JP2000107937A - Gear machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely discharge chips in tooth profile formation and to suppress the occurrence of so-called gouge by biting of chips by performing a hobbing by reverse winding conventional cut or an equal winding conventional cut. SOLUTION: A high-speed tool steel hob 1 and a work 2 are mounted in a prescribed position of a gear hobbing machine, and the hob 1 and the work 2 are rotated in a rotating direction for forming equal winding conventional cut or reverse winding conventional cut. The hob 1 is set to a rotating speed suitable for dry cut. The hob 1 is brought into contact with the work 2 without supplying hydraulic oil to cut the work 2, and a tooth profile is formed. In the equal winding conventional cut and reverse winding conventional cut, chips are originally hardly welded to the hob 1, and even if the chips are adhered to the hob 1, the chips are fallen while the hob 1 is rotated. Accordingly, a gear can be formed without causing biting of chips or gouge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear cutting method for creating a tooth profile by dry cutting.

[0002]

2. Description of the Related Art Conventionally, as a hobbing method for generating a gear, there have been known a hoisting cut, a reverse winding climbing cut, a conventional winding cut (see FIG. 2) and a reverse winding conventional cut (see FIG. 1). Although four methods are mainly known, among them, generally, the same-wind climb cut is generally adopted in consideration of a cycle time, a tool life, and the like.

[0003] In general, when a gear made of a metal material such as a steel material is created by using these techniques, a cutting oil is usually used in any case. By performing the machining while supplying the steel to the cutting portion, the seizure of the hob (hob cutter) is prevented and the discharge of the chips is promoted. On the other hand, if cutting oil is used, post-processing of the cutting oil after processing is difficult,
There has been a demand for creating a tooth profile without using cutting oil.

[0004] In response to such a demand, in recent years, a technology for processing a gear without using cutting oil has been developed. As such a technique, for example, a cutting speed of 200 to 300 m / mi using a hob made of cemented carbide.
In some cases, high-speed machining is performed at n. Such a cemented carbide hob has much higher heat resistance and abrasion resistance than a conventional hob, and therefore can be processed by so-called dry cutting without using cutting oil. However, in such a super hard hob, sudden chipping occurs, so that practical use is difficult, and dry cut has hardly been widespread. However, dry cutting with a hob made of high-speed tool steel has recently become possible,
It is expected that dry cutting will become widespread because the problem of chipping is eliminated.

[0005]

However, in a hob made of high-speed tool steel, seizure can be prevented without using cutting oil, but the hob itself is a special tool for discharging chips during machining. If no machining oil is used, machining without using cutting oil will cause so-called swarf due to biting of chips on the tooth surface, and the processed gear may be defective. There are issues.

[0006] Also, the super hard hob is a work (gear material).
Because of its low affinity with chips, chips did not adhere to the rake face of the hob, and there was no problem of chip entrapment.However, the coating film was removed during use with the hob made of high-speed tool steel. When the base material comes into contact with the workpiece, the chips are deposited on the rake face. For this reason, there is a possibility that the chips may bite into the cutting portion when the hob rotates once while the chips are welded and the next cutting is performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to use a hob cutter made of a high-speed tool steel to process a gear made of a metal material such as a steel material without using a cutting oil. It is an object of the present invention to provide a gear machining method capable of reliably discharging the gears and preventing the gears from being wrinkled.

[0008]

According to the present invention, there is provided a gear machining method according to the present invention, wherein a tooth profile is formed by dry cutting using a hob cutter made of high-speed tool steel without using a cutting oil. In the gear processing method to be created, hobbing is performed by reverse winding conventional cut or the same winding conventional cut in order to avoid biting of chips.

A gear machining method according to a second aspect of the present invention is characterized in that, in addition to the first aspect, the gear in which the tooth profile is created is made of a steel material. The gear processing method according to the present invention described in claim 3 is characterized in that, in addition to the above-described claim 2, the gear in which the tooth profile is created is made of a steel material other than a casting material.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a gear machining method according to an embodiment of the present invention;
FIG. 2 is a schematic view showing the state during the processing, and is a schematic view showing a cutting state in the case of performing the processing by the reverse winding conventional cut.
FIG. 3 is a schematic view showing the state during the processing, and is a schematic view showing a cutting state in the case of performing processing by the same winding conventional cut;
FIG. 4 is a diagram showing the ratio of defective products when a gear is processed without using cutting oil, in comparison with other processing methods.

In FIGS. 1 and 2, reference numeral 1 denotes a hob (hob cutter), 2 denotes a work (gear material), and the hob 1 is rotated at a high speed to cut the work 2.
A tooth profile is created on the work 2. During cutting, cutting is performed by dry cutting without supplying cutting oil. As the hob 1, TiA
A hob made of high-speed tool steel coated with 1 nitride or TiAl carbonitride is applied.

In this case, a hob coated with at least one layer of a TiAl nitride film having a composition of (Ti _(1-x) Al _x ) N in the range of 0.2 ≦ x ≦ 0.85, In the range of 2 ≦ x ≦ 0.85, 0.25 ≦ y ≦ 1.0, a carbon nitride of TiAl having a composition of (Ti _(1-x) Al _x ) (N _y C _(1-y) ) A hob coated with at least one film is used. The hob 1 coated with the TiAl nitride or TiAl carbonitride described above.
Then, the cutting speed is 80m / min or more and 400m / min.
It is set as follows.

A steel material is used as a material of the work 2, and a tooth profile is formed on the outer peripheral side of the work 2 of the steel material.

In the gear machining method of the present invention, a tooth profile is created by performing dry cutting by reverse winding or conventional cutting using the hob 1 and the work 2 described above. As a result, the gear can be created without causing the chips to be caught or ragged. In other words, of the four types of hobbing methods, namely, the same-size climb cut, the reverse-type climb cut, the same-type conventional cut and the reverse-type conventional cut, in the same-type climb cut and the reverse-type climb cut, chips are generated when dry cutting is performed. In some cases, it may not be reliably ejected and may cause stuffiness.On the other hand, in the case of reverse winding conventional cut or wrapping conventional cut, even if dry cutting is performed without supplying cutting oil, no stuffiness occurs and low Gears can be created at high cost and high efficiency.

Since the gear machining method according to one embodiment of the present invention is configured as described above, when machining a gear, a tooth profile is created as follows. First, a hob 1 and a work 2 made of high-speed tool steel are attached to a predetermined portion of a hob machine (not shown), and the hob 1 and the work 2 are rotated in a rotation direction of the same winding conventional cut or the reverse winding conventional cut. At this time, the rotation speed of the hob 1 is set to a value suitable for dry cutting. And
The hob 1 is brought into contact with the work 2 without supplying the hydraulic oil, and the work 2 is cut to form a tooth profile.

FIG. 3 shows the rate of occurrence of tooth flank due to biting of chips when a gear is machined without using cutting oil. In this case, the hob 1 has 1.3 modules, 4 ports, 60 outer diameters, and 14 grooves,
The work 2 has a material SCM415, module 1.3, number of teeth 21, and a helix angle of 20 °. The processing conditions were as follows: cutting speed 200 m / min, axial feed 2.4 mm / rev
It is. Then, the vertical axis indicates the number of workpieces in which 100 workpieces were machined under the above-mentioned conditions, and the tooth surface had a wrinkle.

As a result of this comparative test, as shown in FIG.
It can be seen that in the reverse winding conventional cut and the conventional winding cut, no whirling occurs due to biting, but in the winding wound and the reverse winding cut, whirling occurs at a high rate in the gears. Therefore, in dry cutting in which cutting is performed without using a cutting fluid, it can be said that reverse winding conventional cut or same winding conventional cut is suitable.

[0018] The results are as follows: steel materials such as castings, various structural carbon steels and structural alloy steels, for example, SCM420, SCM420
The same applies to Cr420, S50C, SNCM420, etc., which are suitable for use in these steel materials. In the case of the casting material, the chips were cracked, that is, were in a powdery form, so that the chips were originally not easily welded and did not cause much problems such as biting, but other structural carbon steels and structural steels were used. Since chip chips having a certain length are produced in alloy steel for industrial use, the conventional dry cut is liable to cause stuffiness due to biting. On the other hand, according to the present invention, since the occurrence of stuffiness can be greatly reduced, it can be said that the present invention is optimal for these steels.

It has been confirmed that even if the size of the work 2 changes, the same result as that of FIG. 3 is obtained in the range of the cutting speed of 80 m / min to 400 m / min.

Incidentally, the result of the comparative test shown in FIG.
When dry cutting is performed, the reverse winding conventional cut and the conventional winding cut mean that chips during cutting are reliably discharged. This indicates that the chips cannot be reliably discharged without using.

This is because, in the conventional winding cut and the conventional cutting in the reverse winding, the chips are originally difficult to weld to the hob 1, and even if the chips adhere to the hob 1, the chips are removed during one rotation of the hob. It is thought to fall. Furthermore, in such a conventional winding cut and a conventional winding reverse, the chips are discharged in a direction in which the chips do not adhere to the hob 1 (a direction in which the chips do not bite). You might also say that.

In particular, the above-mentioned structural carbon steel and structural alloy steel discharge chips having a predetermined length, which is a so-called flow type or shear type, and chips having such a shape are surely discharged. Otherwise, it would easily weld to the hob 1 and easily bite. On the other hand, in the above-described reverse winding conventional cut or the same winding conventional cut, since chips are discharged without welding to the hob 1, generation of stuffiness due to biting can be reduced.

As described above, the gear processing method of the present invention is as follows.
When cutting gears by dry cutting without using cutting oil, hobbing by reverse winding conventional cut and the same winding conventional cut makes it possible to reliably discharge chips at the time of cutting. There is an advantage that generation of stuffiness due to biting can be suppressed. In addition, the ratio of the processed gear as a defective product is greatly reduced, and the productivity is greatly improved. In addition, the gear can be processed with high efficiency and low cost. Further, the working environment and the global environment can be improved by dry cutting.

The gear processing method according to the embodiment of the present invention is not limited to the above-described method, and various modifications can be made without departing from the gist of the present invention. For example, the hob 1 can be widely applied to anything other than the above as long as the hob 1 is configured to be capable of dry cutting.

[0025]

As described above in detail, according to the gear machining method of the first aspect of the present invention, dry cutting is performed by using a hob cutter made of high-speed tool steel without using a cutting oil. In a gear machining method for creating a tooth profile, by performing hobbing with a reverse winding conventional cut or the same winding conventional cut, chips generated at the time of tooth profile generation can be reliably discharged. There is an advantage in that generation of odor can be suppressed. In addition, the ratio of rejected processed gears is greatly reduced, and productivity is greatly improved.
There is an advantage that gears can be processed with high efficiency and low cost. Furthermore, the improvement of the working environment and the global environment can be achieved by dry cutting.

Further, according to the gear machining method of the present invention, when a steel material is used as the material of the gear in which the tooth profile is created, chips generated when the tooth profile is created can be reliably discharged. The occurrence of stuffiness can be suppressed. According to the gear machining method of the present invention, when a steel material other than a casting material is used as a material of a gear in which a tooth profile is created, a flow type or a shear type generated when the tooth profile is created. There is an advantage that chips having a predetermined length can be reliably discharged, and the occurrence of stuffing can be reliably reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a gear machining method according to an embodiment of the present invention at the time of machining, and is a schematic diagram showing a cutting state when machining by reverse winding conventional cut.

FIG. 2 is a schematic view of a gear machining method according to an embodiment of the present invention at the time of machining, and is a schematic view showing a cutting state in the case of machining with the same conventional winding cut.

FIG. 3 is a diagram showing the occurrence rate of defective products in a gear processing method as one embodiment of the present invention in comparison with other processing methods.

[Explanation of symbols]

 1 Hob (hob cutter) 2 Work (gear material)

Continued on the front page (72) Inventor Hiroyuki Fukunaga 130 Rokujizo, Ritsuto-cho, Kurita-gun, Shiga Prefecture Mitsubishi Heavy Industries, Ltd.Kyoto Seiki Seisakusho Inside the Seiki Seisakusho (72) Inventor Akihide Tsunoya 130 Rokujizo, Ritto-cho, Kurita-gun, Shiga Prefecture F-term in the Mitsubishi Heavy Industries, Ltd. Kyoto Seiki Seisakusho 3C025 AA16

Claims (3)

[Claims] 1. Using a high speed tool steel hob cutter,
A gear cutting method that creates a tooth profile by dry cutting, which does not use cutting oil, is characterized by performing hobbing by reverse winding conventional cutting or the same winding conventional cutting in order to avoid biting of chips. , Gear processing method. 2. The gear processing method according to claim 1, wherein the gear in which the tooth profile is created is made of a steel material. 3. The gear machining method according to claim 2, wherein the gear in which the tooth profile is created is made of a steel material other than a casting material.