JPS591625A - Surface heating method of shaft body having bulged part - Google Patents

Abstract

PURPOSE:To heat uniformly the surface of a titled shaft body with high energy conversion efficiency, by heating inductively the bulged part continuously or continuourly or intermittently for a prescribed time during heating of the shaft body by direct conduction of high frequency electric current. CONSTITUTION:When a high-frequency power source is turned on while a heating coil C is held open, high-frequency electric current flows in an arrow direction and passes through the surface layer of a shaft body W and heats by resistance the surface layer of the shaft body. Upon lapse of a prescribed time, a coil closing device is driven to press the contact pieces 211 and 221 of the coil C in an arrow Q direction so as to bring the same into contact with each other, thereby closing the coil C. The high-frequency current shown by double arrows flows from an electric power source E in such a state, then a magnetic flux is generated from the coil C and heats inductively the surface layer of a bulged part Wa facing the coil apart from a prescribed spacing. If the power source E is turned off after a prescribed time, the shaft parts Wb1, Wb2 are heated only by the direct conduction of said current and the bulged part Wa heated by the direct conduction and the induction, heating, whereby both parts are heated uniformly or at a prescribed temp. difference.

Description

[Detailed description of the invention] The present invention relates to a method for heating the surface of a shaft body having an ampulla.

It is well known that induction heating is used as a uniform heating means for surface hardening or tempering the surface hardened layer of a shaft body having approximately the same diameter over the entire length, and also as a heating means for uniform heating over the entire cross section. It is also known to use direct current heating from electrodes connected to a low frequency, eg commercial frequency power supply. However, for example, in the case of a shaft body W having an enlarged portion Wa at a predetermined portion as shown in FIG. Even if the ampullae part Wa is heated to a lower temperature than the shaft part wb,
It is difficult to obtain a uniform heating temperature. Moreover, the huge ζ
It has been considered impossible to meet the requirement for heating conditions that make the surface heating temperature of Wa higher than that of the shaft portion wb.

The present invention was made in order to solve the difficulty of uniform surface heating when heating the surface of a shaft body having a large portion, and the impossibility of surface heating that reduces the temperature difference. The object of the present invention is to provide a surface heating method that can perform heating with a desired temperature difference between the shaft part and the shaft part.

The gist of the present invention is that when surface-heating a shaft body having an enlarged portion, both ends of the shaft body are gripped with electrodes connected to a high frequency power source and electrically heated, and the high frequency power source is heated in parallel with the electrodes. An induction heating coil connected to a power supply and wound around the outer periphery of the ampullae with a predetermined gap is used to continuously or intermittently inflate the ampullae for a predetermined period of time during which electricity is applied from the electrodes. The shaft is heated by induction to bring the entire surface layer of the shaft to a uniform temperature, and the surface of the shaft is heated at a temperature difference between the surface layer of the splintered or enlarged portion and the surface layer of the shaft. A method for heating the surface of a shaft body having an ampulla.

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 pongee 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 section 1 consists of one input terminal member 1a and the other input terminal member 1b forming an L-shape bent in opposite directions with an insulating material 11 in between, and each side opening in opposite directions. A plurality of bolt holes 12 are bored through the bolt holes 12, and bolts (not shown) passing through the bolt holes 12 are used to tighten and electrically connect to respective output terminals of a high frequency power source (also not shown).

The induction heating section 2 is disposed such that its axis is parallel to the end surface of the insulating material 11, which is separated by a predetermined distance from the protruding edges of the input terminal members 1a and 1b protruding from the power supply side of the input terminal section 1, for example. It consists of a heating coil C and coil leads 21 and 22 of the heating coil C.

The hill coil leads 21 and 22 extend in the direction of the input terminal portion 1 across the insulating material 23, and after being bent outward, one of the coil leads 21 extends further, with the inner surface of the coil lead 21 extending outside the input terminal member 1a. The other coil lead 22 has its inner surface fixed to the input terminal member 1b.
is fixed to the outer surface opposite to the position where the lead 21 is fixed, and is electrically connected to each of the input terminal members 1a and 1b. However, on the other hand, the heating coil C is connected to the connection side with the coil leads 21 and 22, for example.
It is a split type coil that is divided on a circumference separated by 80 degrees, and under normal conditions, the end faces of each end face each other with a predetermined distance apart from the source, and are kept electrically disconnected. Contact pieces 211 and 221 are provided at the divided ends of the heating coil C, respectively, and the contact pieces 211 and 221 extend in the circumferentially outward direction, and the contact pieces 211 and 221 extend in the direction according to the arrow Q generated by driving a coil closing device (not shown). When a pressing force is applied, they are displaced in the direction toward each other, and their opposing closed end surfaces are brought into close contact and electrically connected. Therefore, the inner circumferential surface of the annularly closed heating coil C is the enlarged part W of the shaft body W to be tempered.
It is set to have an inner diameter that faces the outer periphery of point a with a predetermined gap therebetween. One electrode part 3 is located at a predetermined distance to the right of the heating coil C, and is connected to an electrode 31 made of a plate-shaped body having a plate surface parallel to the end surface of the heating coil C, for example. The electrode lead 32 bends toward the front from the end in the input terminal direction of the electrode 310 and extends toward the input terminal member 1a, and the electrode lead connection terminal 321 formed at the tip of the electrode sand lead 32, The inner surface of the electrode lead connection terminal 321 is connected to the input terminal member 1ai
abutting against the outer surface of the protruding side and being tightened by the bolt 34;
electrically connected. The other electrode part 4 is located at a predetermined distance to the left of the heating coil C, and is made of a plate-shaped body having a plate surface parallel to the end face of the heating coil C, for example, like the electrode part 3. 41, and an electrode lead 42 and an electrode lead 4 bent in the forward direction from the end of the electrode 41 in the direction of the input terminal part 1 and extending in the direction of the input terminal member 1b.
The inner surface of the electrode lead connecting terminal 41'l is brought into contact with the outer surface of the protruding side of the input terminal member 1b, and is tightened with a bolt, electrically. Connected.

Therefore, the distance between the opposing planes of both electrodes 31 and 41 is the axial length of the shaft body W to be tempered, and J is slightly narrower.
The distance between them, including the thickness, is wider than the axial length of the shaft W to be tempered, and the distance between them is wider than the axial length of the shaft W to be tempered, and the distance between the two is wider than the axial length of the shaft W to be tempered. The specifications are set so that the length matches the distance between the heating coil C and the electrode 31, and the length of the left shaft portion Wb2 of the enlarged portion Wa matches the distance between the heating coil C and the electrode 41. Cut electrodes 31 and 4
1 is provided with a through hole having an inner diameter equal to the diameter of the shaft portion wb of the shaft body W, which penetrates the electrode along the axis from a point that meets the extension of the axis of the heating coil C to the opposite side. 33
There are 43 tools in place. The above through hole 33
and 43 are each formed by a notch S of a predetermined width including the axis of the through-hole 33 and 43, such that the electrode 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 expanded or reduced, and the through holes 33 and
43 can be enlarged or reduced within a predetermined range. In addition, an electrode clamping device (not shown) is added to the device of this embodiment, and by driving the mold bar clamping device, the widthwise end faces of the electrodes 31 and 41 can be clamped in accordance with the arrow 3. It is configured.

Using the apparatus having the above configuration, the ampullae Wa shown in FIG.
The case of tempering a certain shaft body W will be described below.

First, the shaft body W is aligned so that the shaft parts wb and wb2 are positioned in accordance with the arrangement direction of the electrode 31 and the cut 41 with respect to the coil C of the tempering device, and then the lengths of the shaft parts Wbt and wb2 are determined. For example, if wbl>wb2, the shaft W is advanced toward the apparatus from a state where the ampulla Wa is in front of the space between the heating coil C and the electrode 31, and the shaft W is
(b) into the notch S of the electrode 31 and push it into the through hole 33. Next, the shaft body W is moved to the left while fixating, and the shaft portion wb2 is inserted into the heating coil C and advanced, and its tip is fitted into the through hole 43 of the electrode 41. Above type Th
31 into the through hole 33 of the shaft portion Wb through the notch S, and the through hole 43 of the electrode 41 at the tip of the shaft portion Wb2.
As mentioned above, the electrode segments can be inserted without any problem because they are flexible. In this state, both shaft ends of the shaft W are inside the through hole 33 of the electrode 31 and the electrode 4.
It is accommodated in the through hole 43 of No. 1, and the enlarged portion Wa is surrounded by the dividing peripheral wall of the heating coil C which is in a divided state. Next, drive the electrode clamping device shown in the figure to clamp the electrodes 31 and 41 from the direction of the arrow y, and open the through holes 33 ↓
Both ends of the shaft W accommodated in the holes of the electrodes 31 and 43 are pressed against the hole walls, and the shaft body W is thereby gripped by the electrodes 31 and 41.

In this state, for example, the tempering temperature of the ampullae Wa is 3.
A case will be described in which the heating temperature is specified as W a )wb, such as 00° C1 and the tempering temperature of the shaft portion wb is 200° C.

When the high-frequency power source E is turned on with the heating coil C in an open state, the high-frequency current flows as shown by the arrow → in FIG. A base paper electrode part 3 is connected to a circuit consisting of a terminal part 1 and a power supply E.
The shaft body W held in the through holes 33 and 43 of the electrode 31 and the electrode 41 of the electrode part 4 generates resistance heat due to the high wave current flowing through the surface layer. However, the ampulla W of the shaft W
Since the mass of the second layer of aF'i is larger than that of the shaft part wb, the heating temperature during machining of the shaft part wb is low. After a predetermined period of time has elapsed, the coil closing device is driven to press the contact pieces 211 and 221 of the heating coil C into contact in the direction of arrow Q, thereby closing the heating coil C. In this state, a high-frequency current shown by a double arrow →→ flows through the high-frequency power source E, separate from the circuit including the electrodeposition parts 3 and 4, and a magnetic flux is generated from the closed heating coil C to a predetermined level. Ampulla W facing each other with a gap
The surface layer of a is heated by induction. The induction heating is performed using heating coil C.
The coil leads 21 and 22 are attached to the center of the Y of the input terminal section 1, and the circuit is more sufficient than the circuit including the electrodeposition sections 3 and 4 connected to the high frequency power source E in parallel with the circuit of the induction heating section 2. Because it is short, high frequency current flows well and is effective.

Thus, if the high frequency power source E is turned off after a predetermined period of time has elapsed,
By only direct energization throughout the entire energization time of the shaft portion WbrI'i, the ampulla Wa is heated to a heating temperature with a desired temperature difference due to the additive effect of direct energization throughout the entire energization time and induction heating for a predetermined time. be done.

After heating, drive the coil closing device to release the applied pressing force Q, drive the electrode clamping device to release the clamping force 1, and then attach the shaft body W in the reverse order. Discharge from the tempering equipment.

In the above embodiment, only direct energization is performed at the beginning of the total energization time, and then direct energization and induction heating are used together. , is determined according to the ratio of the width of the enlarged portion Wa to the length of the shaft portion Wb. It is also possible to use both direct energization and induction heating at the beginning of the entire energization time, and then heat only with direct energization, and furthermore, it is also possible to use induction heating intermittently during the entire energization time. Since the heat of the heated surface layer in the ampullae Wa is transferred in the axial direction, it has the effect of increasing the thickness of the heating layer.

The present invention is applicable not only to tempering with a temperature difference but also to
It goes without saying that it is possible to uniformly heat the surface layers of the shaft portion a and the shaft portion wb by appropriately setting the time for the combined use of direct current and induction heating.

Furthermore, the present invention is also applied to heating for hardening. In this case, the surface layer of the shaft body is uniformly heated to a predetermined quenching temperature and then placed in a cooling water tank to be rapidly cooled, or a cooling liquid injection mechanism for the shaft portion is provided in addition to the apparatus of the embodiment, and Coolant injection holes for the enlarged portion may be provided in the heating coil, and the coolant may be injected when heating is completed.

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.

Furthermore, the output of the high frequency power source is appropriately set in consideration of temperature conditions, heating layer performance, and other factors.

The electrodes that grip both ends of the moving part are limited to the shapes shown in the examples.
In addition, the heating coil is not limited to a split type heating coil divided by an annular part as shown in the embodiment, but a part of one lead of an annular heating coil can be used. After the heating coil is cut, separately provided conductor members may be placed over both ends of the cut portion so that they can be brought into contact with or separated from each other, thereby turning off and on the current supply to the heating coil.

According to the present invention, it is possible to uniformly heat the surface of the shaft body with the ampullae, both the ampullae and the shaft, and to heat the ampullae to a temperature higher than that of the shaft, which was previously considered impossible. - Since it is also possible to heat with a desired temperature difference, as a result, quenching and tempering with a hardness difference between the ampulla and the shaft can be easily achieved in one step. Furthermore, since it is a method of using electrical energy that mainly uses resistance heat generation through direct energization and secondary heating, it has high energy conversion efficiency and excellent economic efficiency, making it extremely practical.

[Brief explanation of drawings]

#, Figure 1 is a front view of a shaft body with an enlarged portion to which the present invention is applied, Figure 2 is a perspective view of an apparatus according to an embodiment of the present invention, and Figure 3 is a
The figure is a current circuit diagram of an embodiment of the present invention. 31.41... Electrode C... Induction heating coil W...
・Shaft Wa... Huge part of the shaft Wb... Shaft of the shaft Patent applicant Koshuha Netoren Co., Ltd. Agent Patent attorney Fu Kobayashi Figure 1 Figure 3

Claims (1)

[Claims] When surface heating a shaft body with an ampulla, both ends of the shaft body are gripped with electrodes connected to a high-frequency power source and heated with electricity, and at the same time, an ampullae connected to the high-frequency power source in parallel with the electrodes is heated. The ampullae is inductively heated continuously or intermittently during the energization time from the electrode, or continuously or intermittently for a predetermined time period during the energization time, by an induction heating coil wound around the outer periphery of the part with a predetermined gap. A shaft body with an ampullae, characterized in that the entire surface layer of the shaft body is heated to a uniform temperature, or the surface layer of the ampullae and the coating layer of the moving part are heated at a different temperature. Surface heating method.