JPH11179472A - Blank process design method for forged parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a rougher where no forging defects are generated in a rough stock at a low cost avoiding a trial-and-error method by vertically moving a temporary die surface obtained from the parting contour, the blank contour, and the surface smoothness relative to the parting surface based on a three-dimensional model of the rough stock. SOLUTION: A three-dimensional model of a rough stock is processed by a computer. First, the parting contour which is the intersection line of the parting surface including the line of the center of gravity of the rough stock with the model, is obtained. The parting contour is offset inward on the parting surface to obtain the parting offset line. The separation position which is farthest and outermost from the parting surface is specified on the intersection line of a plurality of imaginary perpendicular planes orthogonal to the parting surface and the line of the center of gravity with the model. Each separation position is smoothly connected on each perpendicular plane to obtain the blank contour. Then, the parting offset line and the blank contour are smoothly connected to each other to obtain a temporary die surface. The temporary die surface is vertically moved relative to the parting surface from the volumetric comparison of the model with the temporary die surface to determine the die surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for designing a rough land process for forged parts. This design method is suitable for use, for example, when manufacturing a forged part having a different shape such as a connecting rod, which is a part of an engine, and an arm, which is a part of a chassis.

[0002]

2. Description of the Related Art For example, a connecting rod constituting an engine is formed into a rough material by forging a round bar or the like in several rough land processes, and forging and burr forming a finishing process are performed on the rough material. The blanks are punched and finished. Conventionally, in order to shorten the design time to design a rough land mold surface for forging material by these rough land processes,
Standardized design methods were mainly employed. In other words, taking a connecting rod as an example of a forged part, in a conventional connecting rod wasteland process design method, first, a uniform length is offset by a fixed length in a width direction and a longitudinal direction of a model composed of a three-dimensional shape of a coarse material. Set the line. In addition, a line that is uniformly offset by a certain length in the height direction of the model is set. Further, a line having a fixed curvature at each corner and each corner is set. Then, the mold surface of the first wasteland mold is determined by each line. Also, by changing the length and curvature of offset of each line,
Determine the mold surface of the wasteland type.

In this way, each mold surface is designed, and each rough land mold is manufactured so as to have the designed mold surface, and the rough land process is performed.

[0004]

However, in the above-mentioned conventional design method, when the first try-out is performed on a rough terrain manufactured by the above-mentioned method, a forging defect such as underfill or scratch may be generated in the coarsely formed material. . In this case, it is necessary to change the offset length and the curvature of each line, determine the mold surface of each wasteland type again, and manufacture the wasteland type again. Such a change must be made by trial and error, and the volume ratio before and after the rough land process is not always optimal, or the surface change of the mold surface may not be gently smooth, even if it depends on the changed rough land type This does not necessarily mean that a forging defect does not occur in the crude material. For this reason, the manufacturing cost of the wasteland type actually used in the wasteland process of the forged part increases. And the wasteland type with a short service life has to carry out frequent repairs of the mold surface and to make the replacement cycle earlier,
Since the mold surface is designed by trial and error each time, an increase in manufacturing cost is further promoted. In particular, when the volume ratio before and after the rough land process is not always optimal, a large load acts on the rough land mold at the time of forging, thereby further shortening the life of the rough land mold and further increasing the manufacturing cost. Becomes

The present invention has been made in view of the above-mentioned conventional situation, and has as its object to provide a method for designing a rough land process of a forged part capable of inexpensively manufacturing a rough land mold having no forging defects in a coarse material. It is an issue to be solved.

[0006]

According to the present invention, there is provided a method for designing a rough terrain process for a forged part. In a method for designing a rough land process of a forged part, a first step of inputting a model having a three-dimensional shape of the rough material to a computer, and a center line including a center of gravity of the rough material for the model, A second step of obtaining a parting outline which is an intersection of the parting plane of the wasteland type including the center of gravity line and the model, and a parting outline on the model which is separated from the parting plane; And a temporary mold surface is assumed from the rough land outline and the surface smoothness, and the volume of the model is compared with the volume of the temporary mold surface for each vertical plane orthogonal to the parting plane and the center of gravity line. A third step of determining a mold surface by moving the mold surface perpendicular to the parting surface; Characterized in that it.

In the design method of the present invention, a temporary mold surface is assumed from a model on a computer while considering surface smoothness.
The mold surface is determined from the temporary mold surface so that the volume ratio before and after the rough land process is optimized. For this reason, it is not necessary to manufacture a rough land mold by trial and error, and there is no forging defect in the rough shaped material, and a rough land mold that can be actually used in a rough land process of a forged part can be quickly manufactured.

Therefore, according to the design method of the present invention,
It is possible to inexpensively manufacture a rough land type in which a forging defect does not occur in a crude material. In the design method of the present invention, it is practical to perform the following operations. That is, first, in the second step, the parting outline is offset inward on the parting plane to obtain the parting offset line. Also, a plurality of vertical planes orthogonal to the parting plane and the center of gravity are assumed. Then, an intersection line between each vertical plane and the model is obtained for each vertical plane, and a position farthest from the parting plane and away from the outside is specified on each intersection line. Then, each separation position is smoothly connected to each vertical plane, and a rough land outline is obtained.

In a third step, the parting offset line and the rough land outline are connected by a smooth surface to form a temporary mold surface, and the volume of the model and the volume of the temporary mold surface are compared for each vertical plane. The surface is moved perpendicular to the parting plane to obtain the mold surface.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the design method of the present invention is embodied in a method for designing a connecting rod in a rough land will be described below with reference to the drawings. In the embodiment, the computer is processed according to the processing procedure shown in FIG. [First Step] First, in step S1, as shown in FIG. 2, a model 1 consisting of a three-dimensional shape of a rough material is input to a three-dimensional CAD operated on a computer.
The model 2 is input by inverting the model 1 horizontally by 180 ° on the CAD. [Second Step] Next, in step S2 shown in FIG. 1, a center line 3 including the center of gravity of the coarse material is input to the models 1 and 2, as shown in FIG.

Also, in step S3 shown in FIG.
As shown in FIG. 3, it is assumed that a wasteland type parting plane 4 includes the center of gravity line 3 for the models 1 and 2. Then, in step S4 shown in FIG. 1, as shown in FIG. 3, parting outlines 5, 6 which are intersections of the parting plane 4 and the models 1, 2 are obtained.
Thereafter, in step S5 shown in FIG. 1, as shown in FIG. 4, the parting outlines 5 and 6 are offset inward by a fixed length on the parting plane 4 to obtain parting offset lines 7 and 8. Here, when designing a wasteland type mold surface for the second wasteland process, the fixed length is 0.5 mm. Also, when designing a wasteland type mold surface for the first wasteland process,
The fixed length is 1 mm.

In step S6 shown in FIG. 1, a plurality of vertical planes 9 orthogonal to the parting plane 4 and the center of gravity line 3 are provided.
(See FIGS. 8 and 9). Here, when designing the mold surface of the wasteland type for the second wasteland process, the vertical plane 9 is assumed to have a pitch of 5 mm. When designing the mold surface of the wasteland type for the first wasteland process, the vertical plane 9 is set to 1
Assume a 0 mm pitch. Note that one of the vertical planes 9 is an AA line shown in FIG.

Thereafter, in step S7 shown in FIG. 1, as shown in FIG.
A line of intersection between the model and the models 1 and 2 is determined, and a separation position 10 farthest above or below the parting plane 4 and from the outside is specified on each line of intersection. Here, when designing a wasteland type mold surface for the second wasteland process, the separation position 10 is specified at the end point of the outer curvature portion on each intersection line. Also, when designing a wasteland mold surface for the first wasteland process, 0.5 mm inward from the separation position 10 for the wasteland mold surface for the second wasteland process.
The separation position 10 is specified at the offset position.

Thereafter, in step S8 shown in FIG. 1, a CAD spline command is executed. In this way, as shown in FIG.
0 is smoothly connected under a predetermined tangent condition, and
Is obtained. "Third Step" Then, in step S9 shown in FIG. 1, as shown in FIG. 8, a temporary mold surface 12 in which the parting offset lines 7, 8 and the rough land outline 11 are connected by a smooth surface is obtained. The temporary mold surfaces 12 at every vertical plane 9 are as shown in FIG. The three-dimensional object formed by the temporary mold surface 12 between the vertical planes 9 is as shown in FIG.

Thereafter, the volume of the models 1 and 2 is compared with the volume of the temporary mold surface 12 at every interval 9 between the vertical planes. here,
The optimum volume ratio is predetermined as shown in Table 1 below.

[0016]

[Table 1] For this reason, in step S10 shown in FIG. 1, if the mold surface of the wasteland type for the first wasteland process is designed, as shown in FIG. The mold surface 13 is obtained by moving the temporary mold surface 12 perpendicularly to the cutting surface 4. Further, when designing a wasteland mold surface for the second wasteland process, as shown in FIG. 7, the temporary mold surface 12 is cut off to the parting surface 4 so that the value of the volume ratio becomes 1.05. The mold surface 13 is obtained by vertically moving the mold surface.

In this manner, each of the first and second rough land mold surfaces 13
, And as shown in FIG. 11, each wasteland mold is manufactured so that the mold surface is as designed. Then, a material such as a round bar is subjected to forging including the first and second rough land processes to obtain a coarse material.
The obtained crude material is subjected to forging and deburring in a finishing process to be a finished product. Thus, in the design method of the embodiment, the temporary mold surface 12 is assumed from the models 1 and 2 on the computer while considering the surface smoothness, and the volume ratio before and after the first and second rough land processes is optimized. This temporary mold surface 1
The mold surface 13 is determined from 2. For this reason, it is not necessary to manufacture each wasteland mold by trial and error, and there is no forging defect in the rough material, and each wasteland mold that can be actually used in the first and second wasteland processes of the connecting rod is quickly manufactured. can do.

Therefore, according to the design method of the embodiment, it is possible to inexpensively manufacture each rough land mold in which a forging defect does not occur in a rough material. According to the test results of the inventors, since a large load does not act during forging in each of the wasteland molds according to the embodiment, it was possible to achieve a life extension of about 1.5 times as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing procedure for a computer according to an embodiment.

FIG. 2 is a computer screen showing a plan view of an input model according to the embodiment.

FIG. 3 is a computer screen showing a model corresponding to an AA cross-sectional view of FIG. 2, a parting plane, and a barycentric line according to the embodiment;

FIG. 4 is a computer screen showing a model corresponding to the AA cross-sectional view of FIG. 2, a parting plane, a center of gravity line, and a parting offset line according to the embodiment;

5 is a computer screen showing a model corresponding to the AA cross-sectional view of FIG. 2, a parting plane, a center of gravity line, a parting offset line, and a rough land outline according to the embodiment;

FIG. 6 is a computer screen showing a model and a temporary mold surface corresponding to the AA cross-sectional view of FIG. 2 according to the embodiment.

FIG. 7 is a computer screen showing a model corresponding to the AA cross-sectional view of FIG. 2 and a temporary mold surface after vertical movement according to the embodiment.

FIG. 8 is a computer screen showing a vertical plane and a plan view of a temporary mold surface according to the embodiment.

FIG. 9 is a computer screen showing a vertical plane and a plan view of a temporary mold plane between two vertical planes according to the embodiment.

FIG. 10 is a computer screen showing a solid by a temporary mold surface between two vertical planes according to the embodiment.

FIG. 11 is a computer screen showing a wasteland type having a determined die surface according to the embodiment.

[Explanation of symbols]

 1, 2 ... Model 3 ... Center of gravity line 4 ... Parting plane 5, 6 ... Parting outline line 7, 8 ... Parting offset line 9 ... Vertical plane 10 ... Separation position 11 ... Wasteland outline line 12 ... Temporary mold surface 13 ... Mold surface

Claims (1)

[Claims] 1. A method for designing a rough land process of a forged part for designing a die surface of the rough land mold in order to forge a raw material with a rough land mold in a rough land process to obtain a rough material of the forged part. A first step of inputting a model consisting of a three-dimensional shape of the shape member; and, for the model, a center line including the center of gravity of the coarse member; A second step of obtaining a parting outline which is an intersection line and a rough land outline on the model separated from the parting plane; and assuming a temporary mold surface from the parting outline, the rough land outline and the surface smoothness. Comparing the volume of the model with the volume of the temporary mold surface for each vertical plane orthogonal to the parting plane and the center of gravity line, and moving the temporary mold plane perpendicular to the parting plane to move the mold surface. And a third step of determining.