KR100692620B1 - Method of producing the pinion gear of an automobile start motor using cold forging process - Google Patents

Abstract

By simultaneously molding the outer and inner helical gear parts of the pinion gear to be manufactured, additional cost reduction and manufacturing time can be reduced due to separate mechanical cutting for the outer and inner helical gear parts, thereby maximizing productivity. Disclosed is a method for manufacturing a pinion gear for an automobile start motor using a cold forging method which can improve the working environment and has excellent dimensional accuracy and mechanical properties. According to the present invention, after cutting the material, the material is subjected to an upsetting process, and the first back extrusion process is performed to form the outer diameter flange portion and the inner diameter in the upset material, and the outer diameter flange portion and the inner diameter of the A second back extrusion process is performed to secure the length. After forming the preform by shaping the shape of the outer diameter flange part and forming the first undercut by forming a step on the lower side of the inner diameter, the outer diameter gear part of the preform is manufactured by using the front extrusion method. While the inner diameter portion is pressed from the side while reducing the inner diameter portion to enlarge the step of the lower side of the inner diameter upwards to form the molded part of the inner diameter helical gear and the first gearing process to form the second undercut after the first gearing process is completed The second gearing process of forming the inner diameter helical gear portion in the molding portion of the upper diameter helical gear of the upper part of the second undercut formed in the inner diameter while completing the molding of the outer diameter gear portion again is completed to complete the pinion gear for the automobile start motor.

Description

Method for producing pinion gear for automobile start motor using cold forging method {Method of producing the pinion gear of an automobile start motor using cold forging process}

1 is a view schematically showing a manufacturing process of a pinion gear for an automobile start motor according to the present invention,

2 is a mold assembly diagram according to the sizing process shown in FIG.

3A and 3B are mold assembly views showing the first gearing process shown in FIG. 1, and

4A to 4D are mold assembly views sequentially illustrating the second gearing process illustrated in FIG. 1.

Explanation of symbols on the main parts of the drawing

10: material 20: finished product of upsetting process

32: outer diameter flange portion 30: 1st back extrusion process completed

33: step 34: inner diameter

40: second back extrusion process completed 50: preform

52: 1st undercut 60: 1st gearing process completed

62: outer diameter gear part 63: inner diameter helical gear forming part

64: second undercut 70: pinion gear for automobile start motor

72: inner diameter helical gear unit 110: gearing punch

112: first outer gear block 114: first gear lower die

120: helical punch assembly 122: housing

124: helical punch 126: bearing

128: helical forming unit 130: thrust bearing

132: needle bearing 140: second gearing lower die

142: second outer gear block 144: guide ball

146: guide die

The present invention relates to a method for manufacturing a pinion gear for an automobile start motor using a cold forging method, and more particularly, by forming an outer diameter gear portion and an inner diameter helical gear portion of a pinion gear to be manufactured simultaneously, the outer diameter gear portion and the inner diameter helical gear In addition to saving additional costs due to separate mechanical cutting for the part, the manufacturing time can be shortened, thereby maximizing productivity and improving the working environment, and using the cold forging method with excellent dimensional precision and mechanical properties. A method for manufacturing a pinion gear for an automobile start motor.

In general, a start motor for a motor is a part that supplies driving force necessary for an initial intake stroke and a compression stroke for starting an engine, and receives a ring gear of a flywheel fixed to an outer end of the crankshaft of the engine by receiving battery power. By rotating the pinion gear, the crankshaft causes the initial suction stroke and compression stroke. When the engine is operated as described above, the engine does not need to be rotated anymore, and thus, when the overrunning clutch causes the rotational force of the engine to be reversed, the start motor stops the function of turning the engine to protect the start motor.

Components for transmitting power of the above-described start motor include a barrel that is a sleeve clutch, a pinion gear, a shaft, and the like. At this time, the pinion gear (pinion gear) is the outer diameter gear portion is formed on the outer diameter and the helical gear portion is formed on the inner diameter. In order to manufacture such a pinion gear, the outer diameter gear portion and the inner diameter helical gear portion are formed through mechanical cutting processing under the state of determining the overall shape by using the cold forging method.

However, the above-described pinion gear has to be manufactured separately because the external gear part and the helical gear part have to be manufactured separately through mechanical cutting, and the production time increases. In order to process the external gear part and the helical gear part, specialized technical personnel and expensive dedicated equipment are required. As a result, there is a problem that productivity as well as increase in labor costs are lowered, and the dimensional precision and mechanical properties of the outer diameter gear are inferior.

The present invention has been made to solve the conventional problems as described above, an object of the present invention by forming the outer diameter gear portion and the inner diameter helical gear portion of the pinion gear to be manufactured, the outer diameter gear portion and the inner diameter helical gear portion In addition to saving additional costs due to the separate mechanical cutting process, manufacturing time can be shortened, thus maximizing productivity and improving the working environment, and starting the car using the cold forging method with excellent dimensional accuracy and mechanical properties. The present invention provides a method for manufacturing a pinion gear for a motor.

In order to achieve the object of the present invention as described above, the present invention,

Cutting the material so that the steel bar has the weight of quantification (S1);

Performing an upsetting process on the prepared material (S2);

Performing a first back extrusion process to form an outer diameter flange portion and an inner diameter in the upset material (S3);

When the step (S3) is completed, performing a second back extrusion process to secure the length of the outer diameter flange portion and the inner diameter (S4);

When the step (S4) is completed, forming a shape of the corner portion of the outer diameter flange portion and forming a step on the lower side of the inner diameter to perform a sizing process to form a first undercut to produce a preform (S5) ;

On the inner circumferential surface of the first gearing lower die is provided with a gearing punch and a first gearing lower die having the first outer gear block formed on the inner circumferential surface to form the outer gear portion on the outer flange portion of the preform. When the gearing punch is lowered to the inner diameter side of the preform while the preform is placed, the outer flange portion of the preform is extruded to the first outer gear block side by the gearing punch to form an outer gear part. At the same time, the first gearing process of pressing the inner diameter of the preform from the side by the gearing punch to reduce the inner diameter to enlarge the step on the lower side of the inner diameter upwards to form the molded portion of the inner diameter helical gear and form the second undercut. Performing step (S6); And

" 자 형상을 가지면서 중앙부에는 상기 헬리컬펀치를 안내하는 가이드공이 형성되는 가이드다이를 구비하여 상기 제 2 기어링하부다이의 내주면 상에 상기 제 1 기어링공정이 완료된 상기 성형물을 배치시킨 상태 하에서 상기 헬리컬기어 성형부로 하강시키면 상기 헬리컬펀치는 리드각과 동일한 각도로 정회전하면서 상기 내경헬리컬기어 성형부에 내경 헬리컬기어부를 형성함과 동시에 상기 외경기어부의 성형하는 제 2 기어링공정을 실시하여 자동차 스타트모터용 피니언 기어를 완성하는 단계(S7)를 포함하는 냉간단조공법을 이용한 자동차 스타트모터용 피니언 기어의 제조방법을 제공한다.A helical punch, a second gearing lower die having a second outer gear block formed on an inner circumferential surface thereof so as to complete formation of the outer gear portion formed in step S6, and mounted on the second gearing lower die.

The helical gear is provided with a guide die in which a guide hole for guiding the helical punch is formed in a central portion of the second gearing lower die, and the molded article having the first gearing process is disposed on the inner circumferential surface of the second gearing lower die. When descending to the forming part, the helical punch is rotated forward at the same angle as the lead angle while forming the inner diameter helical gear part in the inner diameter helical gear forming part and at the same time performing the second gearing process of forming the outer diameter gear part to pinion gear for the automobile start motor. It provides a method for manufacturing a pinion gear for a motor start motor using a cold forging method comprising the step (S7) of completing.

As described above, according to the present invention, by simultaneously forming the outer diameter gear portion and the inner diameter helical gear portion of the pinion gear to be manufactured, additional costs due to separate mechanical cutting for the outer diameter gear portion and the inner diameter helical gear portion are reduced. In addition, the manufacturing time can be shortened to maximize productivity, improve working environment, and provide pinion gear for automotive start motor with superior dimensional accuracy and mechanical properties.

Hereinafter, a method of manufacturing a pinion gear for an automobile start motor using a cold forging method according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a view schematically showing a manufacturing process of a pinion gear for an automobile start motor according to the present invention.

Referring to FIG. 1, in order to manufacture the pinion gear 70 for a motor vehicle start motor according to the present invention, first, a raw material (BLANK) 10 is cut (step S1). When the material 10 is cut in this way, the spheroidizing annealing is performed within a normal temperature range and time to soften the cut material 10 to improve cold workability, and then scale and foreign matter after spheroidizing annealing. After the blast treatment (SHOT BLAST) for removal to form a phosphate coating layer on the surface of the material (10).

Preferably, the material 10 is cut to have a weight of 179 g of steel bar having a diameter of 25 mm.

The material 10 prepared in the above-described step S1 performs an upsetting process (step S2), and the material 20 that is upset is an outer diameter flange portion 32 and an inner diameter 34. After forming the first backward extrusion process (step S3), the second backward extrusion process of securing the length of the outer diameter flange portion 32 and the inner diameter 34 is performed again. (Step S4).

At this time, the material 20 having the upsetting process is completed within the normal temperature range and time so as to soften the material 20 and remove the internal stress before improving the cold workability before performing the first back extrusion process. After the annealing heat treatment (Annealing) at, and then undergo a shot (blast shot) treatment for removing the scale and foreign matter after the annealing to form a phosphate coating layer on the surface.

Similarly, the material 30 having completed the first backward extrusion process has a normal temperature to soften the material 30 and remove internal stress before improving the cold workability before performing the second back extrusion process. After performing annealing heat treatment (annealing) in the range and time, and after undergoing a shot blast (SHOT BLAST) for removing the scale and foreign matter after the annealing to form a phosphate coating layer on the surface.

2 is a mold assembly view according to the sizing process shown in FIG.

When the second backward extrusion process is completed (step S4), the shape of the outer diameter flange portion 32 of the material 40 formed in the second back extrusion process (step S4) is molded and the lower side of the inner diameter 34 is formed. A preform 50 is produced by forming a step 33 to form a first undercut 52 to form a sizing step (step S5).

When the sizing process is completed, a shot blast treatment is performed to remove foreign substances on the surface of the preform 50, and then a phosphate coating layer is formed on the surface, and the local severe deformation and deformation of the preform 50 are again performed. The MOS2 lubrication layer is formed with MOLYSOL # 430, a high-purity molybdenum disulfide-based lubricant, to perform the forging process.

3A and 3B are mold assembly diagrams illustrating the first gearing process illustrated in FIG. 1, and FIGS. 4A to 4D are mold assembly diagrams sequentially illustrating the second gearing process illustrated in FIG. 1.

When the preform 50 is completed (step S5), the inner diameter 34 is first formed by forming the outer diameter gear portion 62 on the outer diameter flange portion 32 of the preform 50 using a forward extrusion method. The first gearing to form the forming portion 63 of the inner diameter helical gear and to form a second under cut (64) by expanding the step (33) of the lower inner diameter to the upper side while being pressed in the additional side to increase the step (33) of the lower inner diameter After the gearing process (step S6), the inner diameter of the upper portion of the second undercut 64 formed in the inner diameter 34 is completed while the outer diameter gear portion 62 is completed again in the molded product 60 in which the first gearing process is completed. A second gearing step of forming the inner diameter helical gear portion 72 in the forming portion 63 of the helical gear is performed to complete the pinion gear 70 for the motor start motor according to the present invention (step S7).

In the above-described first gearing process (step S6), the gearing punch 110 and the outer diameter gear portion 62 can be formed on the outer diameter flange portion 32 of the preform 50 on the inner circumferential surface. A first gearing lower die 114 having a first outer gear block 112 is provided. That is, the preform 50 is disposed on the inner circumferential surface of the first gearing lower die 114, and the gearing punch 110 is lowered to the inner diameter 34 side of the preform 50. At this time, the outer diameter flange portion 32 of the preform 50 is extruded toward the first outer gear block 112 by the gearing punch 110 descending to form the outer diameter gear portion 62, and similarly the preform 50 The inner diameter 34 of the) is pressed from the side to reduce the inner diameter portion to enlarge the step 33 of the lower inner diameter upwards to form the molded portion 63 of the inner diameter helical gear and the second undercut 64 is formed. Preferably, the shaping portion 63 of the inner diameter helical gear is formed smaller than the outer diameter of the inner diameter helical gear portion 72 to be formed.

On the other hand, in the second gearing step (step S7), the helical punch assembly 120 for forming the helical gear portion 72 in the forming portion 63 of the inner diameter helical gear and the outer diameter gear portion 62 are formed. The second gearing lower die 140 and the second gearing lower die 140 formed on the inner circumferential surface and the second gearing lower die 140 are formed on the inner circumferential surface so as to complete the shape. The guide die 144 is formed therein to guide the helical punch 124, and the guide die deviating from the helical punch 124 to release the pinion gear 70 for the completed motor start motor which rises together with the helical punch 124. 146).

Preferably, the helical punch assembly 120 has a housing 122 having an open bottom, a top of which is disposed in the housing 122, and a lower helical punch 124 extending below the housing 122. And a bearing unit 126 disposed in the housing 122 to control the helical punch 124 to rotate forward and reverse. At this time, on the outer peripheral surface adjacent to the lower end of the helical punch 124, the helical forming portion 128 having the same lead angle as the inner diameter helical gear portion 72 to be formed in the forming portion 63 of the inner diameter helical gear is integrally formed. . Meanwhile, the bearing part 126 rotates in different directions, that is, a thrust bearing 130 that rotates in a different direction, and a needle bearing 132 disposed below the thrust bearing 130. It is provided. At this time, the thrust bearing 130 is operated such that the helical punch 124 is rotated forward when pressing the helical punch 124 to the molding portion 63 of the inner diameter helical gear, the needle bearing 132 is a guide die 136 When the helical punch 124 is separated from the pinion gear 70 for the automobile start motor in close contact with the helical punch 124, the helical punch 124 operates to reverse.

That is, the molding 60 in which the first gearing process (step S6) is completed is disposed on the inner circumferential surface of the second gearing lower die 140. Under this condition, the helical punch 124 is lowered to the forming part 63 side of the inner diameter helical gear. At this time, the descending helical punch 124 rotates forward at the same angle as the lead angle of the helical forming unit 128 while forming the helical gear portion 72 in the forming portion 63 of the inner diameter helical gear and at the same time the outer diameter gear portion 62 Complete molding). The pinion gear 70 for the automobile start motor after the molding is completed is separated from the second gearing lower die 140 together with the helical punch 124 to rise. At this time, the ascending pinion gear 70 for the automobile start motor is in close contact with the lower surface of the upper surface of the guide die 146 and rotates at the same angle as the lead angle of the helical forming portion 128 of the helical punch 124 that continues to rise. The inner helical gear portion 72 is separated.

As described above, according to the present invention, the outer gear part 62 and the inner diameter helical gear part 72 are simultaneously molded by the pinion gear 70 for the motor start motor in a precise cold forging process. It has excellent properties, and does not need to perform cutting work as in the prior art, so that no cutting chips are generated by machining and no cutting oil is used. Not only can this be done, but it can also prevent environmental damage.

In addition, by cutting the pinion gear 70 for an automobile start motor, the productivity can be dramatically increased, thereby reducing the production cost, and even an inexperienced worker can easily make the pinion gear 70 for an automobile start motor. This has the advantage of producing.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the invention described in the claims. You will understand.

Claims (4)

Cutting the material so that the steel bar has the weight of quantification (S1); Performing an upsetting process on the prepared material (S2); Performing a first back extrusion process to form an outer diameter flange portion and an inner diameter in the upset material (S3); When the step (S3) is completed, performing a second back extrusion process to secure the length of the outer diameter flange portion and the inner diameter (S4); When the step (S4) is completed, forming a shape of the corner portion of the outer diameter flange portion and forming a step on the lower side of the inner diameter to perform a sizing process to form a first undercut to produce a preform (S5) ; On the inner circumferential surface of the first gearing lower die is provided with a gearing punch and a first gearing lower die having the first outer gear block formed on the inner circumferential surface to form the outer gear portion on the outer flange portion of the preform. When the gearing punch is lowered to the inner diameter side of the preform while the preform is placed, the outer flange portion of the preform is extruded to the first outer gear block side by the gearing punch to form an outer gear part. At the same time, the first gearing process of pressing the inner diameter of the preform from the side by the gearing punch to reduce the inner diameter to enlarge the step on the lower side of the inner diameter upwards to form the molded portion of the inner diameter helical gear and form the second undercut. Performing step (S6); And A helical punch, a second gearing lower die having a second outer gear block formed on an inner circumferential surface thereof so as to complete formation of the outer gear portion formed in step S6, and mounted on the second gearing lower die.

The helical gear is provided with a guide die in which a guide hole for guiding the helical punch is formed in a central portion of the second gearing lower die, and the molded article having the first gearing process is disposed on the inner circumferential surface of the second gearing lower die. When descending to the forming part, the helical punch is rotated forward at the same angle as the lead angle while forming the inner diameter helical gear part in the inner diameter helical gear forming part and at the same time performing the second gearing process of forming the outer diameter gear part to pinion gear for the automobile start motor. Method of manufacturing a pinion gear for a motor start motor using a cold forging method characterized in that it comprises a step (S7) of completing. delete The pinion for the vehicle start motor according to claim 1, wherein the guide die in the step S7 releases the completed pinion gear for the car start motor, which rises together with the helical punch, from the helical punch. The gear moves away from the second gearing lower die together with the helical punch and ascends, closes to the lower surface of the upper surface of the guide die, and rotates at the same angle as the lead angle of the helical punch that continues to rise. Method for producing a pinion gear for a motor start motor using a cold forging method characterized in that. The helical punch of claim 1, wherein the helical punch is disposed inside the housing, and the upper part of the helical punch is disposed inside the housing, and the lower end of the helical punch extends into the lower part of the housing. A helical gear having a bearing angle for controlling the helical punch to be rotated forward and reverse, and having a lead angle equal to that of the inner diameter helical gear to be formed on the inner diameter helical gear forming portion on an outer circumferential surface adjacent to the lower end of the helical punch; The bearing unit is integrally formed, and the bearing unit is operated when pressing the helical punch to the inner diameter helical gear forming unit, and a thrust bearing for forward rotation of the helical punch; and a needle operating when the helical punch is released from the helical gear. Cold forging method, characterized in that consisting of a bearing A method of manufacturing a pinion gear for a car start motor.

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