KR20190042123A - Method for manufacturing parking gear and parking gear manufactured thereby - Google Patents

Abstract

The present invention relates to a method to manufacture a parking gear and a parking gear manufactured by the same. According to the present invention, the method to manufacture the parking gear comprises: (a) a step of hot forging to manufacture a ring-shaped molded product; (b) a step of extending an internal diameter and an external diameter of the ring-shaped molded product; and (c) a step of cold forging to form a tooth form on the inner circumferential surface and outer circumferential surface of the ring-shaped molded product at the same time. According to the present invention, the method is able to, in comparison with a method to pre-mold a part of a tooth form by hot forging and to perform a sizing and form an additional tooth form by cold forging, form an internal tooth and an external tooth at the same time by making a simple ring-shaped molded product, going through a process of extending the internal diameter and external diameter, and performing a cold forging, to remarkably reduce material loss due to an additional processing for a precise processing, simplify and reduce the processing processes and working hours, and improve productivity. In addition, the method is able to continue a metal flow up to an end of the tooth form, mold the tooth form by cold forging, make the tissue finer, increase the hardness of the tooth form, and easily secure concentricity of the internal tooth and the external tooth.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a parking gear,

The present invention relates to a method of manufacturing a parking gear for an automobile and a parking gear manufactured thereby.

The parking gear or the parking lock gear is a gear that fixes the output shaft of the transmission to prevent rotation when the vehicle is parked in an automatic transmission vehicle. When the vehicle is parked and then the shift lever is moved to the P range, Quot; and " fixed "

In the conventional manufacturing process of the parking gear, since gearing is dependent on machining, cycle time is long, productivity is low, and material utilization is low, resulting in high resource and energy consumption. For example, raw material is processed in the shape of a disk in the form of a bar, then subjected to roughing in the form of a ring, and then the product is produced through one or two finishing operations. As a result, the material utilization rate is low and the production cycle time is long.

In view of the problems of the above-mentioned conventional processes, in some overseas and domestic advanced companies, intermediate materials having ring shapes or preliminary teeth are formed by forging molding of initial materials in heat / warming, thereby shortening the processing amount and time. In the case of the domestic parent company, the middle gear is manufactured by hot forging, the pre-gear tooth is formed with the simple gear, and the parking gear is developed by machining the tooth profile and final shape.

In the case of machining, the structure is broken according to the tooth profile, so that the tooth structure may be broken under a high load. On the other hand, when the gear structure is formed at a temperature lower than the above temperature, However, in order to obtain the final shape of the tooth profile, it is only necessary to rely on the machining, so that the long machining time is still a problem. Warm forging also has a lower molding load than cold forging, but consumes energy for temperature maintenance and has a disadvantage that the dimensional accuracy is also lower than that of cold forging.

Korean Patent Laid-Open Publication No. 1020170059375 (Disclosure Date: 2017.05.30.) Korean Patent Publication No. 1020170046450 (Disclosure Date: 2017.05.02.) Korean Patent Publication No. 1020130042215 (Publication date: April 26, 2013).

The present invention provides a method of manufacturing a high-quality parking gear having excellent mechanical properties and minimizing waste of material and work processes for forming a tooth shape located on the inner circumferential surface and the outer circumferential surface of a ring-shaped gear, and a parking gear manufactured thereby There is a purpose.

In order to accomplish the above-mentioned technical object, the present invention provides a method of manufacturing a molded product, comprising: (a) a hot forging step of producing a ring-shaped molded article; (b) enlarging an inner diameter and an outer diameter of the ring-shaped molded article; And (c) a cold forging step of simultaneously forming teeth on the inner circumferential surface and the outer circumferential surface of the ring-shaped molded article.

Further, in the step (a), a ring-shaped molded article is formed by using a hot foamer.

In the step (a) of forming the ring-shaped molded article using the hot foamer, the material is pressurized by the foamer mold to expand the material in the width direction, and at the same time, A first step of pressing in a state; A second step of forming a preliminary groove in the center by pressing the squeezed material with a molder mold; And a third step of pressing the material having the preliminary groove formed thereon with a former mold to form a central hole at the center to obtain a ring-shaped molded product having a hollow.

The present invention also provides a method of manufacturing a parking gear, wherein spherodizing annealing is performed after completion of the step (a) and after completion of the step (b).

The present invention also provides a method of manufacturing a parking gear, characterized in that the ring-shaped molded article subjected to spheroidization annealing is subjected to a shot treatment and a lubricating treatment after completion of the step (b).

In the step (c), by using the cold forging mold 1 including the punch 11, the lower mold die 13, the lower mold mandrel 14 and the sleeve 15,

The lower mold mandrel 14 is positioned inside the lower die 13 so that the machining portion of the lower mold mandrel 14 is spaced apart from the machining portion of the lower die 13 by a predetermined distance,

After the hollow-shaped raw material, that is, the ring-shaped molded product 12 is inserted into the upper portion of the lower mandrel,

When the ring shaped molded product 12 is pressed from above by using the punch 11 on the upper side, the outer circumferential surface and the inner circumferential surface of the ring-shaped molded article 12 are engaged with the teeth of the lower die 13, And the teeth are formed on the inner circumferential surface and the outer circumferential surface of the ring-shaped molded article (12) at the same time.

And, in another aspect of the invention, the present invention provides a parking gear manufactured according to the above manufacturing method.

The method of manufacturing a parking gear according to the present invention, in contrast to the case where sizing and additional tooth formation are performed through cold forging after preliminarily forming a part of a tooth profile through hot forging, , The inner and outer diameters are increased and the inner and outer teeth are simultaneously formed by cold forging. Thus, the loss of material due to further processing for the precision machining is significantly reduced, and the processing time and the time required are further simplified and shortened, , The metal flow is continued to the tooth tip, and the tooth is formed through cold forging to make the structure finer, which makes it possible to increase the hardness of the tooth profile and to secure the concentricity of the inner tooth and the outer tooth.

1 is a process flow chart showing each step of a method for manufacturing a parking gear according to the present invention in order.
Fig. 2 is a schematic view showing each step of a method for manufacturing a parking gear according to the present invention in order.
3 is an exploded view showing an example of a mold used for cold forging in step (c) of the method for manufacturing a parking gear according to the present invention.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application. It should be understood, however, that the embodiments according to the concepts of the present invention are not intended to be limited to any particular mode of disclosure, but rather all variations, equivalents, and alternatives falling within the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms " comprises ", or " having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Hereinafter, the present invention will be described in detail.

Plastic forming is one of the important production base industries that can manufacture mass production of basic core parts of automobile, ship, and aircraft industry, and it has a very wide industrial scope.

Among such plastic working, forging can be classified into hot forging, warm forging and cold forging depending on the manufacturing method and manufacturing equipment. Among them, the hot forging is performed by heating the material at a high temperature of 1000 to 1200 ° C, (A) Upsetting process, (a) It is easy to mold by giving a large deformation by small force, and because it is easy to mold product with complex shape because productivity is good because production speed is fast. b) Blocker process, (c) Finisher process, and (d) Piercing process. The cold forging is performed at room temperature to improve the precision of the product, and it is possible to produce a product with a clean surface.

In order to improve the mechanical properties and increase productivity by taking advantage of each of the hot forging and cold forging described above, a complex forging technique is known in which the large deformation is ensured by an on-off simple or hot forging process and the precision is dependent on a cold sizing process.

The present invention relates to a method for manufacturing a parking gear for a vehicle, which is based on a conventional hot / cold composite forging to overcome the problems of overworking and waste of the material, wherein both the inner and outer teeth of the ring- And the like.

1 and 2, a method of manufacturing a parking gear according to the present invention includes: (a) a hot forging step of manufacturing a ring-shaped molded article; (b) enlarging an inner diameter and an outer diameter of the ring-shaped molded article; And (c) a cold forging step of simultaneously forming teeth on the inner circumferential surface and the outer circumferential surface of the ring-shaped molded article.

The step (a) is a step of producing a simple ring-shaped molded product having a smooth surface on which no irregularities are formed, such as a tooth or the like, on the inner and outer circumferential surfaces, and is preferably performed through a hot forging process using a hot former .

The hot form method is a process in which the material is heated in a high temperature state so that the material is softened. In the form method, since the multi-step process is continuously performed in one former device, In particular, it can be expected that the productivity compared to the press molding is improved 10 times or more.

For example, in the step of forming a ring-shaped molded article using the hot foamer in this step, the material obtained by cutting the rods is pressed by the foamer mold to expand in the width direction of the material, In a compressed state; A second step of forming a preliminary groove at the center so as to reduce the load applied to the mold when the hollow is formed in the subsequent step by pressing the pressed material with a molder mold; And a third step of pressing the material having the preliminary groove formed thereon with a molder to form a central hole at the center to obtain a ring-shaped molded product having a cavity.

Next, in step (b), the inner diameter and the outer diameter of the ring-shaped molded article are enlarged in consideration of the size of the parking gear to be finally obtained, and hot cast rolling such as roll forming, It is desirable to perform this step through the process.

After the completion of the step (a) and after the completion of the step (b), spherodizing annealing is preferably performed. Further, since the crystal grains of the material are refined through the spheroidizing annealing to increase the ductility, It can be performed more smoothly.

 Further, it is possible to further perform a shot process and a lubrication process (bond process) on the ring-shaped molded product subjected to spheroidization annealing after completion of the step (b).

Scale cleaning and scraping of a ring-shaped molded product hot-forged by shot blasting are carried out. A lubricating treatment is applied to the surface of the ring-shaped molded article so that the coating layer by the above- So that adhesion between the mold and the ring-shaped molded article can be prevented in the cold forging step of step (c) described later.

Finally, in step (c) of the method for manufacturing a parking gear according to the present invention, the inner teeth and the outer teeth are simultaneously formed on the inner and outer circumferential surfaces of the ring-shaped molded article through cold forging.

Fig. 3 is an exploded view showing an example of a cold forging die 1 that can be used to simultaneously form teeth on the inner circumferential surface and the outer circumferential surface of the ring-shaped molded article in this step.

3, the cold forging die 1 includes a punch 11, a lower die 13, a lower die mandrel 14, and a sleeve 15. As shown in FIG.

The lower die 13 includes a machined portion in which a tooth profile corresponding to the external teeth of the parking gear to be finally obtained is formed. The lower mandrel portion 14 is provided on the lower side of the metal mold and is inserted into the hollow portion of the ring-shaped molded product when pressed by the punch to pressurize radially from the inner center, And a toothed portion is formed on the inner peripheral surface of the ring-shaped molded product.

The process of this step using the mold for cold forging 1 will be described below so that the machining portion of the lower mold mandrel 14 is separated from the machined portion of the lower mold die 13 by a predetermined distance, Is placed inside the lower mold die 13, and a hollow raw material, that is, a ring-shaped molded product 12 is inserted into the upper portion of the lower mold mandrel to be seated thereon, When the ring-shaped molded article 12 is pressed, the outer peripheral surface and the inner peripheral surface of the ring-shaped molded article 12 are processed into the tooth profile of the lower die 13 and the tooth profile of the lower mandrel 14, respectively.

In this step, by forming the inner teeth and the outer teeth simultaneously by cold forging as described above, it is possible to easily secure the inner and outer concentricity without further precision machining.

According to the method of manufacturing a parking gear according to the present invention as described in detail above, in contrast to the case where a part of the tooth profile is preliminarily formed by hot forging and then sizing and additional tooth profile formation are performed through cold forging, By forming inner and outer diameters simultaneously by forming inner and outer diameters by cold forging, the loss of material due to further processing for precision machining is significantly reduced, and the processing time and the time required are greatly simplified and shortened The productivity is increased and the flow of the metal is not cut off to the end of the tooth to be formed without the process such as cutting, trimming and piercing so that the tooth strength is prevented from being lowered and the tooth is formed through cold forging, It is possible to increase the hardness and to secure the concentricity of the inner tooth and the outer tooth.

1: Mold for cold forging
11: Punch
12: Ring-shaped molded article
13: Lower die
14: Lower mold mandrel
15: Sleeve

Claims (7)

(a) a hot forging step of producing a ring-shaped molded article;
(b) enlarging an inner diameter and an outer diameter of the ring-shaped molded article; And
(c) forming a tooth on an inner circumferential surface and an outer circumferential surface of the ring-shaped molded article at the same time. The method according to claim 1,
Wherein the ring-shaped molded article is formed using the hot foamer in the step (a). 3. The method of claim 2,
In the step (a) of forming the ring-shaped molded article using the hot foamer,
A first step of pressing the material with a foamer mold to expand the material in the width direction and pressing the material in a compressed state in the height direction of the material;
A second step of forming a preliminary groove in the center by pressing the squeezed material with a molder mold; And
And a third step of pressing the material having the preliminary groove formed thereon with a former mold to form a central hole at the center to obtain a ring-shaped molded product having a hollow. The method according to claim 1,
Wherein the spherodizing annealing is performed after completion of the step (a) and after the completion of the step (b). 5. The method of claim 4,
Wherein the ring-shaped molded article subjected to spheroidization annealing after completion of the step (b) is subjected to a shot treatment and a lubrication treatment. The method according to claim 1,
In the step (c), by using the cold forging mold 1 including the punch 11, the lower mold die 13, the lower mold mandrel 14 and the sleeve 15,
The lower mold mandrel 14 is positioned inside the lower die 13 so that the machining portion of the lower mold mandrel 14 is spaced apart from the machining portion of the lower die 13 by a predetermined distance,
After the hollow-shaped raw material, that is, the ring-shaped molded product 12 is inserted into the upper portion of the lower mandrel,
When the ring shaped molded product 12 is pressed from above by using the punch 11 on the upper side, the outer circumferential surface and the inner circumferential surface of the ring-shaped molded article 12 are engaged with the teeth of the lower die 13, And the teeth are simultaneously formed on the inner and outer circumferential surfaces of the ring-shaped molded article (12). A parking gear manufactured using the method according to any one of claims 1 to 6.

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