KR101715518B1 - Spline gear manufacturing method using cold former - Google Patents

Abstract

According to the present invention, a method for forming a spline gear of a reaction shaft using a cold former comprises: a multi-stage cold forging step of deforming an inputted annular rod-shaped initial material into a tube and forming an involute spline gear on one side outer circumferential surface; and a post-processing step proceeded after the multi-stage cold forging step. The post-processing step comprises: lathe processing; a rolling process; a milling process; a drilling process; a deburring process; and a polishing process except a hobbing process.

Description

TECHNICAL FIELD [0001] The present invention relates to a spline gear forming method for a reaction shaft using a cold former,

The present invention relates to a method of forming a spline gear of a reaction shaft using a cold former. More particularly, the present invention relates to a molding technique capable of ensuring the dimensional accuracy of gears, securing the concentricity of gears, and preventing breakage of molds for gear forming by carrying out multi-step cold forging processes using a former with respect to materials provided at an early stage will be.

A torque converter, which is an automatic transmission of a passenger car, is a device that converts torque to transmit power by using a fluid. The torque converter is composed of a pump connected to the engine side, a turbine connected to the transmission side, and a stator and oil. In the torque converter, when the rotation speed of the turbine is low, the stator is fixed and the torque is increased. However, when the turbine speed is close to the pump speed, the stator revolves and operates only as a fluid clutch.

The stator is a part of the torque converter, which changes the direction of rotation of the oil returning from the turbine to the direction of rotation of the pump to increase the torque of the engine. The reaction shaft of the stator is a component that maintains and supports the rotation of the stator. For example, a chromium-molybdenum steel material is used as a material, and high reliability is required due to the characteristics of a transmission part.

One end of the reaction shaft, which is engaged with the stator for rotation and support of the stator, is composed of involute spline gears, and the other end is serrated. Therefore, if the dimensional and shape of the gear, the inner-outer-diameter concentricity, and the reliability of the parts are directly related to the quality of the parts, there is a problem in the dimension and the mechanical characteristics, the accurate power transmission may not be performed or noise such as vibration may occur .

In the conventional reaction shaft production method, there are problems such as reduction of yield of material, increase of the unit price of the material, and difficulty in processing involute spline gear.

Conventional production of reaction shafts consists of machining except for the heat treatment and rolling processes. Specifically, the preparation of initial materials, drilling, primary turning, secondary turning, hobbing, rolling, milling , Drilling, deburring, gas carburizing, polishing, and inspection.

In the above-mentioned conventional process, the yield of the material is reduced to about 30% or less from the initial material prepared by a large amount of machining to the final product, and the overall cost of the parts is increased due to the expensive hobbing process for involute spline gear processing .

If you look at the unit price of each part of the reaction shaft, most of the cost is consumed in the cutting ratio such as material ratio and hobbing. Especially, about 20 ~ 30% of the cost of parts is consumed in material cost, so the reduction of material yield and hobbing are the main causes of component cost increase. In addition, the reaction shaft manufacturing technology is a universalized processing technology, and the demand for parts is largely eroded on the basis of excellent price competitiveness in the market of China and Southeast Asia. Therefore, the improvement of raw material yield and the development of new molding method Is essential.

In addition, in order to improve the lubrication inputting ability, the manufacturing method of the reaction shaft for producing the fitting portion in the involute spline gear portion is difficult to produce the initial shape for the hobbing by turning the gear portion due to the gear portion, There is a possibility that there is a reduction in the gear strength, and accordingly, there is a demand for a new involute spline processing method for machining a coupled gear and forming a high-strength gear part.

As a conventional literature suggesting a spline shaft processing method, reference is made to Registration No. 10-0705535 (Apr. 13, 2007). In this document, a blank is cut into an appropriate size blank using a cold forging method of a forward extrusion method, a hollow body is formed by punching a central portion, and a spline is formed by deforming the shape to form two or more spline portions formed in the longitudinal direction However, there is a limitation in improving the material yield and productivity by replacing the conventional drilling or hobbing process, which is a problem in the molding process.

(Patent Document 1) KR10-0705535 B

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art, and it is an object of the present invention to provide a method of manufacturing a gear, in which a plurality of forging operations are performed using a cold former for a material to be initially provided to form a whole tube shape of a reaction shaft and a involute spline gear shape together It is an object of the present invention to provide a molding method capable of ensuring dimensional accuracy, securing concentricity of gears, and preventing breakage of a mold for gear forming.

In order to accomplish the above object, there is provided a method of forming a spline gear of a reaction shaft using a cold former, comprising the steps of: forming an involute spline gear on an outer circumferential surface of one side, step; And a post-machining step after the multi-step cold forging step, wherein the post-machining step includes lathe machining, rolling machining, milling machining, drilling machining, deburring machining, and abrasive machining in a state excluding the hobbing machining.

The multi-step cold forging includes an upsetting step, a rear extruding step, a piercing step, and an involute spline gear forming step.

The forging die used in the multistage cold forging step is in the form of a plurality of salt molds arranged in a line within a mold for performing a plurality of processes.

In the method of forming a spline gear of a reaction shaft using a cold former according to the present invention, a forging operation is performed by using a cold former as one of a plurality of processes for an initially provided material, We will strengthen the competitiveness of overall parts manufacturing technology by improving the productivity of the reaction shaft and reducing the cost through the method of shaping the shape and the involute spline gear together.

The present invention can replace the reaction shaft method in which the tube is formed through drilling at the initial stage of the process through the above-described method, and then the gear is manufactured through the hobbing process.

In the present invention, when a component is developed using a cold multi-stage former, it is possible to improve the yield of the material by 70% or more, reduce the cost of the parts by about 25%, form the gear part by gear and improve the gear strength by cold forming.

In addition, although the total number of processes can be increased arithmetically by using the multi-stage cold formers, since the production time is about 4 seconds to 6 seconds, when the cold formers are applied, the total processing time can be shortened by about 15% Improvement may be possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram showing a spline gear forming step of a reaction shaft using a cold former in accordance with the present invention. FIG.
FIG. 2 shows six process steps for performing a multi-stage cold forging operation constituting the present invention and a mold state for performing the six process steps.
3 is a view showing a detailed structure of a mold for performing a multistage cold forging operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely. Wherein like reference numerals refer to like elements throughout.

It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. 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.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

The present invention is applicable to a process of manufacturing a reaction shaft of a stator which is a front-wheel six-speed automatic transmission torque converter part applied to a passenger car.

Hereinafter, a method for forming a spline gear of a reaction shaft using a cold former according to the present invention will be described with reference to FIGS. 1 and 3. FIG.

In the present invention, a multi-stage cold forging operation is performed on an initial material to be introduced to deform an initial material into a tube shape, and at the same time, an involute spline gear is formed on one outer peripheral surface.

After the multi-step cold forging, a post-finishing work is performed.

The multi-stage cold forging operation is, for example, made in the form of a tube so as to be axially penetrated with respect to the supplied reaction shaft raw material, thereby forming an involute spline gear shape on the outer circumference of the tube-shaped tube.

In the multi-stage cold forging, six processes are carried out without replacing the equipment through the cold former, which is a single device. The approximate process time is about 6 to 6 seconds, and the final reaction shaft Forged products can be produced one at a time. In addition, the yield of the material can be maintained at 70% or more.

The forging die used in the multistage cold forging operation is formed by arranging six salt molds, each of which performs six processes, in a line within a mold. That is, the upper mold includes six upper molds arranged in a line along the progress direction of the process, and six lower molds spaced apart from the lower side of the six upper molds by a predetermined distance.

The gear forming portion is formed on a lower inner circumferential surface of the upper mold, and the punch is disposed on the lower mold. The punch is disposed in a state of being penetrated through the tube-formed action shaft material. It is installed to secure the inner diameter dimension. On the other hand, after each forging process is completed, the ejector disposed at the lower outer side of the punch on the lower mold is discharged through the process of moving to the upper and lower sides.

The upper mold and the lower mold may be structured such that they are vertically arranged vertically to the ground in the case of referring to Fig. 2, and on the other hand, they may be arranged in the upper and lower directions parallel to the ground. The six prized molds are scooped up and down through one integral cylinder drive in the state of being contained in one pie mold.

Forging molds for cold forging are required to ensure the precision of the gear dimensions in order to secure the concentricity in the manufacturing process.

The operation state of the forging die is that the material of the reaction shaft entering the one side of the forging die through the spacing space between the upper die and the lower die is formed and transported through one reciprocating stroke movement of the upper die through cylinder drive do. In the molding and transferring process, the material is discharged by the ejector of the first lower mold after the molding is performed through the process of close contact between the first upper mold and the first lower mold. Then, The molding is continuously performed through the following stroke movement in the state where the transfer is proceeding to the space between the second lower dies.

In the present invention, a first upset is performed on a reaction shaft material having a coil cut as an initial material to be inserted, through a first forging process, thereby reducing the axial length of the initially supplied shaft material and increasing the cross- Setting a length of the material formed in the first upsetting step through a second forging step; performing a first rear extrusion through a third forging step to press the punch on the inside of the material to form a predetermined depth Forming a groove, performing a second backward extrusion through a fourth forging process to form a groove deeper on the material, and increasing the overall length of the material, and a fifth step of forging the punch through the material And forming an engagement portion and an involute spline gear on the outer circumferential surface on one upper side of the shaft material on which the piercing has proceeded 6 includes a forging process step. In the sixth forging process step, the formation of the coupling portion is formed on the involute spline gear to improve the lubricating ability.

The post-finishing work after the multi-stage cold forging is as follows.

The reaction shaft having the piercing and involute spline gears is formed by a plurality of stages of a lathe machining process, a serpentine rolling process, a hole milling process, an inner diameter drilling process, a burr ), Etc., a gas carbo-nitriding process, a polishing process, and a nitriding process.

As described above, the method of forming a spline gear of a reaction shaft using a cold former according to the present invention is an application method for forming an involute spline gear on an initial material supplied through a multi-step cold forging process Thereby eliminating drilling and hobbing steps.

Through this, the hobbing cutter used in the hobbing process can be removed, the gear strength can be improved, and the competitiveness of the overall parts manufacturing technology can be enhanced by improving the yield, productivity and cost of the material.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (3)

A multi-stage cold forging step of deforming a tubular shape of an initial material of a round bar type introduced through a single cold material former and simultaneously forming an involute spline gear on one peripheral surface; And
And a post-processing step after the multi-step cold forging step,
In the multi-stage cold forging,
Performing a plurality of upsetting operations on the initial material through a first and a second forging process to increase the cross section and reduce the length of the material; performing a plurality of rear extrusion through the third and fourth forging processes, Forming a groove having a predetermined depth in a plurality of steps and increasing the overall length of the material; performing a piercing so that the punch penetrates the work through a fifth forging step; And a sixth forging step of forming an involute spline gear and forming an involute spline gear, wherein in the sixth forging step, the formation of the engaging portion is formed on the involute spline gear,
In the post-machining step, it is possible to carry out a machining process including a lathe machining, a rolling machining, a milling machining, a drilling machining, a deburring machining, a gas carburizing nitriding process,
A method of forming a spline gear of a reaction shaft using a cold former.
delete The method according to claim 1,
Wherein the forging die used in the multi-stage cold forging includes a plurality of salt molds, each of which performs a plurality of processes,
A method of forming a spline gear of a reaction shaft using a cold former.

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