JP2020110876A - Surface processing method of gear tooth surface - Google Patents

Abstract

To press particles on a tooth surface before carburization, and remove the particles after the carburization to thereby form recesses on the tooth surface.SOLUTION: A surface processing method of a tooth surface 22 of a gear 2 of a steel material is provided as follows: a tooth-shaped gear blank before the quenching processing is immersed in liquid 12 containing particles 12a with hardness higher than that of steel material and having a predetermined particle size; the imposition of the particles 12a to the tooth surface 22 is executed by a tool body 11 having a shape corresponding to the tooth shape so as to immerse the particles 12a in the liquid 12 into the tooth surface 22; and the quenching of the gear 2 is executed, and the tooth surface 22 is polished so as to make the particles 12a immersed in the tooth surface 22 fall off.SELECTED DRAWING: Figure 3

Description

The present invention relates to a surface processing method for a tooth surface of a gear that has been machined.

In recent years, in order to improve power transmission efficiency in gears, dimples capable of sufficiently retaining lubricating oil have been formed on tooth surfaces while maintaining tooth surface strength.

Conventionally, as a technique in such a field, there is JP-A-2004-345022. In the method for processing the tooth flank of the gear described in this publication, steel ball particles are shot on the tooth flank of the gear that has been cut to provide dimples on the tooth flank, and the surface is hardened by carburizing treatment, and then shot. It is disclosed that a tooth surface having a flat portion and a concave portion is formed by performing a peening process.

JP, 2004-345022, A

However, in the above-described conventional gear tooth surface processing method, the first shot peening treatment is performed before the carburizing treatment for hardening the surface, and the second shot peening treatment is performed after the carburizing treatment. Although it is desired to reduce the manufacturing cost in gear manufacturing, shot peening is a costly process in gear manufacturing.
The present invention provides a method for surface-treating a tooth flank of a gear capable of forming dimples on the tooth flank at low cost.

A tooth surface treatment method for a gear according to the present invention is a method for processing a tooth surface of a gear made of a steel material, in which a gear material having a toothed shape before quenching treatment has a predetermined hardness higher than that of the steel material. Of the particles are immersed in a liquid containing particles having a particle size of, and the tool in the liquid has a shape corresponding to the shape of the teeth so that the particles in the liquid are embedded in the tooth surface. The tooth surface is pressed, the gear is hardened, and the tooth surface is polished so as to remove the particles embedded in the tooth surface.
As a result, the particles can be pressed against the tooth surface before carburizing, and the particles can be removed after carburizing to form a depression on the tooth surface.

Thereby, dimples can be formed on the tooth surface at low cost.

It is a figure which shows the state in which the gearwheel was set to the apparatus main body of a surface processing apparatus. FIG. 7 is an enlarged view of a part of a state where gears are set on the main body of the surface processing apparatus. It is a figure which shows an example of the manufacturing process of a gearwheel.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a tooth surface treating apparatus 1 includes an annular tool body 11 in which an annular gear 2 can be set inside, and a liquid 12 for dipping the gear 2 in the tool body 11. And

A plurality of teeth 21 are formed on the outer peripheral surface of the gear 2 so as to project outward. The plurality of teeth 21 are arranged continuously along the circumferential direction of the annular gear 2. In the following description, the tooth surface 22 is the contour of the tooth 21. The gear 2 is made of steel.

The tool body 11 is made of a material harder than the gear 2 before quenching. As shown in FIG. 2, the tool main body 11 is formed with a plurality of protrusions 13 protruding from the inner peripheral surface toward the center. The plurality of protruding portions 13 are arranged so as to be continuous in the circumferential direction on the inner peripheral surface of the tool body 11 so as to correspond to the teeth 21 of the gear 2.

Further, the shape of the protruding portion 13 is a shape corresponding to the shape of the tooth surface 22. In other words, the tool main body 11 has a shape corresponding to the gear material before the quenching treatment having the tooth shape. Further, for example, the tool main body 11 may be capable of sealing with the gear 2 and the liquid 12 inserted therein. 2 is an enlarged view of a part of FIG.

For example, as shown in FIG. 1, when a force is applied to move the tool main body 11 in the counterclockwise direction in a state where the gear 2 is set in the tool main body 11 so that the central axes thereof are aligned, as shown in FIG. The curved surface of the contact portion 22a of the tooth surface 22 and the curved surface of the contact portion 13a of the protruding portion 13 match. That is, the protruding portion 13 is formed such that the gap between the contact portion 22 a on the tooth surface 22 and the contact portion 13 a on the protruding portion 13 is small.

The liquid 12 immerses the gear 2 in the tool body 11. The liquid 12 is filled so as to fill at least the space between the outer peripheral side of the gear 2 and the inner peripheral side of the tool body 11. The liquid 12 contains particles 12a having a hardness higher than that of the material of the gear 2 before the quenching treatment and having a predetermined diameter. That is, as the particles 12a, those having a hardness higher than that of the steel material used as the material of the gear 2 are used.

The particles 12a are arranged so as to be sandwiched between the protrusion 13 and the tooth surface 22 when the protrusion 13 is pressed against the tooth surface 22 of the gear 2 by operating the tool main body 11, so that the tooth surface 22 Immerse yourself in For example, the particles 12a are spherical with a diameter of 100 to 110.

Next, a manufacturing flow of the gear 2 will be described. FIG. 3 shows an example of the manufacturing process of the gear 2.

First, gear cutting is performed to cut the gear material into the shape of the gear 2 (step S1).

Next, the dimple processing of the gear 2 is performed (step S2).

Specifically, the soft gear 2 before quenching is set on the tool body 11 (step S21). At this time, the projecting portions 13 of the tool body 11 are set in such a manner that they mesh with the teeth of the gear 2 in an alternating manner.

In the surface processing apparatus 1, the liquid 12 containing the particles 12a is inserted and the gear 2 is immersed (step S22). At this time, the particles 12a having a diameter of about φ100 to φ110 are in a state of entering between the tooth surface 22 of the gear 2 and the protruding portion 13 of the tool body 11.

The tool body 11 is operated and pressed against the gear 2 (step S23). More specifically, as shown in FIG. 1, the tool body 11 is moved counterclockwise in a top view with the axial directions of the tool body 11 and the gear 2 being the vertical directions. As a result, the protruding portion 13 of the tool body 11 is pressed against the tooth surface 22 of the gear 2.

Here, the space between the tooth surface 22 of the gear 2 and the protruding portion 13 of the tool body 11 is filled with the liquid 12, and the particles 12a are arranged. Therefore, as shown in FIG. 2, by operating the tool main body 11 so as to press it against the gear 2, the particles 12a are embedded in the tooth surface 22 of the gear 2 (step S24).

Next, the gear 2 is quenched (step S3). The gear 2 is hardened by performing the quenching.

Next, the tooth surface 22 is ground (step S4). For example, in grinding the tooth surface 22, the particles 12a embedded in the surface of the tooth surface 22 are removed by grinding 0.1 mm. As a result, the tooth surface 22 is provided with dimples having a depth of several μm.

In this way, in the manufacturing process of gears, a step of embedding extremely small particles in the tooth surface is added between the gear cutting step and the quenching step, and after the quenching performed thereafter, the particles are The pressed tooth surface can be scraped. As a result, the tooth surface is in a state in which depressions of an appropriate size are formed to sufficiently hold the lubricating oil while excluding the pressed particles. By such a method, dimples can be formed on the tooth surface without using a costly method of performing shot peening a plurality of times.

The present invention is not limited to the above-mentioned embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, it has been described that the tool body 11 is operated in the counterclockwise direction in the top view to press the particles 12a against the tooth surface 22 by the protrusion 13, but the invention is not limited to this. For example, the tool body 11 may be moved clockwise in a top view, and the particles 12a may be pressed against the tooth surface 22 by another method.

DESCRIPTION OF SYMBOLS 1 Surface processing apparatus 2 Gear 11 Tool main body 12 Liquid 12a Particle 13 Projection part 13a Contact part 21 Teeth 22 Tooth surface 22a Contact part

Claims (1)

A method for processing the tooth surface of a steel gear,
The gear material before the quenching treatment having a tooth shape is immersed in a liquid containing particles having a hardness higher than the steel material and a predetermined particle diameter,
The tool body having a shape corresponding to the shape of the tooth portion is used to press the particles onto the tooth surface so that the particles in the liquid are dented into the tooth surface.
Quenching the gears,
Polishing the tooth surface so as to remove the particles embedded in the tooth surface,
Surface finishing method for gear tooth surfaces.

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