KR100288892B1 - Drawing apparatus of automobile engine pulley and method for producing the same - Google Patents

Abstract

PURPOSE: The drawing apparatus of an automobile engine pulley and its producing method are provided, thereby simplifying the total processes and decreasing the production rate of inferior products. CONSTITUTION: The method for producing an automobile engine pulley comprises the steps of: firstly drawing a flat material into a cup-shape; secondly drawing the first product by redrawing the cup-shaped material in the reverse direction; trimming the second product by cutting the exterior of the second product to have the predetermined size; carrying out an ironing process of the third product by adjusting its thickness and corner according to the predetermined size; and carrying out a piercing process by forming a piercing with the predetermined size on the fourth product.

Description

Drawing device and manufacturing method of pulley of automobile engine

The present invention relates to a tensioner pulley attached to an automobile engine, and more particularly, to a mold used to manufacture a pulley and a manufacturing method that can be manufactured through a simpler process using the mold.

Normally, the tensioner pulley is a part for connecting the rotation of the engine output shaft for a vehicle to another part, for example, a timing belt. These parts must have accurate characteristics depending on the driving conditions of the car engine. For example, when the driving conditions of an automobile engine are often high speed and high pressure, sufficient rigidity is required so that the tensioner pulley is not deformed by an overload such as rotational imbalance by the rotating body at high speed. Therefore, the engine pulley, in which the bearing is mounted inside, must be produced while satisfying the precise dimensional molding conditions by a welding seamless multi-stage precision drawing process.

In the conventional process of manufacturing the tensioner pulley used for the engine in this way, various problems in the process, such as requiring manual work between each process has been raised through various processes using the upper and lower molds. Specifically, not only is the process itself for manufacturing pulleys complicated, but also the manual work inserted during the process and a separate process without using a mold are added, resulting in a decrease in overall productivity and a defective rate. .

In the description of the present invention to be described later, these problems will be explained in part by comparing with each other, thereby making the configuration of the present invention more apparent.

The present invention is to solve the conventional problems as described above, and to provide a device and method particularly suitable for the molding of the tensioner pulley of the automotive engine.

Another object of the present invention is to provide a method for manufacturing a tensioner pulley of an automotive engine, which can lower a simpler process and a defective rate.

1 is a cross-sectional view of a mold for performing the first process of the present invention.

Figure 2 is a front view showing the configuration of the lower die of the present invention.

3 is a cross-sectional view of a mold for performing the second process of the present invention.

4 is a cross-sectional view of a mold for performing a third process of the present invention.

5 is a cross-sectional view of a mold for carrying out the fourth process of the present invention.

6 is a cross-sectional view of a mold for performing a fifth process of the present invention.

7 is a molding process drawing of the pulley according to the present invention.

* Explanation of symbols for main parts of the drawings

6: stopper 7: blank holder

8: die 9: punch

10: pad 11: spring

12: center punch 13: spring

14: Milpin 17: Holder

18: Die 19: Lower Punch

According to a feature of the present invention for achieving the above object, the present invention uses a die and a punch of a shape corresponding to each other in a mechanical press, wherein the circumferential projection formed on the die is in close contact with the surface protruding the iron bar of the flat specimen The first drawing process for drawing the specimen in a cup shape while flattening the iron barbed, and the first molded product produced in the first drawing process using a die and a punch having a shape corresponding to each other with a force provided by a mechanical press. A secondary reverse drawing step of drawing again, a trimming step of cutting the outside of the secondary molded product produced in the second reverse drawing step to a predetermined dimension with a force provided by a mechanical press, and a third step produced in the trimming step Ironing ball that adjusts the thickness and edge of the molded part to the predetermined dimension by the force provided by the mechanical press Is configured in a fourth-order shaped article produced in the ironing process, the piercing process for forming the piercings having a predetermined size, the process is characterized in that sequentially carried by a mold consisting of a predetermined die and punch.

In the primary drawing process, the specimen is pulled by the punch while the circumferential protrusion formed on the lower surface of the die is brought into close contact with the upper surface of the specimen so that the iron bar formed on the cutting surface of the edge of the specimen is pressed by the circumferential protrusion. The specimen is flattened in the opposite direction of travel.

The secondary reverse drawing step is characterized in that stress concentration can be prevented by applying a predetermined reaction force using hydraulic pressure to a corresponding portion of the primary molded product to be reverse drawn.

According to another feature of the invention, the invention is a motor engine pulley comprising a die having a hole to be drawn, a holder for holding the specimen drawn between the die and a punch for drawing the specimen toward the hole of the die In the drawing device, a contact projection for planarizing a burr formed on the outer circumferential surface of the specimen moving to the center portion by drawing is formed in the circumferential shape along the contact surface on the specimen contact surface of the die.

According to another feature of the invention, the holding means having a projection for holding the specimen to be reverse-drawn, the iron bar formed on the cutting surface of the specimen, a punch moving to draw the held specimen, A lower punch having a shape in which the specimen is drawn in reverse contact with the moving punch; reaction force generating means for exerting a uniform reaction force on the specimen to a corresponding portion of the specimen drawn by the punch; And a separating means comprising an elastic member exerting an elastic force in a direction in which the molded article is separated from the holding means for smooth removal of the molded article formed in the process, and an air hole formed through the punch in the longitudinal direction. .

The reaction force generating means is composed of a hydraulic device capable of applying hydraulic pressure to the reverse drawing portion of the specimen.

Next, the present invention will be described in more detail with reference to the drawings.

Figure 1 shows an example of the configuration of the mold for the primary drawing process according to the present invention.

The primary drawing process refers to a process of drawing in a cup shape by pressing a punch by placing a disc-shaped blank on a die cavity using a mechanical press of up to 250 tons. The material specification of the rolled steel sheet to be a specimen is the same as that of KSD3512, and an initial blank diameter of 122.00 mm and an initial thickness of 1.2 mm are used. Referring to FIG. 1, the primary drawing process is performed by pushing the punch 9 upward while the specimen is held and supported between the blank holder 7 and the die 8. At this time, the upward movement of the punch 9 is determined by the stroke until the bottom flange 9a of the punch 9 comes into contact with the stopper 6. When the punch 9 moves downward again by a mechanical press, the primary molded product is automatically extracted by the pad 10 by the elastic restoring force of the spring 11. At this time, the punch 9 is provided with a molded air hole (9b) so that the molded article is easily separated from the punch (9).

In addition, the test piece is often provided with a burr generated at its edge part by a blanking step of cutting the flat sample to an appropriate size in order to manufacture the pulley, i.e., the pulley. In order to eliminate such defects due to scratches, the die 8 has a shape as shown in FIG. As described above, the die 8 holds a specimen for making a pulley between the holder 7. Referring to FIG. 2, a circumferential protrusion 8a protruded along the circumferential direction is formed on the lower surface of the die 8. Therefore, the specimen for making the pulley is substantially in the state in which the upper surface is in close contact with the circumferential projection 8a, and when pressing is performed while the punch 9 is raised, the specimen is pulled toward the center direction, and the projection 8a is The metal bar formed on the edge of the specimen entering through the inside is completely processed in a plane, so that it is cut in the trimming process described later.

In the above-described primary drawing process, as if the specimen is pressed into a cup shape, the scrape generated in the specimen is completely removed, thereby preventing a defective rate due to scratching. The primary molded product formed through the primary drawing process as described above is indicated by A in FIG.

Next, the secondary reverse drawing process will be described with reference to FIG. This process refers to a process of drawing the cup-shaped primary blank formed by the primary drawing process in the opposite direction using a smaller punch. Such a secondary drawing process is carried out continuously in the primary drawing process, when the redrawing is performed continuously, an efficient drawing effect can be expected.

As shown in FIG. 3, the mold used in this process is reversed as the center punch 12 moves downward when the holder 17 and the die 18 hold the primary molded part similarly to FIG. Drawing is carried out. The center punch 12 is paired with the lower mold punch 19 to perform secondary molding. That is, a groove in which the center punch 12 is accommodated is formed in the upper portion of the lower die punch 19, and the primary molded article reversely drawn therebetween is made in the shape (dotted line) shown by “B” in FIG.

Also in this secondary reverse drawing step, similarly to the primary drawing step, air holes are formed in the center punch 12 to facilitate the removal of the molded article. The secondary molded article can be easily pushed out by the mil pin 14 which is operated by the elastic force of the spring 13.

In this secondary reverse drawing, the lower punch 19 can support the lower portion of the primary molded product only when the center punch 12 moves downward to prevent wrinkles and dimensional defects occurring during the secondary molding. have. That is, as shown in FIG. 3, the oil passage 19a for actuating hydraulic pressure is formed in the center of the lower die punch 19 in the longitudinal direction, and the oil passing through the oil passage 19a is centered. When drawing the test piece while the punch 12 moves downward, the hydraulic pressure acts below the test piece. Therefore, while the secondary punching is performed while the center punch 12 descends, the oil supplied to the inside through the oil passage 19a supports the free end portion of the lower end of the reverse drawing of the test piece. And the oil will be discharged to the outside through the oil passage (19a) by the lowering of the center punch 12. The oil through the oil passage (19a) can adopt a structure using a conventional hydraulic cylinder, the configuration of such a hydraulic cylinder is already known, so a detailed description thereof will be omitted.

As described above, since the lower end portion of the primary molded product is subjected to a predetermined pressure by hydraulic pressure during the secondary reverse drawing, the problem of wrinkle failure due to stress concentration occurring in a normal drawing process can be solved.

In the above description of the mold, the main parts that operate in the same manner as in the present invention have been described in detail, but detailed descriptions of the parts common to the molds for the general drawing process have been omitted, and the conventional molds in the subsequent process as well. Detailed description of the same operations and components as will be omitted.

Next, the trimming process of the present invention will be described with reference to FIG. The trimming step is a step of cutting out the excess portion around the flange of the secondary molded article made through the above process. The secondary molded article completed through the above-described drawing process is necessarily caused by the anisotropy of the plate material (earing) is generated, and is cut except for the necessary dimensions through the trimming process. As shown in FIG. 4, the trimming process is performed while cutting the punch die 29 and the lower die 28, while holding the secondary molded article, while the upper die 27 is lowered, cutting is performed to a predetermined dimension. That is, the secondary molded article mounted on the fixed lower die | dye 28 is cut | disconnected by predetermined dimension on the outer periphery of the lower die | dye 28 by the upper die 27 which descend | falls. And also in this process, the molded article between the punch 29 and the lower die | dye 28 can be easily removed by the restoring force of the spring 26. FIG. The part trimmed by this process is marked with "C" in FIG.

Next, the ironing process which is the 4th process of this invention is demonstrated, referring FIG. The ironing process pushes the punch while keeping the gap between the die and the punch smaller than the thickness of the cylindrical cell, thereby reducing the thickness of the wall by using the frictional force difference between the punch and the die, and precisely measuring the edges and the like. Refers to the process of molding. As shown in FIG. 5, the die 38 and the blank holder 37 are formed by the above-described process between the lower die punch 39 and the center punch 42 while the flange portion of the pulley is held. Pulley is formed by the above-described process between the lower mold punch 39 and the center punch 42 pulley is formed by the above-described process between the lower punch 39 and the center punch 42 lower punch ( Ironing by pressurization occurs in the clearance between 39 and the center punch 42. By the ironing process, the thickness and the edge portion of the pulley are molded to a desired dimension. That is, in Fig. 7, the part of the dotted line denoted by the symbol B is reworked to the exact shape shown by hatched cross section. At this time, when the punch 39 is moved downward by a mechanical press, the mill pin 44 acts by elasticity by the spring 50, and the fourth molded article is automatically extracted. Similarly to the above process, the punch 39 is also formed with an air hole 39a to facilitate separation from the molded article. By the above process, the shape dimension, the inner diameter and the outer diameter dimension of the pulley are determined, and at the same time, the radial dimension of each corner portion of the pulley is determined.

Next, a piercing process, which is the final process of the present invention, will be described with reference to FIG. This process is to pierce the inside of the fourth molded product to have a diameter of the size necessary to connect the bearing and the shaft. As shown in FIG. 6, while the die 48 is lowered, piercing is performed on the quaternary molded article between the lower punch 49. As shown in FIG. Also in this step, the molded article is automatically extracted by the spring 60.

It can be seen that the series of steps as described above is relatively simple as compared with the conventional steps. In addition, there is no need for manual operation as a whole, which is advantageous for automation and provides an advantage of lowering a defective rate. The lowering of the defective rate by the present invention is based on the above-described series of process steps and the mold structure of the present invention in each step.

In addition, the primary drawing process has the advantage of lowering the overall defective rate by configuring the mold to remove the iron bark generated in the previous step through the primary drawing process. According to the secondary reverse drawing process, the reaction force acts on the free end portion of the primary molded product to be drawn by using hydraulic pressure, thereby preventing the stress concentration phenomenon generated and reducing the defective rate.

The overall process is simplified by the process sequence and the drawing device according to the present invention can be expected to reduce the productivity as well as to minimize the defect rate.

Claims (5)

In the mechanical press, a die and a punch having a shape corresponding to each other are used, and the circumferential protrusion formed on the die is brought into close contact with the surface where the iron bark of the plate-shaped specimen protrudes, thereby drawing the flat barb while drawing the test piece in a cup shape. Drawing process; A secondary reverse drawing process of drawing the primary molded products produced in the primary drawing process in a reverse direction by using a die and a punch having a shape corresponding to each other with a force provided by a mechanical press; A trimming step of cutting the outside of the secondary molded product produced in the second reverse drawing process to a predetermined dimension with a force provided by a mechanical press; An ironing step of adjusting the thickness and edges of the third molded product produced in the trimming process to a predetermined dimension with the force provided by the mechanical press; And a piercing process for forming a piercing having a predetermined dimension on the fourth molded product produced in the ironing process, wherein the process is sequentially performed by a mold consisting of a predetermined die and a punch. Method of making pulleys. The method of claim 1, wherein in the secondary reverse drawing step, the concentration of stress can be prevented by applying a predetermined reaction force using hydraulic pressure to a corresponding part of the primary molded product to be reverse drawn. Way. A drawing apparatus of an automotive engine pulley comprising a die having a hole to be drawn, a holder for holding a specimen drawn between the die, and a punch for drawing the specimen toward the hole of the die, the drawing device comprising: A mold structure of an automobile engine pulley, characterized in that the contact projection for planarizing the burrs formed on the outer circumferential surface of the specimen moving to the center by drawing is formed in a circumferential shape along the contact surface. Holding means for holding a specimen to be reverse drawn and having a projection for removing the iron bar formed on the cut surface of the specimen; A punch moving to draw the held specimen; A lower punch formed between a specimen and having a shape reversely drawn in contact with the moving punch; Reaction force generating means for exerting a uniform reaction force on the specimen to a corresponding portion of the specimen drawn by the punch; In order to smoothly remove the molded article formed in each process, the molded article includes an elastic member that exerts an elastic force in a direction in which the molded article is separated from the holding means, and separation means consisting of air holes formed through the punch in the longitudinal direction. Drawing device of automobile engine pulley composed. 5. The drawing apparatus of claim 4, wherein the reaction force generating means comprises a hydraulic device capable of applying hydraulic pressure to the reverse drawing portion of the specimen.

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