JPH0159335B2 - - Google Patents

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 that has approximately the same diameter over its entire length. It is also known to use direct current heating from electrodes connected to a power supply at frequency, for example commercial frequency. However, in the case of a shaft W having an ampullae Wa at a predetermined portion as shown in FIG. 1, for example, there is a difference in mass between the ampulla Wa and the shaft Wb, so
No matter which heating means, induction heating or direct current heating, is used, the heating temperature of the ampullae part Wa is lower than that of the shaft part Wb, and it is difficult to obtain a uniform heating temperature. Furthermore, the surface heating temperature of the ampullae Wa is
It was considered impossible to meet the requirement for heating conditions higher than those for Wb.

The present invention has been made in order to solve the difficulty of uniformly heating the surface of a shaft body having an ampullae and the impossibility of heating the surface with a 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 portion and the shaft portion.

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 heat the ampulla continuously or intermittently during the energization time from the electrode, or continuously or intermittently over a predetermined time period during the energization time. The ampullae is heated by induction heating so that the entire surface layer of the shaft is heated at a uniform temperature, or the surface of the ampullae is heated at a temperature difference between the surface layer of the ampullae and the surface layer of the shaft. There is a method for heating the surface of a certain shaft body.

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,
It is composed of an electrode section 3 on one side and an electrode section 4 on the other side. The input terminal section 1 has an insulating material 11
One input terminal member 1a and the other input terminal member 1 form an L shape bent in opposite directions across the
A plurality of bolt holes 12 are drilled in each side that opens in opposite directions, and bolts (not shown) passing through the bolt holes 12 are used to connect each of the high frequency power sources (also not shown). is connected electrically to the output terminal of the 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. heating coil C
and coil leads 21 and 22 of the heating coil C. Coil leads 21 and 22 extend toward input terminal section 1 with insulating material 23 in between.
are bent outward and further extended, one coil lead 21 has its inner surface fixed to a predetermined outer surface of input terminal member 1a, and the other coil lead 22 has its inner surface fixed to 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
It is a split type coil divided on the circumference separated by, for example, 180 degrees from the connection side with 1 and 22, and under normal conditions, the end faces of each end face each other with the source separated by a predetermined distance and are electrically disconnected. Hold. Contact pieces 211 and 221 are provided at the divided ends of the heating coil C, respectively, and extend toward the outer circumferential direction, and the contact pieces 211 and 221 follow arrows Q generated by driving a coil closing device (not shown). When a pressing force is applied in that direction, they are displaced in the same direction, and their opposing closed end surfaces are brought into close contact and electrically connected. The inner circumferential surface of the annularly closed heating coil C is set to have an inner diameter such that it faces the outer circumference of the enlarged portion Wa of the shaft W to be tempered with a predetermined gap therebetween. One electrode section 3 is located at a predetermined distance to the right of the heating coil C, and includes an electrode 31 made of a plate-shaped body having a plate surface parallel to the end surface of the heating coil C, and an input terminal of the electrode 31. Electrode lead 3 bent toward the front from the end in the end portion 1 direction and extending toward the input terminal member 1a.
2 and an electrode lead connection terminal 321 formed at the tip of the electrode lead 32, and the inner surface of the electrode lead connection terminal 321 is connected to the input terminal member 1.
A is brought into contact with the outer surface of the protruding side of a and is tightened by a bolt 34 to be electrically connected. The other electrode section 4
is located at a predetermined distance to the left of the heating coil C, and includes an electrode 41 made of a plate-shaped body having a plate surface parallel to the end surface of the heating coil C, similar to the electrode section 3; The input terminal member 1 is bent in the forward direction from the end of the input terminal part 1 of the input terminal member 1.
Consisting of an electrode lead 42 extending in the b direction and an electrode lead connecting terminal 421 formed at the tip of the electrode lead 42, the inner surface of the electrode lead connecting terminal 421 is brought into contact with the outer surface of the protruding side of the input terminal member 1b to connect the bolt. and are electrically connected. Therefore, the distance between the opposing planes of the electrodes 31 and 41 is slightly narrower than the axial length of the shaft W to be tempered, and the distance between the electrodes 31 and 41 including their thickness is equal to the axial length of the shaft W to be tempered. For example, the length of the right shaft portion _Wb1 of the ampulla Wa shown in FIG. The specifications are set so that the length of Wb ₂ matches the distance between the heating coil C and the electrode 41. Further, 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 of the heating coil C. through holes 33 and 43 are provided, respectively. The through holes 33 and 43 are formed by cutouts S having 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. ,
Each is divided into two parts. Therefore, flexibility is imparted to the divided pieces of each electrode 31, 41, and the width of the notch S can be expanded or reduced, and the inner diameter of the through holes 33, 43 can be expanded or reduced within a predetermined range. becomes. Further, an electrode clamping device (not shown) is added to the device of this embodiment, and by driving the electrode clamping device, the width direction end faces of the electrodes 31 and 41 can be clamped in accordance with the arrow P. has been done.

The case where the shaft body W having the enlarged portion Wa shown in FIG. 1 is tempered using the apparatus having the above configuration will be described below.

First, the shaft body W is oriented so that the shaft parts Wb ₁ and Wb ₂ are positioned in accordance with the arrangement direction of the electrodes 31 and 41 with respect to the coil C of the tempering device, and then the lengths of the shaft parts Wb ₁ and Wb ₂ are determined. For example, Wb ₁ >
If Wb ₂ , the shaft body W is moved from a state where the ampulla Wa is in front of the space between the heating coil C and the electrode 31.
is advanced in the direction of the device, the shaft portion Wb ₁ is inserted into the notch S of the electrode 31, and pushed into the through hole 33. Next, the shaft body W is moved to the left in the figure, and the shaft portion Wb ₂ 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 33 of shaft portion Wb ₁ through notch S of electrode 31
As described above, the insertion of the tip of the shaft Wb ₂ into the through hole 43 of the electrode 41 can be carried out without any problem because the divided parts of the electrode are flexible. In this state, both ends of the shaft body W are connected to electrodes 31, respectively.
is accommodated in the through hole 33 of the electrode 41 and the through hole 43 of the electrode 41, and the enlarged portion Wa is surrounded by the dividing peripheral wall of the heating coil C in a divided state. Next, an electrode clamping device (not shown) is driven to tighten the electrodes 31 and 4.
1 from the direction of arrow P , and the through hole 33
and 43 shafts W accommodated in respective holes.
Both ends of the electrode 3 are crimped with the hole wall, thereby making the electrode 3
1 and 41 grip the shaft body W.

In this state, for example, the tempering temperature of the ampullae part Wa is 300°C, and the tempering temperature of the shaft part Wb is 200°C.
The case where the heating temperature is specified as Wa>Wb will be explained.

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. Flows into the circuit consisting of part 1-power supply E, through holes 33 and 4 of electrode 31 of electrode part 3 and electrode 41 of electrode part 4, respectively.
The shaft body W held by the shaft member 3 generates resistance heat due to the high frequency current flowing through its surface layer. However, the bulk of the shaft W
Since the mass of the surface layer of Wa is larger than that of the shaft portion Wb, the heating temperature is lower than that of the shaft portion Wb. 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 from the high-frequency power supply E apart from the circuit including the electrode parts 3 and 4, and a magnetic flux is generated from the closed heating coil C, which spreads through a predetermined gap. Ampullae Wa facing apart
heating the surface layer by induction. In the induction heating, the coil leads 21 and 22 of the heating coil C are attached almost to the center of the input terminal section 1, and the electrode sections 3 and 4 are connected to the high frequency power source E in parallel with the circuit of the induction heating section 2. Since the circuit is sufficiently shorter than the circuit containing the circuit, high frequency current flows well and is carried out effectively. Thus, if the high-frequency power source E is turned off after a predetermined period of time has elapsed, the shaft portion Wb is only directly energized throughout the entire energizing period, and the ampullae portion Wa is subjected to a mutual effect of direct energization throughout the energizing period and induction heating for a predetermined period of time. As a result of this action, it is heated to a heating temperature with a desired temperature difference.

After heating, the coil closing device is driven to release the pressing force Q that was pressing the contact pieces 211, 221 of the heating coil C, and the electrode clamping device is driven to release the clamping force P. The shaft body W is discharged from the tempering device in the reverse order of the mounting procedure.

In the above example, only direct energization is used at the beginning of the total energization time, and then direct energization and induction heating are used together.
It is determined according to the magnitude of the temperature difference between the shaft portion Wb and the shaft portion Wb, the ratio of the width of the enlarged portion Wa to the length of the shaft portion Wb, and the like. 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. is the ampullae
Since the heat of the heated surface layer of Wa is conducted in the axial direction, there is an effect of increasing the thickness of the heating layer.

The present invention is not limited to tempering with a temperature difference.
Of course, it is also possible to uniformly heat the surface layers of the ampullae Wa and the shaft Wb by appropriately setting the time for the combination of direct energization 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 put into a cooling water tank to be rapidly cooled, or a cooling liquid injection mechanism for the shaft part is provided in addition to the apparatus of the embodiment, and a A cooling liquid injection hole is provided in the heating coil for
Coolant may be injected at the end of heating.

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, continuous operation rate, etc.

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

The electrodes that grip both ends of the shaft are not limited to the shape shown in the examples, but may be any shape as long as they can be gripped and energized, and the heating coil is not limited to the split-type heating coil divided by the annular part shown in the examples. For example, cut a part of one lead of the annular heating coil,
A separately provided conductor member may be provided at both ends of the cut portion so that it can be brought into contact with or separated from the cut portion to turn on and off electricity 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 ampulla to a higher temperature than the shaft, which was previously considered impossible.
It is also possible to heat with a desired temperature difference, and as a result, quenching and tempering with a hardness difference between the enlarged part and the shaft part 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]

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, W...
Shaft body, Wa... Ampulla of the shaft body, Wb... Shaft part of the shaft body.

Claims (1)

[Claims] 1. When surface heating a shaft body with an enlarged part, both ends of the shaft body are held with electrodes connected to a high frequency power source and heated with electricity, and at the same time, the ends of the shaft body are heated with electricity, and at the same time The ampullae is inductively heated by an induction heating coil that is wound around the outer periphery of the ampullae with a predetermined gap, continuously or intermittently during the energization time from the electrode, or continuously or intermittently over a predetermined time period during the energization time. 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 surface layer of the shaft are heated with a temperature difference. Surface heating method.