Precise correction die for ultra-large crankshaft
By designing precision correction molds, the problem of deformation of super-large crankshafts during forging and heat treatment is solved, and the dimensional accuracy of forgings and the saving of production costs is achieved.
Patent Information
- Application Number
- CN202323493679.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-20
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2033-12-20
AI Technical Summary
Extra-large crankshafts are prone to bending or twisting during forging and heat treatment, resulting in a reduction in the pass rate of forging parts and require precise calibration to improve dimensional accuracy.
A precision correction mold including a square correction module with an upper and lower symmetry was designed. The design between the module gap and cavity surface was precise. The square locking and locking structure were used to ensure the stability of the mold, and the cavity size shrinkage rate was controlled at 0.8. %-1.0% to ensure the dimensional accuracy of the forgings.
Through the use of precision correction molds, the dimensional accuracy of forgings is significantly improved, the rework caused by unqualified size is reduced, and production costs and energy consumption are saved.
Smart Images
Figure CN222175809U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of forging and molding, and relates to a precision correction die for an ultra-large crankshaft. Background Art
[0002] The super-large crankshaft is an important component in the structure of generators such as locomotives and ships. The material is 40CrNiMoA. During the entire thermal deformation process, the complex structure is very easy to bend or even twist. The existence of this deformation will significantly reduce the dimensional qualification rate of forgings. To improve the dimensional qualification rate of forgings, it is necessary to find a way to correct the shape of the forgings, which requires a comprehensive measurement of the deformation degree of each part of the forging after the forging and heat treatment process.
[0003] As a very important structural part, the eight-turn sixteen-cylinder crankshaft forging is used in generators such as locomotives and ships. Therefore, the dimensional accuracy of this type of forging plays a vital role in the operation of the entire generator. To improve the dimensional accuracy of forgings, it is necessary to improve the dimensional accuracy. The precision correction process is crucial, among which the design of the mold is the top priority. Utility Model Content
[0004] The purpose of the utility model is to provide a precision correction die for an ultra-large crankshaft, which can obtain a forging with completely qualified dimensional accuracy after use, thereby fully ensuring its use requirements.
[0005] Technical solution:
[0006] Provided is a precision correction mold for an ultra-large crankshaft, comprising: an upper correction module and a lower correction module with completely symmetrical upper and lower cavities; a cavity formed by the combination of the upper correction module and the lower correction module is compatible with standard parts of an ultra-large crankshaft, and has a cavity with 8 turns and 16 cranks;
[0007] The correction module is a square module;
[0008] The cavity parts corresponding to the main journals at both ends are designed as through holes;
[0009] The vertical clearance between the longitudinal section of the connecting rod neck of the first turn and the connecting rod neck of the eighth turn and the corresponding cavity surface is 2 to 4 mm, and the left and right are locked;
[0010] The vertical clearance between the longitudinal section of the connecting rod neck from the second bend to the seventh bend and the corresponding cavity surface is 3 to 5 mm, and the left and right are locked;
[0011] The upper clearance between the boss between the first crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm;
[0012] The upper clearance between the boss between the sixteenth crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm;
[0013] The i-th crank and the i+1-th crank are combined into a whole, and the upper clearance between the whole and the corresponding cavity surface is 10-15 mm, the lower clearance is 10-25 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm; i is an even number from 2-14.
[0014] Furthermore, the four top corners of the upper correction module are designed with square locks, which are convex structures.
[0015] The four top corners of the lower correction module are designed with square locks, which are concave structures.
[0016] The square lock buckle and the square lock mouth cooperate to lock the upper correction module and the lower correction module to prevent movement.
[0017] Furthermore, the shrinkage rate of the through hole cavity size is 0.8-1.0%.
[0018] Furthermore, the shrinkage rate of the lateral spacing between the connecting rod neck of the first turn and the connecting rod neck of the eighth turn, that is, the shrinkage rate of the left and right gaps, is 0.8-1.0%.
[0019] Furthermore, the shrinkage rate of the lateral spacing dimension from the connecting rod neck of the second bend to the connecting rod neck of the seventh bend, that is, the shrinkage rate of the left and right clearance is 0.9-1.0%.
[0020] Furthermore, the shrinkage rate of the remaining dimensions of the correction mold is 1.0%.
[0021] Furthermore, the upper and lower correction modules are designed to have no burrs along the outer contour of the cavity, that is, no bridge or bin.
[0022] Beneficial effects: Compared with the conventional die forging correction method, this method adopts the method of precision-designed correction die, which ensures the deformation of the forging during correction, improves the dimensional accuracy of the forging, and the dimensional requirements of the forging meet the standards. The use of the correction die reduces the rework of the product due to unqualified dimensions, saves energy consumption and saves production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 Schematic diagram of the upper and lower correction module of the forging.
[0024] Figure 2 A schematic diagram of an oversized crankshaft. DETAILED DESCRIPTION
[0025] The utility model provides a precision correction mold for an ultra-large crankshaft, such as Figure 1As shown, it includes: an upper correction module 1 and a lower correction module 2 with completely symmetrical upper and lower cavities; the cavity formed by the combination of the upper correction module 1 and the lower correction module 2 is compatible with the standard parts of the super-large crankshaft 3, and has a cavity with 8 turns and 16 cranks; Figure 2 As shown, a crank 31 is composed of two cranks 32 and a connecting rod neck 33 sandwiched in between; the even-numbered cranks 32 are connected to the next crank 32 through a connecting rod 34 to form a whole.
[0026] The correction module is a square module;
[0027] The vertical clearance between the longitudinal section of the connecting rod neck of the first turn and the connecting rod neck of the eighth turn and the corresponding cavity surface is 2 to 4 mm, and the left and right are locked;
[0028] The vertical clearance between the longitudinal section of the connecting rod neck from the second bend to the seventh bend and the corresponding cavity surface is 3 to 5 mm, and the left and right are locked;
[0029] The upper clearance between the boss between the first crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm;
[0030] The upper clearance between the boss between the sixteenth crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm;
[0031] The i-th crank and the i+1-th crank are combined into a whole, and the upper clearance between the whole and the corresponding cavity surface is 10-15 mm, the lower clearance is 10-25 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm; i is an even number from 2-14.
[0032] Furthermore, the four top corners of the upper correction module are designed with square locks, which are convex structures.
[0033] The four top corners of the lower correction module are designed with square locks, which are concave structures.
[0034] The square lock buckle and the square lock mouth cooperate to lock the upper correction module and the lower correction module to prevent movement.
[0035] Furthermore, the shrinkage rate of the lateral spacing between the connecting rod neck of the first turn and the connecting rod neck of the eighth turn, that is, the shrinkage rate of the left and right gaps, is 0.8-1.0%.
[0036] Furthermore, the shrinkage rate of the lateral spacing dimension from the connecting rod neck of the second bend to the connecting rod neck of the seventh bend, that is, the shrinkage rate of the left and right clearance is 0.9-1.0%.
[0037] Furthermore, the shrinkage rate of the remaining dimensions of the correction mold is 1.0%.
[0038] Furthermore, the upper and lower correction modules are designed to have no burrs along the outer contour of the cavity, that is, no bridge or bin.
[0039] A precision correction die for an ultra-large crankshaft, comprising:
[0040] Upper correction module and lower correction module.
[0041] Among them, the design of the parting surface is consistent with that of the forging die; the module is designed to have no burrs along the outer contour of the cavity, that is, no bridges or bins.
[0042] Square lock buckles are designed at the four top corners of the square module, of which the upper module lock buckle is convex and the lower module lock buckle is concave.
[0043] The main journals at both ends are the key correction parts. This part in the mold is designed as a through hole, the cavity size shrinkage rate is 0.8-1.0%, and does not include the boss parts connected to the cranks at both ends.
[0044] The first and eighth bends of the connecting rod neck are the key correction parts. The longitudinal section of this part in the mold is designed to be rectangular, and the horizontal side has a gap of 2 to 4 mm with the longitudinal dimension of the forging; the transverse section follows the contour of the connecting rod neck, and the transverse spacing shrinkage rate is 0.8 to 1.0%.
[0045] The connecting rod neck from the second bend to the seventh bend is the key correction part. The longitudinal section of this part in the mold is designed to be rectangular, and the horizontal side has a gap of 3 to 5 mm with the longitudinal dimension of the forging; the transverse section follows the contour of the connecting rod neck, and the transverse spacing size shrinkage rate is 0.9 to 1.0%.
[0046] The boss areas between the first crank and the sixteenth crank and the main journal are respectively designed with a combined longitudinal section of the mold cavity being rectangular, with a clearance of 8 to 12 mm with the upper part of the crank and a clearance of 10 to 20 mm with the lower part of the crank; the transverse section is along the crank contour, with a clearance of 8 to 12 mm with the upper part of the crank and a clearance of 10 to 20 mm with the lower part of the crank.
[0047] The second and third cranks to the fourteenth and fifteenth cranks are respectively adjacently combined, and the mold cavity is designed to have a rectangular longitudinal section, with a gap of 10 to 15 mm with the upper part of the crank and a gap of 10 to 25 mm with the lower part of the crank; the transverse section is along the crank contour, with a gap of 8 to 12 mm with the upper part of the crank and a gap of 10 to 20 mm with the lower part of the crank.
[0048] The shrinkage rate of the remaining dimensions of the correction mold is 1.0%.
[0049] The material of a certain eight-turn sixteen-cylinder crankshaft forging is 40CrNiMoA, the outline size of the forging is φ372×2738mm, the weight is 630kg, and a 630KJ hammer is used for production.
[0050] Step 1: Preheat the blank in a natural gas furnace at 700℃ and heat it to 1180℃ for 70 minutes. Preheat the mold at 350℃ for 12 hours. Lubricate the mold with motor oil and graphite. After the blank is laid flat in the cavity, lightly hit it with 2 hammers and then hit it hard to form it.
[0051] Step 2: Place the above-mentioned blank into an electric furnace for heat treatment, keep it at 870°C for 270 minutes, and then air-cool it after it is taken out of the furnace.
[0052] Step 3: Preheat the above blank in a natural gas furnace at 860°C for 70 minutes. The equipment uses a 31500KN hydraulic press, the mold is preheated at 350°C for 12 hours, the mold is lubricated with motor oil and graphite, and the blank is flattened in the cavity and tapped for correction.
[0053] The mold material is 5CrNiMo; after the forgings are calibrated, the dimensions meet the requirements of the forging drawings, avoiding the rework process caused by defects such as warping and deformation of the forgings.
Claims
1. A precision correction mold for an ultra-large crankshaft. It is characterized in that include: The upper and lower correction modules are completely symmetrical in the upper and lower cavities; the cavity formed by the combination of the upper and lower correction modules is compatible with the standard parts of super-large crankshafts, and has a cavity with 8 turns and 16 cranks; The correction module is a square module; The cavity parts corresponding to the main journals at both ends are designed as through holes; The vertical clearance between the longitudinal section of the connecting rod neck of the first turn and the connecting rod neck of the eighth turn and the corresponding cavity surface is 2 to 4 mm, and the left and right are locked; The vertical clearance between the longitudinal section of the connecting rod neck from the second bend to the seventh bend and the corresponding cavity surface is 3 to 5 mm, and the left and right are locked; The upper clearance between the boss between the first crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm; The upper clearance between the boss between the sixteenth crank and the main journal and the corresponding cavity surface is 8-12 mm, the lower clearance is 10-20 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm; The i-th crank and the i+1-th crank are combined into a whole, and the upper clearance between the whole and the corresponding cavity surface is 10-15 mm, the lower clearance is 10-25 mm, the left clearance is 8-12 mm, and the right clearance is 10-20 mm; i is an even number from 2-14.
2. The mold according to claim 1, It is characterized in that The four top corners of the upper correction module are designed with square locks, which are convex structures. The four top corners of the lower correction module are designed with square locks, which are concave structures. The square lock buckle and the square lock mouth cooperate to lock the upper correction module and the lower correction module to prevent movement.
3. The mold according to claim 1, It is characterized in that The shrinkage rate of the through hole cavity size is 0.8-1.0%.
4. The mold according to claim 1, It is characterized in that The shrinkage rate of the lateral spacing dimension of the connecting rod neck of the first turn and the connecting rod neck of the eighth turn, that is, the shrinkage rate of the left and right clearances is 0.8-1.0%.
5. The mold according to claim 1, It is characterized in that The shrinkage rate of the lateral spacing dimension from the connecting rod neck of the second turn to the connecting rod neck of the seventh turn, that is, the shrinkage rate of the left and right clearance is 0.9-1.0%.
6. The mold according to claim 1, It is characterized in that The shrinkage rate of the remaining dimensions of the correction mold is 1.0%.
7. The mold according to claim 1, It is characterized in that The upper and lower correction modules are designed to have no burrs along the outer contour of the cavity, that is, no bridge or bin.