Main machine hammerhead adjusting method for improving forging precision of mechanical-hydraulic hybrid radial forging machine

Abstract

The invention discloses a host hammerhead adjusting method for improving the forging precision of a mechanical-hydraulic hybrid radial forging machine. The method comprises the following steps: firstly, determining a target depth value L0 and a forging force F1 based on blank characteristics; solving the pressure variation dP1 of the return oil cylinder and the compensation return force F2 in a linkage manner; after the target oil pressure P21 of the hydraulic adjusting pad is deduced, the compression compensation length L3 is calculated in combination with the oil volume elastic modulus beta, the initial volume V20 and the pressure difference dP2; and finally, the initial extension lengths L1 and L3 are superposed to set a compensation position L4. According to the method, the oil compression amount of the hydraulic adjusting pad is calculated in real time, the extension length of the hammer head is dynamically compensated, and the problem of depth negative deviation caused by oil compression under high forging force is completely solved. And actual production verifies that the size error rate of the forge piece is reduced to be within 10% from 47-80% of a conventional method, waste loss and subsequent finishing cost caused by size out-of-tolerance are effectively avoided, and the production cost is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal plastic forming, in particular to a main machine hammer head adjusting method for improving the forging precision of a machine-oil mixed radial forging machine. BACKGROUND

[0002] Radial forging technology has significant advantages in the manufacturing field of precision forgings such as shafts and pipes due to its synchronous forging characteristics of multiple hammer heads, combining high forming precision and production efficiency. This technology uses ingots or billets as raw materials and can flexibly adopt hot forging or cold forging processes to produce various products covering circular, square, rectangular cross-sections, including light shafts, stepped shafts, tapered shafts, and thick-walled pipes, and other diversified forgings. The machine-oil mixed radial forging machine uses a hydraulic cylinder to achieve precise adjustment of the hammer head position, and its structural design has double advantages: on the one hand, the integrated forging force measurement and overload protection function of the oil cylinder improves the reliability and safety of the system; on the other hand, the compact layout of the oil cylinder significantly reduces the installation space requirement, making the overall machine structure more compact and efficient. This design ensures process performance while optimizing the space utilization of the equipment.

[0003] However, in the machine-oil mixed radial forging process, the oil compression effect in the hydraulic adjusting pad is a key factor affecting the forging precision: under high forging force (greater than 10 MN), the oil compression in the hydraulic adjusting pad causes the actual displacement of the hammer head to decrease by 0.5-8.0 mm (error rate 5%-80%) compared to the target value. The existing technology does not consider this dynamic compression process, resulting in size overruns, decreased pass rates, and increased trimming costs. SUMMARY

[0004] The purpose of the present application is to provide a main machine hammer head adjusting method for improving the forging precision of a machine-oil mixed radial forging machine, which calculates the hammer head compression in real time and uses it as a dynamic compensation value for the forging depth to offset the displacement loss caused by oil compression, thereby solving the problems raised in the background technology.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a main machine hammer head adjusting method for improving the forging precision of a machine-oil mixed radial forging machine, comprising the following steps: Step one, determine the initial conditions, determine the forging force F1 required to make the billet reach the predetermined deformation and the main machine target forging depth L0 according to the billet material properties and target forging requirements; Step two, calculate the initial volume V10 of the return oil cylinder: S1, subtract the initial extension length L1 of the main machine hammer head from the maximum extension length of the return oil cylinder to obtain a first difference; S2, multiply the first difference obtained in S1 by the effective action area A1 of the return oil cylinder to obtain a first product; S3, add the first product obtained in S2 to the dead volume of the return oil cylinder at the minimum extension length, and the result is the initial volume V10 of the return oil cylinder; Step three, calculate the volume change dV1 of the return oil cylinder: determine the forging feed length L2 according to the size of the eccentric wheel of the machine-oil mixed radial forging machine, and calculate the volume change dV1 of the return oil cylinder: dV1 is equal to the product of the forging feed length L2 and the effective action area A1 of the return oil cylinder; Step four, calculate the pressure change dP1 of the return oil cylinder oil: dP1 is equal to the value obtained by multiplying the oil volume elastic modulus β by the volume change dV1 of the return oil cylinder obtained in step three, and then dividing by the initial volume V10; Step five, calculate the return force F2 under the target forging depth: S1, add the return oil cylinder oil supply pressure P10 and the pressure change dP1 to obtain the first algebraic sum; S2, multiply the first algebraic sum obtained in S1 by the effective action area A1 of the return oil cylinder, and the result is the return force F2; Step six, calculate the target oil pressure P21 of the hydraulic adjusting pad: S1, add the forging force F1 and the return force F2 to obtain the second algebraic sum; S2, divide the second algebraic sum by the effective action area A2 of the hydraulic adjusting pad, and the result is the target oil pressure P21 of the adjusting pad; Step seven, calculate the pressure change dP2 of the hydraulic adjusting pad: dP2 is equal to the difference obtained by subtracting the hydraulic adjusting pad oil supply pressure P20 from the target oil pressure P21 of the hydraulic adjusting pad; Step eight, calculate the initial volume V20 of the hydraulic adjusting pad: S1, multiply the initial extension length L1 by the effective action area A2 of the hydraulic adjusting pad to obtain the second product; S2, add the second product in S1 to the dead volume of the hydraulic adjusting pad at the minimum extension length, and the result is V20; Step nine, calculate the compression compensation length L3 of the hydraulic adjusting pad: S1, multiply the oil volume elastic modulus β, the initial volume V20 and the pressure change dP2 to obtain the third product; S2, multiply the effective action area A2 of the hydraulic adjusting pad by the volume elastic modulus β to obtain the fourth product; S3, add the fourth product and the pressure change dP2 to obtain the third algebraic sum; S4, divide the third product by the third algebraic sum, and the result is the oil compression dV2; S5, divide the oil compression amount dV2 by the effective action area A2 of the hydraulic adjusting pad, and the result is L3; Step ten, set the hammer head position after compensation: S1, add the initial extension length L1 and the compression compensation length L3 to obtain the extension length L4 after compensation; S2, adjust the main machine hammer head to L4 and perform the forging operation.

[0006] Preferably, the oil volume elastic modulus β in steps four and nine is the same measured value.

[0007] Preferably, the main machine hammer head uses the eccentric wheel slider assembly 1 to drive the hammer rod rear cap 2 to move, compress the oil in the hydraulic adjusting pad, and then drive the main machine hammer head piston and the hammer head tool assembly 4 to forge the workpiece 5. Preferably, the main machine hammer head uses the return oil cylinder 3 to drive the main machine hammer head piston and the hammer head tool assembly 4 to return.

[0008] Preferably, the hydraulic adjusting pad is composed of a closed oil cavity between the hammer rod rear cap 2 and the main machine hammer head piston and the hammer head tool assembly 4, and the effective action area A2 is the piston pressure bearing area.

[0009] The beneficial effects of the present application are: (1) The main machine hammer head adjusting method for improving the forging precision of the machine-oil mixed radial forging machine provided by the present application significantly improves the forging size precision and product qualification rate. The method calculates the oil compression amount of the hydraulic adjusting pad in real time and dynamically compensates the hammer head extension length, completely solving the problem of deep negative deviation caused by oil compression under high forging force. According to actual production verification, the forging size error rate is reduced from 47-80% of the conventional method to within 10%, effectively avoiding the loss of waste products and subsequent trimming costs caused by size out-of-tolerance.

[0010] (2) The main machine hammer head adjusting method for improving the forging precision of the machine-oil mixed radial forging machine provided by the present application creatively proposes a two-way compensation adjusting mechanism of return oil circuit pressure compensation and hydraulic adjusting pad compression compensation. Within the range of 0-200mm of the initial extension length of the hammer head, the accurate compensation amount is calculated by formula, and the compensation method is dynamic compensation. When the compensation length L3 is dynamically adjusted according to the working condition, it can ensure that the actual forging depth fluctuation is controlled within the allowable deviation range, and it breaks through the working condition adaptation problem caused by fixed compensation amount in the traditional method.

[0011] (3) The main machine hammer head adjusting method for improving the forging precision of the machine-oil mixed radial forging machine provided by the present application is suitable for large-scale application of radial forging machines, shortens the single forging cycle, reduces the product trimming time, saves direct production cost, and at the same time improves the product precision grade and the product fatigue life, and the economic benefit is remarkable. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Flow chart for oil compression compensation calculation; Figure 2 Structure diagram of main hammer head of machine-oil mixed radial forging machine; Wherein: 1- eccentric wheel slider assembly, 2- hammer rod rear cap, 3- return oil cylinder, 4- main hammer head piston and hammer head tooling assembly, 5- processing blank. DETAILED DESCRIPTION

[0013] The application will be further described in detail below with reference to the drawings.

[0014] As shown in the drawings, Figure 1 A main hammer head adjusting method for improving the forging precision of a machine-oil mixed radial forging machine, comprising the following steps: Step one, determine the initial condition, according to the blank material properties and target forging requirements, determine the forging force F1 required for the blank to reach the predetermined deformation and the main target forging depth L0; Step two, calculate the initial volume V10 of the return oil cylinder: S1, subtract the initial extension length L1 of the main hammer head from the maximum extension length of the return oil cylinder to obtain a first difference; S2, multiply the first difference obtained in S1 by the effective action area A1 of the return oil cylinder to obtain a first product; S3, add the first product obtained in S2 to the dead volume under the minimum extension length of the return oil cylinder, and the result is the initial volume V10 of the return oil cylinder; Step three, calculate the volume change dV1 of the return oil cylinder: according to the eccentric wheel size of the machine-oil mixed radial forging machine, determine the forging feed length L2, and calculate the volume change dV1 of the return oil cylinder: dV1 is equal to the product of the forging feed length L2 and the effective action area A1 of the return oil cylinder; Step four, calculate the oil pressure change dP1 of the return oil cylinder: dP1 is equal to the value obtained by multiplying the oil volume elastic modulus β by the volume change dV1 of the return oil cylinder obtained in step three, and then dividing by the initial volume V10; Step five, calculate the return force F2 under the target forging depth: S1, add the oil supply pressure P10 of the return oil cylinder to the pressure change dP1 to obtain a first algebraic sum; S2, multiply the first algebraic sum obtained in S1 by the effective action area A1 of the return oil cylinder, and the result is the return force F2; Step six, calculate the target oil pressure P21 of the hydraulic adjusting pad: S1, add the forging force F1 to the return force F2 to obtain a second algebraic sum; S2, divide the second algebra by the effective action area A2 of the hydraulic adjusting pad, and the result is the target oil pressure P21 of the adjusting pad; Step seven, calculate the pressure change amount dP2 of the hydraulic adjusting pad: dP2 is equal to the difference between the target oil pressure P21 of the hydraulic adjusting pad and the oil supply pressure P20 of the hydraulic adjusting pad; Step eight, calculate the initial volume V20 of the hydraulic adjusting pad: S1, multiply the initial extension length L1 by the effective action area A2 of the hydraulic adjusting pad to obtain a second product; S2, add the second product in S1 to the dead volume at the minimum extension length of the hydraulic adjusting pad, and the result is V20; Step nine, calculate the compression compensation length L3 of the hydraulic adjusting pad: S1, multiply the oil volume elastic modulus β, the initial volume V20, and the pressure change amount dP2 to obtain a third product; S2, multiply the effective action area A2 of the hydraulic adjusting pad by the volume elastic modulus β to obtain a fourth product; S3, add the fourth product to the pressure change amount dP2 to obtain a third algebraic sum; S4, divide the third product by the third algebraic sum, and the result is the oil compression amount dV2; S5, divide the oil compression amount dV2 by the effective action area A2 of the hydraulic adjusting pad, and the result is L3; Step ten, set the position of the hammer head after compensation: S1, add the initial extension length L1 to the compression compensation length L3 to obtain the compensated extension length L4; S2, adjust the main machine hammer head to L4 and perform the forging operation.

[0015] The oil volume elastic modulus β in steps four and nine uses the same measured value.

[0016] The action process of the execution mechanism is: The main machine hammer head uses an eccentric slide assembly 1 to drive the hammer rod rear cap 2 to move, compress the oil in the hydraulic adjusting pad, and then drive the main machine hammer head piston and hammer head tool assembly 4 to perform forging on the processed blank 5; the main machine hammer head uses a return oil cylinder 3 to drive the main machine hammer head piston and hammer head tool assembly 4 to return. The hydraulic adjusting pad is formed by the closed oil cavity between the hammer rod rear cap 2 and the main machine hammer head piston and hammer head tool assembly 4, and the effective action area A2 thereof is the piston pressure bearing area.

[0017] Example 1: 1045 steel blank forging (Φ300×3000mm).

[0018] 1. Basic parameters: Target forging depth L0 = 10mm, forging force F1 = 12.1MN Oil elastic modulus β = 700MPa, P10 = 16.5MPa, P20 = 10.9MPa.

[0019] 2. Compensation calculation process: I. Before forging, the forging force F1 required for the main hammer head to make the workpiece 5 reach the predetermined deformation in the forging process is determined as 12.1MN and the target forging depth L0 of the main machine is determined as 10mm according to the material properties and the forging depth requirements.

[0020] II. The compression amount of the hydraulic adjusting pad of the main hammer head is affected by the initial volume of the hydraulic adjusting pad. The initial extension length L1 of the main hammer head is determined in advance for forging. The maximum extension length of the return cylinder 3 is 250mm, which is subtracted from the initial extension length L1 by algebraic operation, and then multiplied by the effective action area of the return cylinder 3 by algebraic operation. Finally, the calculation result is added to the dead volume of the return cylinder 3 at the minimum extension length by algebraic operation. This algebraic result is the initial volume V10 of the return cylinder 3. The initial extension length L1 of the hammer head and the initial volume V10 of the return cylinder 3 in this example are shown in Table 1.

[0021] III. According to the size of the eccentric block assembly 1 of the main hammer head of the machine-hydraulic mixed radial forging machine, the maximum feeding length L2 of the return cylinder 3 in the forging process is determined as 50mm. L2 is multiplied by the effective action area of the return cylinder 3 by algebraic operation. This algebraic result is the volume change dV1 of the return cylinder 3 in the forging process, which is 785000mm 3 .

[0022] IV. According to the main hammer head cylinder oil compression calculation formula, V10 in step II, dV1 in step III and oil volume elastic modulus of 700MPa are brought into the formula for algebraic operation. This algebraic result is the oil pressure change dP1 of the return cylinder 3 in the forging process. The oil pressure change dP1 of the return cylinder 3 in the forging process in this example is shown in Table 1.

[0023] V. dP1 in step IV and the supply pressure P10 of the return cylinder 3 are added by algebraic operation, which is 16.5MPa. Then the calculation result is multiplied by the effective action area of the return cylinder 3 by algebraic operation. This algebraic result is the return force F2 of the return cylinder 3 at the target forging depth. The return force F2 of the return cylinder 3 at the target forging depth in this example is shown in Table 1.

[0024] Ⅵ. The F1 in step I is subjected to algebraic addition with the F2 in step V, and the calculation result is subjected to algebraic division with the effective action area of the hydraulic adjusting pad of the host hammer head, and the algebraic result is taken as the target oil pressure P21 of the hydraulic adjusting pad. The target oil pressure P21 of the hydraulic adjusting pad of the host hammer head in the example is shown in Table 1.

[0025] Ⅶ. The P21 in step VI is subjected to algebraic subtraction with the oil supply pressure P20 of 10.9 MPa of the hydraulic adjusting pad of the host hammer head, and the algebraic result is taken as the oil pressure change dP2 when the hydraulic adjusting pad exceeds the oil supply pressure in the forging process. The oil pressure change dP2 when the hydraulic adjusting pad exceeds the oil supply pressure in the forging process in the example is shown in Table 1.

[0026] Ⅷ. The L1 in step II is subjected to algebraic multiplication with the effective action area of the hydraulic adjusting pad of the host hammer head, and the calculation result is subjected to algebraic addition with the dead volume of the hydraulic adjusting pad at the minimum extension length, and the algebraic result is taken as the initial volume V20 of the hydraulic adjusting pad. The initial volume V20 of the hydraulic adjusting pad in the example is shown in Table 1.

[0027] Ⅸ. According to the oil compression calculation formula of the hydraulic adjusting pad, the dP2 in step VIII, the V20 in step VIII and the oil volume elastic modulus of 700 MPa are brought into the formula for algebraic operation, and the oil compression amount dV2 of the hydraulic adjusting pad is subjected to algebraic division with the effective action area of the hydraulic adjusting pad, and the algebraic result is taken as the compression length L3 of the hydraulic adjusting pad in the forging process. The compression length L3 of the hydraulic adjusting pad in the forging process in the example is shown in Table 1.

[0028] Ⅹ. Before the host hammer forging, the L1 in step II and the L3 in step IX are subjected to algebraic summation, and the algebraic result is taken as the forging compensation amount L4 of the extension length of the host hammer head. After the extension length is adjusted to L4, the host starts to forge. The forging compensation amount L4 of the extension length of the host hammer head in the example is shown in Table 1.

[0029] The parameters in the host forging process under the forging method of the example are shown in Table 2.

[0030] The parameters in the host forging process under the conventional forging method (without compensation for the extension length of the host hammer head) are shown in Table 3.

[0031] Both the above two methods meet the requirement of the maximum forging size of the host (the maximum extension length of the hammer head is 200 mm).

[0032] Table 1 Parameters in the host forging process of Example 1 Table 2 Host forging depth and error statistics of Example 1 Table 3 Main host forging process parameters of conventional forging method As can be seen from Table 2 and Table 3, when forging the same workpiece, the forging error and the forging error rate of the forging method obtained in the scope of the present application are obviously reduced compared with the conventional forging method, which meets the host forging precision requirement of the machine-oil mixed radial forging machine, greatly improves the production efficiency, and saves the production cost. Meanwhile, when the working conditions such as the extension length of the hammer head and the forging depth change, the forging method obtained in the scope of the present application shows strong adaptability and stability, which provides reliable technical support for high-precision forging under complex working conditions, and increases economic benefits.

[0033] The above are only preferred examples of the present application. It should be noted that for those skilled in the art, under the technical inspiration provided by the present application, other equivalent modifications and improvements can also be made as the common knowledge in the art, and should also be considered as the protection scope of the present application.

Claims

1. A host hammer head adjusting method for improving forging accuracy of a machine-hydraulic mixed radial forging machine, characterized in that, The method comprises the following steps: Step one, determining initial conditions, according to the material properties of the blank and the target forging requirements, determine the forging force F1 required to make the blank to a predetermined deformation and the target forging depth L0 of the main machine; Step two, calculate the initial volume V10 of the return oil cylinder: S1, subtract the initial extension length L1 of the main machine hammer head from the maximum extension length of the return oil cylinder to obtain a first difference; S2, multiply the first difference obtained in S1 by the effective action area A1 of the return oil cylinder to obtain a first product; S3, add the first product obtained in S2 to the dead volume under the minimum extension length of the return oil cylinder, and the result is the initial volume V10 of the return oil cylinder; Step three, calculate the volume change dV1 of the return oil cylinder: according to the size of the eccentric wheel of the machine-oil mixed type radial forging machine, determine the forging feed length L2, and calculate the volume change dV1 of the return oil cylinder: dV1 is equal to the product of the forging feed length L2 and the effective action area A1 of the return oil cylinder; Step four, calculate the pressure change dP1 of the return oil cylinder: dP1 is equal to the value obtained by multiplying the oil volume elastic modulus β by the volume change dV1 obtained in step three, and then dividing by the initial volume V10; Step five, calculate the return force F2 under the target forging depth: S1, add the oil supply pressure P10 of the return oil cylinder to the pressure change dP1 to obtain a first algebraic sum; S2, multiply the first algebraic sum obtained in S1 by the effective action area A1 of the return oil cylinder, and the result is the return force F2; Step six, calculate the target oil pressure P21 of the hydraulic adjusting pad: S1, add the forging force F1 to the return force F2 to obtain a second algebraic sum; S2, divide the second algebraic sum by the effective action area A2 of the hydraulic adjusting pad, and the result is the target oil pressure P21 of the adjusting pad; Step seven, calculate the pressure change dP2 of the hydraulic adjusting pad: dP2 is equal to the difference obtained by subtracting the oil supply pressure P20 of the hydraulic adjusting pad from the target oil pressure P21 of the hydraulic adjusting pad; Step eight, calculate the initial volume V20 of the hydraulic adjusting pad: S1, multiply the initial extension length L1 by the effective action area A2 of the hydraulic adjusting pad to obtain a second product; S2, add the second product in S1 to the dead volume under the minimum extension length of the hydraulic adjusting pad, and the result is V20; Step nine, calculate the compression compensation length L3 of the hydraulic adjusting pad: S1, multiply the oil volume elastic modulus β, the initial volume V20, and the pressure change dP2 to obtain a third product; S2, multiply the effective action area A2 of the hydraulic adjusting pad by the volume elastic modulus β to obtain a fourth product; S3, add the fourth product to the pressure change dP2 to obtain a third algebraic sum; S4, divide the third product by the third algebraic sum, and the result is the oil compression dV2; S5, divide the oil compression dV2 by the effective action area A2 of the hydraulic adjusting pad, and the result is L3; Step ten, set the position of the hammer head after compensation: S1, add the initial extension length L1 to the compression compensation length L3 to obtain the compensated extension length L4; S2, adjust the main machine hammer head to L4 and perform the forging operation.

2. The main hammer head adjusting method for improving the forging accuracy of a machine-hydraulic mixed radial forging machine according to claim 1, characterized in that: The oil volume elastic modulus β in steps four and nine uses the same measured value.

3. The main hammer head adjusting method for improving the forging accuracy of a machine-hydraulic mixed radial forging machine according to claim 1 or 2, characterized in that: The host hammer head adopts an eccentric wheel slider assembly (1) to drive the hammer rod rear cap (2) to move, compress the oil in the hydraulic adjusting pad, and then drive the host hammer head piston and the hammer head tool assembly (4) to forge the processing blank (5).

4. The main hammer head adjusting method for improving the forging accuracy of a machine-hydraulic mixed radial forging machine according to claim 3, characterized in that: The host hammer head adopts a return oil cylinder (3) to drive the host hammer head piston and the hammer head tool assembly (4) to return.

5. The main hammer head adjusting method for improving the forging accuracy of a machine-hydraulic combined radial forging machine according to claim 4, characterized in that: The hydraulic adjusting pad is composed of the closed oil cavity between the hammer rod rear cap (2) and the host hammer head piston and the hammer head tool assembly (4), and the effective acting area A2 is the piston pressure bearing area.

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