Multi-cylinder forging method and equipment for aviation thin-walled parts

Abstract

The present invention discloses a multi-cylinder forging method and equipment for aviation thin-walled parts, which belongs to the technical field of thin-walled part forging processing. In the multi-cylinder forging method for aviation thin-walled parts of the present invention, the first throttling device drives the active die via the main hydraulic cylinder, the second throttling device drives the side movable die via the side hydraulic cylinder, and the third throttling device maintains a self-locking state. If the attitude angle is greater than the stability threshold, the third throttling device drives the active die to the corresponding leveling point via the leveling hydraulic cylinder. The present invention monitors the stroke data of the movable die and the hydraulic pressure of the throttling device, and coordinates the leveling of the active die through the leveling hydraulic cylinder to ensure that the active die is in a balanced state, thereby improving the forming quality of thin-walled parts. At the same time, the present invention predicts the attitude angle of the active die based on the active die flip angle, thereby estimating the leveling response function of the leveling hydraulic cylinder, ensuring that when the flow of the third throttling device acts on the leveling hydraulic cylinder, the leveling hydraulic cylinder can respond to the instantaneous working condition in real time, thereby improving the leveling control accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of forging processing, and in particular to a multi-cylinder forging method and equipment for aviation thin-walled parts. Background Art

[0002] Aviation thin-walled parts are widely used in key areas such as aircraft cabins and tail nozzles. Due to the requirements of the use environment, aviation thin-walled parts have high mechanical properties and are usually processed using forging processes. For example, Chinese Patent Publication No. CN115673197A discloses a thin-walled part forging process, which sets the forging block to the same shape as the thin-walled part. During operation, the hydraulic mechanism drives the forging block to move downward, and the forging block extends into the interior of the circular forging. For special-shaped thin-walled parts, the unidirectional pressure of the forging block will cause excessive local deformation of the thin-walled part. In order to make the thin-walled parts more uniformly formed, the prior art discloses multi-directional forging technology. Chinese Patent Publication No. CN116638041A discloses a titanium alloy T-profile multi-directional forging die and method. When the upper die is pressed into place for the first time, the horizontal plate and the vertical plate are not completely filled. When the side die is formed into place, the vertical plate is basically full. When the upper die is pressed into place for the second time, the side of the horizontal plate is filled. This forming method not only achieves precise distribution of the required metal volume for the horizontal and vertical plates during multi-directional forging, but also ensures the required quality of the T-profile forging. However, when multiple dies work together, the movement of the moving dies affects each other, which can easily lead to uneven forming. Therefore, further improvement of the existing technology is necessary. Summary of the Invention

[0003] In response to the above problems, the present invention provides a multi-cylinder forging method and equipment for aviation thin-walled parts, which monitors the stroke data and pressure data of the movable mold and adopts multi-cylinder collaborative control to ensure more stable movement of the movable mold and improve the forming quality of thin-walled parts.

[0004] The invention objectives of this application can be achieved through the following technical means:

[0005] A multi-cylinder forging method for aviation thin-walled parts comprises the following steps:

[0006] Step 1: Setting a first displacement sequence and a bottom dead center of the active die, and setting a second displacement sequence of the side movable die, wherein the active die and the side movable die perform a reciprocating motion together according to the first displacement sequence and the second displacement sequence;

[0007] Step 2: The first throttling device drives the active die via the main hydraulic cylinder, measures the stroke data of the active die center point, and adjusts the flow rate of the first throttling device according to the hydraulic pressure of the first throttling device and the first displacement sequence;

[0008] Step 3: The second throttling device remains in the cut-off state, and the third throttling device remains in the self-locking state. Repeat step 2 until the active die reaches the bottom dead center;

[0009] Step 4: The second throttling device is released from the cut-off state, and the second throttling device drives the side movable mold via the side hydraulic cylinder, measures the stroke data of the side movable mold, and adjusts the flow of the second throttling device according to the hydraulic pressure of the second throttling device and the second displacement sequence;

[0010] Step 5: Measure the travel data of each leveling point and calculate the attitude angle of the active module. If the attitude angle is greater than the stability threshold, proceed to step 6; otherwise, proceed to step 7.

[0011] Step 6: The third throttle device releases the self-locking state, generates the leveling displacement of each third throttle device, and the third throttle device drives the active mold to the corresponding leveling point via the leveling hydraulic cylinder;

[0012] Step 7: Calculate the output load difference of the leveling hydraulic cylinder, update the leveling response function of the leveling hydraulic cylinder, and adjust the effective flow of the third throttling device according to the leveling displacement and the leveling response function;

[0013] Step 8: Calculate the load moment of the active mode, then calculate the load eccentricity coefficient and update the stability threshold;

[0014] Step 9: Repeat steps 4 to 8 until the first displacement sequence and the second displacement sequence are completed, initialize the stroke data of the active mold center point and the side movable mold, and return to step 2.

[0015] In the present invention, in step 2, the displacement increment v of the active die is calculated based on the first displacement sequence S1 and the stroke data h1 of the active die center point. 1t ,S1={s 11 ,s 12 ,...,s 1t ,...,s 1T}, T is the number of forging sampling moments, s 1t is the displacement of the active die at the forging sampling time t, v 1t =s 1t -h1.

[0016] In the present invention, in step 4, the displacement increment v of the side movable mold is calculated based on the second displacement sequence S2 and the stroke data h2 of the side movable mold. 2t ,S2={s 21 ,s 22 ,...,s 2t ,...,s 2T}, v 2t =s 2t -h2, calculate the flow gain k of the second throttling device according to the oil supply pressure of the second pump 2q and pressure coefficient k 2c , and then calculate the flow rate q of the second throttling devicet , 2q t =k 2q v 2t +k 2c P 22 , P 22 is the hydraulic pressure of the second throttling device, and t is the forging sampling time.

[0017] In the present invention, in step 5, the travel data of the four sets of leveling points are h 31 、h 32 、h 33 、h 34 , calculate the flip angles β1, β2, β3, and β4 of the four sets of leveling points, and then calculate the attitude angle γ. , where h 31 =sinβ1b2 / 2+cosβ1b3 / 2-b3 / 2, b2 is the diagonal length of the active mode, and b3 is the thickness of the active mode.

[0018] In the present invention, in step 7, the output load force F of the leveling hydraulic cylinder is measured. 31 、F 33 , calculate the output load difference F 31 -F 33 , calculate the total external torque M corresponding to the flip angle of the active mode 4y and damping torque M 5y , measure the input load force F of the leveling hydraulic cylinder 31 '、F 33 ', then calculate the input load difference F 31 '-F 33 ', F 31 '-F 33 '=(M 4y +M 5y ) / b1, update the leveling response function G y (ΔF), ΔF=(F 31 -F 33 )-(F 31 '-F 33 '), b1 is the horizontal distance between the leveling hydraulic cylinder and the main hydraulic cylinder, and ΔF is the error of the active mold in the current working condition.

[0019] In the present invention, in step 7, the ideal flow rate q of the third throttling device is first calculated. 3t ', and then calculate the effective flow rate in combination with the leveling response function.

[0020] In the present invention, in step 8, the output torque M of the leveling hydraulic cylinder is calculated. 2x and M 2y, the eccentric torque is calculated by combining the output torque and the load torque of the active module, the load eccentricity L1 of the thin-walled part is predicted, and the load eccentricity coefficient λ is calculated based on the load eccentricity L1 and the workpiece eccentricity L0.

[0021] A forging device for implementing the multi-cylinder forging method for aviation thin-walled parts, comprising:

[0022] a fixed die, comprising a chamber for placing the thin-walled part;

[0023] an active die, adapted to cooperate with the chamber;

[0024] a side movable mold, adapted to cooperate with the cavity;

[0025] A first driving unit is used to control the displacement of the active die, and the first driving unit includes a first throttling device and a master hydraulic cylinder;

[0026] Multiple sets of second drive units, used to control the displacement of the side movable mold, the second drive units include a second throttling device and a side hydraulic cylinder;

[0027] A leveling unit is used to adjust the attitude angle of the active mold. The leveling unit includes multiple sets of third throttle devices and a leveling hydraulic cylinder;

[0028] a hydraulic control unit, configured to control the first drive unit, the second drive unit, and the leveling unit;

[0029] Displacement sensing unit, used to measure the stroke data of the active die center point and leveling point as well as the stroke data of the side movable die;

[0030] a pressure sensing unit, used for measuring the hydraulic pressure of the first throttling device, the second throttling device and the third throttling device;

[0031] a first processing unit, configured to update the flow rates of the first throttling device, the second throttling device, and the third throttling device;

[0032] The second processing unit is configured to update the stability threshold.

[0033] In the present invention, the first driving unit also includes a first pressure regulating valve and a first three-way valve, and the leveling unit also includes a third pressure regulating valve and a third three-way valve. The hydraulic pressure of the third pressure regulating valve is higher than the hydraulic pressure of the first pressure regulating valve. When the first three-way valve introduces hydraulic medium to the main hydraulic cylinder and the third three-way valve introduces hydraulic medium to the leveling hydraulic cylinder, the third throttling device remains in a self-locking state. When the first three-way valve is cut off and the third three-way valve introduces hydraulic medium to the leveling hydraulic cylinder, the third throttling device releases the self-locking state.

[0034] In the present invention, the second drive unit also includes a second three-way valve and a one-way rectifying valve. The second throttling device is connected to the one-way rectifying valve. The outlets of adjacent one-way rectifying valves are connected in series through adjacent side hydraulic cylinders. When the second three-way valve introduces hydraulic medium into the side hydraulic cylinder, the second throttling device remains in a cut-off state. When the second three-way valve is cut off, the second throttling device is released from the cut-off state.

[0035] The beneficial effects of the multi-cylinder forging method and equipment for aviation thin-walled parts implemented in the present invention are as follows: the active die and the side movable die of the present invention reciprocate together to forge and form aviation thin-walled parts. In order to ensure the stable movement of the movable die, the stroke data of the movable die and the hydraulic pressure of the throttling device are monitored, and the active die is coordinated and leveled by the leveling hydraulic cylinder to ensure that the active die is in a balanced state, thereby improving the forming quality of thin-walled parts. Furthermore, the present invention predicts the attitude angle of the active die based on the active die flip angle, thereby estimating the leveling response function of the leveling hydraulic cylinder, ensuring that when the flow of the third throttling device acts on the leveling hydraulic cylinder, the leveling hydraulic cylinder can respond to the instantaneous working conditions in real time, thereby improving the leveling control accuracy. At the same time, the present invention calculates the load eccentricity during forging, dynamically adjusts the upper limit of the attitude angle, and further ensures the stability of the movable die pressing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of the multi-cylinder forging method for aviation thin-walled parts of the present invention;

[0037] Figure 2 This is a hydraulic principle diagram of the first pump driving the master hydraulic cylinder of the present invention;

[0038] Figure 3 This is a hydraulic principle diagram of the hydraulic cylinder on the second pump driving side of the present invention;

[0039] Figure 4 This is a hydraulic principle diagram of the first pump driving the leveling hydraulic cylinder of the present invention;

[0040] Figure 5 It is a preferred schematic diagram of the third throttling device of the present invention;

[0041] Figure 6 is a top view of a third throttling device of the present invention;

[0042] Figure 7 For the Figure 6 Cross-sectional view along line AA;

[0043] Figure 8 Schematic diagram of the force on the active mold of the present invention in the leveling state;

[0044] Figure 9 Schematic diagram of the posture change of the active mold in the leveling state of the present invention;

[0045] Figure 10Schematic diagram of the active die load eccentricity and workpiece eccentricity of the present invention;

[0046] Figure 11 A schematic diagram of a forging device for implementing the multi-cylinder forging method for aviation thin-walled parts according to the present invention;

[0047] Figure 12 Schematic diagram of the motion of the active die and the side movable die of the present invention;

[0048] Figure 13 It is a top view of the active mold of the present invention.

[0049] Reference numerals in the accompanying drawings: thin-walled part 100, first pump 201, second pump 202, fixed die 203, active die 204, side movable die 205, first throttling device 301, main hydraulic cylinder 302, first pressure regulating valve 303, first three-way valve 304, pressure relief valve 305, liquid collecting tank 306, second throttling device 401, side hydraulic cylinder 402, second three-way valve 403, one-way rectifying valve 404, third throttling device 501, leveling hydraulic cylinder 502, first Three pressure regulating valves 503, third three-way valve 504, one-way valve 505, electro-hydraulic controller 610, terminal 611, coil 612, magnet 613, feedback rod 614, servo valve 620, inlet 621, first outlet 622, main channel 623, valve core 624, oil return port 625, second outlet 626, auxiliary channel 627, feedback channel 628, nozzle 629, shaft shoulder 631, first circulation channel 632, second circulation channel 633. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Example 1

[0051] like Figures 1 to 11 The multi-cylinder forging method for thin-walled aviation parts of the present invention is shown. Multiple leveling hydraulic cylinders coordinately level the active die to ensure that the active die is in a balanced state. The present invention defines a coordinate system OXYZ, where the origin O is the center point of the active die, the positive direction of the X-axis is horizontally eastward, the positive direction of the Y-axis is horizontally northward, and the Z-axis is vertically upward. The attitude angles in this embodiment are referenced to this coordinate system. The multi-cylinder forging method for thin-walled aviation parts of the present invention includes the following steps.

[0052] Step 1: Set the first displacement sequence and bottom dead center of the active die, and set the second displacement sequence of the side movable die. The active die and the side movable die perform reciprocating motion together according to the first displacement sequence and the second displacement sequence. The first displacement sequence and the second displacement sequence are the displacements of the active die and the side movable die at different forging sampling moments. The first displacement sequence S1={s 11 ,s 12,...,s 1t ,...,s 1T}, T is the number of forging sampling moments, s 1t is the displacement of the active die at the forging sampling time t. The second displacement sequence S2={s 21 ,s 22 ,...,s 2t ,...,s 2T}, s 2t is the displacement of the side movable die at forging sampling time t. In this embodiment, the thin-walled aviation part has a special-shaped structure. The forging process requires the coordinated operation of the active die and the side movable die. The active die moves downward first, and the side movable die begins to move inward after the active die reaches the bottom dead center. In this embodiment, due to the hysteresis of the side movable die, the displacement of the side movable die at at least some forging sampling times is zero.

[0053] Step 2: The first throttling device drives the active die via the master hydraulic cylinder, measures the stroke data of the active die center point, and adjusts the flow rate of the first throttling device based on the hydraulic pressure of the first throttling device and the first displacement sequence. The active die center point is the connection point of the master hydraulic cylinder. The stroke data of the active die center point is h1. The displacement increment v of the active die is calculated based on the first displacement sequence S1 and the stroke data h1 of the active die center point. 1t h1 is the position that the active die has reached, and the displacement s 1t is the target position of the active module, v 1t is the displacement increment of the active mode, that is, v 1t =s 1t In this embodiment, the stroke data refers to the stroke at the current forging sampling time t. The method for adjusting the flow rate of the first throttling device refers to the method for adjusting the flow rate of the third throttling device in the fourth embodiment.

[0054] The first, second, and third throttling devices of the present invention are devices that change the flow rate of the hydraulic medium by adjusting the cross-sectional area of ​​the valve port. In the field of precision forging technology, the first, second, and third throttling devices are typically electro-hydraulic servovalves. The electro-hydraulic servovalves primarily include an electric controller and a servo valve. The electric controller provides an actuation signal, and the servo valve adjusts the cross-sectional area of ​​the valve port. See Example 2 for details.

[0055] Step 3: The second throttle device remains in a closed state, and the third throttle device remains in a self-locking state. Repeat step 2 until the active die reaches bottom dead center. The second throttle device can be kept in a closed state by means of a shutoff valve or by shutting down the second pump. The third throttle device can be kept in a self-locking state by means of a self-locking valve or a high-pressure self-locking unit. The specific technical features for achieving the closed state and self-locking can be found in Example 6 and are not limited thereto by the present invention.

[0056] Step 4: The second throttling device is released from the cut-off state. The second throttling device drives the side movable die through the side hydraulic cylinder, measures the stroke data of the side movable die, and adjusts the flow rate of the second throttling device according to the hydraulic pressure of the second throttling device and the second displacement sequence. The displacement increment v of the side movable die is calculated based on the second displacement sequence and the stroke data h2 of the side movable die. 2t , v 2t =s 2t -h2. Calculate the flow gain k based on the oil supply pressure of the second pump 2q and pressure coefficient k 2c The calculation method of flow gain and pressure coefficient can refer to the fourth embodiment, which is not limited in this embodiment. Then calculate the flow rate q of the second throttling device t According to formula 2q t =(k 2q v 2t +k 2c P 22 ) Solve for q t , P 22 is the hydraulic pressure of the second throttling device, and t is the forging sampling time.

[0057] Step 5: Measure the travel data of each leveling point and calculate the attitude angle of the active module. If the attitude angle is greater than the stability threshold, proceed to step 6, otherwise proceed to step 7. The active module of this embodiment is a rectangle, and its four endpoints are the leveling points. The travel data of the four groups of leveling points are h 31 、h 32 、h 33 、h 34 Calculate the flip angles β1, β2, β3, and β4 of the four leveling points, and then calculate the attitude angle γ. The attitude angle is the angle between the active module normal vector and the Z axis. Depending on the precision requirements of thin-walled aviation parts, the stability threshold can be 0.3° to 0.5°.

[0058] Step 6: The third throttle device releases its self-locking state, generating a leveling displacement for each third throttle device. The third throttle device then drives the active die to the corresponding leveling point via a leveling hydraulic cylinder. Excessive attitude angles can cause the active die to deflect, impacting forging stability and workpiece accuracy. The present invention allows the self-locking state of the third throttle device to be released using a self-locking valve, as further detailed in Example 6.

[0059] Step 7: Calculate the output load difference of the leveling hydraulic cylinder, update the leveling response function of the leveling hydraulic cylinder, and adjust the effective flow of the third throttling device according to the leveling displacement and the leveling response function. The leveling response function refers to the influence of the input and output force difference on the X-axis and Y-axis of the active module on the flow. The leveling response curve can be generated through multiple measurements and the leveling response function can be fitted. Input the error ΔF of the current working condition of the active module to determine the influence of the input and output load force difference on the flow, and then calculate the effective flow q of the third throttling device in combination with the throttling model of the third throttling device. 3t The throttling model of the third throttling device is described in Example 4. In this embodiment, the hydraulic pressure refers to the pressure of the medium, and the load force refers to the pressure.

[0060] Specifically, a pressure sensor or other device is used to measure the load force output by the leveling hydraulic cylinder to the active mold. The output load difference of the diagonal line (Y axis) formed by the first leveling point and the third leveling point is calculated. In this embodiment, the output load forces on both sides of the diagonal line (Y axis) are F 31 、F 33 , the output load difference is F 31 -F 33 , the output load difference is the load variable output by the leveling hydraulic cylinder to the active die. Calculate the total external torque M of the active die corresponding to the flip angle 4y and damping torque M 5y (around the Y axis), the input load forces on both sides of the diagonal (Y axis) are F 31 '、F 33 ', then calculate the input load difference F 31 '-F 33 ', F 31 '-F 33 '=(M 4y +M 5y ) / b1.

[0061] ΔF reflects the difference between the load of the leveling hydraulic cylinder around the Y axis and the response of the active module under the current working condition. ΔF=(F 31 -F 33 )-(F 31 '-F 33 '), the present invention establishes the relationship between ΔF and the flow rate of the third throttling device, which is used as the leveling response function G y (ΔF), based on which the flow response error of the third throttling device is predicted, and then flow compensation is provided according to the flow response error to improve the accuracy of flow control. The same method can be used to measure the output load force F on both sides of the diagonal (X axis) 32 、F 34 , measure the input load force F on both sides of the diagonal (X axis) 32 '、F 34 ', update the leveling response function G around the X axisx (ΔF'), ΔF'=(F 32 -F 34 )-(F 32 '-F 34 ').

[0062] Step 8: Calculate the load torque of the active module, then calculate the load eccentricity coefficient and update the stability threshold. Specifically, the load torque is calculated from the flip angle in step 5, and then the output torque M of the leveling hydraulic cylinder is calculated. 2x and M 2y The eccentricity torque is calculated by combining the output torque and the load torque, and the load eccentricity L1 of the thin-walled workpiece is predicted. The load eccentricity coefficient λ is calculated based on the load eccentricity L1 and the workpiece eccentricity L0. The calculation steps for the load eccentricity coefficient and the method for updating the stability threshold are described in detail in Example 5.

[0063] Step 9: Repeat steps 4 through 8 until the first and second displacement sequences are complete. Initialize the stroke data for the active die center and the side movable die, and return to step 2. Each time steps 4 through 8 are repeated, t = t + 1. When t = T, the first and second displacement sequences are complete, the active die and side movable die return to their initial positions, and the next forging process begins. Example 2

[0064] This embodiment further discloses the preferred structure of the first throttling device, the second throttling device and the third throttling device. In this embodiment, the first throttling device, the second throttling device and the third throttling device are electro-hydraulic servo valves, which include servo valves and electro-hydraulic controllers. Figure 5 and Figure 6 As shown, the electro-hydraulic controller 610 includes a terminal 611, a coil 612, a magnet 613, and a feedback rod 614. The terminal 611 introduces an external voltage signal, the coil 612 receives the voltage signal to generate a magnetic field, the magnet 613 deflects in the magnetic field, and the feedback rod 614 rotates with the magnet 613.

[0065] like Figure 7As shown, the servo valve 620 includes an inlet 621, a first outlet 622, a main channel 623, a valve core 624, an oil return port 625, a second outlet 626, an auxiliary channel 627, a feedback channel 628, and a nozzle 629. The main channel 623 and the shoulder 631 of the valve core 624 form a valve port. The position of the valve core 624 can adjust the size of the valve port. Hydraulic medium enters the main channel 623 from the inlet 621, enters the first circulation channel 632 of the valve core 624 through the valve port, and then enters the first outlet 622. The hydraulic medium in the auxiliary channel 627 enters the nozzle 629 through the feedback channel 628 and then acts on the feedback rod 614 to offset the force applied by the magnet 613 to the feedback rod 614. When the inlet 621 is connected to the first outlet 622, the oil return port 625 can be connected to the second outlet 626 through the second circulation channel 633. The hydraulic medium entering the second outlet 626 can compensate for the pressure of the liquid medium in the inlet 621 on the valve core 624.

[0066] When the electro-hydraulic servo valve is working, the external voltage signal adjusts the force of the magnet acting on the feedback rod, and the feedback rod deflects, driving the valve core to move. The hydraulic medium in the auxiliary channel acts on the feedback rod through the nozzle, causing the deflection to stop at a certain angle. At the same time, the hydraulic medium from the return oil port enters the second circulation channel to compensate for the thrust exerted on the valve core. After the valve core moves, the area of ​​the valve port changes, realizing throttling of the hydraulic medium. The various coefficients are generally determined by the design of the servo valve supplier. The area of ​​the first circulation channel affects the flow coefficient, and the area of ​​the main channel affects the valve port area gradient, thereby determining the throttling model of the electro-hydraulic servo valve. The commonly used model is the D791-4046 electro-hydraulic servo valve produced by Moog (MOOG) in the United States. The third throttling device of the present invention uses the electro-hydraulic servo valve to calculate the ideal flow and the actual flow, as described in Example 4. Example 3

[0067] This embodiment further discloses a preferred method for calculating the attitude angle of the active module. Figure 8 and Figure 9 In this embodiment, the active mold is rectangular and may flip along its two diagonals during movement. This embodiment predicts the active mold's attitude angle based on the flip angle. In a more preferred embodiment, the active mold is square, with the two diagonals representing the X and Y axes, and the master hydraulic cylinder moves along the Z axis.

[0068] Step 501: Calculate the flip angle β1 of the first leveling point. The travel data of the first leveling point is h 31 , according to the geometric relationship, h 31 =sinβ1b2 / 2+cosβ1b3 / 2-b3 / 2, where b2 is the diagonal length of the active mode (i.e., the three-dimensional diagonal length) and b3 is the thickness of the active mode. Solve the above equation to find the flip angle β1, which is less than π / 2.

[0069] Step 502: Calculate the second leveling point, the third leveling point, and the flip angles β2, β3, and β4 of the third leveling point. The travel data of the second leveling point is h 32 , h 32 =sinβ2b2 / 2+cosβ2b3 / 2-b3 / 2, the stroke data of the third leveling point is h 33 , h 33 =sinβ3b2 / 2+cosβ3b3 / 2-b3 / 2, the stroke data of the fourth leveling point is h 34 , h 34 =sinβ4b2 / 2+cosβ4b3 / 2-b3 / 2. Using the method in step 501, solve for the flip angles β2, β3, and β4 that are less than π / 2.

[0070] Step 503: Calculate the attitude angle γ. Figure 9 , the first leveling point and the third leveling point are at opposite angles, usually β1=β3. The present invention can determine the diagonal flip angle based on the average of the flip angles β1 and β3. The attitude angle of the active module is the sum of the diagonal flip angles in the vector direction. In a preferred embodiment, the diagonal lines are parallel to the X-axis and the Y-axis respectively. Attitude angle . Example 4

[0071] Reference Figure 10 , this embodiment further discloses a preferred method for adjusting the flow rate of the third throttling device.

[0072] Step 701: Calculate the output load difference of the leveling hydraulic cylinder. In this embodiment, the pressure sensor on the first circulation channel of the third throttling device can be used to measure the pressure and calculate the output load force F on both sides of the diagonal (Y axis) in combination with the cross-sectional area. 31 、F 33 , then calculate the output load difference F 31 -F 33 The same method can be used to calculate the input load difference F of the leveling hydraulic cylinder on both sides of the diagonal (X axis) 32 -F 34 .

[0073] Step 702: Calculate the input load difference of the active mode. First calculate the first differential [d(β1+β3) / 2]dt and the second differential [d 2 (β1+β3) / 2]dt 2 . Resulting external moment M 4y =J1[d 2 (β2+β4) / 2]dt 2 , damping torque M 5y =B1[d(β2+β4) / 2]dt. Active mode input load difference F 31 '-F33 '=(M 4y +M 5y ) / b1. J1 is the moment of inertia of the active die around the diagonal (Y axis), B1 is the viscous damping coefficient of the active die around the diagonal (Y axis), and b1 is the horizontal distance between the leveling hydraulic cylinder and the main hydraulic cylinder. The same method can be used to calculate the input load difference F on the diagonal (X axis) 32 '-F 34 '.

[0074] Step 703: Update the leveling response function. Leveling response function G y (ΔF) is the environmental impact gain of the load of the hydraulic cylinder on the Y axis and the response of the active module, which is used to reduce or eliminate the impact of the flow response error under the current working conditions. ΔF=(F 31 -F 33 )-(F 31 '-F 33 '), similarly, the leveling response function G of the X axis can be updated x (ΔF'), ΔF'=(F 32 -F 34 )-(F 32 '-F 34 ').

[0075] Step 704: Calculate the ideal flow of the third throttling device. The third throttling device is an electro-hydraulic servo valve, including an electro-hydraulic controller and a servo valve. The servo valve has a valve core. The structure of the servo valve is as described in Example 2. The throttling model of the third throttling device is: q 3t '=[k 3q (h 31 +h 33 ) / 2+k 3c P 32 ], calculate the ideal flow rate q of the third throttling device according to the throttling model of the third throttling device 3t ', k 3q is the flow gain of the third throttling device, k 3c is the pressure coefficient of the third throttling device, P 32 is the hydraulic pressure of the third throttling device, and t is the forging sampling time. , .P 31 is the oil supply pressure of the first pump, C3 is the flow coefficient of the servo valve of the third throttling device, W3 is the valve port area gradient of the servo valve of the third throttling device, v3 is the spool displacement of the servo valve of the third throttling device, and ρ is the density of the hydraulic medium, which is usually 0.8 to 1 kg / m 3n is the cross-sectional area ratio of the rod cavity to the rodless cavity. The same method can be used to calculate the corresponding flow rate using the throttling model of the first throttling device and the second throttling device. In this embodiment, when t>1, (h 31 +h 33 ) / 2 is replaced by the displacement increment of the active die at time t. In the field of hydraulic technology, the pressure of the hydraulic medium is also called pressure. In order to distinguish the applied force from the pressure of the hydraulic medium, the oil supply pressure in this embodiment refers to the pressure of the hydraulic medium, and the unit is N / m 2 The load force refers to the pressure of the load, and its unit is N.

[0076] Step 705: Calculate the effective flow rate of the third throttling device. 3t =q 3t '+G y (ΔF)+ G x (ΔF')=[k 3q (h 31 +h 33 ) / 2+k 3c P 32 ]+G y (ΔF)+G x (ΔF'). The effective flow rate is the actual flow rate. Due to the coordinated operation of multiple sets of third throttling devices, its value is affected by the current operating conditions of the active module. The present invention eliminates this influence by adjusting the response function. Example 5

[0077] This embodiment further discloses a preferred method for updating the attitude angle in step 8.

[0078] Step 801: Calculate two sets of load moments M perpendicular to each other on the active modulus 1x and M 1y . Referring to the fourth embodiment, the load moment M 1y =J1[d 2 (β1+β3) / 2]dt 2 +B1[d(β1+β3) / 2]dt, load moment M 1x =J2[d 2 (β2+β4) / 2]dt 2 +B2[d(β2+β4) / 2]dt. J1 is the moment of inertia of the active module around the Y axis, B1 is the rotational viscous damping coefficient of the active module around the Y axis, J2 is the moment of inertia of the active module around the X axis, and B2 is the rotational viscous damping coefficient of the active module around the X axis.

[0079] Step 802: Calculate the output torque M of the leveling hydraulic cylinder 2x and M 2y According to the relationship between torque and force, the output torque of the X-axis is equal to the product of the output load difference of the leveling hydraulic cylinder and the lever arm.2x =(F 32 -F 34 )b4,M 2y =(F 31 -F 33 )b5. b4 is the length of the active mode perpendicular to the X axis, b5 is the length of the active mode perpendicular to the Y axis, usually b4=b5.

[0080] Step 803: Calculate the eccentric torque by combining the output torque and the load torque. Under ideal conditions, the active die's force application point is at the origin O, and the main hydraulic cylinder does not generate torque on the active die. Due to the instability of the active die's descent, the main hydraulic cylinder generates an eccentric torque M around the X-axis on the active die. 3x , an eccentric moment M is generated in the active mode around the Y axis 3y . Eccentric moment M 3x =M 1x -M 2x , eccentric moment M 3y =M 1y -M 2y .

[0081] Step 804: Calculate the load eccentricity L1 of the thin-walled part. Calculate the load eccentricity based on the eccentric moment and the load force of the main hydraulic cylinder. Specifically, the load force of the main hydraulic cylinder is F0, and the eccentricity L in the X-axis direction is 1x =M 3y / F0, eccentricity L in the Y-axis direction 1y =M 3y / F0. Load eccentricity L1 2 =L 1x 2 +L 1y 2 .

[0082] Step 805: Calculate the load eccentricity coefficient λ based on the load eccentricity L1 and the workpiece eccentricity L0. Load eccentricity coefficient λ = L1 / L0. In this implementation, the stability threshold is fitted as an exponential function, and the stability threshold γ max =γ0exp(-λ), γ0 is the initial attitude angle, usually ranging from 0.2° to 0.3°. Figure 10 The length of OO1 is the load eccentricity L1, and the length of OO2 is the workpiece eccentricity L0. Ideally, the active die's force application point is at the origin O. The workpiece eccentricity L0 is the distance between the workpiece's geometric center O2 and the ideal active die's force application point.

[0083] For workpieces with regular shapes, the geometric center of the workpiece is located at the centroid. For workpieces with special shapes, the geometric center of the workpiece can be calculated using numerical integration. First, a two-dimensional model of the workpiece is established. The interval of the two-dimensional model in the X-axis direction is [x1, x2], and the interval in the Y-axis direction is [y1, y2]. The area of ​​the workpiece is S, and the area of ​​the grid with coordinates (x, y) is S xy The coordinates of the workpiece's geometric center (x0, y0) are obtained by solving the integral formula: , . Example 6

[0084] Reference Figures 2 to 13 A forging device for implementing the multi-cylinder forging method for aviation thin-walled parts includes: a first pump 201, a second pump 202, a fixed die 203, a driving die 204, a side movable die 205, a first drive unit, multiple sets of second drive units, a leveling unit, a hydraulic control unit, a displacement sensing unit, a pressure sensing unit, a first processing unit, and a second processing unit. The fixed die 203 includes a cavity for placing the thin-walled part 100. The driving die 204 is used to cooperate with the cavity and has a first die core. The side movable die 205 is used to cooperate with the cavity and has a second die core. The first drive unit is used to control the displacement of the driving die 204 and includes a first throttling device 301 and a main hydraulic cylinder 302. Multiple sets of second drive units are used to control the displacement of the side movable die 205 and include a second throttling device 401 and a side hydraulic cylinder 402. The leveling unit is used to adjust the attitude angle of the active die 204. It includes multiple sets of third throttle devices 501 and a leveling hydraulic cylinder 502. A hydraulic control unit controls the first and second drive units, as well as the leveling unit. The first pump 201 drives the active die 204 via the first drive unit, while the second pump 202 drives the side movable die 205 via the second drive unit. When the active die 204 reaches its bottom dead center, the hydraulic control unit controls the second throttle device 401 to release its closed state. When the attitude angle of the active die 204 is greater than or equal to a stability threshold, the hydraulic control unit controls the third throttle device 501 to release its self-locking state.

[0085] The displacement sensing unit is used to measure the stroke data of the center point and leveling point of the active mold 204, as well as the stroke data of the side movable mold 205. The pressure sensing unit is used to measure the hydraulic pressure of the first throttling device 301, the second throttling device 401, and the third throttling device 501. The first processing unit is used to update the flow rate of the first throttling device 301, the second throttling device 401, and the third throttling device 501. The second processing unit is used to update the stability threshold. The present invention monitors the stroke data of the movable mold and the hydraulic pressure of the throttling device, and coordinates the leveling of the active mold 204 through the leveling hydraulic cylinder 502 to ensure that the active mold 204 is in a balanced state, thereby improving the molding quality of the thin-walled part 100.

[0086] The first drive unit also includes a first pressure-regulating valve 303, a first three-way valve 304, a pressure relief valve 305, and a liquid collection tank 306. The first pump 201 is connected to the first three-way valve 304 via the first pressure-regulating valve 303. One output end of the first three-way valve 304 is connected to the rodless chamber of the master hydraulic cylinder 302 via the first throttle device 301. The first pump 201 also returns to the liquid collection tank 306 via the pressure relief valve 305. The other output end of the first three-way valve 304 is connected to the rodless chamber of the master hydraulic cylinder 302. The leveling unit also includes a third pressure-regulating valve 503, the third three-way valve 504, and a check valve 505. The hydraulic pressure of the third pressure-regulating valve 503 is higher than that of the first pressure-regulating valve 303. The first pump 201 is connected to the third three-way valve 504 via the third pressure-regulating valve 503. One output end of the third three-way valve 504 is connected to the rodless chamber of the leveling hydraulic cylinder 502 via the third throttle device 501. The other output end of the third three-way valve 504 is connected to the rod chamber of the leveling hydraulic cylinder 502. The rodless chamber of the leveling hydraulic cylinder 502 is also connected to the rodless chamber of the master hydraulic cylinder 302 via a one-way valve 505. The one-way valve 505 of the present invention is a ball-type one-way valve that relies on the pressure of the hydraulic medium to push open the valve disc. It opens during forward flow and automatically closes due to the pressure differential during reverse flow.

[0087] The present invention discloses a preferred structure for maintaining the third throttle device 501 in a self-locking state. When the first three-way valve 304 is in a forward-conducting state and the third three-way valve 504 is in a blocked state, hydraulic medium enters the main hydraulic cylinder 302 through the first throttle device 301. Then, the hydraulic medium enters the leveling hydraulic cylinder 502 through the first throttle device 301 and the one-way valve 505 of the leveling unit. At this point, the leveling hydraulic cylinder 502 and the main hydraulic cylinder 302 maintain simultaneous movement, and the third throttle device 501 remains in a self-locking state.

[0088] When the first three-way valve 304 and the third three-way valve 504 are in forward conduction, the hydraulic pressure in the third pressure-regulating valve 503 is higher than that in the first pressure-regulating valve 303. The hydraulic medium enters the rodless chamber of the master hydraulic cylinder 302 through the first pressure-regulating valve 303 and the first throttle device 301. Then, the hydraulic medium enters the rodless chamber of the leveling hydraulic cylinder 502 through the third pressure-regulating valve 503 and the third throttle device 501. The third throttle device 501 is released from its self-locking state and is now operational. Adjusting the flow rate in the third throttle device 501 can influence the posture of the active mold 204.

[0089] When the first three-way valve 304 and the third three-way valve 504 are in the closed state, the main hydraulic cylinder 302 and the leveling hydraulic cylinder 502 remain stationary, and the main mold 204 and the side movable mold 205 are in a pressure-maintaining state. When the first three-way valve 304 and the third three-way valve 504 are in the switched-on state, the hydraulic medium enters the main hydraulic cylinder 302 (rod chamber) through the first pressure-regulating valve 303, and the hydraulic medium enters the leveling hydraulic cylinder 502 (rod chamber) through the third pressure-regulating valve 503, and the main mold 204 and the side movable mold 205 return to their initial state.

[0090] The second drive unit also includes a second three-way valve 403 and a one-way regulating valve 404. The second throttle device 401 is connected to the one-way regulating valve 404, and the outlets of adjacent one-way regulating valves 404 are connected in series through adjacent side hydraulic cylinders 402. When the second three-way valve 403 is in the closed state, the second throttle device 401 and the side hydraulic cylinder 402 are deprived of hydraulic oil, and the second throttle device 401 remains in the closed state.

[0091] The present invention discloses a preferred structure for maintaining the second throttle device 401 in a shut-off state. When the second three-way valve 403 is in a forward-conducting state, hydraulic medium enters the main hydraulic cylinder 302 (rodless chamber) through the second throttle device 401 and the one-way rectifying valve 404, releasing the shut-off state of the second throttle device 401. The second throttle devices 401 are connected in series to ensure that the hydraulic pressure provided by the second pumps 202 is uniform. The second throttle device 401 can adjust the actual flow rate entering the corresponding side hydraulic pump. When the second three-way valve 403 is in a reverse-conducting state, hydraulic medium enters the main hydraulic cylinder 302 (rod chamber) through the second throttle device 401 and the one-way rectifying valve 404, and the side movable mold 205 returns to its initial position.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-cylinder forging method for aviation thin-walled parts, characterized in that: The following steps are involved: Step 1: Setting a first displacement sequence and a bottom dead center of the active die, and setting a second displacement sequence of the side movable die, wherein the active die and the side movable die perform a reciprocating motion together according to the first displacement sequence and the second displacement sequence; Step 2: The first throttling device drives the active die via the main hydraulic cylinder, measures the stroke data of the active die center point, and adjusts the flow rate of the first throttling device according to the hydraulic pressure of the first throttling device and the first displacement sequence; Step 3: The second throttling device remains in the cut-off state, and the third throttling device remains in the self-locking state. Repeat step 2 until the active die reaches the bottom dead center; Step 4: The second throttling device is released from the cut-off state, and the second throttling device drives the side movable mold via the side hydraulic cylinder, measures the stroke data of the side movable mold, and adjusts the flow of the second throttling device according to the hydraulic pressure of the second throttling device and the second displacement sequence; Step 5: Measure the travel data of each leveling point and calculate the attitude angle of the active module. If the attitude angle is greater than the stability threshold, proceed to step 6; otherwise, proceed to step 7. Step 6: The third throttle device releases the self-locking state, generates the leveling displacement of each third throttle device, and the third throttle device drives the active mold to the corresponding leveling point via the leveling hydraulic cylinder; Step 7: Calculate the output load difference of the leveling hydraulic cylinder, update the leveling response function of the leveling hydraulic cylinder, and adjust the effective flow of the third throttling device according to the leveling displacement and the leveling response function; Step 8: Calculate the load moment of the active mode, then calculate the load eccentricity coefficient and update the stability threshold; Step 9: Repeat steps 4 to 8 until the first displacement sequence and the second displacement sequence are completed, initialize the stroke data of the active mold center point and the side movable mold, and return to step 2.

2. The multi-cylinder forging method for aviation thin-walled parts according to claim 1, characterized in that: In step 2, the displacement increment v of the active die is calculated based on the first displacement sequence S1 and the stroke data h1 of the active die center point. 1t ,S1={s 11 ,s 12 ,...,s 1t ,...,s 1T }, T is the number of forging sampling moments, s 1t is the displacement of the active die at the forging sampling time t, v 1t =s 1t -h1.

3. The multi-cylinder forging method for aviation thin-walled parts according to claim 1, characterized in that: In step 4, the displacement increment v of the side movable die is calculated based on the second displacement sequence S2 and the stroke data h2 of the side movable die. 2t ,S2={s 21 ,s 22 ,...,s 2t ,...,s 2T }, v 2t =s 2t -h2, calculate the flow gain k of the second throttling device according to the oil supply pressure of the second pump 2q and pressure coefficient k 2c , and then calculate the flow rate q of the second throttling device t , 2q t =k 2q v 2t +k 2c P 22 , P 22 is the hydraulic pressure of the second throttling device, t is the forging sampling time, and T is the number of forging sampling times.

4. The multi-cylinder forging method for aviation thin-walled parts according to claim 1, characterized in that: In step 5, the travel data of the four sets of leveling points are h 31 、h 32 、h 33 、h 34 , calculate the flip angles β1, β2, β3, and β4 of the four sets of leveling points, and then calculate the attitude angle γ. , where h 31 =sinβ1b2 / 2+cosβ1b3 / 2-b3 / 2, b2 is the diagonal length of the active mode, and b3 is the thickness of the active mode.

5. The multi-cylinder forging method for aviation thin-walled parts according to claim 4, characterized in that: In step 7, measure the output load force F of the leveling hydraulic cylinder. 31 、F 33 , calculate the output load difference F 31 -F 33 , calculate the total external torque M corresponding to the flip angle of the active mode 4y and damping torque M 5y , measure the input load force F of the leveling hydraulic cylinder 31 '、F 33 ', then calculate the input load difference F 31 '-F 33 ', F 31 '-F 33 '=(M 4y +M 5y ) / b1, update the leveling response function G y (ΔF), ΔF=(F 31 -F 33 )-(F 31 '-F 33 '), b1 is the horizontal distance between the leveling hydraulic cylinder and the main hydraulic cylinder, and ΔF is the error of the active mold in the current working condition.

6. The multi-cylinder forging method for aviation thin-walled parts according to claim 5, characterized in that: In step 7, first calculate the ideal flow rate q of the third throttling device 3t ', and then calculate the effective flow rate in combination with the leveling response function.

7. The multi-cylinder forging method for aviation thin-walled parts according to claim 6, characterized in that: In step 8, calculate the output torque M of the leveling hydraulic cylinder 2x and M 2y , the eccentric torque is calculated by combining the output torque and the load torque of the active module, the load eccentricity L1 of the thin-walled part is predicted, and the load eccentricity coefficient λ is calculated based on the load eccentricity L1 and the workpiece eccentricity L0.

8. A forging device for implementing the multi-cylinder forging method for aviation thin-walled parts according to any one of claims 1 to 7, characterized in that: include: a fixed die, comprising a chamber for placing the thin-walled part; an active die, adapted to cooperate with the chamber; a side movable mold, adapted to cooperate with the cavity; A first driving unit is used to control the displacement of the active die, and the first driving unit includes a first throttling device and a master hydraulic cylinder; Multiple sets of second drive units, used to control the displacement of the side movable mold, the second drive units include a second throttling device and a side hydraulic cylinder; A leveling unit is used to adjust the attitude angle of the active mold. The leveling unit includes multiple sets of third throttle devices and a leveling hydraulic cylinder; a hydraulic control unit, configured to control the first drive unit, the second drive unit, and the leveling unit; Displacement sensing unit, used to measure the stroke data of the active die center point and leveling point as well as the stroke data of the side movable die; a pressure sensing unit, used for measuring the hydraulic pressure of the first throttling device, the second throttling device and the third throttling device; a first processing unit, configured to update the flow rates of the first throttling device, the second throttling device, and the third throttling device; The second processing unit is configured to update the stability threshold.

9. The forging equipment according to claim 8, characterized in that The first driving unit also includes a first pressure regulating valve and a first three-way valve, and the leveling unit also includes a third pressure regulating valve and a third three-way valve. The hydraulic pressure of the third pressure regulating valve is higher than the hydraulic pressure of the first pressure regulating valve. When the first three-way valve introduces hydraulic medium to the main hydraulic cylinder and the third three-way valve introduces hydraulic medium to the leveling hydraulic cylinder, the third throttling device remains in a self-locking state. When the first three-way valve is cut off and the third three-way valve introduces hydraulic medium to the leveling hydraulic cylinder, the third throttling device releases the self-locking state.

10. The forging equipment according to claim 8, characterized in that The second drive unit also includes a second three-way valve and a one-way rectifying valve. The second throttling device is connected to the one-way rectifying valve. The outlets of adjacent one-way rectifying valves are connected in series through adjacent side hydraulic cylinders. When the second three-way valve introduces hydraulic medium into the side hydraulic cylinder, the second throttling device remains in a cut-off state. When the second three-way valve is cut off, the second throttling device is released from the cut-off state.

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