sizes and different input forms can be solved, which is convenient for use.

[0013] Furthermore, combined with the assumptions about the oil film in the friction pair flow field analysis, the Reynolds equation of the oil film considering the influence of centrifugal force in the cylindrical coordinate system is derived as follows:

[0014]

[0015] Among them, V 1 and V 2 is the radial motion speed of the friction plate and the dual steel plate surface of the friction pair; h is the friction pair clearance; μ is the viscosity of the lubricating oil; ρ is the density of the lubricating oil; p is the pressure; ω 1 and ω 2 Indicates the rotation speed of the friction plate and the dual steel plate; U 1 and U 2 Indicates the speed parameters of the friction plate and the dual plate, U 1 =ω 1 r,U 2 =ω 2 r; r and θ represent the radial and circumferential directions of the friction pair respectively, and t represents time.

[0016] Simple structure and easy to use.

[0017] Furthermore, the pressure flow factor and shear flow factor are introduced to correct the fluid Reynolds equation as follows:

[0018]

[0019] Among them, r and θ represent the radial and circumferential directions of the friction pair respectively; μ represents the viscosity of the lubricating oil; Indicates the average pressure of the oil film between the friction pairs; φ θ and φ r is the rough surface pressure flow factor, which represents the ratio of the average pressure flow between the rough surface and the pressure flow between the smooth surface in the r and θ directions respectively; φ s is the shear flow factor, which is used to characterize the influence of the additional flow generated when two rough surfaces slide relative to each other; φ c is the contact factor, considering the influence of the rough peak contact on the average value of the actual oil film thickness; U 1 and U 2 Represents the speed parameters of the friction plate and the dual plate; ω 1 and ω 2 Indicates the rotational speed of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness on the rough surface of the random variable.

[0020] Correct the errors in solving the rough surface lubrication problem and optimize the equations.

[0021] Furthermore, the friction pair gap flow field characteristic parameters include the bearing capacity P and the transmission torque T in the friction slip stage and the mixed friction stage;

[0022] According to Newton's law of internal friction, the friction pair fluid torque T under the average shear stress model in the mixed friction stage h for:

[0023]

[0024] Among them, k a Indicates the actual contact area ratio when the rough surface contacts; ψ is the correction coefficient; R 1 and R 2 is the inner and outer diameters of the friction pair; μ represents the viscosity of the lubricating oil; ω 1 and ω 2 Indicates the rotational speed of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness of the random variable rough surface; r and θ represent the radial and circumferential directions of the friction pair respectively; φ h is the shear stress factor in the film thickness direction;

[0025] The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the mutual contact state, contact load and friction torque between micro-convex peaks; the total load of the contact area is estimated using the size distribution n(a) of the contact points. If the maximum contact point area is larger than the critical area, some contact points are in plastic deformation, while the other contact points are in elastic deformation, and the total load is:

[0026]

[0027] Among them, the first term is the elastic contact load, and the second term is the plastic contact load; W a is the total load, E is the comprehensive elastic modulus obtained by Hertz analysis, G and D are the rough surface scale factor and fractal dimension, respectively, and a l represents the area of ​​the maximum contact point, a c represents the critical deformation, a s Indicates the area of ​​the minimum contact point; K represents the hardness H and yield strength σ y The correlation coefficient, that is, H = Kσ y ;

[0028] When all contact points are in plastic contact, the total load is:

[0029]

[0030] Among them, A r Represents the actual contact area;

[0031] Assuming the friction coefficient f a And friction pair pressure P a The relationship between them is:

[0032] f a =f(p a )

[0033] Among them, f is the relative pressure p of the friction pair a Function of

[0034] Friction torque T caused by asperity peak contact a for:

[0035]

[0036] An average fluid shear stress model is established, and the fluid torque of the friction pair is obtained from Newton's internal friction law. The WM fractal function is used to describe the rough surface profile, and an MB fractal contact model is established to simulate the contact state between micro-convex peaks, and the micro-convex peak bearing capacity and friction torque are obtained for easy use.

[0037] Furthermore, the method for obtaining the output speed at the load end is as follows:

[0038] After obtaining the characteristic parameters of the friction pair gap flow field, the differential equations of axial and torsional vibration motion under the bearing capacity and transmission torque of the friction pair are established respectively, and the dynamic mapping relationship between the load end and the input end speed is obtained by solving:

[0039] Differential equation of friction plate motion:

[0040]

[0041] Where F(t) is the axial system force, f k is the spring force, f p is the bearing capacity of the friction pair clearance, m f is the mass of the friction disk, xf is the axial displacement of the friction disk; the subscript (i) represents the force acting on the i-th friction element, f k(i) 、f p(i) f k(i) 、f p(i) represents the spring force on the i-th friction element and the bearing capacity of the friction pair clearance; n f Indicates the number of friction plates; Indicates the axial movement acceleration of the friction plate;

[0042] Differential equation of motion of the separation disk:

[0043]

[0044] Among them, m s is the mass of the separation plate, x s is the axial displacement of the separation disc, n s Indicates the number of separation discs; Indicates the axial movement acceleration of the separation disc;

[0045] Differential equation of torsional vibration of separation disk:

[0046]

[0047] Among them, J s is the moment of inertia of the separation disc, k b is the torsional stiffness of the output shaft, c b is the torsional damping of the output shaft, θ s , Respectively represent the angular displacement, angular velocity and angular acceleration of the separation disk; θ 2 , Respectively represent the angular displacement and angular velocity of the load end;

[0048] The differential equation of torsional vibration at the load end is:

[0049]

[0050] Among them, J 2 is the load end moment of inertia, M 2 Transmit torque to the load end;

[0051] Since the friction plate input speed is constant n f , solve to get the load end output speed n 2 .

[0052] Through the characteristics of the load-bearing capacity and the transmitted torque changing with the friction pair clearance, the hydraulic-viscous clutch flat-torsion coupling dynamics model is substituted for discretization processing, and the load end speed value under no axial force can be solved. The operation is simple and easy to use.

[0053] Further, the transmission ratio ii of the liquid-viscous clutch system is defined as follows:

[0054]

[0055] Among them, n 2 is the output speed at the load end; n f Indicates the number of friction plates; represents the angular velocity of the load end; under the axial force, the clearance value of the friction pair decreases, and the friction slip state transitions to the mixed friction stage, thereby achieving power transmission; assuming that the axial force range [0, F max ], then the force is 0, F max i 0 、i max are the minimum and maximum transmission ratios of the system, i.e., the amplitude range of the liquid viscosity speed regulation domain [i 0 ,i max ].

[0056] The calculation process is simple and easy to operate.

[0057] The present invention also provides a liquid-viscous clutch speed regulation domain detection device based on dynamic solution, including a friction plate, a dual plate, an input shaft, an output shaft, a load-end driving gear, a load-end passive gear, a fan and a processor. The processor executes the method of the present invention to perform liquid-viscous clutch speed regulation domain detection.

[0058] The device utilizes a processor to calculate a dynamic mapping relationship between the speed transmission of the load end and the input end, which is convenient for use. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a flow chart of a method for detecting a speed regulation domain of a liquid-viscous clutch based on dynamics solution of the present invention;

[0060] Figure 2 It is a structural schematic diagram of a speed regulation domain detection device of a liquid-viscous clutch based on dynamics solution of the present invention;

[0061] Figure 3 It is a schematic diagram of the force analysis of the liquid-viscous friction element of the liquid-viscous clutch speed regulation domain detection method based on dynamic solution of the present invention.

[0062] The reference numerals in the drawings of the specification include: friction plate 1, dual plate 2, input shaft 3, output shaft 4, load-end driving gear 5, load-end passive gear 6, and fan 7. DETAILED DESCRIPTION

[0063] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0064] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0065] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0066] The speed regulation process of the liquid-viscous clutch is a complex problem of thermal, fluid and solid coupling. There is a lack of a dynamic mapping transmission relationship between the structural parameters of the liquid-viscous friction plate, the characteristic parameters of the gap oil (oil film bearing capacity, viscous torque), and the actual output speed of the load end. Therefore, the present invention discloses a liquid-viscous clutch speed regulation domain detection method based on dynamic solution. The dynamic solution concept is adopted. Through the characteristics of the bearing capacity and the transmission torque changing with the friction pair gap, the flat-torsion coupling dynamic equation is established, and a discretized numerical solution method is proposed. The flat-torsion coupling dynamic model of the liquid-viscous clutch is substituted for discretization processing, and the load end speed value under different sizes and different input forms of axial forces can be solved. Figure 1 As shown, the method for detecting the speed regulation range of the liquid-viscous clutch includes the following steps:

[0067] Obtaining the axial system force and / or force range of the liquid-viscous clutch;

[0068] Obtain the Reynolds equation of the fluid considering the influence of centrifugal force in the cylindrical coordinate system;

[0069] Based on the mean flow model, the pressure flow factor and shear flow factor are introduced into the fluid Reynolds equation to correct the error of the fluid Reynolds equation when solving the rough surface lubrication.

[0070] The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the contact state between micro-convex peaks, and the characteristic parameters of the friction pair gap flow field, namely the bearing capacity P and the transmitted torque T in the friction-slip stage and the mixed friction stage, are obtained.

[0071] A hydroviscous clutch torsional coupling dynamics calculation model is established, and the friction pair clearance flow field characteristic parameters are discretized and substituted into the hydroviscous clutch torsional coupling dynamics model to obtain the output speed and / or output speed range at the load end.

[0072] According to the input speed, the system transmission ratio or system transmission ratio range is obtained according to the output speed and / or output speed range. The system transmission ratio range is the speed regulation domain range corresponding to the axial system force range. By changing the axial system force, the speed regulation domain amplitude under different input forces is obtained.

[0073] In a preferred embodiment of the present invention, the following assumptions are made about the oil film in the friction pair flow field analysis: (1) The fluid in the gap of the friction pair of the liquid-viscous speed control clutch is an incompressible Newtonian fluid, the density of the fluid is a constant, and an isothermal assumption is made for the oil film in the friction pair, and the viscosity of the fluid in the gap is a constant; (2) The flow of the working oil in the gap of the friction pair is laminar; (3) The influence of mass force is ignored; (4) The gap of the friction pair is much smaller than the radius of the friction plate, the axial velocity component of the fluid is ignored, and the change in pressure in the film thickness direction is ignored; (5) The maximum shear stress of the fluid in the friction pair will not exceed the limiting shear stress, and the fluid has no relative sliding on the surface of the friction pair; (6) The friction plate and the dual steel plate are rigid bodies, and no tilting, warping, or deformation occurs during operation. The Reynolds equation for the oil film in the cylindrical coordinate system considering the influence of centrifugal force is derived as follows:

[0074]

[0075] Among them, V 1 and V 2 is the radial motion speed of the friction plate and the dual steel plate surface of the friction pair; h is the friction pair clearance; μ is the viscosity of the lubricating oil; ρ is the density of the lubricating oil; p is the pressure; ω 1 and ω 2 Indicates the rotation speed of the friction plate and the dual steel plate; U 1 and U 2 Indicates the speed parameters of the friction plate and the dual plate, U 1 =ω 1 r,U 2 =ω 2 r; r and θ represent the radial and circumferential directions of the friction pair respectively, and t represents time.

[0076] In a preferred embodiment of the present invention, the fluid in the gap of the friction pair in the mixed friction stage is separated by micro-convex peaks and cannot form a complete oil film. Based on the average flow model, the pressure flow factor and the shear flow factor are introduced into the classic Reynolds equation, and the method for correcting the fluid Reynolds equation is as follows:

[0077]

[0078] Where r and θ represent the radial and circumferential directions of the friction pair, respectively; μ represents the viscosity of the lubricating oil; p represents the average pressure of the oil film between the friction pairs; φ θ and φ r is the rough surface pressure flow factor, which represents the ratio of the average pressure flow between the rough surface and the pressure flow between the smooth surface in the r and θ directions respectively; φ s is the shear flow factor, which is used to characterize the influence of the additional flow generated when two rough surfaces slide relative to each other; φ c is the contact factor, considering the influence of the rough peak contact on the average value of the actual oil film thickness; U 1 and U 2 Represents the speed parameters of the friction plate and the dual plate; ω 1 and ω 2 Indicates the rotational speed of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness on the rough surface of the random variable.

[0079] In a preferred embodiment of the present invention, the friction pair gap flow field characteristic parameters include the bearing capacity P and the transmission torque T in the friction slip stage and the mixed friction stage;

[0080] According to Newton's law of internal friction, the friction pair fluid torque T under the average shear stress model in the mixed friction stage h for:

[0081]

[0082] Among them, k a Indicates the actual contact area ratio when the rough surface contacts; ψ is the correction coefficient; R 1 and R 2 is the inner and outer diameters of the friction pair; μ represents the viscosity of the lubricating oil; ω 1 and ω 2 Indicates the rotational speed of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness of the random variable rough surface; r and θ represent the radial and circumferential directions of the friction pair respectively; φ h is the shear stress factor in the film thickness direction;

[0083] The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the mutual contact state, contact load and friction torque between micro-convex peaks; the total load of the contact area is estimated using the size distribution n(a) of the contact points. If the maximum contact point area is larger than the critical area, some contact points are in plastic deformation, while the other contact points are in elastic deformation, and the total load is:

[0084]

[0085] Among them, the first term is the elastic contact load, and the second term is the plastic contact load; W a is the total load; E is the comprehensive elastic modulus obtained by Hertz analysis, expressed as:

[0086]

[0087] ν 1 and ν 2 are the Poisson's ratios of the friction plate and the dual steel plate materials, E 1 and E 2 are the elastic moduli of the two materials respectively; G and D represent the rough surface scale coefficient and fractal dimension respectively, a l represents the area of ​​the maximum contact point, a c represents the critical deformation, a s Indicates the area of ​​the minimum contact point; K represents the hardness H and yield strength σ y The correlation coefficient, that is, H = Kσ y ;

[0088] When all contact points are in plastic contact, the total load is:

[0089]

[0090] Among them, A r Represents the actual contact area;

[0091] Assuming the friction coefficient f a And friction pair pressure P a The relationship between them is:

[0092] f a =f(p a )

[0093] Among them, f is the relative pressure p of the friction pair a The function is an empirical formula obtained from experiments;

[0094] Friction torque T caused by asperity peak contact a for:

[0095]

[0096] In a preferred embodiment of the present invention, the method for obtaining the output speed at the load end is as follows:

[0097] After obtaining the friction pair gap flow field characteristic parameters, such as Figure 3 As shown in the figure, according to the force analysis diagram of the liquid-viscous friction element, the differential equations of axial and torsional vibration motion under the bearing capacity and transmission torque of the friction pair are established respectively, and the dynamic mapping relationship between the speed of the load end and the input end is obtained by solving:

[0098] Differential equation of friction plate motion:

[0099]

[0100] Where F(t) is the axial system force, f k is the spring force, f p is the bearing capacity of the friction pair clearance, m f is the mass of the friction disc, x f is the axial displacement of the friction disk; the subscript (i) represents the force acting on the i-th friction element, f k(i) 、f p(i) f k(i) 、f p(i) represents the spring force on the i-th friction element and the bearing capacity of the friction pair clearance; n f Indicates the number of friction plates; Indicates the axial movement acceleration of the friction plate;

[0101] Differential equation of motion of the separation disk:

[0102]

[0103] Among them, m s is the mass of the separation plate, x s is the axial displacement of the separation disc, n s Indicates the number of separation discs; Indicates the axial movement acceleration of the separation disc;

[0104] Differential equation of torsional vibration of separation disk:

[0105]

[0106] Among them, J s is the moment of inertia of the separation disc, k b is the torsional stiffness of the output shaft, c b is the torsional damping of the output shaft, θ s , Respectively represent the angular displacement, angular velocity and angular acceleration of the separation disk; θ 2 , Respectively represent the angular displacement and angular velocity of the load end;

[0107] The differential equation of torsional vibration at the load end is:

[0108]

[0109] Among them, J 2 is the load end moment of inertia, M 2 Transmit torque to the load end;

[0110] Since the friction plate input speed is constant n f , the load-end output speed n is obtained by solving the above dynamic model 2 ,Right now

[0111] The transmission ratio ii of the hydroviscous clutch system is defined as follows:

[0112]

[0113] Among them, n 2 is the output speed at the load end; n f Indicates the number of friction plates; represents the angular velocity of the load end; under the axial force, the clearance value of the friction pair decreases, and the friction slip state transitions to the mixed friction stage, thereby achieving power transmission; assuming that the axial force range [0, F max ], then the force is 0, F max i 0 、i max are the minimum and maximum transmission ratios of the system, i.e., the amplitude range of the liquid viscosity speed regulation domain [i 0 ,i max ].

[0114] This scheme uses the average flow model and MB fractal function to describe the contact state between friction pairs, and calculates the torque and load-bearing capacity transmitted by the gap fluid and micro-convex peak contact in the mixed friction stage. In view of the problems in the background technology, the "friction pair gap flow field characteristics" are associated with the dynamic characteristics of the liquid-viscous clutch, the gap fluid and micro-convex peak contact mechanism under discrete distribution is clarified, and the load-bearing capacity and transmission torque calculation model is established. Through the flat-torsion coupling dynamics model of the liquid-viscous clutch system, the dynamic mapping relationship between the load end and the input end speed transmission is obtained by coupling solution.

[0115] The present invention also provides a liquid-viscous clutch speed range detection device based on dynamic solution, such as Figure 2As shown, it includes a friction plate 1, a pair of plates 2, an input shaft 3, an output shaft 4, a load-end driving gear 5, a load-end passive gear 6, a fan 7 and a processor. The liquid-viscous clutch structure of this scheme can adopt an existing conventional liquid-viscous clutch, and the processor executes the method described in the present invention to perform liquid-viscous clutch speed regulation domain detection. The device uses a processor to calculate the dynamic mapping relationship between the speed transmission of the load end and the input end, which is convenient for use.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0117] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for detecting the speed range of a liquid-viscous clutch based on dynamics solution, characterized in that: The steps include: Obtaining the axial system force and / or force range of the liquid-viscous clutch; Obtain the Reynolds equation of the fluid considering the influence of centrifugal force in the cylindrical coordinate system; Based on the mean flow model, the pressure flow factor and shear flow factor are introduced into the fluid Reynolds equation to correct the error generated when solving the rough surface lubrication. The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the contact state between micro-convex peaks, and the flow field characteristic parameters of the friction pair gap are obtained. A hydroviscous clutch torque coupling dynamics calculation model is established, and the friction pair clearance flow field characteristic parameters are discretized and substituted into the hydroviscous clutch torque coupling dynamics model to obtain the output speed and / or output speed range at the load end; The method to obtain the output speed at the load end is as follows: After obtaining the characteristic parameters of the friction pair gap flow field, the differential equations of axial and torsional vibration motion under the bearing capacity and transmission torque of the friction pair are established respectively, and the dynamic mapping relationship between the load end and the input end speed is obtained by solving: Differential equation of friction plate motion: Where F(t) is the axial system force, f k is the spring force, f p is the bearing capacity of the friction pair clearance, m f is the mass of the friction disc, x f is the axial displacement of the friction disk; the subscript (i) represents the force acting on the i-th friction element, f k(i) 、f p(i) represents the spring force on the i-th friction element and the bearing capacity of the friction pair clearance; n f Indicates the number of friction plates; Indicates the axial movement acceleration of the friction plate; Differential equation of motion of the separation disk: Among them, m s is the mass of the separation plate, x s is the axial displacement of the separation disc, Indicates the axial movement acceleration of the separation disc; n s Indicates the number of separation discs; Differential equation of torsional vibration of separation disk: Among them, J s is the moment of inertia of the separation disc, k b is the torsional stiffness of the output shaft, c b is the torsional damping of the output shaft, θ s , Respectively represent the angular displacement, angular velocity, and angular acceleration of the separation disk; θ2, Respectively represent the angular displacement and angular velocity of the load end; The differential equation of torsional vibration at the load end is: Among them, J2 is the moment of inertia at the load end, and M2 is the torque transmitted at the load end; Since the friction plate input speed is constant n f , solve for the load-end output speed n2.

2. The method for detecting the speed range of a liquid-viscous clutch based on dynamic solution according to claim 1 is characterized in that: According to the input speed, the system transmission ratio or the system transmission ratio range is obtained according to the output speed and / or the output speed range. The system transmission ratio range is the speed regulation domain range corresponding to the axial system force range.

3. The method for detecting the speed range of a liquid-viscous clutch based on dynamic solution according to claim 1 is characterized in that: Combined with the assumptions about the oil film in the friction pair flow field analysis, the Reynolds equation of the oil film considering the influence of centrifugal force in the cylindrical coordinate system is derived as follows: Among them, V1 and V2 are the radial movement speeds of the friction plate and the dual steel plate surfaces of the friction pair; h is the friction pair clearance; μ represents the viscosity of the lubricating oil; ρ represents the density of the lubricating oil; p represents the pressure; ω1 and ω2 represent the rotation speeds of the friction plate and the dual steel plate; U1 and U2 represent the speed parameters of the friction plate and the dual plate, U1=ω1r, U2=ω2r; r and θ represent the radial and circumferential directions of the friction pair respectively, and t represents time.

4. The method for detecting the speed range of a liquid-viscous clutch based on dynamics solution according to claim 1 is characterized in that: The method of introducing pressure flow factor and shear flow factor to correct the fluid Reynolds equation is as follows: Among them, r and θ represent the radial and circumferential directions of the friction pair respectively; μ represents the viscosity of the lubricating oil; Indicates the average pressure of the oil film between the friction pairs; φ θ and φ r is the rough surface pressure flow factor, which represents the ratio of the average pressure flow between the rough surface and the pressure flow between the smooth surface in the r and θ directions respectively; φ s is the shear flow factor, which is used to characterize the influence of the additional flow generated when two rough surfaces slide relative to each other; φ c is the contact factor, considering the influence of the rough peak contact on the average value of the actual oil film thickness; U1 and U2 represent the speed parameters of the friction plate and the dual plate; ω1 and ω2 represent the rotation speed of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness on the rough surface of the random variable.

5. The method for detecting the speed range of a liquid-viscous clutch based on dynamic solution according to claim 1, characterized in that: The friction pair gap flow field characteristic parameters include the bearing capacity P and the transmission torque T in the friction slip stage and the mixed friction stage; According to Newton's law of internal friction, the friction pair fluid torque T under the average shear stress model in the mixed friction stage h for: Among them, k a It represents the actual contact area ratio when the rough surfaces are in contact; ψ is the correction coefficient; R1 and R2 are the inner and outer diameters of the friction pair; μ represents the viscosity of the lubricating oil; ω1 and ω2 represent the rotation speeds of the friction plate and the dual steel plate; is the overall average value of the actual oil film thickness of the random variable rough surface; r and θ represent the radial and circumferential directions of the friction pair respectively; φ h is the shear stress factor in the film thickness direction; The WM fractal function is used to describe the rough surface profile, and the MB fractal contact model is established to simulate the mutual contact state, contact load and friction torque between micro-convex peaks; the total load of the contact area is estimated using the size distribution n(a) of the contact points. If the maximum contact point area is larger than the critical area, some contact points are in plastic deformation, while the other contact points are in elastic deformation, and the total load is: Among them, the first term is the elastic contact load, and the second term is the plastic contact load; W a is the total load, E is the comprehensive elastic modulus obtained by Hertz analysis, G and D are the rough surface scale factor and fractal dimension, respectively, and a l represents the area of ​​the maximum contact point, a c represents the critical deformation, a s Indicates the area of ​​the minimum contact point; K represents the hardness H and yield strength σ y The correlation coefficient, that is, H = Kσ y ; When all contact points are in plastic contact, the total load is: Among them, A r Represents the actual contact area; Assuming the friction coefficient f a And friction pair pressure P a The relationship between them is: f a =f(p a ) Among them, f is the relative pressure p of the friction pair a Function of Friction torque T caused by asperity peak contact a for:

6. The method for detecting the speed range of a liquid-viscous clutch based on dynamic solution according to claim 1, characterized in that: The transmission ratio ii of the hydroviscous clutch system is defined as follows: Where n2 is the output speed at the load end; n f Indicates the number of friction plates; represents the angular velocity of the load end; under the axial force, the clearance value of the friction pair decreases, and the friction slip state transitions to the mixed friction stage, thereby achieving power transmission; assuming that the axial force range [0, F max ], then the force is 0, F max When i0 and i max are the minimum and maximum transmission ratios of the system, that is, the amplitude range of the liquid viscosity speed regulation domain [i0, i max ].

7. A liquid-viscous clutch speed range detection device based on dynamic solution, characterized in that: The invention comprises a friction plate, a pair of plates, an input shaft, an output shaft, a load-end driving gear, a load-end passive gear, a fan and a processor, wherein the processor executes the method according to any one of claims 1 to 6 to perform a speed regulation domain detection of a liquid-viscous clutch.

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