Active control device and method for preventing thermal failure of a hydro-viscous transmission friction plate

Abstract

The application provides an active control device and method for preventing thermal failure of a liquid viscous transmission friction plate. The device comprises a temperature sensor for detecting the surface temperature of a local area of the friction plate in real time; each circular ring is provided with n temperature sensors on the side facing the oil film gap; a hydraulic circuit is provided with one, which adjusts the flow of cooling oil into the clutch box according to the maximum temperature of the local area of the friction plate; a controller outputs a cooling flow signal to a command potentiometer according to the surface temperature of the local area; displacement sensors are used to measure the axial displacement of the local area of the friction plate in real time, and there are 3n displacement sensors, each of which is arranged on the side of the strain gauge facing the oil film gap; and a friction plate axial deformation constraint mechanism, which has 3n. The application adopts the method of adjusting the flow of cooling oil for local high temperature and mechanically restraining the axial thermal deformation of the friction plate to actively prevent the thermal failure of the friction plate.

Description

Technical Field

[0001] This invention belongs to the field of liquid viscous transmission technology, and in particular, it is an active control device and method for preventing thermal failure of friction plates in liquid viscous transmission. Background Technology

[0002] Viscous fluid transmission is a novel form of fluid transmission that utilizes the viscosity or shear force of a fluid to transmit power. Its working principle is based on Newton's law of internal friction, enabling stepless speed regulation and offering significant advantages such as smooth start-up and high controllability. However, due to the uneven distribution of thermal stress in the friction pair system, the friction plates are prone to warping deformation in the radial direction, which significantly impacts the viscous fluid transmission process.

[0003] Most existing patents control friction plate deformation by detecting the thermal deformation and applying displacement constraints. For example, patent CN114151465A incorporates a new hydraulic circuit in a fluid viscosity differential transmission device. A resistive displacement sensor embedded in a strain gauge detects the radial deformation of the friction plate, and the hydraulic circuit drives a hydraulic cylinder to apply radial constraints, thereby controlling warping deformation. Patent CN115059699A uses a friction plate deformation reduction mechanism to apply magnetic attraction or repulsion along the circumferential direction. By controlling both axial and circumferential directions, it reduces warping deformation of the friction plate, achieving stable transmission.

[0004] As can be seen from the above patents, existing technical solutions for the drawback of friction pads being prone to thermal deformation lack the ability to address the problem of thermal failure of friction pads by focusing on the two aspects of local temperature rise and the generation of minute deformation. Summary of the Invention

[0005] The purpose of this invention is to provide an active control device and method for preventing thermal failure of friction plates in fluid-viscous transmissions. This is achieved by adjusting the flow rate of cooling oil to address localized high temperatures and by mechanically constraining the axial thermal deformation of the friction plates. To achieve the above objective, the technical solution adopted is as follows:

[0006] An active control device for preventing thermal failure of fluid-viscous transmission friction plates, comprising: Temperature sensors are used to detect the surface temperature of local areas in the friction pad in real time. They are distributed on the surface of annular rings with radii r1, r2, and r3. n temperature sensors are evenly distributed on the side of each ring facing the oil film gap. There is one hydraulic circuit, which adjusts the flow rate of cooling oil into the clutch housing based on the maximum temperature of various local areas in the friction plates. The output end of the hydraulic circuit is connected to the oil inlet of the clutch housing. The hydraulic circuit includes: An electro-hydraulic servo valve 19 and a flow meter 24 are provided. The flow meter 24 is installed on the oil line between the electro-hydraulic servo valve 19 and the clutch housing. The oil inlet of the electro-hydraulic servo valve 19 is connected to the oil inlet pipeline. Command potentiometer 22, comparator 21 and servo amplifier 20 are connected in sequence. The output of command potentiometer 22 is connected to the first input of comparator 21; the second input of comparator 21 is connected to the output of flow meter 24; the output of servo amplifier 20 is connected to electro-hydraulic servo valve 19 to adjust the opening degree of electro-hydraulic servo valve 19. The controller outputs a cooling flow signal to the command potentiometer 22 based on the surface temperature of the local area. Displacement sensors are used to measure the axial displacement of local areas in the friction plate in real time. There are 3n sensors in total, which are set up in correspondence with temperature sensors to characterize the same local area. Each displacement sensor is set on the side of the strain gauge facing the oil film gap. There are 3n friction plate axial deformation constraint mechanisms, which are used to compensate for the axial displacement of local areas in the friction plate. Each local area is connected to a friction plate axial deformation constraint mechanism on the side facing away from the viscous fluid.

[0007] Preferably, the opening / closing degree model of the electro-hydraulic servo valve 19 is as follows:

[0008] In the formula, G(s) is the degree of opening; K sv It is the servo valve flow gain, m 3 / s·A,ω sv It is the natural frequency of the servo valve, rad / s, ξ sv is the damping ratio of the servo valve; s is the amplified cooling flow difference signal output by servo amplifier 20.

[0009] Preferably, the relationship between the local surface temperature and the required cooling flow rate is as follows: Y = AX 3 -BX 2 +CX+D In the formula, Y is the temperature (°C), X is the required cooling flow rate (L / min), and A, B, C, and D are all constants.

[0010] Preferably, there are two sets of axial deformation constraint mechanisms for the friction plates: an active axial deformation constraint mechanism and a passive axial deformation constraint mechanism. The active axial deformation constraint mechanism is used to eliminate the deformation of the active friction plates, and the passive axial deformation constraint mechanism is used to eliminate the deformation of the passive friction plates.

[0011] Preferably, the active friction pad axial deformation constraint mechanism includes: The base 5 is fixed to the active plate support 2 by screws 7; The piezoelectric ceramic actuator 12 has its housing fixed to the base 5, and its output end is connected to the movable slider 8; the piezoelectric ceramic actuator 12 is powered by a power supply and is connected to the controller signal; both the power supply and the controller are located outside the clutch housing.

[0012] The strain gauge 6, the movable slider 8, and the flexible hinge 9 are connected in sequence. The strain gauge 6 is positioned facing the oil film gap, and its surface facing the oil film gap is fixed to a local area of ​​the active friction plate 1. The movable slider 8 is used to connect the strain gauge and transmit the displacement of the piezoelectric ceramic actuator. The movable slider 8 is provided with limiting sliders 10 at both ends. The limiting sliders 10 are placed on the slide rails on the baffles 11 on both sides of the piezoelectric ceramic actuator. The slide rails extend axially. The baffle 11 is fixed to the base 5 and extends axially.

[0013] Preferably, the transfer function of the piezoelectric ceramic actuator 12 is:

[0014] U(S) is the driving voltage of the piezoelectric ceramic actuator; X(S) is the displacement of the piezoelectric ceramic actuator; K m This is the piezoelectric displacement conversion coefficient; R is the equivalent resistance of the piezoelectric ceramic actuator, in Ω; C is the equivalent capacitance of the piezoelectric ceramic actuator, in uf; S is the Laplace operator.

[0015] Preferably, the oil inlet pipe of the hydraulic circuit further includes: The oil tank 13, oil filter 14, oil pump 15 and cooler 17 are connected in sequence, and the output end of the cooler 17 is connected to the oil inlet of the electro-hydraulic servo valve 19. Electric motor 16 is used to drive oil pump 15; An overflow valve 18 is located between the flow meter 24 and the electro-hydraulic servo valve 19.

[0016] An active control method for preventing thermal failure of friction plates in liquid-viscous transmissions includes the following steps: S1. Steps to reduce the surface temperature of the friction plate: First, receive the signal data T from each temperature sensor. i ; Then, select the highest value T. iAs a control signal, the controller drives the hydraulic circuit. The command potentiometer 22 in the hydraulic circuit receives the cooling flow signal output by the controller, thereby increasing the cooling oil flow of the electro-hydraulic servo valve 19 and reducing the surface temperature of the friction plate. S2. Steps to mechanically constrain the axial thermal deformation of localized areas of the friction plate: First, receive the signal data H from each displacement sensor. i If H i ≠0, then H i The current control quantity is used to control the axial deformation constraint mechanism of the corresponding local area through the controller, thereby realizing the axial displacement control of the local area of ​​the friction plate.

[0017] Preferably, the method further includes the following steps: Pre-set the initial surface temperature T of the friction plate. If T is less than T... i Then the controller outputs a cooling flow signal to the command potentiometer 22.

[0018] Compared with the prior art, the advantages of the present invention are: The thermal failure of the friction plates is actively prevented by adjusting the flow rate of cooling oil to address localized high temperatures and by mechanically constraining the axial thermal deformation of the friction plates. Attached Figure Description

[0019] Figure 1 A schematic diagram of the overall structure of an active control device to prevent thermal failure of friction plates in liquid-viscous transmission. Figure 2 A simplified closed-loop flowchart of an active control method for preventing thermal failure of friction plates in liquid-viscous drives; Figure 3 This is a partial enlarged view of the friction plate axial deformation constraint mechanism; Figure 4 This is a schematic diagram of a hydraulic circuit. Figure 5 This is a structural diagram of a piezoelectric ceramic actuator; Figure 6 This is a control principle diagram of the friction plate axial deformation constraint mechanism; Figure 7 This is a distribution diagram of the friction plate temperature sensors; Figure 8 This is a diagram illustrating the effect of temperature control. Figure 9 This is a diagram showing the effect of axial displacement adjustment.

[0020] 1-Active friction plate, 2-Active plate support, 3-Passive friction plate, 4-Passive plate support; 5-Base, 6-Strain gauge, 7-Screw, 8-Moving slider, 9-Flexible hinge, 10-Limit slider, 11-Baffle, 12-Piezoelectric ceramic actuator; 13-Oil tank, 14-Oil filter, 15-Oil pump, 16-Motor, 17-Cooler, 18-Relief valve, 19-Electro-hydraulic servo valve, 20-Servo amplifier, 21-Comparator, 22-Command potentiometer, 23-Friction pair, 24-Flow meter. Detailed Implementation

[0021] The active control device and method for preventing thermal failure of fluid-viscous transmission friction plates according to the present invention will be described in more detail below with reference to schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving the advantageous effects of the invention. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0022] like Figures 1-7 An active control device for preventing thermal failure of friction plates in viscous transmissions utilizes two methods: adjusting the flow rate of cooling oil to address localized high temperatures and mechanically constraining the axial thermal deformation of the friction plates to actively prevent thermal failure. Specifically, it includes: Temperature sensors are used to detect the surface temperature of local areas in the friction pad in real time. They are distributed on the surface of annular rings with radii r1, r2, and r3. n temperature sensors (n≥4) are evenly distributed on the side of each ring facing the oil film gap. In this embodiment, 12 temperature sensors are provided in each ring, and each sensor is evenly distributed with a 30° interval within the same radial dimension.

[0023] There is one hydraulic circuit, which adjusts the flow rate of cooling oil entering the clutch housing according to the maximum temperature of a local area in the friction plate. The output end of the hydraulic circuit is connected to the oil inlet of the clutch housing, so that the cooling oil eventually surrounds the friction pair 23.

[0024] Hydraulic circuit schematic diagram as follows Figure 4 As shown, its principle is to change the flow rate of lubricating oil in the friction pair by controlling the opening and closing degree of the electro-hydraulic servo valve 19, increasing the flow rate to remove more heat and reduce the temperature of the friction plate.

[0025] Specifically, the command element sends a digital signal (cooling flow signal), which is converted into an analog signal by a D / A converter and then sent to a comparator. The comparator compares the signal with the feedback signal from the flow meter to form a deviation signal. After correction, the amplifier outputs a control current to operate the electro-hydraulic servo valve to generate a hydraulic signal, thereby ensuring that the lubricating oil flow reaches the desired value (cooling flow signal).

[0026] Each hydraulic circuit includes: An electro-hydraulic servo valve 19 and a flow meter 24 are provided. The flow meter 24 is installed on the oil line between the electro-hydraulic servo valve 19 and the clutch housing. The oil inlet of the electro-hydraulic servo valve 19 is connected to the oil inlet pipeline. The hydraulic circuit's inlet line includes: The oil tank 13, oil filter 14, oil pump 15 and cooler 17 are connected in sequence, and the output end of the cooler 17 is connected to the oil inlet of the electro-hydraulic servo valve 19. Electric motor 16 is used to drive oil pump 15; An overflow valve 18 is located between the flow meter 24 and the electro-hydraulic servo valve 19.

[0027] Command potentiometer 22, comparator 21 and servo amplifier 20 are connected in sequence. The output of command potentiometer 22 is connected to the first input of comparator 21; the second input of comparator 21 is connected to the output of flow meter 24; the output of servo amplifier 20 is connected to electro-hydraulic servo valve 19 to adjust the opening degree of electro-hydraulic servo valve 19.

[0028] The opening / closing degree model of the electro-hydraulic servo valve 19 is as follows:

[0029] In the formula, G(s) is the degree of opening; K sv It is the servo valve flow gain, m 3 / s·A,ω sv It is the natural frequency of the servo valve, rad / s, ξ sv is the damping ratio of the servo valve; s is the amplified cooling flow difference signal output by the servo amplifier (20).

[0030] The controller outputs a cooling flow signal to the command potentiometer 22 based on the local surface temperature. This selects the highest T value. i The value is used as the control temperature. The required flow rate is calculated based on the formula of friction plate surface temperature and required cooling flow rate. Then, the hydraulic circuit is driven to increase the flow rate to implement control.

[0031] The relationship between local surface temperature and required cooling flow rate is as follows: Y = AX 3 -BX 2 +CX+D In the formula, Y is the temperature (°C), X is the required cooling flow rate (L / min), and A, B, C, and D are all constants.

[0032] Displacement sensors, used to measure the axial displacement of local areas within the friction plate in real time, number 3n in total. They are positioned corresponding to temperature sensors to characterize the same local area. Each displacement sensor is located on the side of the strain gauge facing the oil film gap. Circular arc strain gauges are uniformly fixed on the r1, r2, and r3 rings of the friction plate. Each ring contains 12 circular arc strain gauges. Each ring encompasses 12 local areas.

[0033] There are 3n friction plate axial deformation constraint mechanisms, which are used to compensate for the axial displacement of local areas in the friction plate. Each local area is connected to a friction plate axial deformation constraint mechanism on the side facing away from the viscous fluid.

[0034] There are two sets of friction plate axial deformation constraint mechanisms: an active friction plate axial deformation constraint mechanism and a passive friction plate axial deformation constraint mechanism. The active friction plate axial deformation constraint mechanism is used to eliminate the deformation of the active friction plate 1. The passive friction plate axial deformation constraint mechanism is fixed on the passive plate support 4 and is used to eliminate the deformation of the passive friction plate 3.

[0035] The active friction plate axial deformation constraint mechanism includes: The base 5 is fixed to the active plate support 2 by screws 7; it rotates together with the active friction plate.

[0036] The piezoelectric ceramic actuator 12 has its housing fixed to the base 5, and its output end is connected to the movable slider 8. The piezoelectric ceramic actuator 12 is powered by a power supply and is connected to the controller signal; both the power supply and the controller are located outside the clutch housing. The piezoelectric ceramic actuator 12 is a P-842.60 piezoelectric ceramic actuator from PI Company.

[0037] The transfer function (displacement model) of the piezoelectric ceramic actuator 12 is:

[0038] U(S) is the driving voltage of the piezoelectric ceramic actuator; X(S) is the displacement of the piezoelectric ceramic actuator; K m This is the piezoelectric displacement conversion coefficient; R is the equivalent resistance of the piezoelectric ceramic actuator, in Ω; C is the equivalent capacitance of the piezoelectric ceramic actuator, in uf; S is the Laplace operator.

[0039] Strain gauge 6, movable slider 8, and flexible hinge 9 are connected in sequence. Strain gauge 6 is positioned facing the oil film gap, and its surface facing the oil film gap is fixed to a local area of ​​the active friction plate 1. Movable slider 8 is used to connect the strain gauge and transmit the displacement of the piezoelectric ceramic actuator. In this embodiment, a ring contains 12 local areas.

[0040] The movable slider connects two flexible hinges. Without strain gauges, the force exerted by the flexible hinges on the friction plate's working surface would be very small.

[0041] The movable slider 8 is provided with limit sliders 10 at both ends. The limit sliders 10 are placed on the slide rails on the baffles 11 on both sides of the piezoelectric ceramic actuator. The slide rails extend axially to ensure the accuracy of axial extension and retraction of the piezoelectric ceramic actuator.

[0042] The baffle 11 is fixed to the base 5 and extends along the axial direction.

[0043] An active control method for preventing thermal failure of friction plates in viscous drives includes the following steps: S1. Steps to reduce the surface temperature of the friction plate: First, receive the signal data T from each temperature sensor. i ; Then, select the highest value T. i As a control signal, the controller drives the hydraulic circuit. The command potentiometer 22 in the hydraulic circuit receives the cooling flow signal output by the controller, thereby increasing the cooling oil flow and reducing the surface temperature of the friction plate.

[0044] Furthermore, the controller uses the initial value T as the desired temperature of the friction plate, and the maximum value T... i The signal is converted into a cooling flow rate signal and input to the command potentiometer 22. The temperature sensor in this local area measures the temperature T of the friction plate after cooling. i ; According to the controller, when T i When T is not equal to T, the controller outputs T. i The corresponding cooling flow signal is sent to the command potentiometer 22.

[0045] S2. Steps to mechanically constrain the axial thermal deformation of localized areas of the friction plate: Receive signal data H from each displacement sensor i If H i ≠0, then H i As the current control quantity, the axial displacement of the friction plate in the corresponding local area is controlled by the controller through the axial deformation constraint mechanism of the corresponding local area; Furthermore, the controller will output displacement H i The desired displacement of this local region is input to the piezoelectric ceramic actuator (12), and the displacement sensor of this local region measures the output displacement H of this local region in real time. i '; The controller determines that when H i '≠H iAt that time, the controller outputs the displacement difference signal between the two to the piezoelectric ceramic actuator (12).

[0046] That is, both the hydraulic circuit and the friction plate axial deformation constraint mechanism are controlled by a PID controller. The PID controller can be described as follows:

[0047] In the formula, G(s) is the output control quantity of the controller; P is the proportional coefficient; I is the integral coefficient; and D is the derivative coefficient.

[0048] In this embodiment, assuming the initial temperature of the friction plate is 20°C and the oil temperature is 25°C, the highest T value is selected from the sensor signal data. i The value is 93°.

[0049] Through simulation calculations, the relationship between the surface temperature of the friction plate and the required cooling flow rate is calculated, with A, B, C, and D taking values ​​of 4.25 × 10⁻⁶. 8 3.575×10 6 2300, 93, the calculated cooling flow rate X is 0.09527 L / min.

[0050] According to the transfer function of the electro-hydraulic servo valve, K sv Take 0.056m 3 / s·A,ω sv Take 0.7 rad / s, ξ sv Take 500.

[0051] The PID controller used in the hydraulic circuit was tested, and the values ​​of P, I, and D were 0.01645, 5.6947, and 1.1779, respectively.

[0052] Friction plate temperature change as follows Figure 8 As shown, after 0.013s, the temperature of the friction plate drops to the initial temperature, i.e., T. i =T.

[0053] Assuming the detected axial displacement is 0.1 mm, the friction plate axial deformation constraint mechanism is used to control the axial displacement of the friction plate. The PID controller used in the piezoelectric drive system has P, I, and D values ​​of 10289079.33, 6426808813.55, and -1195.714, respectively, after testing.

[0054] According to the transfer function of the piezoelectric ceramic actuator system, K m Take 1.3 × 10 -7 C is taken as 1.6 × 10 -6 uf, R is set to 2000Ω.

[0055] By controlling the extension and retraction of the piezoelectric ceramic actuator, displacement constraints are applied to the friction plate.

[0056] like Figure 9 As shown in the displacement diagram, the axial displacement can approach 0 at 0.015s.

[0057] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. An active control device for preventing thermal failure of friction plates in liquid-viscous transmissions, characterized in that, include: Temperature sensors are used to detect the surface temperature of local areas in the friction pad in real time. They are distributed on the surface of annular rings with radii r1, r2, and r3. n temperature sensors are evenly distributed on the side of each ring facing the oil film gap. There is one hydraulic circuit, which adjusts the flow rate of cooling oil into the clutch housing based on the maximum temperature of various local areas in the friction plates. The output end of the hydraulic circuit is connected to the oil inlet of the clutch housing. The hydraulic circuit includes: An electro-hydraulic servo valve (19) and a flow meter (24) are provided on the oil line between the electro-hydraulic servo valve (19) and the clutch housing; the oil inlet of the electro-hydraulic servo valve (19) is connected to the oil inlet pipeline; The command potentiometer (22), comparator (21) and servo amplifier (20) are connected in sequence. The output of the command potentiometer (22) is connected to the first input of the comparator (21); the second input of the comparator (21) is connected to the output of the flow meter (24); the output of the servo amplifier (20) is connected to the electro-hydraulic servo valve (19) to adjust the opening degree of the electro-hydraulic servo valve (19). The controller outputs a cooling flow signal to the command potentiometer (22) based on the local surface temperature. Displacement sensors are used to measure the axial displacement of local areas in the friction plate in real time. There are 3n sensors in total, which are set up in correspondence with temperature sensors to characterize the same local area. Each displacement sensor is set on the side of the strain gauge facing the oil film gap. There are 3n friction plate axial deformation constraint mechanisms, which are used to compensate for the axial displacement of local areas in the friction plate. Each local area is connected to a friction plate axial deformation constraint mechanism on the side facing away from the viscous fluid. There are two sets of axial deformation constraint mechanisms for the friction plates: an active axial deformation constraint mechanism and a passive axial deformation constraint mechanism. The active axial deformation constraint mechanism is used to eliminate the deformation of the active friction plates, while the passive axial deformation constraint mechanism is used to eliminate the deformation of the passive friction plates. The active friction plate axial deformation constraint mechanism includes: The base (5) is fixed to the active plate support (2) by screws (7); A piezoelectric ceramic actuator (12) has its housing fixed to a base (5) and its output end connected to a movable slider (8); the piezoelectric ceramic actuator (12) is powered by a power supply and is connected to a controller signal; both the power supply and the controller are located outside the clutch housing; The strain gauge (6), the movable slider (8), and the flexible hinge (9) are connected in sequence. The strain gauge (6) is positioned facing the oil film gap, and its surface facing the oil film gap is fixed to a local area of ​​the active friction plate (1). The movable slider (8) is used to connect the strain gauge and transmit the displacement of the piezoelectric ceramic actuator. The movable slider (8) is provided with limiting sliders (10) at both ends. The limiting sliders (10) are placed on the slide rails on the baffles (11) on both sides of the piezoelectric ceramic actuator. The slide rails extend axially. The baffle (11) is fixed to the base (5) and extends axially.

2. The active control device for preventing thermal failure of fluid-viscous transmission friction plates according to claim 1, characterized in that, The opening / closing degree model of the electro-hydraulic servo valve (19) is as follows: In the formula, G(s) is the degree of opening; K sv It is the servo valve flow gain, m 3 / s·A,ω sv It is the natural frequency of the servo valve, rad / s, ξ sv is the damping ratio of the servo valve; s is the amplified cooling flow difference signal output by the servo amplifier (20).

3. The active control device for preventing thermal failure of fluid-viscous transmission friction plates according to claim 1, characterized in that, The relationship between local surface temperature and required cooling flow rate: Y=AX 3 -BX 2 +CX+D In the formula, Y is the temperature (°C), X is the required cooling flow rate (L / min), and A, B, C, and D are constants.

4. The active control device for preventing thermal failure of fluid-viscous transmission friction plates according to claim 1, characterized in that, The transfer function of the piezoelectric ceramic actuator (12) is: U(S) is the driving voltage of the piezoelectric ceramic actuator; X(S) is the displacement of the piezoelectric ceramic actuator; K m This is the piezoelectric displacement conversion coefficient; R is the equivalent resistance of the piezoelectric ceramic actuator, in Ω; C is the equivalent capacitance of the piezoelectric ceramic actuator, in uf; S is the Laplace operator.

5. The active control device for preventing thermal failure of fluid-viscous transmission friction plates according to claim 1, characterized in that, The hydraulic circuit's inlet pipe also includes: The oil tank (13), oil filter (14), oil pump (15) and cooler (17) are connected in sequence, and the output end of the cooler (17) is connected to the oil inlet of the electro-hydraulic servo valve (19). An electric motor (16) is used to drive an oil pump (15); An overflow valve (18) is located between the flow meter (24) and the electro-hydraulic servo valve (19).

6. An active control method for preventing thermal failure of fluid-viscous transmission friction plates, applied to the active control device for preventing thermal failure of fluid-viscous transmission friction plates as described in claim 1, characterized in that, Includes the following steps: S1. Steps to reduce the surface temperature of the friction plate: First, receive the signal data T from each temperature sensor. i ; Then, select the highest value T. i As a control signal, the controller drives the hydraulic circuit. The command potentiometer (22) in the hydraulic circuit receives the cooling flow signal output by the controller, thereby increasing the cooling oil flow of the electro-hydraulic servo valve (19) and reducing the surface temperature of the friction plate. S2. Steps to mechanically constrain the axial thermal deformation of localized areas of the friction plate: First, receive the signal data H from each displacement sensor. i If H i ≠0, then H i The current control quantity is used to control the axial deformation constraint mechanism of the corresponding local area through the controller, thereby realizing the axial displacement control of the local area of ​​the friction plate.

7. The active control method for preventing thermal failure of fluid-viscous transmission friction plates according to claim 6, characterized in that, It also includes the following steps: Pre-set the initial surface temperature T of the friction plate. If T is less than T... i Then the controller outputs a cooling flow signal to the command potentiometer (22).

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