JPS591624A - Uniform heating method of surface of shaft body having bulged part - Google Patents

Abstract

PURPOSE:To heat uniformly and quicly the surface of a shaft body having a bulged part in the stage of heating said shaft body by direct conduction of high frequency electric current by heating supplementally the bulged part of the shaft body with an induction heating coil in which said high frequency electric current flows. CONSTITUTION:The high frequency electric current flowing from a high frequency power source E in an arrow direction passes through an induction heating coil C winding the bulged part Wa of a shaft body W to an electrode part 3, from which the current flows to the end part of the shaft part Wb1. The current flows from the part Wb1 in the direction of the shaft part Wb2, flows from the end part of the part Wb2 to an electrode part 4 and is fed back to the source E. The output of the high frequency current to be conducted is requlated according to the thickness of a tempering layer, a tempering temp. and various other conditions, and is conducted for a prescribed time. The surface layer of the body W is thus resistance-heated by the high frequency current flowing in the surface layer, and the bulged part Wa is superposed with the induction heating by the magnetic flux from the coil C, and is thereby heated to approximately the same temp. as the temp. in the shaft parts Wb1, Wb2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for uniformly heating the surface of a shaft having an enlarged portion.

Induction heating is used to uniformly heat the surface of a shaft body for hardening and tempering, which has approximately the same diameter over its entire length. However, for example, as shown in FIG.
In the case of a shaft W with a, there is a difference in mass between the ampullae Wa and the shaft wb, so when heated by induction heating means, the temperature increase in the ampulla Wa is lower than that of the shaft wb, and the total It is extremely difficult to obtain uniform heating over the surface. For this reason, when forming a uniform hardened layer on the surface of the shaft body W having the enlarged portion Wa, a carburizing method has conventionally been used, and when uniformly tempering the surface, heating in an electric furnace has been used. As is well known, both the carburizing method and electric furnace heating require a long time, resulting in poor production efficiency and a need for improvement.

The present invention has been made in order to solve the above-mentioned problems that exist in the conventional method when uniformly hardening or uniformly tempering the surface of the shaft W having the ampullae Wa.
The present invention provides a heating method that makes it possible to raise the surface of the shaft portion wb to a uniform temperature, thereby contributing to the formation of a hardened layer through uniform surface hardening and uniform tempering.

The gist of the present invention is that when heating a shaft body having an ampulla, both ends of the shaft body are gripped by electrodes, and one of the two electrodes is connected in series to the ampullae and a predetermined gap. One side is connected to a high frequency power source through an induction heating coil facing the other side, and the other side is directly connected to a high frequency power source, and a high frequency current is passed through the adjusted output from the high frequency power source, and the shaft is heated by direct energization. This method provides a method for uniformly heating the surface of a shaft body having an ampulla, characterized in that the ampullae in which resistance heat generation is low is reheated by induction heating with the magnetic flux of an induction heating coil.

The present invention will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows an embodiment of an apparatus in which the present invention is applied to tempering and heating a shaft body having an enlarged portion. The tempering device includes an input terminal section 1, an induction heating section 2, one electrode section 3, and the other electrode section 4. The input terminal portion 1 is bent in opposite directions with an insulating material 11 in between.
(It consists of one input terminal member 1a and the other input terminal member 1b that form an L shape, and a plurality of holes 12 are bored in each side that opens in opposite directions. By bolts (not shown) passing through the holes 12, these are tightened and electrically connected to respective output terminals of a high frequency power source (also not shown).

The induction heating section 2 is arranged, for example, at a position separated by a predetermined distance from the protruding sides of the input terminal members 1a and 1b that protrude from the power supply side of the input terminal section 1, and whose axis line is on the plane containing the insulating material 11. Coil leads 22 and 23 extending perpendicularly toward the input terminal section 1 across the wound heating coil C and the insulating material 21 of the heating coil C, parallel to the end surface of the insulating material 11, Above coil lead 2
2 is bent outward at a predetermined position, and further extends toward the input terminal portion 1, and includes a coil lead connection terminal 221 formed at the tip thereof. The outward refraction of the coil lead 22 is set to be approximately equal to the thickness of the protruding side of the input terminal 1a, and
The outer surface of the protruding side of the coil lead connection terminal 221 is in contact with the inner surface of the coil lead connection terminal 221, and is tightened to the input terminal member 1a via the bolt 222 to be electrically connected. On the other hand, coil lead 23
is bent at a right angle in the figure at a predetermined position, and continues to an electrode lead of one electrode section 3, which will be described later. One electrode part 3 is composed of, for example, a plate-shaped electrode 31 that is parallel to the end surface of the heating coil C at a predetermined distance, and an electrode lead 32 that is bent at a right angle from the electrode 31 and continues to the coil lead 23. Lead 23 and electrode lead 32 are electrically connected. The other electrode section 4 includes a plate-shaped electrode 41 that is parallel to the end surface of the heating coil C at a predetermined distance to the left in the drawing, and an electrode lead that is bent outward from the electrode 41 and further extends in the direction of the input terminal section 1. 42 and an electrode lead connection terminal 421 formed at the tip of the electrode lead 42. The electrode lead 42 bent outward from the electrode 41 is set to be bent by an amount approximately equal to the thickness of the protruding side of the input terminal member 1b, so that the outer surface of the protruding side of the input terminal member 1b and the electrode lead connecting terminal 421 are bent. The input terminal member 1 is in contact with the inner surface, and the input terminal member 1 is connected by bolt fastening.
b and the electrode lead connection terminal 421 are tightened and electrically connected. Therefore, the distance between the opposing planes of both electrodes 31 and 41 is slightly narrower than the axial length of the shaft body W to be tempered.
1.41 The distance between the two including their respective thicknesses is slightly wider than the axial length of the shaft W to be tempered, and the right shaft portion Wb of the ampulla Wa shown in FIG.
The specifications are set so that the length of matches the distance between the heating coil C and the electrode 31, and the length of the left axis wb of the ampulla Wa, and the length of matches the distance between the heating coil C and the electrode 41. .

In addition, the opposing surfaces of the electrodes 31 and 41 have an inner diameter approximately equal to the diameter of the shaft portion wb of the shaft body W that extends from a point corresponding to an extension of the axis of the heating coil C to the opposite side along the axis. Through holes 33 and 43 are provided, respectively. The through holes 33 and 43 are formed by cutouts S of a predetermined width including the axes of the through holes 33 and 43, such that the electrodes 31 and 41 are vertically divided more than halfway from the tip end face to the end in the electrode lead direction. It is divided into two parts. Therefore, flexibility is imparted to the divided pieces in each of the electrodes 31 and 41, and the width of the notch S can be enlarged or reduced, and the inner diameter of the through holes 33 and 34 can be enlarged or reduced within a predetermined range. Become.

Further, an electrode clamping device (not shown) is added to the apparatus of this embodiment, and is configured to clamp the widthwise end surfaces of the electrodes 31 and 41 in the direction of arrow P.

Using the apparatus having the above configuration, the ampulla W shown in FIG.
The case of tempering the shaft body W with a is explained below.

First, the shaft body W is attached to the electrode 3 for the heating coil C of the tempering device.
Shaft portions Wb1 and W in accordance with the arrangement direction of 1 and 41.
After aligning the direction so that b2 is positioned, the shaft portion Wb
If the lengths of 1 and Wb are, for example, WbI>Wb2, the shaft w' is advanced toward the device from a state where the ampulla Wa is in front of the space between the heating coil C and the electrode 31,
The shaft portion wb is inserted into the notch S of the electrode 31 to form the through hole 3.
Push it all the way to 3. Next, the shaft Wb2 is fixedly moved to the left, and the shaft portion Wb2 is inserted into the heating coil C and moved forward, so that its tip is fitted into the through hole 43 of the electrode 41.

Through hole 3 of shaft portion wb through notch S of electrode 31
3 and the insertion of the tip of the shaft portion Wb2 into the through hole 43 of the electrode 410 can be carried out without any problem because the divided parts of the electrode are flexible as described above. In this state, both axial ends of the shaft body W are accommodated in the through hole 33 of the electrode 31 and the through hole 43 of the electrode 410, respectively, and the enlarged portion Wa is inside the heating coil C, and its outer periphery is aligned with the coil peripheral wall. Maintains a gap. Then, using an electrode clamping device (not shown), each of the electrodes 31 and 41 is clamped from the direction of arrow P, and both ends of the shaft KW accommodated in each of the through holes 33 and 43 are crimped with the hole walls. , the shaft body W is gripped by the electrodes 31 and 41. In this state, the high frequency power source is turned on, and a high frequency current of a predetermined frequency due to the adjusted output is passed from the output terminal of the high frequency power source to the input terminal section 1 of the apparatus. FIG. 3 shows a current circuit according to the present invention. For example, a high frequency current flowing in the direction of the arrow from a high frequency power source E reaches the electrode portion 3 via a heating coil C that winds around the enlarged portion Wa of the shaft body W. , flows through the hole wall of the through hole 33 of the electrode 31 of the electrode part 3 to the end of the shaft part WbI, and then flows from the shaft part wb toward the shaft part wb,
The end of the shaft portion Wb2 reaches the electrode portion 4 through the hole wall of the electrode 410 through hole 43 of the electrode portion 4, and the high frequency power source E
to return to.

The output of the high-frequency current is adjusted according to the frequency of the high-frequency power source being used, the thickness of the tempering layer from the surface of the shaft body, the tempering temperature, and other conditions, and the high-frequency current is supplied for a predetermined period of time.

Thus, the surface layer of the shaft body W generates resistance heat due to the high frequency current flowing through the surface layer. At this time, since the mass of the surface layer is large, the current density of the flowing high-frequency current becomes coarse, and the induction heating due to the magnetic flux from the heating coil C is superimposed on the resistance heat generation in the ampulla Wa where the degree of resistance heat generation is low. Therefore, the temperature of the ampullae portion Wa increases almost the same as the temperature increase of the shaft portion wb. After a predetermined energization time has elapsed, the high-frequency power source E is turned off, and then the clamping force of the electrodes 31 and 41 in the direction of the arrow P by the electrode clamping device is released, and then the entire surface layer is heated to a predetermined uniform temperature and tempered. After completion of the process, the shaft Wb2 is moved to the right until the end of the shaft Wb2 escapes from the through hole 43 and the heating coil C, and then the shaft Wb2 is fitted into the through hole 33 by the reverse operation of the installation into the device. The shaft portion W b l that has been removed is removed from the electrode 31 through the notch S, and the entire tempering process is completed.

Although the above is an example in which a shaft body having an enlarged portion is tempered, the present invention can also be used for heating for hardening.

In this case, the surface layer of the shaft body is heated to a predetermined quenching temperature and then put into a cooling water tank for rapid cooling quenching, or a cooling liquid injection mechanism for the shaft part is provided in addition to the apparatus of the embodiment, and a cooling liquid injection mechanism is provided for the ampulla part. A coolant injection hole may be provided in the heating coil, and the heating shaft may be rapidly cooled by injecting the coolant from the coolant injection mechanism and the coolant injection hole.

Although the self-cooling mechanism of the apparatus was not mentioned in the above embodiment, a self-cooling mechanism is naturally added if necessary due to various conditions such as energization time, heating temperature, and continuous operation rate. Note that the electrode is not limited to a plate-like body as shown in the embodiments, but the object of the present invention can be achieved as long as it can be gripped at the end of the shaft and energized.

According to the present invention, it is possible to uniformly heat the surface of a shaft body with a large portion in an extremely short time, and moreover, uniformity of heating temperature is ensured. Since it is a method of using electrical energy, it has remarkable energy conversion efficiency, good economic efficiency, and excellent practicality.

[Brief explanation of drawings]

Fig. 1 is a front view of a shaft body with an enlarged portion to which the present invention is applied, Fig. 2 is a perspective view of a device according to an embodiment of the present invention, and Fig. 3 is a current circuit diagram of an embodiment of the present invention. . 31, 41... Electrode, C... Induction heating coil, E... High frequency power supply, W... Shaft body, Wa... Ampulla of the shaft body. Patent Applicant Koshuha Netsuren Co., Ltd. Agent Patent Attorney Fudai Kobayashi 1WJ Figure 3 Figure 2

Claims (1)

[Claims] When heating a shaft body with an ampulla, both ends of the shaft body are held by electrodes, and one of the two electrodes is connected in series to this and faces the ampullae with a predetermined gap. The induction heating coil is connected to a high frequency power source through an induction heating coil, and the other side is directly connected to a high frequency power source, and a high frequency current is passed through the adjusted output from the high frequency power source, so that the resistance heat generation of the shaft heated by direct current is low. A method for uniformly heating the surface of a shaft body having an ampulla, characterized in that the ampullae is reheated by induction heating with the magnetic flux of an induction heating coil.