JP3347030B2 - Induction hardening apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction hardening apparatus for performing an induction hardening process on an uneven surface of a work having an uneven surface inclined with respect to the axis of a helical gear or a bevel gear. And how to.

[0002]

2. Description of the Related Art For example, an induction hardening apparatus for performing high-frequency contour hardening on a tooth portion, which is an uneven surface formed on the peripheral surface of a helical gear, is provided at a predetermined interval on the peripheral surface of the helical gear. It has a ring-shaped high-frequency heating coil to be installed, and cooling means for cooling the heated peripheral surface with a coolant after the ultra-short-time heating by the high-frequency heating coil is completed.

In such a high-frequency contour hardening apparatus, as soon as heating of the work by the high-frequency heating coil is completed, the work is cooled by immersing the work in a coolant or by spraying the coolant onto the work.

[0004]

However, the conventional high frequency contour hardening apparatus has the following problems. That is, as shown in FIGS. 5 and 6, a hardened layer W _{4 formed} by induction hardening is applied to an end W ₂ of the side surface of the tooth W ₁ of the helical gear W.
May not be formed. This is because that by applying a high frequency current to the high-frequency heating coil, along the teeth W ₁ is the unevenness of the end face of the gear W helical induction current generated in the surface of the gear W helical which is a work This is due to uneven flow. Gear W helical includes teeth W ₁ is the unevenness is not skewed relative to the axial W _5, and since it is heated in a short time current density is high, tooth trace of the tooth portion W ₁ the W ₃ being the ends W ₂ of the side surface of the side on which the angle between the end face of the helical gear W becomes obtuse is no flow induced current. Therefore, since the end portion W ₂ is not heated, it is of hardened layer even when cooled immediately after the completion of heating is not formed. If there is a portion where such a hardened layer is not formed, pitching or the like is likely to occur if the gear of the mating partner meshes with this portion.

The present invention has been made in view of the above circumstances, and forms a uniform hardened layer even on a work having unevenness oblique to an axis, such as a helical gear. It is an object of the present invention to provide an induction hardening apparatus and a method that can perform the above-described steps.

[0006]

Means for Solving the Problems] induction hardening apparatus according to the present invention, teeth teeth skewed relative to the axis is formed
An induction hardening device for performing high-frequency contour quenching on the surface of a tooth portion of the gear, wherein the high-frequency heating coil heats the tooth portion , and the heated tooth portion is cooled by a coolant. Cooling means for inductively heating the tooth surface with a high-frequency heating coil,
After the induction heating is completed, the induction current on the tooth surface
The tooth trace of the tooth part that did not flow and the end face of the gear
Conduction heating of the end of the side where the angle made becomes obtuse
For this reason, after the elapse of a time equal to or more than two times and within eight times the heating time, the tooth portion is cooled with the cooling liquid.

In the induction hardening method according to the present invention, a gear having teeth formed at an angle with respect to the axis is used as a workpiece.
A high-frequency quenching method for performing high-frequency contour quenching on the surface of the tooth portion of the gear, wherein the tooth portion is heated by a high-frequency heating coil, and after the heating by the high-frequency heating coil is completed ,
Of the tooth, which is the portion of the surface of the
The side where the angle between the tooth trace and the end face of the gear is obtuse
In order to conduct conductive heating of the end of the surface, the teeth are cooled with a cooling liquid after a lapse of a time equal to or longer than twice and equal to or less than eight times the heating time.

[0008]

FIG. 1 is a schematic diagram showing the configuration of an induction hardening apparatus according to an embodiment of the present invention. FIG. 2 is a view showing an example of the induction hardening performed by the induction hardening apparatus according to the embodiment of the present invention. Schematic perspective view of a helical gear as a finished work, FIG.
Is a schematic sectional view taken along line AA of FIG. 2, and FIG. 4 is a schematic configuration diagram of an induction hardening apparatus according to another embodiment of the present invention.

In the induction hardening apparatus according to the embodiment of the present invention, the tooth portion W ₁ which is an uneven surface which is inclined with respect to the axis W ₅ .
The tooth portion W ₁ of the helical gear W which is a workpiece having
High-frequency heating coil 100 a induction hardening apparatus for performing the high-frequency contour hardening, for heating the teeth W ₁ of the gear W helical in
And a storage tank 200 as a cooling means for cooling the heated tooth portion W ₁ with the cooling liquid L. After the tooth portion W ₁ is heated by the high-frequency heating coil 100, heating is performed by the high-frequency heating coil 100. After a predetermined time has passed since the end of the process, the helical gear W is added to the coolant L in the storage tank 200.
Is immersed and cooled.

[0010] Gear W helical which is a work, as shown in FIG. 2, and has a toothed portion W ₁ which is oblique with respect to the axial center W _5. More precisely, the helical gear W refers to a cylindrical gear having a helical toothed line.

The high-frequency heating coil 100 is formed in a ring shape, and has a heating conductor 110 facing the tooth portion W ₁ of the helical gear W at a predetermined interval,
Feeder 1 for connecting power supply 10 and high-frequency power supply 400
20.

The high-frequency heating coil 100 is formed of a conductive pipe made of copper or the like, and circulates a cooling liquid such as water inside to prevent overheating of itself.

On the other hand, the storage tank 200 stores the cooling liquid L, and is provided immediately below the high-frequency heating coil 100.

Further, the induction hardening device includes a work supporting portion 300 for supporting the helical gear W, and a handling device (not shown) for attaching and detaching the helical gear W to and from the work supporting portion 300. Is provided. The work supporting portion 300 is configured to move the helical gear W, which is a work, to a heating position inside the high-frequency heating coil 100 and a storage tank 2 directly below the heating position.
00 and a cooling position of 00. The upper and lower surfaces of the helical gear W are provided with a concentrating ring 3.
10 is set.

Next, the operation of the induction hardening apparatus will be described. First, the gear W helical is supported horizontally on the work supporting unit 300, the periphery of the teeth W ₁ of the gear W helical shall frequency heating coil 100 is set.
That is, the helical gear W is at the heating position.

A high frequency current is supplied to a high frequency heating coil 100 from a high frequency power supply. For example, in the case of a helical gear W having a diameter of 160 mm and a thickness of 10 mm and made of FCD700, a high-frequency current of 200 KHz is supplied to the high-frequency heating coil 100 for 0.2 seconds. During this time, that is, while the heating by the high-frequency heating coil 100 is performed, the helical gear W
It is for uniform heating, as indicated by arrow A in FIG. 1, and is rotated by O and around the axis W ₅ by workpiece support 300.

[0017] Thus, the induced current in the teeth W ₁ of the surface of the gear W helical heating the surface flow. However, the teeth W
The _first tooth trace W ₃ and the end portion W ₂ of the side surface on the side obtuse angle formed by the end face of the helical gear W is the induced current does not flow. When 0.2 seconds have elapsed since the start of the application of the high-frequency current, the application of the high-frequency current is stopped.

After 1.0 second, the work support 300
Is lowered to the cooling position (see the arrow B in FIG. 1), so that the helical gear W is immersed in the cooling liquid L in the storage tank 200. The said end portion W _2, since the induced current does not flow, but not to directly be heated, until the gear W is immersed in the cooling liquid L helical, said end W ₂ The portion is heated by the heat of the portion heated by the induced current.
Incidentally, while immersing the gear W to the cooling liquid L helical, the rotational driving around the shaft center W ₅ is stopped.

After the elapse of 1.0 second, that is, after the heat has been transmitted to the end portion W ₂ , it is immersed in the coolant L. Thus, conventionally would cured layer W ₄ is formed to the end W ₂ of the hardened layer W ₄ is not formed. Also shows a portion of the hardened layer W ₄ 2 and 3 are formed by oblique lines.

[0020] Gear W helical induction hardening has been performed in this manner, as shown in FIG. 3, conventionally hardened layer W ₄ is formed in an end portion W ₂ of the hardened layer is not formed Was confirmed.

However, if the time from the end of the heating to the start of the cooling is too long, the temperature of the root may decrease, and the depth of the root may become shallow, or burning may not occur. For this reason, it is important to forcibly cool the coolant L by injecting the coolant L within 1.0 second after the supply of the high-frequency current is stopped.

As a result of actually performing induction hardening on various helical gears W, the following was found. First, when the heating time is A (second), after the supply of the high-frequency current is stopped, at least 2 A (second) has elapsed and 8 A
It is necessary to cool with the cooling liquid L before (second) elapses. This is because, as described above, when the time from the stop of the heating to the start of cooling is too short, induction is not heated the end W ₂ that has not been heated by the current, the time until the start of cooling from the stop of the heating If the length is too long, the portion heated by the induced current will be cooled.

In the above-described embodiment, a storage tank 200 storing the cooling liquid L is used as the cooling means.
Although the helical gear W is immersed in the storage tank 200, the present invention is not limited to this. For example, as shown in FIG. 4, a cooling jacket 500 is provided below the high-frequency heating coil 100, and the helical gear W is heated while facing the heating conductor 110 of the high-frequency heating coil 100. 300 is lowered so that the helical gear W faces the cooling jacket 500 and the injection holes 510
The helical gear W may be cooled by injecting the cooling liquid L from the nozzle.

The heating time also depends on the size of the helical gear W, the depth of the hardened layer to be formed, and the like.
The time to start cooling after stopping heating is 2A to 8A
Turned out to be.

In the above-described embodiment, the helical gear W is used as the work. However, it is needless to say that the present invention can be applied to a helical internal gear and a helical gear.

[0026]

The induction hardening apparatus according to the present invention uses a gear having teeth formed at an angle with respect to the axis as a work.
And it is, an induction hardening apparatus for performing the high-frequency contour hardening the surface of the teeth of said gears, to cool the high-frequency heating coil for heating the teeth, the heated teeth in the coolant cooling and and means, the teeth in the high-frequency heating coil
The surface was induction heating, the induction heating is completed by the high-frequency heating coil, not flow induced current of the surface of the teeth
The angle between the tooth trace of the tooth part, which is the
In order to conduct and heat the end of the side of the obtuse side, after a time equal to or more than two times and within eight times the heating time has elapsed,
The cooling unit is configured to cool the teeth .

According to this induction hardening device, the gear tooth portion
After the supply of the high-frequency current is stopped, the heat of the portion heated by the induction current flowing on the surface of the substrate is transmitted to the portion not heated by the induction current, and the portion is reliably heated. Moreover, the portion heated by the induced current does not cool down due to heat radiation. As a result, the teeth
The surface is heated throughout. In this state, the teeth are cooled by the cooling liquid, so that the induction hardening can be reliably performed on the teeth . Therefore, since induction hardening is performed over the entire tooth width, problems such as pitching do not occur.

On the other hand, in the induction hardening method according to the present invention, a gear having teeth formed at an angle with respect to an axis is formed on a workpiece.
And a high-frequency quenching method for performing high-frequency contour quenching on the surface of the tooth portion of the gear, wherein the high-frequency heating coil heats the tooth portion, and after the heating by the high-frequency heating coil is completed , The part of the tooth surface where the induced current did not flow
The angle between the tooth trace of the gear tooth and the end face of the gear becomes obtuse.
2 hours of heating time to conduct conductive heating
After the time of more than double and within eight times has elapsed,
The teeth are cooled.

According to this induction hardening method, the tooth portion of the gear
After the supply of the high-frequency current is stopped, the heat of the portion heated by the induction current flowing on the surface of the substrate is transmitted to the portion not heated by the induction current, and the portion is reliably heated. Moreover, the portion heated by the induced current does not cool down due to heat radiation. As a result, the teeth
The surface is heated throughout. In this state, the teeth are cooled by the cooling liquid, so that the induction hardening can be reliably performed on the teeth . Therefore, since induction hardening is performed over the entire tooth width, problems such as pitching do not occur.

[0030]

[0031]

[0032]

[0033]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an induction hardening device according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a helical gear as a workpiece on which high-frequency contour hardening has been performed by the high-frequency hardening apparatus according to the embodiment of the present invention.

FIG. 3 is a schematic sectional view taken along line AA of FIG. 2;

FIG. 4 is a schematic configuration diagram of an induction hardening device according to another embodiment of the present invention.

FIG. 5 is a schematic perspective view of a helical gear as a work on which high-frequency contour hardening has been performed by a conventional high-frequency hardening apparatus.

FIG. 6 is a schematic sectional view taken along the line BB of FIG. 5;

[Explanation of symbols]

REFERENCE SIGNS LIST 100 high frequency heating coil 200 storage tank (cooling means) L cooling liquid W helical gear (work) W ₁ tooth portion (irregularities) W ₅ axis core

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C21D 1/10 C21D 1/42 C21D 9/32

Claims (2)

(57) [Claims] 1. A has a gear tooth portion which is oblique with respect to the axis is formed as a work, a induction hardening apparatus for performing the high-frequency contour hardening the surface of the teeth of the gear, the teeth
A high frequency heating coil for heating the part, the heated teeth are provided with a cooling means for cooling by the cooling liquid, and induction heating the surface of the teeth in the high frequency heating coil, induction heating by high-frequency heating coil After finishing, induction on the tooth surface
Tooth traces and gear ends where no current flowed
Conducting the end of the side surface on the side where the angle between the
An induction hardening device characterized in that after heating for at least two times and at most eight times the heating time, the teeth are cooled with a cooling liquid. 2. A has a gear tooth portion which is oblique with respect to the axis is formed as a work, a induction hardening method of applying a high-frequency contour hardening the surface of the teeth of the gears, high-frequency heating After the tooth is heated by the coil and the heating by the high-frequency heating coil is completed, no induced current flows on the surface of the tooth.
The angle between the tooth trace of the tooth part, which is the toothed part, and the end face of the gear
Conduction heating of the end of the side with the obtuse angle
In addition, the induction hardening method is characterized in that the tooth portion is cooled with a cooling liquid after a lapse of a time equal to or more than two times and within eight times the heating time.