JP2000345241A - Apparatus and method for induction-hardening rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction-hardening apparatus of a rack and the induction-hardening device thereof, with which a strain (curving) direction in the case of applying the hardening on the whole circumference of the rack, can suitably be controlled. SOLUTION: This induction-hardening apparatus is provided with an induction-heating coil body 100 for heating the rack W, a rotating mechanism for rotating the rack W when the rack W is heated with the induction-heating coil body 100 and a cooling means 200, etc. for more quickly cooling the region having tooth W10 in the rack W heated by the induction-heating body 100 than the region in the opposite side of the above region in the rack W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction hardening device and an induction hardening method for a rack.

[0002]

2. Description of the Related Art Conventional induction hardening devices for racks are classified into a direct current type and a high frequency induction heating type (a method of heating only by a high frequency induction current). Induction hardening devices using a high-frequency induction heating system include, for example, a moving hardening system using a round coil and a half-open saddle coil.

The rack W is, for example, as shown in FIG.
It is a substantially columnar body, in which a notch is provided in the longitudinal direction of the cylinder, and a plurality of teeth W10 are formed in the notch at a predetermined pitch.

[0004] A conventional induction hardening apparatus for a rack using a direct energization method is, for example, as shown in FIG. 5A, a high-frequency power supply (not shown) and conductors 800 and 8 connected thereto.
10 and a cooling liquid ejecting means provided on a heating conductor portion 811 of the conductor portion 810 described later. In the case of the conventional induction hardening device for a rack by the direct current method, the region where the teeth W10 are provided in the rack W and the region on the opposite side of the region in the rack W are subjected to high-frequency heating in a separate process, After each heating,
The cooling liquid is injected from the cooling liquid injection means to the rack W, and the quenching of the rack W is completed.

In FIG. 5A, a tooth W1 on a rack W is shown.
0 is shown only for a pair of conductors 800 and 810 for high-frequency heating of the area provided with 0
A pair of conductors for high-frequency heating the region opposite to the region where 0 is provided is not shown. Note that a portion of the conductor portion 810 facing the region of the rack W in parallel with the region where the teeth W10 are provided is a heating conductor portion 811. The heating conductor 811 is provided with a coolant injection hole on a surface facing the rack W. The rack W
After the heating, the cooling liquid is injected. As described above, the heating conductor 811 is also provided with the cooling liquid injection unit.

For example, when heating a region of the rack W where the teeth W10 are provided as a region to be hardened (that is, also a region to be heated), as shown in FIG. The ends of a pair of conductors 800 and 810 are pressed into contact with both ends of the wire to be electrically connected. Accordingly, a high-frequency current is supplied from the high-frequency power source to the region between the conductors 800 and 810, and the region is directly heated by high-frequency current. When a high-frequency current is supplied from the high-frequency power supply to the heating conductor 811, a high-frequency induction current also flows in the region, and the region is also heated by the high-frequency induction current.

When the cooling liquid is injected from the cooling liquid injection mechanism and the quenching of the area is completed, the area (namely, the tooth W10)
The quenching pattern WP1 in the region where is provided) is shown in FIG.
As shown in FIG. 3B, a substantially uniform depth is formed in the region.

When a region on the opposite side of the region where the teeth W10 are provided in the rack W is set as a region to be hardened, a pair of conductors (not shown) are pressed against and electrically connected to both ends of the region. As a result, the region is subjected to high-frequency direct current heating and high-frequency induction heating. When the coolant is ejected from the coolant ejection mechanism and the quenching of the region is completed, the quenching pattern WP2 of the region of the rack W becomes the region (that is, the teeth W10 are provided) as shown in FIG. (A region on the opposite side of the set region) with a substantially uniform depth.

A conventional induction hardening apparatus for a high frequency induction heating type rack, which employs a moving hardening method using a round coil, is shown in, for example, FIGS. 6 (A) and 6 (B).
As shown in FIG. 2, a round coil 900 provided concentrically with the rack W, a high-frequency power supply (not shown) connected to the round coil 900, and the rack W
And a horizontal / horizontal movement mechanism (not shown) for horizontally moving in the longitudinal direction of the rack W while being rotated inside, and a cooling liquid ejecting means provided on the round coil 900. The cooling liquid injection means is configured to inject cooling liquid obliquely from a cooling liquid injection hole provided on an inner surface of the round coil 900 toward a region immediately after heating of the rack W being moved. It is.

A conventional induction hardening apparatus for a high-frequency induction heating type rack, which employs a semi-open saddle coil, includes, for example, a semi-open saddle coil 9 for heating a rack W.
50 (see FIG. 7), a high-frequency power supply (not shown) connected to the semi-open saddle coil 950, a rotating mechanism (not shown) for rotating the rack W at a fixed position during heating, and a rack W after heating. And a coil retracting mechanism (not shown) for moving the semi-open saddle coil 950 to a position where it does not interfere with the operation of the cooling jacket.

The half-open saddle coil 950 is a general half-open saddle coil. That is, the semi-open saddle coil 950
Is a pair of heating conductor portions 951 and 952, a connection conductor portion 953 for connecting one end of the heating conductor portions 951 and 952 in a semicircular detour, and approximately one end from each other end of the heating conductor portions 951 and 952. Connecting conductor portions 954 and 955 extending so as to detour in a / 4 circle shape;
55, connecting conductors 956 and 957 extending from each end to connect to a high-frequency power supply (not shown). The length of the heating conductors 951 and 952 is set to the length of the hardening target area of the rack W.

[0012]

However, the conventional induction hardening device for a rack by a direct current system has
When the rack W is quenched, the tooth W1 shown in FIG.
5 and the quenching pattern WP1 in the region where
A quenching pattern obtained by combining the quenching pattern WP2 in the area opposite to the area where the teeth W10 are provided as shown in FIG. That is, the quenching pattern cannot be formed over the entire circumference of the rack W.

[0013] This is because the hardening of the remaining portion of the rack W is performed regardless of which of the region where the teeth W10 are provided and the region of the rack W opposite to the above-mentioned region. This is because if high heat is applied to the region where the heat is completely introduced, cracks occur, and it is necessary to avoid such cracks. That is, the quenching pattern WP1 in the region where the tooth W10 is provided and the tooth W
Quenching pattern W in an area opposite to the area where 10 is provided
It was necessary to provide a region in which no quenching pattern was formed between P2 and P2.

Therefore, in the conventional induction hardening apparatus for a rack by the direct current type, even if it is desired to quench the entire circumference of the rack W, there is an area where a quenching pattern cannot be formed. There was a problem that can be.

However, in the case of a conventional induction hardening apparatus for a rack using a direct current supply method, a quenching pattern WP1 in the area where the teeth W10 are provided and a quenching pattern in the area opposite to the area where the teeth W10 are provided. When forming the pattern WP2,
Since the cooling amount can be controlled, the two quenching patterns WP
1. The generation direction of the distortion (curvature) of the rack W after the formation of the WP2 could be controlled, and the generated distortion could be properly corrected.

This is because if both sides of the rack W are deformed due to both quenching, the side of the rack W on which the teeth W10 are provided becomes concave, it is necessary to bend the side on which the teeth W10 are provided so as to be widened. However, if the side on which the teeth W10 are provided is widened, cracks are very likely to occur. That is, if distortion occurs in which the side of the rack W where the teeth W10 are provided becomes concave, it is difficult to correct the distortion.

If the rack W has a distortion in which the side on which the teeth W10 are provided is convex due to the above-mentioned quenching, in order to correct the distortion, it is necessary to bend the side on which the teeth W10 are provided so as to contract. But in this case,
Cracks are unlikely to occur on the side where the teeth W10 are provided, and almost no cracks occur on the side of the rack W opposite to the side where the teeth W10 are provided even if the rack W is expanded. Rack W
Is inevitable, and if such a distortion is generated so that the side of the rack W on which the teeth W10 are provided is convex, the yield rate of the hardened rack W can be improved.

In general, the work becomes more convex when cooled earlier after heating. Therefore, in the case of the conventional induction hardening apparatus for a rack by a direct current supply method, the quenching pattern WP1 in the area where the teeth W10 are provided and the quenching pattern WP2 in the area opposite to the area where the teeth W10 are provided. Can be controlled so that the side on which the teeth W10 are provided becomes convex, so that the generated distortion can be properly corrected.

FIG. 6C shows a conventional induction hardening apparatus for a high-frequency induction heating type rack in which a rack W is hardened by a moving hardening method using a round coil. As shown in FIG. 5, the region on the opposite side of the region where the teeth W10 are provided (except the region where the teeth W10 are provided) has a substantially uniform quenching depth. (This is the center of the region where the teeth W10 are provided in a cross section orthogonal to the center axis of the rack W. Hereinafter, also simply referred to as the "center of the rack W.") The quenching pattern WP3 is such that the quenching depth becomes shallower nearer. I was

This is because the gap between the rack W which is rotated inside the round coil 900 and the round coil 900 is the tooth W
This is because, if the gap a and the gap b are respectively set in a region where the teeth 10 are provided and a region other than the region where the teeth W10 are provided, the gap a> the gap b.

In this case, it is possible to satisfy the specification of the quenching depth by increasing the entire quenching depth, but the direction of the distortion cannot be controlled. This is because, for the rack W being rotated, the coolant is injected in the region where the teeth W10 are provided and in the region opposite to the region where the teeth W10 are provided (other than the region where the teeth W10 are provided). This is because the configuration is such that the amount to be performed cannot be adjusted. The inability to control the direction in which the strain is generated has been an obstacle for improving the yield rate of the hardened rack W.

In a conventional induction hardening apparatus for a high-frequency induction heating type rack, when the rack W is hardened by a semi-open saddle coil, the moving hardening by the round coil is performed. The quenching pattern was the same as that by the method. This is because the heating conductors 951 and 952
And the gap between the region where the tooth W10 is provided is larger than the gap between the heating conductor portions 951 and 952 and the region on the opposite side of the region where the tooth W10 is provided (other than the region where the tooth W10 is provided). It is because it becomes.

Therefore, the quenching pattern of the rack W has a substantially uniform quenching depth except for the region where the teeth W10 are provided, as in the case of FIG. 6C, but the region where the teeth W10 are provided. The quenching depth was shallow near the center.

In the case of a conventional induction hardening apparatus for a high-frequency induction heating type rack, which uses a semi-open saddle coil, the amount of coolant sprayed from the cooling jacket to the rack W is made uniform. Therefore, the direction in which the strain was generated was not controlled.

A main object of the present invention is to provide an induction hardening device and an induction hardening method for a rack which can appropriately control the direction of distortion (curvature) of the rack when the entire periphery of the rack is hardened. It is in.

[0026]

In order to solve the above-mentioned problems, a high frequency quenching apparatus for a rack according to a first aspect of the present invention comprises: a high frequency heating coil for heating a rack; A rotating mechanism for rotating the rack when heating the rack, and a region provided with teeth in the rack heated by the high-frequency heating coil body is faster than a region on the opposite side of the region in the rack. Cooling means for cooling.

In the induction hardening apparatus for a rack according to a second aspect of the present invention, in the induction hardening apparatus for a rack according to the first aspect, the cooling means cools an area of the rack where teeth are provided. A first cooling jacket for injecting a liquid, and a second cooling jacket for injecting a cooling liquid to a region on the opposite side of the region in the rack, wherein a unit area per unit area of the first cooling jacket is provided. Is larger than the coolant injection amount per unit area of the second cooling jacket.

According to a third aspect of the present invention, there is provided an induction hardening apparatus for a rack, wherein the cooling means comprises a cooling liquid storing a cooling liquid for immersing and cooling the rack. A tank, and a moving means for moving the rack heated by the high-frequency heating coil body to below the surface of the cooling liquid in the cooling liquid tank, and the rack is immersed in the cooling liquid by the moving means. Occasionally, the rack is immersed in a region where teeth are provided on the rack.

According to a fourth aspect of the present invention, there is provided an induction hardening apparatus for a rack, wherein the cooling means comprises a cooling liquid storing a cooling liquid for immersing and cooling the rack. A bath, a moving means for moving the rack heated by the high-frequency heating coil body to a position below the surface of the cooling liquid in the cooling bath, and a tooth provided on the rack immersed below the surface of the cooling liquid and immersed. A first cooling jacket for injecting the cooling liquid to the provided area and a second cooling jacket for injecting the cooling liquid to the area of the rack opposite to the area where the teeth are provided. When the rack is immersed in the cooling liquid by the moving means, the area of the rack where the teeth are provided is lowered and immersed, and the unit of the first cooling jacket is Injection amount of the cooling liquid per product is to many configuration and than the injection amount of the cooling liquid per unit area of the second cooling jacket.

According to a fifth aspect of the present invention, there is provided an induction hardening apparatus for a rack according to any one of the first to third aspects, wherein the high-frequency heating coil body is a semi-open saddle type high-frequency hardening apparatus. A heating coil body, comprising a pair of side heating conductors, and a top heating conductor electrically connected to the pair of side heating conductors, and the pair of side heating conductors. The heating conductor portion and the top-side heating conductor portion are connected so that currents flowing therefrom are in a shunting / merging relationship with each other, and before the rack starts rotating by the rotating mechanism, An area of the rack where the teeth are provided is arranged at a position facing the top-side heating conductor, and is configured to be stopped and heated.

According to a sixth aspect of the present invention, there is provided an induction hardening method for a rack, in which the rack is rotated and heated by a high-frequency heating coil, and after the heating is completed, an area of the rack provided with teeth is provided. Cooling the rack faster than a region on the opposite side of the region in the rack.

[0032] According to a seventh aspect of the present invention, in the induction hardening method for a rack according to the sixth aspect, the step of cooling includes providing teeth in the rack after the completion of the heating. The amount of the coolant to be injected per unit area by the first cooling jacket that injects the coolant to the set area is changed by the amount of the coolant that is injected to the area of the rack opposite to the area where the teeth are provided. 2, the amount of the cooling liquid injected per unit area by the cooling jacket is larger than that of the rack, and the side of the rack where the teeth are provided,
Allow the rack to cool faster than the opposite side of the rack.

According to an eighth aspect of the present invention, in the induction hardening method for a rack according to the sixth aspect, the step of cooling includes providing teeth in the rack after the completion of the heating. The rack is immersed in a cooling liquid so that the area of the rack where the teeth are provided is cooled faster than the area of the rack opposite to the area where the teeth are provided.

In the induction hardening method for a rack according to a ninth aspect of the present invention, in the induction hardening method for a rack according to the sixth aspect, the step of cooling includes providing teeth in the rack after the completion of the heating. After immersing the rack in the coolant with the region facing down, the amount of coolant sprayed from the first cooling jacket provided in the coolant to cool the region of the rack where the teeth are provided is determined by the rack. The cooling liquid spray amount from the second cooling jacket provided in the cooling liquid for cooling the area on the opposite side of the area provided with the teeth in the area of the rack provided with the teeth. Is cooled faster than the area of the rack opposite the area where the teeth are provided.

According to a tenth aspect of the present invention, in the induction hardening method for a rack according to the sixth, seventh, eighth or ninth aspect, the pair of side-surface-side heating conductors and the pair are hardened. And a top-side heating conductor section electrically connected to the top-side heating conductor section, and the paired side-side heating conductor section and the top-side heating conductor section shunt currents to each other. A top-side heating conductor of a semi-open saddle-type high-frequency heating coil body connected in a merging relation is opposed to a region where the teeth are provided in the rack, and the region is stopped and heated before the heating step. .

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An induction hardening apparatus for a rack according to an embodiment of the present invention for realizing an induction hardening method for a rack according to the present invention will be described below with reference to FIGS.
The rack is the above-mentioned rack W, that is, a substantially columnar body, in which a notch is provided in the longitudinal direction of the cylinder, and a plurality of teeth W10 are formed in the notch at a predetermined pitch.

FIG. 1 is a schematic explanatory view showing a main part and a rack of an induction hardening apparatus for a rack according to an embodiment of the present invention for realizing the method of induction hardening of a rack according to the present invention, and FIG. An arrangement relationship between a heating conductor portion of a high-frequency heating coil body used in an induction hardening device for a rack according to an embodiment of the present invention for realizing the induction hardening method for a rack according to the present invention and a rack at the time of stop heating will be described. FIG. 3 is a schematic perspective view showing a high-frequency heating coil body used in the high-frequency hardening device for a rack according to the embodiment of the present invention for realizing the high-frequency hardening method for the rack according to the present invention. .

The induction hardening apparatus for a rack according to the embodiment of the present invention includes a high-frequency heating coil 1 for heating a rack W.
00, a high-frequency power supply (not shown) connected to the high-frequency heating coil 100, and the high-frequency heating coil 10
0 is provided with a rotation mechanism (not shown) for rotating the rack W during the main heating period when the rack W is heated, and a tooth W10 in the rack W after heating by the high-frequency heating coil body 100. Cooling means 200 for cooling the area faster than the area of the rack W on the side opposite to the area, a loading / unloading device (not shown) for the rack W,
A coil retracting mechanism (not shown) for retracting the high-frequency heating coil body 100 upward when loading and unloading the rack W;
And a control unit (not shown) for controlling these.

The high-frequency heating coil 100 is a semi-open saddle-type high-frequency heating coil, and includes a pair of side-surface-side heating conductors 110 and 111 and a pair of the side-surface-side heating conductors 11.
Top heating conductor 12 electrically connected to 0, 111
0, a connecting conductor 130 for bypass-connecting one end of each of the side-side heating conductor section 110 and the top-side heating conductor section 120 in a substantially quarter circle shape, and the side-surface heating conductor section 111 and a top-side heating conductor. A connecting conductor 131 for bypassing and connecting each end between the conductor 120 and the conductor 120 in a substantially quarter circle shape;
In order to connect a high-frequency power supply (not shown) from the connection conductor 132 that makes a detour connection between the other ends of 0 and 111 in a semicircular shape, the other end of the top heating conductor 120, and the apex of the connection conductor 132. The connection conductors 134 and 135 are extended.

Therefore, the pair of side-surface-side heating conductors 110 and 111 and the top-side heating conductor 120 are connected so that currents flowing therethrough have a shunt / merge relationship. Therefore, a current twice as large as that of the side surface heating conductor portion 110 (or the side surface heating conductor portion 111) flows through the top side heating conductor portion 120.

The pivoting mechanism includes a chuck center pin mechanism (not shown) for rotating the rack W while holding both sides thereof, and a position A at the time of loading, unloading, and quenching. A moving means (not shown) using a hydraulic cylinder or a pneumatic cylinder for moving up and down between the cooling liquid tank 250 and a cooling position B in the cooling liquid tank 250, and a tooth W10 of the rack W are provided. A detection mechanism (not shown) for detecting a state where the region is directly above or below.

Incidentally, the moving means is arranged to move the rack W after a predetermined rotation described later by the chuck / center pin mechanism (that is, the state where the region where the teeth W10 of the rack W are provided is directly below). Cooling rack 20).
By moving the cooling liquid into a cooling liquid tank 200 described later, it also functions as a part of the cooling means. The detection mechanism is, for example, two pairs of light emitting devices and light receiving devices, the pair of light emitting devices and light receiving devices to detect whether the region provided with the teeth W10 of the rack W is facing directly above, Another pair of the light emitting device and the light receiving device detects whether the region of the rack W where the teeth W10 are provided is directly downward.

The cooling means 200 includes a cooling liquid tank 250 storing a cooling liquid L for immersing and cooling the rack W, and a cooling liquid in the cooling liquid tank 250 heated by the high-frequency heating coil body 100. Rack W to below
Moving means (moving means of the rotating mechanism) for moving while the area provided with the teeth W10 is directly below;
The rack W provided under the surface of the cooling liquid and immersed therein
The first cooling jacket 211 that injects the cooling liquid L to the region where the teeth W10 are provided and the pair that injects the cooling liquid L to the region of the rack W opposite to the region where the teeth W10 are provided. The second cooling jackets 212, 212 are provided.

The amount of coolant injected per unit area of the first cooling jacket 211 is determined by the amount of the second cooling jacket 212.
Is configured to be larger than the injection amount of the cooling liquid per unit area. The cooling liquid tank 250 is provided with a cooling mechanism (not shown) for keeping the temperature of the cooling liquid L constant.

The loading / unloading device is, for example, a robot arm.

The coil retracting mechanism is a drive mechanism for raising and lowering the high-frequency heating coil body 100, and uses, for example, a hydraulic cylinder or a pneumatic cylinder.

The induction hardening device for a rack according to the embodiment of the present invention thus configured is controlled by the control unit as follows.

In the initial state, the high-frequency heating coil 1
00 is retracted upward by the coil retracting mechanism. First, the rack W is loaded by the loading / unloading device.
Is carried into the position A at the time of carry-in, carry-out, and quenching, and the rack W
Is received and held by the chuck / center pin mechanism of the rotating mechanism.

Thereafter, the high-frequency heating coil body 100 is returned by the coil retracting mechanism to a position (see FIG. 2) opposed to the rack W at the position A for carrying in, carrying out, and quenching.

Thereafter, the rack W is moved to the tooth W10 of the rack W.
Is rotated by the chuck / center pin mechanism of the rotation mechanism so as to be right above (preferably right above but may be substantially right above), and temporarily stopped.

During the temporary stop, the high-frequency heating coil body 100 is energized, and the area of the rack W where the teeth W10 are provided is stopped and heated. At this time, the top heating conductor portion 120 of the high-frequency heating coil body 100 is connected to the tooth W1 of the rack W.
0 is opposed to the center. In addition, the high-frequency heating coil 1
00 side heating conductor portions 110 and 111 are opposed to both ends of the tooth W10 of the rack W, respectively. Therefore, the top heating conductor 120 through which a current twice that of the side heating conductor 110 flows contributes to the central heating of the center of the tooth W10 of the rack W. In addition, this temporarily stopped time,
This is a time that can compensate for the fact that the quenching depth at the center side of the tooth W10 of the rack W has conventionally been insufficient.

After the stop heating, the rack W is rotated by the chuck / center pin mechanism of the rotating mechanism and is heated. When the main heating is completed, the region of the rack W where the teeth W10 are provided is directly below (preferably directly below, but may be substantially directly below) and stopped.

Thereafter, the rack W is held by the chuck / center pin mechanism while the region where the teeth W10 are provided is directly below, and the rack W is moved by the moving means.
It is moved to the position B at the time of cooling below the cooling liquid level within 0.
Therefore, at this time, the area of the rack W where the teeth W10 are provided is immersed first, and is cooled faster than the area on the opposite side of the area where the teeth W10 are provided.

With respect to the rack W moved to the cooling position B, the first cooling jacket 211 and the pair of second
The cooling liquid L is jetted from the cooling jackets 212 and 212 of the cooling medium L. At this time, as described above, the injection amount of the cooling liquid per unit area is smaller in the first cooling jacket 211 than in the second cooling jacket 211.
, The rack W is cooled faster in the region where the teeth W10 are provided than in the region on the opposite side of the region where the teeth W10 are provided.

At this stage, the quenching of the rack W is completed, and the rack W has a distortion (curve) in which cracks are unlikely to occur at the time of straightening, that is, a region in which the teeth W10 are provided is convex. I have. The quenching pattern of the rack W has a substantially uniform depth over the entire circumference.

After the cooling is completed, the rack W is returned to the carry-in / carry-out / hardening position A by the moving means of the rotating mechanism.
By the time the high-frequency heating coil 100
Are retracted in the initial state, that is, upward, by the coil retracting mechanism.

The rack W returned to the position A at the time of carry-in / carry-out / quenching is carried out by the carry-in / carry-out device. Thereafter, the next new rack W is carried in by the carry-in / out device, and the above-described repetition is performed.

In the induction hardening apparatus for a rack according to the embodiment of the present invention, the first cooling jacket 21 is provided.
Although one and a pair of second cooling jackets 212, 212 are provided, they may be omitted. Even if this is omitted, the area of the rack W where the teeth W10 are provided is immersed first, and is cooled earlier than the area of the rack W opposite to the area where the teeth W10 are provided. ,
The rack W is a strain that hardly generates cracks during straightening, that is,
This is because distortion (curvature) in which the region side where the teeth W10 are provided becomes convex occurs.

In the induction hardening device for a rack according to the embodiment of the present invention, the coil retracting mechanism can be omitted. If the distance between the cooling liquid surface of the cooling liquid tank 250 and the high-frequency heating coil body 100 is set so as not to hinder the loading / unloading operation of the loading / unloading device such as a robot arm, the high-frequency heating coil body 100 does not need to be retracted. This is because the carry-in / carry-out device can directly carry in / carry-out. However, the position of the high-frequency heating coil body 100 is preferably as close to the cooling liquid tank 250 as possible for quenching.

Next, an induction hardening apparatus for a rack according to another embodiment of the present invention for realizing another induction hardening method for a rack according to the present invention will be described with reference to FIG. FIG. 4 is a schematic explanatory view showing a cooling jacket and a rack used in an induction hardening device for a rack according to another embodiment of the present invention for realizing another induction hardening method for a rack according to the present invention. .

An induction hardening device for a rack according to another embodiment of the present invention does not use a cooling liquid tank, and a cooling mechanism of the induction hardening device for a rack according to the embodiment of the present invention. Only the changes have been made.

The cooling mechanism after the change is the first cooling mechanism disposed on both sides of the high-frequency heating coil body 100 during quenching.
Cooling jacket 221 and second cooling jacket 222
And

The first cooling jacket 221 has a rack W
Is for cooling the region provided with the teeth W10. The second cooling jacket 222 is for cooling a region of the rack W opposite to a region where the teeth W10 are provided. The cooling liquid injection amount per unit area of the first cooling jacket 221 is configured to be larger than the cooling liquid injection amount per unit area of the second cooling jacket 212.

In the induction hardening apparatus for a rack according to another embodiment of the present invention having the above-described structure, the control by the control unit is as follows. Since it is the same as the case of the induction hardening device for the rack according to the embodiment, the description after the completion of the main heating will be described.

When the main heating is completed, the high-frequency heating coil body 100 is moved to the initial state by the coil retracting mechanism.
That is, it is retracted upward. At this time, the teeth W of the rack W
The rotation mechanism is stopped so that the area provided with 10 is on the right side in FIG. That is, by this stop, the region of the rack W where the teeth W10 are provided faces the first cooling jacket 221.

Thereafter, the cooling liquid L is injected from the first cooling jacket 221 and the second cooling jacket 222. At this time, as described above, the injection amount of the cooling liquid per unit area is larger in the first cooling jacket 221 than in the second cooling jacket 222, so that the rack W is provided with the teeth W10 of the rack W. The cooled area is cooled faster than the area of the rack W opposite to the area where the teeth W10 are provided.

At this stage, the quenching of the rack W is completed, and the rack W is distorted so that cracks are hardly generated at the time of straightening, that is, distortion (curvature) occurs in which the area where the teeth W10 are provided is convex. I have. The quenching pattern of the rack W has a substantially uniform depth over the entire circumference.

Thereafter, the rack W is carried out by the carry-in / out device. Thereafter, another rack W is carried in by the carry-in / carry-out device, and the above is repeated.

In the induction hardening device for a rack according to another embodiment of the present invention, the first cooling jacket 2 is provided.
Since the arrangement of the first and second cooling jackets 222 and the arrangement of the high-frequency heating coil body 100 are relative,
An arrangement other than the above may be adopted as long as the above-described relative arrangement relation is maintained.

In the induction hardening device for a rack according to another embodiment of the present invention, the coil retracting mechanism can be omitted. When omitted, the loading / unloading device may be a robot arm, but may have a mechanism for loading / unloading in the vertical direction.

In this case, the first cooling jacket 22
If the first and second cooling jackets 222 remain,
A pair of side-surface heating conductors 1 of the high-frequency heating coil body 100
The cooling liquid L hits 10 and 111. Therefore, for example, the first cooling jacket 221 and the second
Of the cooling jacket 222 is divided into upper and lower parts. The two divided parts are placed in a first position so that the cooling liquid L does not hit the pair of side-surface-side heating conductor portions 110 and 111.
Cooling jacket 221 and second cooling jacket 2
What is necessary is just to arrange | position respectively at the slightly upper side and the slightly lower side of the position where 22 was provided.

By the way, in the induction hardening device for racks according to the embodiment of the present invention and the induction hardening device for racks according to another embodiment of the present invention, the rack W is a substantially columnar body. Although a notch is provided in the longitudinal direction of the cylinder and a plurality of teeth W10 are formed at a predetermined pitch in the notch, the cylinder may be substantially a cylinder or may be more angular. Absent.

In the induction hardening device for a rack according to the embodiment of the present invention and the induction hardening device for a rack according to another embodiment of the present invention, the high-frequency heating coil body has a pair of side surfaces as a heating conductor. The heating conductor portion and one top-side heating conductor portion were provided. Alternatively, for example, the number of pairs of the side-surface-side heating conductors may be two or more instead of one. Also in this case, the current flowing through the top-side heating conductor portion is connected to the side-side heating conductor portion by making the current flowing in the top-side heating conductor portion into a shunting / merging relationship with each other. This is because the current flowing through the conductor portion is larger than the current flowing through the conductor portion, so that the current flowing through the top-side heating conductor portion during stop heating can compensate for the conventional insufficient heating at the center side of the tooth W10 of the rack W.

In the induction hardening apparatus for a rack according to the embodiment of the present invention and the induction hardening apparatus for a rack according to another embodiment of the present invention, the high-frequency heating coil body has the top-side heating conductor portion 120. Although it was a semi-open saddle type,
If the uniformity of the quenching depth does not matter, a general semi-open saddle-type high-frequency heating coil without the top-side heating conductor 120 may be used. Also in this case, it is possible to control so that the side of the region where the tooth W10 is provided is convex so that cracks are less likely to occur during the correction.

Of course, the high-frequency heating coil body may be any other than the half-open saddle type, as long as it has the same function.

[0076]

As described above, according to the first aspect of the present invention,
The high-frequency hardening device for a rack according to the present invention includes a high-frequency heating coil body for heating the rack, a rotating mechanism for rotating the rack when the high-frequency heating coil body heats the rack, and the high-frequency heating coil body. Cooling means for cooling the heated area of the rack provided with the teeth faster than the area of the rack opposite to the area.

Therefore, in the case of the induction hardening device for a rack according to the first aspect of the present invention, the cooling in which the area provided with the teeth in the rack is cooled faster than the area on the opposite side of the area in the rack. By this means, the direction in which the distortion (curvature) after quenching of the rack is generated can be controlled to a direction suitable for correction. Therefore, it is possible to improve the yield rate of the hardened rack.

According to an induction hardening device for a rack according to a second aspect of the present invention, in the induction hardening device for a rack according to the first aspect, the cooling means cools an area of the rack provided with teeth. A first cooling jacket for injecting a liquid, and a second cooling jacket for injecting a cooling liquid to a region on the opposite side of the region in the rack, wherein a unit area per unit area of the first cooling jacket is provided. Is larger than the coolant injection amount per unit area of the second cooling jacket.

Therefore, in the case of the induction hardening device for a rack according to claim 2 of the present invention, the injection amount of the cooling liquid per unit area of the first cooling jacket is reduced by the unit of the second cooling jacket. By making the amount of coolant injected per area larger than the amount of coolant injected per unit area, it is possible to control the direction of distortion (curvature) after quenching of the rack in a direction suitable for correction. Therefore, it is possible to improve the yield rate of the hardened rack.

According to a third aspect of the present invention, there is provided an induction hardening apparatus for a rack, wherein the cooling means comprises a cooling liquid storing a cooling liquid for immersing and cooling the rack. A tank, and a moving means for moving the rack heated by the high-frequency heating coil body to below the surface of the cooling liquid in the cooling liquid tank, and the rack is immersed in the cooling liquid by the moving means. Occasionally, the rack is immersed in a region where teeth are provided on the rack.

Thus, in the case of the induction hardening device for a rack according to claim 3 of the present invention, the area provided with the teeth of the rack is first immersed in the cooling liquid tank storing the cooling liquid. The direction in which distortion (curvature) occurs after quenching of the rack can be controlled in a direction suitable for straightening. Therefore, it is possible to improve the yield rate of the hardened rack.

According to a fourth aspect of the present invention, there is provided an induction hardening apparatus for a rack, wherein the cooling means comprises a cooling liquid storing a cooling liquid for immersing and cooling the rack. A bath, a moving means for moving the rack heated by the high-frequency heating coil body to a position below the surface of the cooling liquid in the cooling bath, and a tooth provided on the rack immersed below the surface of the cooling liquid and immersed. A first cooling jacket for injecting the cooling liquid to the provided area and a second cooling jacket for injecting the cooling liquid to the area of the rack opposite to the area where the teeth are provided. When the rack is immersed in the cooling liquid by the moving means, the area of the rack where the teeth are provided is lowered and immersed, and the unit of the first cooling jacket is Injection amount of the cooling liquid per product is to many configuration and than the injection amount of the cooling liquid per unit area of the second cooling jacket.

Therefore, in the case of the induction hardening device for a rack according to claim 4 of the present invention, the area provided with the teeth of the rack is first immersed in the cooling liquid tank storing the cooling liquid, and By making the injection amount of the cooling liquid per unit area of the first cooling jacket larger than the injection amount of the cooling liquid per unit area of the second cooling jacket, the rack after the hardening of the rack is more reliably. The direction in which distortion (curvature) occurs can be controlled to a direction suitable for correction. Therefore,
The non-defective rate of quenching of the rack can be further improved.

A high-frequency hardening device for a rack according to a fifth aspect of the present invention is the high-frequency hardening device for a rack according to the first, second, third or fourth aspect, wherein the high-frequency heating coil body is a semi-open saddle type high-frequency hardening device. A heating coil body, comprising a pair of side heating conductors, and a top heating conductor electrically connected to the pair of side heating conductors, and the pair of side heating conductors. The heating conductor portion and the top-side heating conductor portion are connected so that currents flowing therefrom are in a shunting / merging relationship with each other, and before the rack starts rotating by the rotating mechanism, An area of the rack where the teeth are provided is arranged at a position facing the top-side heating conductor, and is configured to be stopped and heated.

Therefore, in the case of the induction hardening device for a rack according to claim 5 of the present invention, the current flowing through the top-side heating conductor during stop heating is reduced by the conventional method in the region where the teeth are provided in the rack. Make up for insufficient heating. Therefore, the quenching depth of the region is made uniform, and thereby the quenching depth of the entire circumference of the rack is made uniform. Therefore, it is possible to provide a higher quality rack in which the quenching depth is made uniform.

Further, the induction hardening method for racks according to claims 6 to 10 of the present invention can be realized by the rack induction hardening apparatus according to claims 1 to 5 of the present invention, respectively. It has the same effect as the effect of the induction hardening device for a rack according to claims 1 to 5 of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a main part and a rack of an induction hardening device for a rack according to an embodiment of the present invention for realizing the induction hardening method for a rack according to the present invention.

FIG. 2 shows the relationship between the heating conductor portion of the high-frequency heating coil body used in the induction hardening device for a rack according to the embodiment of the present invention for realizing the induction hardening method for the rack according to the present invention and the rack during stop heating. It is a schematic explanatory view explaining arrangement relation.

FIG. 3 is a schematic perspective view showing a high-frequency heating coil body used in the high-frequency hardening apparatus for a rack according to the embodiment of the present invention for realizing the high-frequency hardening method for the rack according to the present invention.

FIG. 4 is a schematic explanatory view showing a cooling jacket and a rack used in an induction hardening device for a rack according to another embodiment of the present invention for realizing another induction hardening method for a rack according to the present invention. is there.

FIG. 5 is a diagram related to a conventional induction hardening device for a rack using a direct energization method, and FIG. 5A shows a tooth surface of a rack used for a conventional induction hardening device for a rack using a direct energization method. FIG. 4B is a schematic side view showing a conductor part and a rack for high-frequency heating, and FIG. 4B is a schematic cross-sectional view of the rack showing a quenching pattern of the tooth surface of the rack quenched by the apparatus; C) is a schematic sectional view of the rack showing a quenching pattern on the opposite side of the tooth surface of the rack quenched by the apparatus.

FIG. 6 is a view showing a conventional induction hardening apparatus for a high frequency induction heating type rack, which is based on a moving hardening method using a round coil, and FIG. 6 (A) shows a round coil and a rack; FIG. 1B is a schematic explanatory view for explaining a gap between a round coil and a rack, and FIG. 1C shows a quenching pattern of a rack quenched by the apparatus. It is a schematic sectional drawing of a rack.

FIG. 7 is a schematic perspective view showing a half-open saddle coil used in a conventional high-frequency induction heating type rack induction hardening apparatus using a half-open saddle coil.

[Explanation of symbols]

 W rack 100 high frequency heating coil body 200 cooling means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C21D 1/10 C21D 1/10 Y

Claims (10)

[Claims] 1. A high-frequency heating coil for heating a rack, a rotating mechanism for rotating the rack when the high-frequency heating coil heats the rack, and the rack heated by the high-frequency heating coil And a cooling means for cooling the area provided with the teeth in the area faster than the area on the opposite side of the area in the rack. 2. The cooling means comprises: a first cooling jacket for spraying a cooling liquid to a region of the rack where teeth are provided; and a cooling liquid to a region of the rack opposite to the region. A second cooling jacket for injecting, wherein the injection amount of the cooling liquid per unit area of the first cooling jacket is larger than the injection amount of the cooling liquid per unit area of the second cooling jacket. The induction hardening device for a rack according to claim 1, wherein the device is configured. 3. The cooling means moves a cooling liquid tank in which a cooling liquid for immersing and cooling the rack is stored, and the rack heated by the high-frequency heating coil body to a level below the cooling liquid in the cooling liquid tank. Moving means for causing
2. The rack according to claim 1, wherein when the rack is immersed in the cooling liquid by the moving unit, the rack is immersed by lowering a region provided with teeth in the rack. Input device. 4. The cooling means moves a cooling liquid tank storing a cooling liquid for immersing and cooling the rack, and moves the rack heated by the high-frequency heating coil body below a cooling liquid level in the cooling liquid tank. Moving means for moving, a first cooling jacket which is provided below the surface of the cooling liquid and injects the cooling liquid to a region provided with the teeth in the immersed rack, and a region provided with the teeth in the rack. And a second cooling jacket for injecting a cooling liquid to an area on the opposite side of the rack, and when the rack is immersed in the cooling liquid by the moving means, an area of the rack where teeth are provided is provided. The second cooling jacket is immersed in a lower position, and the injection amount of the cooling liquid per unit area of the first cooling jacket is larger than the injection amount of the cooling liquid per unit area of the second cooling jacket. 2. The induction hardening device for a rack according to claim 1, wherein the hardening device has a simple structure. 5. The high-frequency heating coil body is a semi-open saddle-type high-frequency heating coil body, and is electrically connected to a pair of side heating conductors and the pair of side heating conductors. A top heating conductor, and the pair of side heating conductors and the top heating conductor are connected so that currents flowing therethrough have a shunting / merging relationship with each other. Before the rotation of the rack is started by the rotation mechanism, the region of the rack where the teeth are provided is arranged at a position facing the top-side heating conductor and is stopped and heated. Claim 1, characterized in that:
The induction hardening device for a rack according to 2, 3 or 4. 6. A step of heating by a high-frequency heating coil body while rotating the rack, and, after the heating is completed, the area of the rack where the teeth are provided is earlier than the area of the rack opposite to the area. And a step of cooling the rack. 7. The cooling step includes, after the completion of the heating, an injection amount of the cooling liquid per unit area by a first cooling jacket that injects the cooling liquid to a region where the teeth are provided in the rack, The rack is provided with teeth in the rack at a rate greater than the amount of coolant injected per unit area by the second cooling jacket that injects coolant into a region on the opposite side of the region provided with the teeth in the rack. 7. The induction hardening method for a rack according to claim 6, wherein a side of the rack is cooled faster than a side of the rack opposite to a side on which the teeth are provided. 8. The step of cooling includes, after the completion of the heating, immersing the rack in a cooling liquid with a region provided with the teeth down in the rack so that the region provided with the teeth in the rack is provided with the teeth in the rack. 7. The induction hardening method for a rack according to claim 6, wherein the rack is cooled faster than a region on the opposite side of the region provided with. 9. The step of cooling includes, after completion of the heating, immersing the rack in a cooling liquid with the area provided with the teeth down, and then cooling the area provided with the teeth in the rack. The amount of the coolant sprayed from the first cooling jacket provided in the coolant is changed to the second coolant provided in the coolant to cool a region of the rack opposite to the region provided with the teeth. The cooling liquid injection amount from the cooling jacket is set to be larger than the cooling liquid, so that the area of the rack where the teeth are provided is cooled faster than the area of the rack opposite to the area where the teeth are provided. 6. The method of induction hardening of a rack according to 6. 10. A pair of side-surface heating conductors having a pair of side-surface heating conductors and a top-side heating conductor electrically connected to the pair of side-surface heating conductors. And the top-side heating conductor portion, the top-side heating conductor portion of the semi-open saddle-type high-frequency heating coil body connected so that the flowing currents are in a shunting / merging relationship with each other. Wherein the region is stopped and heated before the heating step.
7. The method of induction hardening of a rack according to 7, 8, or 9.