JPH0551631A - Method and device for nonoxidative high-frequency quenching - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent coloring of the hardened layer of the non-oxidative induction-hardened work. [Composition] A box-shaped container with an open upper part and a lower semi-closed part, the lower part of which is immersed in a cooling liquid and which penetrates the bottom surface of a cooling liquid receiver 95 installed in a non-oxidizing or reducing gas.
After mounting the gear W on the top of 93, the lower part of the atmosphere case 50, which is filled with the non-oxidizing or reducing gas G and has a box shape of a lower open upper half closed and a high frequency heating coil 24, is cooled. Immerse in the cooling liquid L in the liquid receiver 95, then receive the cooling liquid
Coolant L is supplied to 95 via solenoid valve 64 and atmosphere case
Immediately after the gear W is heated by the high-frequency heating coil 24 after the coolant level in 50 is raised to near the lower end of the gear W, the coolant is supplied to the coolant receiver 95 via the solenoid valve 65 to cool the workpiece. Immerse in liquid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidation-free induction hardening method and apparatus.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to the drawings. FIG. 5 is a plan view of a conventional non-oxidizing induction hardening apparatus for hardening the tooth surface of a gear, for example, and FIG.
It is a line arrow cross section explanatory view. Around the horizontal turntable 90 that makes one rotation about the shaft 94 in 12 steps, six work receivers 93 are arranged at intervals of a rotation angle of 2 steps of the turntable 90.

The work receiver 93 has work supporting rods 92 penetrating around the turntable 90 at equal intervals and capable of moving up and down and rotatably, and a disk shape horizontally formed on the upper end of each work supporting rod 92. And the work placement table 91. The gear W is placed on the work placing table 91 via the lower outlet ring 41. The upper outlet ring 42 is mounted on the gear W. These outlet rings 41, 42
Is for preventing a portion of the gear W that does not need to have a hardened layer from being heated, and for forming a hardened layer on the tooth bottom linearly.

A tunnel-shaped preliminary chamber 10 along the traveling direction of the gear W and a tunnel-shaped heat treatment chamber adjacent to the preliminary chamber 10.
20 are provided, and the lower parts of these chambers are immersed in a cooling liquid (not shown). Further, shutters S1 and S2 that are moved up and down by a cylinder (not shown) are attached to the inlet and the outlet of the preliminary chamber 10 (the inlet of the heat treatment chamber 20).
The heat treatment chamber 20 has a preheating zone 21 and a main heating and quenching zone 22, and a rear wall 27 that seals the heat treatment chamber 20 is provided at the rear end of the main heating and quenching zone 22.

Two pipes 11, eight pipes 25 and three pipes 26 are provided above the pre-chamber 10, the preheating zone 21 and the main heating and quenching zone 22, respectively. A non-oxidizing or reducing gas is supplied from the property gas generator, and the preliminary chamber 10 and the heat treatment chamber 20 are filled with this gas. The preheating zone 21 is provided with a preheating coil 23 that can be moved up and down, and the main heating and quenching zone 22 is provided with a substantially annular heating coil 24. Reference numeral 24a is a high frequency power supply for supplying a high frequency current to the heating coil 24.

[0006] The main heating and quenching zone 22 is provided with a main heating atmosphere case 50 which is lifted up and down by an elevator device (not shown) with the upper half closed and the lower open. An annular high frequency heating coil 24 is attached to the side wall of the atmosphere case 50, and the high frequency heating coil 24 is connected to the high frequency power supply 24a.
Connected via 24b. The pipe 26 is flexible, and its tip is open in the main heating atmosphere case 50.

Next, the operation of quenching using the above-mentioned non-oxidizing induction hardening apparatus will be described. The turntable 90 is rotated stepwise in the direction of arrow P, and the shutter of the preliminary chamber 10 is rotated.
The gear W is mounted together with the outlet rings 41 and 42 on the work mounting table 91 in front of S1. When the shutter S1 is opened and the turntable 90 is rotated by one step, the gear W enters the preliminary chamber 10. At the same time, the shutter S1 is closed. Next, the shutter
When S2 is opened and then the turntable 90 is rotated by one step, the gear W enters the preheating zone 21 and closes the shutter S2.

After the next one step, the preheating coil 23 descends to surround the gear W and the preheating of the gear W starts. The preheating coil is raised before the next step is started, and after one step, the preheating coil is lowered again to preheat the gear W. When the rotation of the turntable 90 advances and the gear W reaches the main heating and quenching zone 22, the atmosphere case 50 descends and the tooth surface of the gear W is heated. The shutters S1 and S2 are opened every other step before the start of one step rotation of the turntable 90, and closed after the start.

When the main heating of the gear W is completed, the work receiver 93
Atmosphere case 50 rises after is lowered. As the work receiver 93 descends, the gear W is immersed in the cooling liquid and the quenching is completed. Next, when the turntable 90 advances one step and then the work receiver 93 is raised, the hardened gear W appears on the cooling liquid surface, so the gear W is taken out. The second gear W is placed on the work placement table 91 in front of the shutter S1 when the first gear W enters the preliminary chamber 10, and
It is quenched like the second gear W. 3rd and lower gear W
Is also the same.

[0010]

When the non-oxidative quenching is performed as described above, a hardened layer having a desired depth and hardness can be formed on the tooth surface of the gear, but the hardened layer is slightly colored. Therefore, even if the work is non-oxidatively quenched, it is not possible to give the customer sufficient satisfaction in terms of the aesthetic appearance of the quenched work. In this way, the coloring of the hardened layer means that after the work is heated by high frequency,
It is considered that the cause is that the cooling start of the work is still slow even if it is immediately dipped in the cooling liquid.

The present invention was devised in view of the above circumstances, and can be quenched so that the formed hardened layer has the same gloss as that of the portion where the hardened layer is not formed. It is an object of the present invention to provide an oxidation induction hardening method and apparatus.

[0012]

In order to solve the above-mentioned problems, the non-oxidation induction hardening method according to claim 1 is a box-like shape having an open upper part and a semi-closed lower part, the lower part being immersed in a cooling liquid. And after placing the work on the top of the work receiver that penetrates the bottom of the cooling liquid receiver installed in the non-oxidizing or reducing gas, it is filled with the non-oxidizing or reducing gas and the lower part is opened and the upper half is closed. The box-shaped lower part of the atmosphere case provided with the high-frequency heating coil is immersed in the cooling liquid in the cooling liquid receiver, and then the cooling liquid is supplied to the cooling liquid receiver so that the cooling liquid level in the atmosphere case is Immediately after the work is heated by the high frequency heating coil after being raised to the vicinity of the lower end, the coolant is further supplied to the coolant receiver to immerse the work in the coolant.

The non-oxidation induction hardening apparatus according to claim 2 is
A horizontal turntable in which a plurality of vertical work supports on which a work is placed penetrates around the periphery at equal intervals and can be moved up and down, a means for rotating the turntable in a step shape to revolve the work, and a turn table. A cooling liquid tank containing the cooling liquid in which the table is immersed, a means for raising and lowering the work receiver to move the work up and down the cooling liquid surface, and the lower part is the cooling liquid in the path of the work that revolves on the cooling liquid surface. The lower part of the heat treatment chamber that is opened so as to be immersed and is almost tunnel-shaped and filled with non-oxidizing or reducing gas, and the lower part that can be moved up and down and is filled with non-oxidizing or reducing gas. A box-shaped atmosphere case with an open upper half closed,
In the non-oxidation induction hardening apparatus provided with the high frequency heating coil provided in the atmosphere case, the atmosphere case, which is lowered and the lower part is immersed in the cooling liquid, surrounds the atmosphere case and the center part of the bottom surface is fixed through the work holder. A box-shaped cooling liquid receiver having an open upper part and a lower semi-closed part provided so that the cage lower part is immersed in the cooling liquid, first means for supplying the cooling liquid to the cooling liquid receiver, and a larger amount of cooling liquid than the first means. A second means for supplying the cooling liquid receiver to the cooling liquid receiver, wherein the atmosphere case surrounds the work placed on the workpiece receiver and the lower part of the atmosphere case is immersed in the cooling liquid in the cooling liquid receiver. Immediately after heating the work by the high-frequency heating coil after lowering the atmosphere case, raising the cooling liquid in the atmosphere case to near the lower end of the work by the first means,
The second means further raises the liquid level of the cooling liquid in the atmosphere case to immerse the work in the cooling liquid.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 4 are drawings for explaining an embodiment of an oxidation-free induction hardening apparatus that can realize the oxidation-free induction hardening method of the present invention, and a cross-section taken along the line BB of FIG. 1 corresponds to the state where the work has arrived at the main heating and quenching zone, FIG. 2 corresponds to the state immediately before heating the work, FIG. 3 corresponds to the state immediately after heating the work, and FIG. 4 indicates that the work is immersed in the cooling liquid. Shows the state.

In the present embodiment, as the work, the gear W is adopted as in the description of the prior art. The non-oxidation induction hardening apparatus of this embodiment is different from the conventional non-oxidation induction hardening apparatus only in the following points.
Therefore, the description of the same points as the conventional non-oxidation induction hardening apparatus will be omitted. In addition, a non-oxidizing or reducing gas outlet 51 is provided on the top surface of the atmosphere case 50 in the same manner as the conventional device (however, not shown in FIGS. 5 and 6 showing the conventional device). There is.

As shown in FIG. 1, the work support rod 92 of the work receiver 93 of the non-oxidation induction hardening apparatus of this embodiment is provided with a cylindrical box-shaped cooling liquid receiver 95 which is open at the upper half and half at the lower half. There is. That is, the work support rod 92 penetrates the central portion of the bottom surface 97 of the cooling liquid receiver, and the cooling liquid receiver is fixed to the work support rod 92 at this penetrating portion. The bottom surface 97 of the cooling liquid receiver 95 is provided with an inlet 96 for the cooling liquid L, and the side surface 99 of the cooling liquid receiver 95 is provided with an opening 98. This hole
98 is set at a position lower than the lower surface of the gear W placed on the work receiver 93.

A pipe 62a and a pipe 62b having a diameter larger than that of the pipe 62a are introduced through the ceiling of the main heating and quenching zone 22 of the heat treatment chamber 20. A solenoid valve 64 is attached to the pipe 62a, and a solenoid valve 65 having a diameter larger than that of the solenoid valve 64 is attached to the pipe 62b. A pump 63 is provided in the middle of a pipe 61 having one end immersed in the coolant L in the coolant tank 70 and the other end connected to the pipes 62a and 62b.

Next, of the operation of this apparatus, only the points different from the operation of the conventional non-oxidizing induction hardening apparatus will be mainly described. First, the operation of the pump 63 is started. When the gear W preheated by the preheating coil 23 arrives at the main heating and quenching zone 22, as shown in FIG. 1, the atmosphere case 50 is lowered by a lifting device (not shown), and the lower portion of the atmosphere case 50 is in the cooling liquid receiver 95. It is immersed in the cooling liquid L.

The pressure of the non-oxidizing or reducing gas G ejected from the pipe 26 into the atmosphere case 50 is higher than the atmospheric pressure by at least 10 / 10,000 atm, and from the pipe 25 into the heat treatment chamber 20. Since the pressure of the ejected non-oxidizing or reducing gas G is higher than the atmospheric pressure in the range of not less than 4 / 10,000 atmospheric pressure and less than 10 / 10,000 atmospheric pressure, the liquid of the cooling liquid L in the atmosphere case 50 is The surface is slightly lower than the liquid surface in the cooling liquid receiver 95.

When the solenoid valve 64 is opened in this state, as shown in FIG. 2, the cooling liquid L sucked up by the pump 63 is drawn.
Falls into the cooling liquid receiver 95, and the liquid levels in the atmosphere case 50 and the cooling liquid receiver 95 rise. When the liquid level reaches near the lower end of the gear W, the solenoid valve 64 is closed. At this time,
The cooling liquid L falls from the opening 98 provided on the side surface of the cooling liquid receiver 95, and the heights of the cooling liquid surfaces in the atmosphere case 50 and the cooling liquid receiver 95 are kept constant.

Next, from the high frequency power supply 24a, the lead 24b
A high-frequency current is supplied to the high-frequency heating coil 24 for a predetermined period of time to heat the gear W. When the solenoid valve 65 is opened immediately after heating, a large amount of the cooling liquid L drops from the tip of the pipe 62b into the cooling liquid receiver 95, and as shown in FIG. Immersed in L. While the cooling liquid L continues to drop from the opening 98, the cooling liquid L overflows and drops from the upper end of the work receiver 93.

After this, as shown in FIG.
And the gear W is immersed in the coolant L in the coolant tank 70 together with the coolant receiver 95 to continue cooling the gear W. Atmosphere case after lowering the work tray 93
Raise 50. After the next step on the turntable,
The gear W is moved onto the liquid surface and removed from the work mounting table 91.

As described above, when non-oxidative induction hardening is performed in this apparatus, after cooling the gear W, the cooling liquid L enters the cooling liquid receiver 95.
In addition, since the liquid level in the atmosphere case 50 rises to near the lower end of the gear W, the liquid level of the cooling liquid L in the atmosphere case 50 rises extremely rapidly and Soak. Therefore, the delay in the start of cooling after heating the gear W is much smaller than in the case where the gear W is lowered into the cooling liquid L as in the conventional case. Therefore, there is an advantage that the hardened layer formed on the gear W does not develop color.

[0024]

As described above, according to the oxidation-free induction hardening method and apparatus of the present invention, the box-like shape with the upper part open and the lower part semi-closed, the lower part being immersed in the cooling liquid, is non-oxidizing or reducing. After the work is placed on the top of the work receiver that penetrates the bottom surface of the cooling liquid receiver installed in the inert gas, it is filled with non-oxidizing or reducing gas and has a box shape with a lower opening and a semi-closed upper part. The lower part of the atmosphere case provided with the high-frequency heating coil is immersed in the cooling liquid in the cooling liquid receiver, and then the cooling liquid is supplied to the cooling liquid receiver to raise the cooling liquid level in the atmosphere case to near the lower end of the work. Immediately after the work is heated by the high frequency heating coil, the coolant is further supplied to the coolant receiver to immerse the work in the coolant.

Therefore, according to the non-oxidizing induction hardening method and apparatus of the present invention, after the work is heated in the non-oxidizing or reducing gas, the cooling is started with a time delay smaller than the conventional one. The formed cured layer is not colored.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of an embodiment of an apparatus capable of realizing an oxidation-free induction hardening method of the present invention, showing a state where a work has arrived at a main heating and hardening zone.

FIG. 2 is a cross-sectional explanatory view of an embodiment of an apparatus capable of realizing the non-oxidation induction hardening method of the present invention, showing a state immediately before heating of a work.

FIG. 3 is a cross-sectional explanatory view of an embodiment of an apparatus capable of realizing the non-oxidation induction hardening method of the present invention, showing a state immediately after heating a work.

FIG. 4 is a cross-sectional explanatory view of an embodiment of an apparatus capable of realizing the non-oxidation induction hardening method of the present invention, showing a state in which a work is immersed in a cooling liquid.

FIG. 5 is a plan view of a conventional non-oxidation induction hardening apparatus.

6 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 20 Heat treatment chamber 24 High frequency heating coil 50 Atmosphere case 61, 62a, 62b Piping 63 Pump 64, 65 Solenoid valve 70 Coolant tank 90 Turntable 93 Workpiece receiver 95 Coolant receiver G Non-oxidizing or reducing gas L Coolant W gear

Claims (3)

[Claims] 1. A top part of a work receiver having a box shape with an open upper part and a lower semi-closed part, the lower part of which is immersed in a cooling liquid and which penetrates a bottom surface of the cooling liquid receiver installed in a non-oxidizing or reducing gas. After the work is placed on the bottom of the atmosphere case filled with non-oxidizing or reducing gas and having a lower open upper half semi-closed box and a high frequency heating coil, Immediately after the work is heated by the high-frequency heating coil, the cooling liquid is supplied to the cooling liquid receiver to raise the cooling liquid surface in the atmosphere case to the vicinity of the lower end of the work. A non-oxidation induction hardening method, characterized in that the work is supplied and the work is immersed in a cooling liquid. 2. A horizontal turntable in which a plurality of vertical work receivers on which a work is placed penetrates the periphery at equal intervals and can be raised and lowered, and the worktable is revolved by rotating the turntable in steps. Means, a cooling liquid tank containing the cooling liquid in which the turntable is immersed, a means for moving the work receiver up and down to raise and lower the work above and below the cooling liquid level, and a work path revolving above the cooling liquid level. A heat treatment chamber whose lower part is opened so as to be immersed in a cooling liquid and which is almost tunnel-shaped and filled with non-oxidizing or reducing gas;
A non-oxidizing high frequency wave that is provided in the heat treatment chamber so as to be able to move up and down, and has a box-shaped atmosphere case that is filled with non-oxidizing or reducing gas and that has a lower open upper half and a semi-closed box In the quenching device, the lower part surrounds the atmosphere case in which the lower part is immersed in the cooling liquid, and the center part of the bottom surface is fixed through the work receiver so that the lower part is provided so as to be immersed in the cooling liquid. The atmosphere is provided with a box-shaped cooling liquid receiver that is semi-closed in the lower part, first means for supplying the cooling liquid to the cooling liquid receiver, and second means for supplying a large amount of the cooling liquid to the cooling liquid receiver from the first means. After lowering the atmosphere case such that the case surrounds the work placed on the work receiver and the lower part of the atmosphere case is immersed in the cooling liquid in the cooling liquid receiver,
Means for raising the cooling liquid in the atmosphere case to near the lower end of the work, and immediately after heating the work by the high-frequency heating coil, the second means further raises the liquid level of the cooling liquid in the atmosphere case to cool the work. An oxidation-free induction hardening apparatus characterized by being immersed in a liquid. 3. The pressure of the non-oxidizing or reducing gas in the atmosphere case is higher than atmospheric pressure by at least 10 / 10,000 atmospheres, and the pressure of the non-oxidizing or reducing gas in the heat treatment chamber is 10,000 minutes above atmospheric pressure. The non-oxidation induction hardening apparatus according to claim 2, wherein the pressure is set to be higher than 4 atm and lower than 10 / 10,000 atm.