CN-122020898-A - Design method, system and die of combined die for hot extrusion of cylindrical gear

CN122020898ACN 122020898 ACN122020898 ACN 122020898ACN-122020898-A

Abstract

The invention relates to the technical field of mold design, in particular to a method, a system and a mold for designing a combined mold for hot extrusion of a cylindrical gear, which are characterized in that design parameters including outer diameter, draft angle and split strategy are obtained according to gear geometric parameters and process requirements, a three-dimensional model is built, after thermal-force coupling simulation verification is carried out on the model, 3D printing is carried out according to a preset reduction ratio to prepare a reduction ratio solid model, then the matching relation and mold opening smoothness among all components are obtained and corrected through physical assembly and demolding test, final parameters are finally determined, a production mold is manufactured, optimization is advanced to a design stage through three-dimensional simulation and 3D printing reduction ratio verification, trial production times are greatly reduced, research and development period is shortened by more than 30%, cost is reduced by more than 60%, structural performance and demolding behavior of the mold under extreme working conditions are comprehensively evaluated through physical verification, and success rate and reliability of hot extrusion molding of a large gear are remarkably improved.

Inventors

Liu Zuofa
LIU ZHIWEI
YIN CAIHONG
LI ZHONGLI
CHEN XIAOCI
FEI GUOSHENG
ZHOU JIE
ZHANG JIANSHENG
LI YANLI
ZHANG YANCHENG

Assignees

四川工程职业技术大学
德阳杰品科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (10)

1. The method for designing the combined die for hot extrusion of the cylindrical gear is characterized by comprising the following steps of: Obtaining design parameters according to geometric parameters and technological requirements of gears, and constructing a design model of a split combined die according to the design parameters, wherein the design parameters comprise the outer diameter of a split inner die, the outer diameter of an annular outer die and the draft angle of the split inner die; verifying a design model of the split combined die; When the verification result meets the preset requirement, 3D printing is carried out on the design model of the split combined die according to the preset scaling proportion so as to obtain a scaling solid model formed by a plurality of split die bodies and an annular outer die; assembling the scaling solid model to obtain a matching relation between the split inner die and the annular outer die and between the split die bodies, and adjusting design parameters according to the matching relation to update the design model of the split combined die until the matching relation meets preset requirements; carrying out demolding test on a design model meeting preset requirements to verify the smoothness of die opening of the split internal die after extrusion forming; And obtaining final design parameters according to the demolding test result and the verification result, and manufacturing the combined die for hot extrusion of the cylindrical gear for production according to the design parameters.
2. The method of claim 1, wherein the design parameters further comprise a clearance value of a compensating structure, the clearance value of the compensating structure being obtained according to thermal expansion characteristics and assembly accuracy requirements of a mold material.
3. The method of designing a split die set for hot extrusion of a cylindrical gear according to claim 1, wherein said verifying a design model of said split die set comprises: setting process parameters including extrusion temperature, extrusion force and dwell time; Performing grid division, and applying a temperature field and mechanical boundary conditions; Obtaining stress distribution, temperature gradient and elastic deformation of the split combined die under the coupling action; and acquiring equivalent stress, contact pressure and deformation data of a corresponding region according to stress distribution, temperature gradient and elastic deformation so as to evaluate the strength and service life of the split combined die.
4. The method for designing a combined die for hot extrusion of a cylindrical gear according to claim 1, wherein the matching relation comprises a joint gap between split die bodies and a fit gap between a split inner die and an annular outer die; the preset requirement of the matching relation is that the joint clearance and the fit clearance accord with a preset tolerance range obtained according to thermal expansion compensation.
5. The method of claim 4, wherein said adjusting the design parameters according to the matching relationship to update the design model of the split die comprises: If the joint gaps between the split die bodies are respectively unequal or exceed a preset range, adjusting arc length design parameters of the split internal die; if the fit clearance between the split inner die and the annular outer die has assembly interference, adjusting the draft angle or the design parameter of the inner diameter of the annular outer die.
6. The method for designing a combined die for hot extrusion of a cylindrical gear according to claim 1, wherein the step of performing a die release test on a design model satisfying a preset requirement comprises: filling test materials in the cavity of the scaled solid model to form a simulated forging; driving the split die body to move outwards in the radial direction, and acquiring the demolding resistance, the movement displacement and the movement synchronism in the demolding process; and acquiring the separation behaviors of the simulated forging and the split die body in the separation process, and acquiring a test result according to the separation behaviors.
7. The method according to claim 6, wherein if the mold release resistance exceeds a preset allowable value or the mold sticking teeth of the simulated forging occur, the design parameters are adjusted by increasing the draft angle or decreasing the surface roughness parameters of the split mold body.
8. A system for designing a combination die for hot extrusion of a cylindrical gear, the system comprising: The parameter acquisition module is used for acquiring design parameters according to the geometric parameters and the technological requirements of the gear, and constructing a design model of the split combined die according to the design parameters, wherein the design parameters comprise the outer diameter of the split inner die, the outer diameter of the annular outer die and the draft angle of the split inner die; the simulation verification module is used for verifying a design model of the split combined die; The physical verification module is used for performing 3D printing on the design model of the split combined die according to a preset shrinkage ratio when the verification result meets the preset requirement so as to obtain a shrinkage ratio entity model formed by a plurality of split die bodies and an annular outer die; The matching adjustment module is used for assembling the scaled solid model to obtain matching relations between the split inner die and the annular outer die and between the split die bodies, and adjusting design parameters according to the matching relations to update the design model of the split combined die until the matching relations meet preset requirements; the demolding test module is used for performing demolding test on the design model meeting the preset requirements so as to verify the smoothness of die opening of the split internal die after extrusion forming; And the manufacturing output module is used for acquiring final design parameters according to the demolding test result and the verification result, and manufacturing a combined die for hot extrusion of the cylindrical gear for production according to the design parameters.
9. A combination die for hot extrusion of a cylindrical gear, characterized in that the die is designed based on the method for designing a combination die for hot extrusion of a cylindrical gear according to any one of claims 1 to 7, the die comprising: the split inner die comprises a plurality of split die bodies, and the outer ring of each split die body is provided with a draft angle; The annular outer die is arranged on the periphery of the split inner die so as to restrain the split inner die.
10. The combined die for hot extrusion of the cylindrical gear according to claim 9, wherein a compensation structure is arranged among the split die bodies, and a gap value of the compensation structure is determined according to the thermal expansion deformation of a die material at a preset working temperature and the actual measurement gap deviation of the scaled solid model at normal temperature assembly, so that the split combined die is mutually extruded and closed to form a seamless die cavity after the split die bodies are heated and expanded in the hot extrusion forming process.

Description

Design method, system and die of combined die for hot extrusion of cylindrical gear Technical Field The invention relates to the technical field of mold design, in particular to a method, a system and a mold for designing a combined mold for hot extrusion of a cylindrical gear. Background The existing hot extrusion die has the defects that the size of the gear is large and the number of teeth is large, so that the joint between a forged piece and a die cavity is too tight after extrusion, smooth demolding is difficult to realize after forming, in addition, the traditional integral die is extremely easy to generate stress concentration and fatigue crack under high-temperature high-pressure alternating load, so that the die is early failed and the manufacturing and maintenance costs are high. Although the split combined die scheme in the prior art has appeared, the split combined die scheme still faces the problem that the assembly clearance is improperly designed due to thermal expansion in actual design and manufacture, and further the forming precision and the service life of the die are affected. Disclosure of Invention The invention mainly aims to provide a design method of a combined die for hot extrusion of a cylindrical gear, and aims to solve the technical problem that a large-sized cylindrical gear hot extrusion die is difficult to rapidly verify the structural rationality, assembly matching property and demolding reliability of the die in the design stage. In order to achieve the above object, the present invention provides a method for designing a combination die for hot extrusion of a cylindrical gear, the method comprising the steps of: Obtaining design parameters according to geometric parameters and technological requirements of gears, and constructing a design model of a split combined die according to the design parameters, wherein the design parameters comprise the outer diameter of a split inner die, the outer diameter of an annular outer die and the draft angle of the split inner die; verifying a design model of the split combined die; When the verification result meets the preset requirement, 3D printing is carried out on the design model of the split combined die according to the preset scaling proportion so as to obtain a scaling solid model formed by a plurality of split die bodies and an annular outer die; assembling the scaling solid model to obtain a matching relation between the split inner die and the annular outer die and between the split die bodies, and adjusting design parameters according to the matching relation to update the design model of the split combined die until the matching relation meets preset requirements; carrying out demolding test on a design model meeting preset requirements to verify the smoothness of die opening of the split internal die after extrusion forming; And obtaining final design parameters according to the demolding test result and the verification result, and manufacturing the combined die for hot extrusion of the cylindrical gear for production according to the design parameters. Optionally, the design parameters further include a clearance value of the compensating structure, the clearance value of the compensating structure being obtained according to thermal expansion characteristics of the mold material and assembly accuracy requirements. Optionally, the verifying the design model of the split combined mold includes: setting process parameters including extrusion temperature, extrusion force and dwell time; Performing grid division, and applying a temperature field and mechanical boundary conditions; Obtaining stress distribution, temperature gradient and elastic deformation of the split combined die under the coupling action; and acquiring equivalent stress, contact pressure and deformation data of a corresponding region according to stress distribution, temperature gradient and elastic deformation so as to evaluate the strength and service life of the split combined die. Optionally, the matching relation specifically comprises a joint gap between split die bodies and a fit gap between a split inner die and an annular outer die; the preset requirement of the matching relation is that the joint clearance and the fit clearance accord with a preset tolerance range obtained according to thermal expansion compensation. Optionally, the adjusting the design parameters according to the matching relationship to update the design model of the split combined mold includes: If the joint gaps between the split die bodies are respectively unequal or exceed a preset range, adjusting arc length design parameters of the split internal die; if the fit clearance between the split inner die and the annular outer die has assembly interference, adjusting the draft angle or the design parameter of the inner diameter of the annular outer die. Optionally, the demolding test for the design model meeting the preset requirement comprises the following steps: filling