KR20020069395A - A flanetary gear fabrication method of a starter - Google Patents

Abstract

PURPOSE: A method for manufacturing planetary gear of a starter is provided to increase strength of the planetary gear by adding pre-sintering and tooth form repressing processes to the powder metallurgy manufacturing process of the planetary gear, thereby improving density and impact strength of the planetary gear. CONSTITUTION: The method for manufacturing planetary gear of a starter comprises the steps of mixing materials for manufacturing the planetary gear in the mixing process; molding the mixed materials in the forming process equipped with a molding frame for forming the gear; pre-sintering the molded planetary gear in the pre-sintering process; tooth form repressing the pre-sintered planetary gear in the tooth form repressing process; second sintering the tooth form repressed planetary gear in the sintering process; second repressing the sintered planetary gear in the repressing process; and washing and drying the repressed planetary gear in the washing and drying processes, wherein density and impact strength of the planetary gear manufactured by the above processes are 7.31 to 7.35 g/cm¬3 and 1720 kgf respectively.

Description

Starter Planetary Gear Manufacturing Method {A FLANETARY GEAR FABRICATION METHOD OF A STARTER}

In the present invention, in manufacturing a planetary gear to transmit the rotational force generated by the starter amateur driving to the internal gear, the planetary gear is manufactured by a manufacturing process by powder metallurgy, pre-sintering The present invention relates to a method for manufacturing a planetary gear of a starter to increase the strength of the planetary gear by adding an overdental repressurization process and improving the density and impact strength of the planetary gear by the process. .

In general, a starter motor installed for engine start of a vehicle has an armature and a field part installed in the housing to start the engine as the armature rotates and the planetary gear rotates to rotate the pinion gear. The amateur rotates the planetary gear and the internal gear while making a strong rotation, and drives the pinion gear through the rotary shaft connected to the armature, and the pinion gear drives the engine by rotating the ring gear installed on the engine output shaft of the vehicle. there was.

On the other hand, the conventional starter has a center bracket for supporting the axis of the amateur in the center of the housing in which the armature is installed, and one of the center brackets to support the planetary gear engaged with the gear installed on the shaft of the armature as a support. Install an internal gear on an outer circumference of the planetary gear, and install a steel ball in the center of the support to support the shaft end of the armature, and connect the housing to one side of the support while being connected to the housing; A front bracket for supporting the gear was installed, a washer was installed between the support and the front bracket, and a packing was installed between the center bracket and the outer circumference of the internal gear.

In addition, the conventional configuration configured as described above, when the armature installed in the housing is rotated to operate, the rotational force thereof is transmitted to the internal gear through the gear and planetary gear and this rotational force is applied to the pinion of the starter, The pinion was rotated while being engaged with the ring gear of the engine to start the engine.

In addition, the manufacturing method of the planetary gear provided in the conventional starter as described above, to produce the planetary gear through a single material mixing process, forming, sintering, re-pressurization, washing and drying process The manufactured planetary gear has a density of 7.1-7.15 g / cm 3 and an impact strength of 1515 kgf, and there is a limit of only the density and impact strength.

Therefore, such a conventional one cannot improve the density and impact strength of the planetary gear, and there is a problem of lighting that the planetary gear is easily damaged or broken.

The present invention has been made in view of the above-mentioned conventional problems, the present invention is to produce a planetary gear to transmit the rotational force generated by the starter amateur drive to the internal gear, the planetary The gears are manufactured by a powder metallurgy manufacturing process, and preliminary sintering and tooth repressurization processes are added to the process, and the density and impact strength of the planetary gears are improved by the process. It is intended to provide a planetary gear manufacturing method of a starter to increase the strength, which will be described in detail below based on the accompanying drawings.

1 is a comparison of the impact strength of the present invention

Explanation of symbols on the main parts of the drawing

Example

The present invention is to mix the material for producing a planetary gear in a mixing process, and to form the mixed material in a molding process having a forming mold for forming a gear, pre-sintering the molded planetary gear After presintering in the process, it is pressurized in the tooth press process and the planetary gear pressurized in the sintering process.

The sintered planetary gear is to be second re-pressurized in the repressing process, and washed and dried in the washing and drying process to have a density of 7.31-7.35 g / cm 3 and an impact strength of 1720 kgf.

That is, the planetary gear manufactured by the manufacturing method as in the above embodiment is to complete the primary molding by the preliminary and tooth pressing process, and in this state, perform the secondary process by the sintering and repressurizing process. By doing so, the density and impact strength of the planetary gear can be increased, and the strength of the planetary gear according to the manufacturing process can be improved as shown in the diagram of FIG. 1.

In addition, the comparison of the impact strength as shown in the diagram of Fig. 1 according to the conventional and the present invention is as shown in the table.

Table 1

sample One 2 3 4 5 6 7 8 9 Conventional 1420.5 1617.4 1412.4 1489.9 1672.3 1583.5 1523.8 1325.2 1588.3 Invention 1666.6 1860.3 1797.7 1682.8 1763.5 1642.4 1715.1 1731.2 1642.4

(Unit is kgf, and the comparison table is for its own test results)

The present invention as described above, by mixing, forming, pre-sintering, dental re-pressing process, and the secondary sintering, re-pressing process to the process as described above, the density and impact strength of the planetary gear is formed and manufactured Compared with the related art, it can be greatly improved, and accordingly, the internal pressure of the planetary gear can be improved to increase the strength thereof, and the damage rate of the planetary gear due to the load and impact is improved according to the improvement of the density and strength. Since it is possible to greatly reduce the damage rate and damage, it has the characteristic of lighting that can improve the performance of the starter.

Claims (2)

Materials for producing planetary gears are mixed in a mixing process, and the mixed materials are molded in a molding process with a forming mold for forming gears, and the molded planetary gears are preliminary in a presintering process. After sintering, it is pressurized in the tooth pressing process, and the toothed planetary gear is secondly sintered in the sintering process, and the sintered planetary gear is secondly pressurized in the repressurizing process, which is washed and dried. Planetary gear manufacturing method of the starter, characterized in that to be manufactured by washing and drying in. The method of claim 1, wherein the planetary gear manufactured by the process has a density and impact strength of 7.31-7.35g / cm 3 and 1720kgf, respectively.