Friction plate 3D micro-deformation control device and method based on oil film shearing transmission

Abstract

The invention discloses a friction plate 3D micro-deformation control device and method based on oil film shearing transmission, the friction plate 3D micro-deformation control device comprises n driving friction plate micro-deformation control mechanisms and m driven friction plate micro-deformation control mechanisms, n is the number of external spline teeth of a driving friction plate, and m is the number of internal spline teeth of a driven friction plate; each friction plate micro-deformation control mechanism comprises a gear sleeve, a piezoelectric ceramic group, a piezoresistive sensor group and a PID (Proportion Integration Differentiation) controller; the tooth sleeves are arranged on the peripheries of the spline teeth in a sleeving manner and are embedded in the corresponding driving drum and the driven drum; the piezoresistive sensor group can detect axial, radial and circumferential displacement variations of the corresponding spline teeth; and the piezoelectric ceramic group can apply displacement control action opposite to the axial, radial or circumferential displacement change direction. The three-dimensional micro-deformation of the friction plate in the axial direction, the radial direction and the circumferential direction, namely, the three-dimensional micro-deformation is kept within a controllable and accurate range, and the three-dimensional micro-deformation friction plate has the advantages of being simple in control mechanism, high in control precision, high in response speed and the like.

Description

Technical Field

[0001] The invention relates to the technical field of oil film shear transmission, and in particular to a friction plate 3D micro-deformation control device and method based on oil film shear transmission. Background Art

[0002] Liquid viscous transmission uses the shear force of the oil film between the friction pairs to transmit power, which can achieve stepless speed regulation. The larger the speed regulation range, the more significant the energy saving effect; it can start with heavy loads to reduce the impact on the power grid during startup; it has a flexible braking function to protect the transmission system; it supports synchronous transmission, and the transmission efficiency can reach 100%. However, due to the uneven distribution of thermal stress and uneven wear of the friction plate, the friction plate is prone to warping and deformation, which in turn has an adverse effect on transmission stability, noise generation, and transmission efficiency.

[0003] At present, there are two main methods for controlling the warping deformation of friction plates. One is to cool the friction plates with oil by opening a cooling oil groove on the surface of the friction plates, which reduces the probability of warping deformation to a certain extent. For example, in the patent disclosed in CN107339350A, the heat dissipation capacity of the wet clutch is greatly improved by changing the structural dimensions of the oil groove, thereby reducing the deformation of the friction plates. The second method is to alleviate the warping deformation of the friction plates by applying a force field to the periphery of the friction plates. For example, in the patent disclosed in CN115059699A, in the friction plate deformation reduction mechanism, magnetic attraction or repulsion is applied along the circumferential direction to reduce the warping deformation of the friction plates and achieve the purpose of stable transmission.

[0004] In the patent publication number CN117620277A, the stress conditions of the milled surface of the part are analyzed, and stress grooves are milled on the milled surface according to the stress conditions. The stress grooves indirectly cut the material longitudinally according to the composite angle surface, and the internal stress modules are divided. The internal force of the surface is divided into independent small composite surfaces, reducing the film force generated by stress concentration and eliminating the warping and deformation of thin plate parts.

[0005] In patent publication number CN117564295A, the solid structure and porous structure of the three-dimensional part are modeled separately, the various parameters of the part are designed separately, and the three-dimensional model is optimized. The support structure is designed according to the support surface angle threshold, and the printing parameters are designed separately, so that the part can avoid warping and deformation.

[0006] In patent publication number CN103823948A, the design of the pavement slab thickness is determined by calculating and comparing the warping height deformation under different conditions, and the maximum allowable warping deformation of the pavement slab is pre-designed, thus solving the warping deformation problem of the concrete pavement slab.

[0007] The technical solutions proposed in the above patents have their own advantages. However, considering that the spline teeth of the friction plate are in contact with the active and passive drum surfaces, in actual engineering applications, due to the uneven heat distribution, mechanical load or constraint form, the deformation of each spline tooth of the friction plate is small and complex, which can easily have an adverse effect on the transmission accuracy and stability. In the existing precision transmission technical solutions based on oil film shear transmission, there is a lack of a device and method for effectively controlling the micro-deformation of the friction plate in the axial, radial and circumferential directions, i.e., 3D. Summary of the invention

[0008] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and to provide a friction plate 3D micro-deformation control device and method based on oil film shear transmission. The friction plate 3D micro-deformation control device and method based on oil film shear transmission installs a gear sleeve on the spline teeth of the active and passive friction plates, and a micro-displacement piezoelectric ceramic group is embedded in the gear sleeve. A piezoresistive sensor group is embedded on the spline teeth of the friction plate. Under the action of feedback regulation, the piezoelectric ceramics can directly exert direct control on the friction plate in the axial, radial and circumferential directions. It has high adjustment sensitivity and micro-nano displacement control, and can realize precise adjustment of the tiny deformation of the friction plate.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A friction plate 3D micro-deformation control device based on oil film shear transmission comprises n active friction plate micro-deformation control mechanisms and m passive friction plate micro-deformation control mechanisms.

[0011] The outer periphery of the active friction plate is connected to the active drum spline through n external spline teeth.

[0012] The inner side of the passive friction plate is connected to the passive drum spline through m internal spline teeth.

[0013] The n active friction plate micro-deformation control mechanisms are arranged on the n external spline teeth, and the m passive friction plate micro-deformation control mechanisms are arranged on the m internal spline teeth.

[0014] Each active friction plate micro-deformation control mechanism and each passive friction plate micro-deformation control mechanism include a gear sleeve, a piezoelectric ceramic group, a piezoresistive sensor group and a PID controller.

[0015] The gear sleeve is sleeved on the outer periphery of the external spline teeth or the internal spline teeth, and is embedded in the corresponding active drum or passive drum.

[0016] The piezoelectric ceramic group and the piezoresistive sensor group are both connected to the PID controller; wherein the piezoresistive sensor group can detect the axial, radial and circumferential displacement changes of the corresponding external spline teeth or internal spline teeth; the piezoelectric ceramic group can apply a control displacement action in the opposite direction of the axial, radial or circumferential displacement change according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group.

[0017] Each piezoresistive sensor group includes 2 axial displacement piezoresistive sensors, 1 radial displacement piezoresistive sensor and 2 circumferential displacement piezoresistive sensors.

[0018] Two axial displacement piezoresistive sensors are symmetrically arranged at the middle of two tooth side surfaces of the same external spline tooth or internal spline tooth, and are used to detect the axial displacement change of the active friction plate or the passive friction plate.

[0019] A radial displacement piezoresistive sensor is radially arranged on one of the tooth side surfaces of the active friction plate or the passive friction plate and corresponds to an external spline tooth or an internal spline tooth; the radial displacement piezoresistive sensor is used to detect the radial displacement change of the active friction plate or the passive friction plate.

[0020] Two circumferential displacement piezoresistive sensors are arranged along the circumferential direction on the tooth side surfaces on the same side of the same external spline tooth or internal spline tooth, and are used to detect the circumferential displacement change of the active friction plate or the passive friction plate.

[0021] Each piezoelectric ceramic group includes two axially controlled piezoelectric ceramics, one radially controlled piezoelectric ceramic and two circumferentially controlled piezoelectric ceramics.

[0022] The two axial control piezoelectric ceramics can apply a control displacement action in the opposite direction of the axial displacement change according to the axial displacement change detected by the piezoresistive sensor group.

[0023] A radial control piezoelectric ceramic can apply a radial control displacement action directed to the center of the active friction plate or the passive friction plate according to the radial displacement change detected by the piezoresistive sensor group.

[0024] The two circumferential control piezoelectric ceramics can apply a control displacement action in the opposite direction of the circumferential displacement change according to the circumferential displacement change detected by the piezoresistive sensor group.

[0025] Both the external spline teeth and the internal spline teeth have two tooth side surfaces, two tooth profile surfaces and a tooth top circle surface.

[0026] Two axial control piezoelectric ceramics are arranged on the inner wall surface of the gear sleeve matching the two tooth side surfaces, one radial control piezoelectric ceramic is arranged on the inner wall surface of the gear sleeve matching the tooth top circular surface; two circumferential control piezoelectric ceramics are arranged on the inner wall surface of the gear sleeve matching the two tooth profile curved surfaces.

[0027] An electromagnet is also arranged on the inner wall surface of the gear sleeve located on one side of the radial control piezoelectric ceramic.

[0028] Both tooth profile curved surfaces of each external spline tooth and internal spline tooth are provided with wedge grooves, one of the wedge edges of the wedge grooves is arranged radially along the active friction plate or the passive friction plate; each circumferential control piezoelectric ceramic has a wedge block matching the wedge groove.

[0029] A friction plate 3D micro-deformation control method based on oil film shear transmission comprises the following steps.

[0030] Step 1: Detection of friction plate displacement variation: Detect the axial, radial and circumferential displacement variations of the external spline teeth or internal spline teeth through the piezoresistive sensor group, and transmit the detection results to the PID controller, specifically:

[0031] A. The axial, radial and circumferential displacement changes of the n external spline teeth in the active friction plate are detected by means of n piezoresistive sensor groups in the n active friction plate micro-deformation control mechanisms.

[0032] B. The axial, radial and circumferential displacement changes of the m internal spline teeth in the passive friction plate are detected by means of the m piezoresistive sensor groups in the m passive friction plate micro-deformation control mechanisms.

[0033] Step 2: 3D micro-deformation control of the friction plate: The PID controller sends instructions to the piezoelectric ceramic group corresponding to the corresponding external spline teeth or internal spline teeth according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group, and applies a control displacement action in the opposite direction of the axial, radial or circumferential displacement change.

[0034] Step 3: Repeat steps 1 to 2 to ensure that the axial, radial and circumferential displacement changes of each external spline tooth or internal spline tooth are within the set allowable threshold range.

[0035] In step 1, it is assumed that the i-th external spline tooth of the active friction plate detects a displacement change d in the axial positive direction Z+; then in step 2, the control method of the 3D micro-deformation of the friction plate includes the following steps:

[0036] Step 2-1, threshold judgment: compare the axial displacement change d with the set axial displacement allowable threshold d0. When d>d0, go to step 2-2; otherwise, the piezoelectric ceramic group does not act.

[0037] Step 2-2, determine the axial control piezoelectric ceramic to be started: the two axial control piezoelectric ceramics corresponding to the i-th external spline tooth in the active friction plate are set as the i-th axial positive direction (Z+) control piezoelectric ceramic and the i-th axial negative direction (Z-) control piezoelectric ceramic respectively; the piezoelectric ceramic to be started is the i-th axial positive direction (Z+) control piezoelectric ceramic;

[0038] Step 2-3, determine the input voltage: According to the axial displacement change d detected in step 1, determine the input voltage U(d) of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axial direction. The specific calculation formula is:

[0039] U(d)=d / d33

[0040] Where, d 33 is the piezoelectric constant of the piezoelectric ceramic.

[0041] Step 2-4, determine the output displacement: According to the PID algorithm, the piezoelectric ceramic controlling the i-th axial positive direction (Z+) converts the input voltage into a control displacement X(d) of the i-th external spline tooth in the axial negative direction (Z-).

[0042] Assume that the two axial displacement piezoresistive sensors corresponding to the i-th external spline tooth are two i-th axial displacement piezoresistive sensors, and select the i-th axial displacement piezoresistive sensor with the largest instantaneous resistance as the force piezoresistive sensor; therefore, in step 2-3, by judging the resistance change of the force piezoresistive sensor, the sensitivity of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axial direction is detected; the specific detection method includes the following steps:

[0043] Step 2-3A: Calculate the actual voltage V. The specific calculation formula is:

[0044]

[0045] Where L0 is the original length of the piezoresistive sensor in the deformation direction;

[0046] k is the piezoresistive coefficient of the force-bearing piezoresistive sensor;

[0047] R0 is the resistance value of the stressed piezoresistive sensor when no stress is applied;

[0048] R is the resistance value of the force-bearing piezoresistive sensor when stress is applied;

[0049] Step 2-3B, by comparing the actual voltage V with the input voltage U(d), determine the sensitivity of controlling the piezoelectric ceramic in the positive direction (Z+) of the i-th axis.

[0050] In step 2-4, the calculation formula for the control displacement X(d) of the i-th external spline tooth in the negative axial direction (Z-) is:

[0051] X(d)=G(d)×U(d)

[0052] in:

[0053]

[0054] Where G(d) is the transfer function in the PID algorithm.

[0055] K is the system gain corresponding to the i-th external spline tooth and is an unknown parameter to be identified.

[0056] ω nis the undamped natural frequency of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axis, and is an unknown parameter to be identified.

[0057] ζ is the damping ratio of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axis and is an unknown parameter to be identified.

[0058] The present invention has the following beneficial effects:

[0059] 1. The present invention installs a gear sleeve on the spline teeth of the active and passive friction plates, a micro-displacement piezoelectric ceramic group is embedded in the gear sleeve, and a piezoresistive sensor group is embedded on the spline teeth of the friction plates. Under the feedback adjustment, the piezoelectric ceramics can directly control the friction plates in the axial, radial and circumferential directions, and have high adjustment sensitivity and micro-nano displacement control, and can realize precise adjustment of tiny deformation of the friction plates.

[0060] 2. The present invention keeps the 3D micro-deformation of the friction plate in the axial, radial and circumferential directions within a controllable and precise range, and has the advantages of simple control mechanism, high control accuracy and fast response speed.

[0061] 3. The PID controller processes the micro-deformation signal transmitted by the piezoresistive sensor feedback circuit and can adjust the micro-displacement output of the piezoelectric ceramic. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A cross-sectional view of a liquid-viscous speed control clutch using the friction plate 3D micro-deformation control device of the present invention is shown.

[0063] Figure 2 A schematic diagram of the structure of the active friction plate is shown.

[0064] Figure 3 A schematic diagram of the structure of the passive friction plate is shown.

[0065] Figure 4 A schematic diagram showing the simulated installation position of the active friction plate micro-deformation control mechanism of the present invention is shown.

[0066] Figure 5 The schematic diagram of the installation position of the piezoelectric ceramic group and the spline teeth in the present invention is shown; wherein (a) is a front view of the spline teeth; and (b) is a side view of the spline teeth.

[0067] Figure 6 A three-dimensional simulation diagram showing the installation position of the piezoelectric ceramic group in the gear sleeve in the present invention.

[0068] Figure 7 A three-dimensional simulation diagram of the circumferentially controlled piezoelectric ceramic of the present invention is shown.

[0069] Figure 8 The external spline tooth structure of the active friction plate in the present invention is shown.

[0070] Fig. 9 The figure shows a schematic diagram of the layout position of the piezoresistive sensor group in the present invention; wherein (a) is a side view of the spline teeth; and (b) is an axial view of the spline teeth.

[0071] Fig.10 The side view of the active friction plate when a circular arc steel plate is added in the present invention is shown.

[0072] Fig.11 The schematic diagram of the principle of determining the micro-deformation direction of the spline teeth in the present invention is shown.

[0073] Fig.12 The schematic diagram of the positioning reference control in the present invention is shown.

[0074] Fig.13 The schematic diagram of the micro-deformation control principle of the spline teeth of the friction plate in the present invention is shown.

[0075] Fig.14 A displacement variation curve diagram of the closed-loop control method simulation of the piezoelectric ceramic group is shown.

[0076] Among them are

[0077] 1. Active friction plate;

[0078] 11. Friction lining; 12. External spline teeth; 121. Tooth side surface; 122. Tooth top circular surface; 123. Tooth profile curved surface;

[0079] 13. Wedge-shaped groove; 14. Radial bevel; 15. Arc steel sheet;

[0080] 2. Passive friction plate; 21. Internal spline teeth;

[0081] 3. Gear sleeve;

[0082] 31. Axially controlled piezoelectric ceramics; 32. Radially controlled piezoelectric ceramics; 33. Circumferentially controlled piezoelectric ceramics; 34. Wedge block; 35. Electromagnet;

[0083] 4. Active drum; 5. Passive drum; 6. Active shaft; 7. Passive shaft;

[0084] 8. Active friction plate micro-deformation control mechanism;

[0085] 81. Axial displacement piezoresistive sensor; 82. Radial displacement piezoresistive sensor; 83. Circumferential displacement piezoresistive sensor. DETAILED DESCRIPTION

[0086] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific preferred embodiments.

[0087] In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second" and the like do not indicate the importance of the components, and therefore cannot be understood as limiting the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution, and do not limit the scope of protection of the present invention.

[0088] like Figure 1 As shown, the friction plate 3D micro-deformation control device of the present invention can be applied to a liquid-viscous speed-regulating clutch. The liquid-viscous speed-regulating clutch adopts oil film shear transmission, and specifically includes an active transmission mechanism and a passive transmission mechanism.

[0089] The active transmission mechanism comprises an active shaft 6 , an active drum 4 and an active friction plate 1 .

[0090] The active drum 5 is coaxially mounted on the active shaft, and the active friction plate is spline-connected to the active drum through n external spline teeth 12. The structure of the active friction plate is as follows: Figure 2 shown.

[0091] like Figure 8 As shown, each external spline tooth on the outer periphery of the active friction plate has two tooth side surfaces 121 , a tooth top circle surface 122 and two tooth profile curved surfaces 123 .

[0092] On each tooth profile surface, it is preferred to provide Figure 5 The wedge-shaped groove 13 is shown, and the wedge-shaped groove has a radial bevel 14 arranged along the radial direction of the active friction plate.

[0093] In addition, if Fig.10 As shown, a friction lining 11 is also provided on one side end face of the active friction plate. Considering the influence of the thickness of the gear sleeve itself and the deformation allowance of the spline teeth on the oil film gap width and the direct friction between the gear sleeve and the dual plate, a layer of arc steel sheet 15 is sandwiched between the active friction plate and the friction lining. The thickness of the arc steel sheet 15 is greater than the sum of the thickness of the gear sleeve itself and the deformation allowance of the spline teeth.

[0094] The passive transmission mechanism includes a passive shaft 7 , a passive drum 5 and a passive friction plate 2 .

[0095] The passive shaft is coaxially arranged with the active shaft, the passive drum is coaxially mounted on the passive shaft, and the inner side of the passive friction plate is spline-connected with the passive drum through m internal spline teeth 21. Figure 3 shown.

[0096] The structure of each internal spline tooth is the same as that of the external spline tooth, and each of the internal spline teeth also has two tooth side surfaces 121 , a tooth top circle surface 122 and two tooth profile curved surfaces 123 .

[0097] A wedge-shaped groove 13 is also preferably provided on each tooth profile curved surface, and the wedge-shaped groove has a radial bevel 14 arranged along the radial direction of the passive friction plate.

[0098] The active shaft drives the active drum to rotate, and the internal spline teeth of the active drum apply tangential force to the external spline teeth of the active friction plate. The active friction plate rotates, and the oil film transmits the shear force to drive the passive friction plate. The internal spline teeth of the passive friction plate apply tangential force to the external spline teeth of the passive drum, and the passive drum drives the passive shaft to rotate.

[0099] A friction plate 3D micro-deformation control device based on oil film shear transmission comprises n active friction plate micro-deformation control mechanisms 8 and m passive friction plate micro-deformation control mechanisms.

[0100] The n active friction plate micro-deformation control mechanisms are arranged on the n external spline teeth, and the m passive friction plate micro-deformation control mechanisms are arranged on the m internal spline teeth.

[0101] like Figure 4 As shown, each active friction plate micro-deformation control mechanism and each passive friction plate micro-deformation control mechanism include a gear sleeve 3, a piezoelectric ceramic group, a piezoresistive sensor group and a PID controller.

[0102] The gear sleeve is sleeved on the outer periphery of the external spline teeth or the internal spline teeth, and is embedded in the corresponding active drum or passive drum.

[0103] The piezoelectric ceramic group and the piezoresistive sensor group are both connected to the PID controller; wherein the piezoresistive sensor group can detect the axial, radial and circumferential displacement changes of the corresponding external spline teeth or internal spline teeth; the piezoelectric ceramic group can apply a control displacement in the opposite direction of the axial, radial or circumferential displacement change according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group.

[0104] like Fig. 9 As shown, each piezoresistive sensor group includes two axial displacement piezoresistive sensors 81 , one radial displacement piezoresistive sensor 82 and two circumferential displacement piezoresistive sensors 83 .

[0105] The above-mentioned single piezoelectric ceramic is mainly composed of multiple thin rectangular piezoelectric ceramics bonded together and can be embedded in the inner side of the gear sleeve. According to the inverse piezoelectric effect of piezoelectric ceramics, a "+" voltage is applied to the contact surface between the upper bottom surface of the piezoelectric ceramic group and the spline tooth, and a "-" voltage is applied to the contact surface between the lower bottom surface of the piezoelectric ceramic group and the gear sleeve. The direction of the electric field is the polarization direction of the piezoelectric ceramic, which is also the direction of the micro-displacement output of the piezoelectric ceramic.

[0106] Two axial displacement piezoresistive sensors are symmetrically arranged in the middle of two tooth side surfaces 121 of the same external spline tooth or internal spline tooth, and are used to detect the axial displacement change of the active friction plate or the passive friction plate.

[0107] A radial displacement piezoresistive sensor is radially arranged on one of the tooth side surfaces of the active friction plate or the passive friction plate and corresponds to an external spline tooth or an internal spline tooth; the radial displacement piezoresistive sensor is used to detect the radial displacement change of the active friction plate or the passive friction plate.

[0108] Two circumferential displacement piezoresistive sensors are arranged along the circumferential direction on the tooth side surfaces on the same side of the same external spline tooth or internal spline tooth, and are used to detect the circumferential displacement change of the active friction plate or the passive friction plate.

[0109] In this embodiment, the two circumferential displacement piezoresistive sensors are preferably symmetrically arranged on both sides of one of the axial displacement piezoresistive sensors and close to the two tooth roots of the corresponding spline teeth.

[0110] Furthermore, since the deformation of the active and passive friction plates increases with the increase of radius, the maximum deformation occurs at the outer diameter, so the length of the piezoresistive sensor is greater than the thickness of the spline teeth. After the piezoresistive sensor is embedded in the friction plate, it can be ensured that when the spline teeth are deformed, the deformation of the upper part of the piezoresistive sensor is greater than the deformation of the lower part. The deformation of the upper part of the piezoresistive sensor becomes the main deformation of the piezoresistive sensor, which can ensure the detection accuracy of the micro-displacement of the friction plate.

[0111] like Figure 5 and Figure 6 As shown, each piezoelectric ceramic group includes two axially controlled piezoelectric ceramics 31 , one radially controlled piezoelectric ceramic 32 and two circumferentially controlled piezoelectric ceramics 33 .

[0112] The two axial control piezoelectric ceramics can apply a control displacement action in the opposite direction of the axial displacement change according to the axial displacement change detected by the piezoresistive sensor group. In this embodiment, the two axial control piezoelectric ceramics are preferably arranged on the inner wall surface of the gear sleeve that matches the two tooth side surfaces.

[0113] One radial control piezoelectric ceramic can apply a radial control displacement action directed to the center of the active friction plate or the passive friction plate according to the radial displacement change detected by the piezoresistive sensor group. In this embodiment, one radial control piezoelectric ceramic is preferably arranged on the inner wall surface of the gear sleeve that matches the tooth top circular surface.

[0114] The two circumferential control piezoelectric ceramics can apply a control displacement action in the opposite direction of the circumferential displacement change according to the circumferential displacement change detected by the piezoresistive sensor group.

[0115] In this embodiment, two circumferential control piezoelectric ceramics are preferably arranged on the inner wall surface of the gear sleeve where two tooth profile curved surfaces match each other.

[0116] Furthermore, each circumferential control piezoelectric ceramic has a wedge block 34 that matches the wedge groove. The provision of the wedge block enables the circumferential force applied by the circumferential control piezoelectric ceramic to always be along the tangent direction of the outer edge of the active friction plate or the passive friction plate, and the circumferential displacement output accuracy is higher.

[0117] Furthermore, the plane area of ​​the radial bevel is slightly larger than the contact surface area with the wedge block, which reduces the effect of the spline tooth deformation on the wedge block force other than the intercepting plane, and is used for the piezoelectric ceramic to directly exert circumferential control on the friction plate.

[0118] Furthermore, an electromagnet 35 is provided on the inner wall surface of the gear sleeve on one side of the radial control piezoelectric ceramic.

[0119] The electromagnet is preferably in the shape of a long strip. When the electromagnet is energized, the gear sleeve is adsorbed on the spline teeth. When the active friction plate is installed to the housing and the passive friction plate is installed to the passive shaft, the electromagnet is de-energized and the gear sleeve is successfully installed.

[0120] The matching type between the gear sleeve and the spline teeth selects the minimum interference fit, the gear sleeve has an annular foot, and all the gear sleeves that match the spline teeth of the friction plate can form a gear sleeve ring, which can realize the reliable matching between the gear sleeve and the spline teeth.

[0121] When the gear sleeve and the spline teeth cannot reach an ideal matching state, before the active and passive friction plates are transmitted, the piezoelectric ceramics are controlled to output micro-displacement. When the piezoresistive sensor used to detect the micro-deformation of the spline teeth along the axial, radial and circumferential directions outputs an instantaneous displacement signal, the piezoelectric ceramics in the corresponding direction are stopped from outputting micro-displacement, and the final positions of the piezoelectric ceramics and the spline teeth in each direction are regarded as the control reference, so that the precise positioning of the piezoelectric ceramics and the spline teeth can be achieved.

[0122] A friction plate 3D micro-deformation control method based on oil film shear transmission comprises the following steps.

[0123] Step 1: Detection of friction plate displacement variation: Detect the axial, radial and circumferential displacement variations of the external spline teeth or internal spline teeth through the piezoresistive sensor group, and transmit the detection results to the PID controller, specifically:

[0124] A. The axial, radial and circumferential displacement changes of the n external spline teeth in the active friction plate are detected by means of n piezoresistive sensor groups in the n active friction plate micro-deformation control mechanisms.

[0125] B. The axial, radial and circumferential displacement changes of the m internal spline teeth in the passive friction plate are detected by means of the m piezoresistive sensor groups in the m passive friction plate micro-deformation control mechanisms.

[0126] Step 2: 3D micro-deformation control of the friction plate: The PID controller sends instructions to the piezoelectric ceramic group corresponding to the corresponding external spline teeth or internal spline teeth according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group, and applies a control displacement action in the opposite direction of the axial, radial or circumferential displacement change.

[0127] When the friction plate is thermally deformed, the deformation on one side of the spline tooth deformation direction is smaller than the deformation on the other side of the spline tooth. According to this characteristic:

[0128] The piezoresistive sensors for detecting the micro-deformation of the friction plate in the axial direction are installed on the two sides of the spline teeth of the friction plate. The PID controller compares the resistance values ​​of the piezoresistive sensors on the two sides of the spline teeth. The side with the smaller resistance value of the output piezoresistive sensor is the side of the spline tooth deformation, and the axial deformation direction of the spline teeth of the friction plate is determined accordingly.

[0129] The piezoresistive sensors for detecting the micro-deformation of the friction plate in the circumferential direction are installed on the two sides of the spline teeth of the friction plate. The PID controller compares the resistance values ​​of the piezoresistive sensors on the two sides of the spline teeth. The side with the smaller output resistance value of the piezoresistive sensor is the side with the spline tooth deformation, and the circumferential deformation direction of the spline teeth of the friction plate is judged based on this.

[0130] Assume that the i-th external spline tooth of the active friction plate in step 1 detects the displacement change d in the positive axial direction (Z+); then in step 2, the control method of the 3D micro-deformation of the friction plate is as follows: Fig.13 As shown, the following steps are included.

[0131] Step 2-1, threshold judgment: compare the axial displacement change d with the set axial displacement allowable threshold d0. When d>d0, go to step 2-2; otherwise, the piezoelectric ceramic group does not act.

[0132] Step 2-2, determine the axial control piezoelectric ceramic to be started: the two axial control piezoelectric ceramics corresponding to the i-th external spline tooth in the active friction plate are set as the i-th axial positive direction (Z+) control piezoelectric ceramic and the i-th axial negative direction (Z-) control piezoelectric ceramic respectively; the piezoelectric ceramic to be started is the i-th axial positive direction (Z+) control piezoelectric ceramic;

[0133] Step 2-3, determine the input voltage: According to the axial displacement change d detected in step 1, determine the input voltage U(d) of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axial direction. The specific calculation formula is:

[0134] U(d)=d / d 33

[0135] Where, d 33 is the piezoelectric constant of the piezoelectric ceramic.

[0136] Further, the two axial displacement piezoresistive sensors corresponding to the i-th external spline tooth are assumed to be two i-th axial displacement piezoresistive sensors, and the i-th axial displacement piezoresistive sensor with the largest instantaneous resistance is selected as the force piezoresistive sensor; therefore, in step 2-3, the sensitivity of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axial direction is detected by judging the change in the resistance value of the force piezoresistive sensor; the specific detection method comprises the following steps:

[0137] Step 2-3A: Calculate the actual voltage V. The specific calculation formula is:

[0138]

[0139] Where L0 is the original length of the piezoresistive sensor in the deformation direction;

[0140] k is the piezoresistive coefficient of the force-bearing piezoresistive sensor;

[0141] R0 is the resistance value of the stressed piezoresistive sensor when no stress is applied;

[0142] R is the resistance value of the force-bearing piezoresistive sensor when stress is applied;

[0143] Step 2-3B, by comparing the actual voltage V with the input voltage U(d), determine the sensitivity of controlling the piezoelectric ceramic in the positive direction (Z+) of the i-th axis.

[0144] 2-4. Determine the output displacement: According to the PID algorithm, the piezoelectric ceramic controlling the i-th axial positive direction (Z+) converts the input voltage into a control displacement X(d) of the i-th external spline tooth in the axial negative direction (Z-).

[0145] The above calculation formula for the control displacement X(d) of the i-th external spline tooth in the negative axial direction (Z-) is:

[0146] X(d)=G(d)×U(d)

[0147] in:

[0148]

[0149] Where G(d) is the transfer function in the PID algorithm.

[0150] K is the system gain corresponding to the i-th external spline tooth and is an unknown parameter to be identified.

[0151] ω n is the undamped natural frequency of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axis, and is an unknown parameter to be identified.

[0152] ζ is the damping ratio of the piezoelectric ceramic controlled in the positive direction (Z+) of the i-th axis and is an unknown parameter to be identified.

[0153] The present invention calls the system identification toolbox System Identification in Matlab software to identify unknown parameters K, ωn, ζ in the transfer function.

[0154] Step 3: Repeat steps 1 to 2 to ensure that the axial, radial and circumferential displacement changes of each external spline tooth or internal spline tooth are within the set allowable threshold range.

[0155] In the present invention, the control systems of the gear sleeve for the axial, radial and circumferential directions of the spline teeth of the friction plate are independent of each other. When the friction plate is deformed, the contact states of the spline teeth of the friction plate with the active and passive drums are different, the force forms of the spline teeth of the friction plate are different, and the deformation amounts of the spline teeth of the friction plate in the axial, radial and circumferential directions are different. Different micro-displacement piezoelectric ceramics in the gear sleeve can output different micro-displacements according to the deformation amounts detected by different piezoresistive sensors, control the micro-deformation amounts of the spline teeth of the friction plate in the axial, radial and circumferential directions, achieve direct action on the spline teeth of the friction plate, and further control the warping deformation of the friction plate.

[0156] In this embodiment, the piezoelectric ceramics exert control on the friction plate spline teeth in the axial, radial and circumferential directions in the same manner and principle, and the micro-deformation control systems of the friction plate spline teeth in the axial, radial and circumferential directions are independent of each other. Therefore, taking the control of the radial micro-deformation of the friction plate spline teeth as an example, according to the relationship between the resistance value and deformation of the piezoresistive sensor: R = R0 (1 + K∈)

[0157] According to the technical specifications of the piezoresistive sensor, the resistance value R0 when no stress is applied is 1000Ω; the piezoresistive coefficient k is 2; and the strain is 0.005. According to relevant papers, under normal working conditions, the micro-displacement of the friction plate in the axial, radial and circumferential directions is about 0 to 0.2 mm.

[0158] Strain∈=ΔL / L0

[0159] Where ΔL is the length change of the piezoresistive sensor; L0 is the original length of the piezoresistive sensor.

[0160] The resistance value R of the piezoresistive sensor when stress is applied is detected to be 1010Ω, so the micro-displacement of the spline teeth of the friction plate in the radial direction is d=ΔL=0.1mm.

[0161] The input voltage of micro-displacement piezoelectric ceramics is proportional to the output displacement. The input voltage can be expressed as

[0162] V=d / d 33

[0163] The piezoelectric constant d of the micro-displacement piezoelectric ceramic can be obtained by referring to the piezoelectric ceramic data sheet. 33 It is 2000μC / m.

[0164] Substitute the known values ​​into the formula: V = 0.0001 / 0.002 = 0.05V

[0165] The present invention calls the system identification toolbox System Identification in Matlab software to identify unknown parameters in the transfer function, and its principle is based on the least square method.

[0166] Given a system controlling the input signal at a mixed frequency The frequencies f1 = 5, f2 = 40, and f3 = 80. The actual output signal of the acquisition system constitutes new experimental data, in which the control input signal is input to the PI model and the output H[v](k) of the PI model is used as the input u(k) of the dynamic model, and the actual output displacement y(k) constitutes new identification data.

[0167] The transfer function of the micro-displacement piezoelectric ceramic can be identified as follows:

[0168]

[0169] The above transfer function is simulated by Simulink, where the PID controller adopts neural network PID control, and the displacement change curve of the closed-loop control method of micro-displacement piezoelectric ceramics can be obtained, as shown in Fig.14 .

[0170] It can be seen that the output displacement after neural network PID adjustment reached the target displacement of 0.1mm at 0.002 seconds, and stabilized at close to 0.1mm at 0.007 seconds. Compared with the 0.015 seconds when not controlled by PID, the displacement output signal of the piezoelectric ceramic after the PID controller has a shorter response time and smaller oscillation.

[0171] Using PID control to compare with not using PID control, 0.007 seconds is just for comparison with 0.015 seconds. These two times are obtained from the displacement change curve. It shows that using PID control can make the displacement output signal response time of piezoelectric ceramics shorter and the oscillation smaller. Because of the error in the control process, whether it is through PID control or not, when the input displacement is 0.1mm, the output displacement can only approach 0.1mm, and cannot reach 0.1mm.

[0172] The matching type of the gear sleeve and the spline teeth is selected to have the minimum interference fit, the gear sleeve has a ring foot, and the n gear sleeves that match the spline teeth of the friction plate form a gear sleeve ring, which can achieve reliable matching between the gear sleeve and the spline teeth. The gear sleeve and the spline teeth cannot reach the ideal matching state. Before the active and passive friction plates are driven, the piezoelectric ceramic output micro-displacement is controlled. When the piezoresistive sensor used to detect the micro-deformation of the spline teeth along the axial, radial and circumferential directions outputs an instantaneous displacement signal, the piezoelectric ceramic output micro-displacement in the corresponding direction is stopped, and the final position of the piezoelectric ceramic and the spline teeth in each direction is regarded as the control reference, which can achieve precise positioning of the piezoelectric ceramic and the spline teeth.

[0173] The present invention uses a piezoresistive sensor to monitor the micro-deformation of the friction plate in the axial, radial and circumferential directions in real time, and outputs the micro-displacement control signal after the PID controller is regulated to the piezoelectric ceramic, so that the control system can achieve a target micro-displacement of about 0.1 mm in 0.007 seconds, with the advantages of high control accuracy and rapid response time. The PID controller performs cyclic control to ensure that the displacement output value in each direction approaches the displacement input value.

[0174] The preferred embodiments of the present invention are described in detail above; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A friction plate 3D micro-deformation control device based on oil film shear transmission, Features: It includes n active friction plate micro-deformation control mechanisms and m passive friction plate micro-deformation control mechanisms; The outer periphery of the active friction plate is connected to the active drum spline through n external spline teeth; The inner side of the passive friction plate is connected to the passive drum spline through m internal spline teeth; n active friction plate micro-deformation control mechanisms are arranged on n external spline teeth, and m passive friction plate micro-deformation control mechanisms are arranged on m internal spline teeth; Each active friction plate micro-deformation control mechanism and each passive friction plate micro-deformation control mechanism include a gear sleeve, a piezoelectric ceramic group, a piezoresistive sensor group and a PID controller; The gear sleeve is sleeved on the outer periphery of the external spline teeth or the internal spline teeth, and is embedded in the corresponding active drum or the passive drum; The piezoelectric ceramic group and the piezoresistive sensor group are both connected to the PID controller; wherein the piezoresistive sensor group can detect the axial, radial and circumferential displacement changes of the corresponding external spline teeth or internal spline teeth; the piezoelectric ceramic group can apply a control displacement action in the opposite direction of the axial, radial or circumferential displacement change according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group.

2. The friction plate 3D micro-deformation control device based on oil film shear transmission according to claim 1, Features: Each piezoresistive sensor group includes 2 axial displacement piezoresistive sensors, 1 radial displacement piezoresistive sensor and 2 circumferential displacement piezoresistive sensors; Two axial displacement piezoresistive sensors are symmetrically arranged in the middle of two tooth sides of the same external spline tooth or internal spline tooth, and are used to detect the axial displacement change of the active friction plate or the passive friction plate; A radial displacement piezoresistive sensor is arranged radially on one of the tooth sides of the active friction plate or the passive friction plate and corresponds to an external spline tooth or an internal spline tooth; the radial displacement piezoresistive sensor is used to detect the radial displacement change of the active friction plate or the passive friction plate; Two circumferential displacement piezoresistive sensors are arranged along the circumferential direction on the tooth side surfaces on the same side of the same external spline tooth or internal spline tooth, and are used to detect the circumferential displacement change of the active friction plate or the passive friction plate.

3. The friction plate 3D micro-deformation control device based on oil film shear transmission according to claim 1, Features: Each piezoelectric ceramic group includes two axial control piezoelectric ceramics, one radial control piezoelectric ceramic and two circumferential control piezoelectric ceramics; the two axial control piezoelectric ceramics can apply a control displacement action in the opposite direction of the axial displacement change according to the axial displacement change detected by the piezoresistive sensor group; A radial control piezoelectric ceramic can apply a radial control displacement action directed to the center of the active friction plate or the passive friction plate according to the radial displacement change detected by the piezoresistive sensor group; The two circumferential control piezoelectric ceramics can apply a control displacement action in the opposite direction of the circumferential displacement change according to the circumferential displacement change detected by the piezoresistive sensor group.

4. The friction plate 3D micro-deformation control device based on oil film shear transmission according to claim 3, Features: Both the external spline teeth and the internal spline teeth have two tooth side surfaces, two tooth profile surfaces and a tooth top circle surface; Two axial control piezoelectric ceramics are arranged on the inner wall surface of the gear sleeve matching the two tooth side surfaces, one radial control piezoelectric ceramic is arranged on the inner wall surface of the gear sleeve matching the tooth top circular surface; two circumferential control piezoelectric ceramics are arranged on the inner wall surface of the gear sleeve matching the two tooth profile curved surfaces.

5. The friction plate 3D micro-deformation control device based on oil film shear transmission according to claim 4, Features: An electromagnet is also arranged on the inner wall surface of the gear sleeve located on one side of the radial control piezoelectric ceramic.

6. The friction plate 3D micro-deformation control device based on oil film shear transmission according to claim 4, Features: Both tooth profile curved surfaces of each external spline tooth and internal spline tooth are provided with wedge grooves, one of the wedge edges of the wedge grooves is arranged radially along the active friction plate or the passive friction plate; each circumferential control piezoelectric ceramic has a wedge block matching the wedge groove.

7. A friction plate 3D micro-deformation control method based on oil film shear transmission, Features: The steps include: Step 1. Detection of friction plate displacement change: Detect the axial, radial and circumferential displacement changes of the external spline teeth or internal spline teeth through the piezoresistive sensor group, and pass the detection results to the PID controller, specifically: A. Detect the axial, radial and circumferential displacement changes of n external spline teeth in the active friction plate through n piezoresistive sensor groups in n active friction plate micro-deformation control mechanisms; B. detecting the axial, radial and circumferential displacement changes of the m internal spline teeth in the passive friction plate through the m piezoresistive sensor groups in the m passive friction plate micro-deformation control mechanisms; Step 2. 3D micro-deformation control of the friction plate: The PID controller sends instructions to the piezoelectric ceramic group corresponding to the corresponding external spline teeth or internal spline teeth according to the axial, radial and circumferential displacement changes detected by the piezoresistive sensor group, and applies a control displacement action in the opposite direction of the axial, radial or circumferential displacement change; Step 3. Repeat steps 1 to 2 to ensure that the axial, radial and circumferential displacement changes of each external spline tooth or internal spline tooth are within the set allowable threshold range.

8. The friction plate 3D micro-deformation control method based on oil film shear transmission according to claim 7, Features: In step 1, it is assumed that the i-th external spline tooth of the active friction plate detects a displacement change d in the axial positive direction Z+, then in step 2, the control method of the 3D micro-deformation of the friction plate includes the following steps: Step 2-1, threshold judgment: compare the axial displacement change d with the set axial displacement allowable threshold d 0 For comparison, when d>d 0 When , it goes to step 2-2; otherwise, the piezoelectric ceramic group does not act; Step 2-2, determine the axial control piezoelectric ceramic to be started: the two axial control piezoelectric ceramics corresponding to the i-th external spline tooth in the active friction plate are set as the i-th axial positive direction Z+ control piezoelectric ceramic and the i-th axial negative direction Z- control piezoelectric ceramic respectively; the piezoelectric ceramic to be started is the i-th axial positive direction Z+ control piezoelectric ceramic; Step 2-3, determine the input voltage: According to the axial displacement change d detected in step 1, determine the input voltage U(d) of the piezoelectric ceramic in the positive direction Z+ of the i-th axis. The specific calculation formula is: U(d)=d / d 33 Where, d 33 is the piezoelectric constant of the piezoelectric ceramic; Step 2-4, determine the output displacement: According to the PID algorithm, the piezoelectric ceramic controlling the i-th axial positive direction Z+ converts the input voltage into a control displacement X(d) of the i-th external spline tooth in the axial negative direction Z-.

9. The friction plate 3D micro-deformation control method based on oil film shear transmission according to claim 8, Features: Assume that the two axial displacement piezoresistive sensors corresponding to the i-th external spline tooth are two i-th axial displacement piezoresistive sensors, and select the i-th axial displacement piezoresistive sensor with the largest instantaneous resistance as the force piezoresistive sensor; therefore, in step 2-3, by judging the resistance change of the force piezoresistive sensor, the sensitivity of the piezoelectric ceramic in the positive direction Z+ of the i-th axis is detected; the specific detection method includes the following steps: Step 2-3A: Calculate the actual voltage V. The specific calculation formula is: Where, L 0 It is the original length of the piezoresistive sensor in the deformation direction; k is the piezoresistive coefficient of the force-bearing piezoresistive sensor; R 0 is the resistance value of the stressed piezoresistive sensor when no stress is applied; R is the resistance value of the force-bearing piezoresistive sensor when stress is applied; Step 2-3B, by comparing the actual voltage V with the input voltage U(d), the sensitivity of the piezoelectric ceramic controlled in the positive direction Z+ of the i-th axis is determined.

10. The friction plate 3D micro-deformation control method based on oil film shear transmission according to claim 8, Features: In step 2-4, the calculation formula for the control displacement X(d) of the i-th external spline tooth in the negative axial direction Z- is: X(d)=G(d)×U(d) in: Where G(d) is the transfer function in the PID algorithm; K is the system gain corresponding to the i-th external spline tooth, which is the unknown parameter to be identified; ω n is the undamped natural frequency of the piezoelectric ceramic controlled in the positive direction Z+ of the i-th axis, and is the unknown parameter to be identified; ζ is the damping ratio of the piezoelectric ceramic controlled in the positive direction Z+ of the i-th axis, and is an unknown parameter to be identified.

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