WO2012147441A1

WO2012147441A1 - Method for electrically heating rod-shaped member and device for same

Info

Publication number: WO2012147441A1
Application number: PCT/JP2012/058132
Authority: WO
Inventors: 雄一平田; 浩之小木曽
Original assignee: 中央発條株式会社
Priority date: 2011-04-25
Filing date: 2012-03-28
Publication date: 2012-11-01
Also published as: JPWO2012147441A1

Abstract

According to the electrical heating method disclosed in the present specification, a pair of first electrodes are placed in contact with a rod-shaped member, with a gap therebetween in the axial direction of the rod-shaped member. Furthermore, a pair of second electrodes are placed in contact with the rod-shaped member on either side of the pair of first electrodes. A second voltage is applied between the pair of second electrodes at the same time as a first voltage is applied between the pair of first electrodes. As a result, first current flows to the portion between the first electrodes and also second current that is different from the first current flows to the portion between the second electrodes and the first electrodes adjacent to the second electrodes to electrically heat the rod-shaped member.

Description

Method and apparatus for electrically heating rod-shaped member

The technique disclosed in this specification relates to a technique for energizing and heating a rod-shaped member (for example, a stabilizer, a torsion bar, etc.).

通電 Electric heating is known as a method of performing heat treatment on a rod-shaped member. In energization heating, electrodes are brought into contact with both ends of a workpiece (bar-shaped member) to be heated, and a voltage is applied between the electrodes brought into contact with both ends of the rod-shaped member. As a result, a current flows through the rod-shaped member from one end side to the other end side, and the rod-shaped member is heated by the generated Joule heat. Japanese Patent Application Laid-Open Nos. 6-136432 and 2004-193033 disclose examples of techniques for heating a rod-shaped member by energization heating.

In a conventional energization heating method, one end of a pair of electrodes is brought into contact with one end of a rod-shaped member, the other of the pair of electrodes is brought into contact with the other end of the rod-shaped member, and a voltage is applied between the pair of electrodes to the rod-shaped member. Apply current. For this reason, the amount of current flowing in the axial direction through the rod-shaped member is the same at any position in the axial direction. Therefore, depending on the shape or the like of the rod-shaped member to be heated, there is a problem that it is difficult to set the temperature distribution in the axial direction of the rod-shaped member to a desired temperature distribution. For example, when the cross-sectional area (area of the cross section orthogonal to the axial direction) of the rod-shaped member to be electrically heated changes in the axial direction, it is difficult to heat the rod-shaped member to a uniform temperature in the axial direction. That is, since the amount of current flowing in the axial direction through the rod-shaped member is constant, the temperature is likely to rise because the resistance is large in the portion with the small cross-sectional area, and the temperature is difficult to rise because the resistance is small in the portion with the large cross-sectional area. As a result, the portion having a small cross-sectional area becomes high temperature, and the portion having a large cross-sectional area becomes low temperature, so that the rod-shaped member cannot be heated to a uniform temperature in the axial direction. In such a case, it is possible to make the rod-shaped member have a desired temperature distribution by changing the position where the electrode is brought into contact and conducting the current heating in multiple times. However, such a method has a problem that the time required for the energization heating becomes long because the energization heating must be performed a plurality of times.

It is an object of the present specification to provide a technique capable of making the temperature distribution in the axial direction of the rod-shaped member to be a desired temperature distribution by a single electric heating.

This specification discloses a method of electrically heating a rod-shaped member. In this energization heating method, the pair of first electrodes are brought into contact with the rod-shaped member with an interval in the axial direction of the rod-shaped member. Moreover, a pair of 2nd electrode is made to contact a rod-shaped member so that a pair of 1st electrode may be pinched | interposed. Next, a first voltage is applied between the pair of first electrodes, and at the same time, a second voltage is applied between the pair of second electrodes. As a result, a first current flows between the first electrodes, a second current different from the first current flows between the second electrode and the adjacent first electrode, and the rod-shaped member is energized and heated.

In this method, a pair of second electrodes are arranged so as to sandwich the pair of first electrodes, and these electrodes are brought into contact with a rod-shaped member. Then, the second voltage is applied between the second electrodes simultaneously with the application of the first voltage between the first electrodes. For this reason, by adjusting the resistance value of the first electrode, the resistance value of the second electrode, the first voltage, and the second voltage, the first current flowing between the first electrodes, the second electrode and the adjacent first electrode The second current flowing between the electrodes can be set to a desired current value. That is, the current flowing in the axial direction of the rod-shaped member can be made different at each portion of the rod-shaped member. As a result, the temperature distribution in the axial direction of the rod-shaped member can be set to a desired temperature distribution by a single electric heating.

Depending on the target temperature distribution, the shape of the rod-shaped member to be heated, etc., in addition to the pair of first electrodes and the pair of second electrodes, the pair of third electrodes are brought into contact with the rod-shaped member, and the first A third voltage may be applied between the three electrodes. That is, the number of electrode pairs to be brought into contact with the rod-shaped member and the positions thereof can be appropriately set according to a desired temperature distribution, the shape of the rod-shaped member, and the like.

Also, the present specification discloses an energization heating apparatus that can be suitably used in the above energization heating method. That is, the electric heating apparatus disclosed in this specification includes a pair of first electrodes that contact the rod-shaped member with an interval in the axial direction of the rod-shaped member, and a pair that contacts the rod-shaped member so as to sandwich the pair of first electrodes. And a voltage applying device that applies a second voltage between the pair of second electrodes simultaneously with applying the first voltage between the pair of first electrodes. When a voltage is applied between the electrodes by the voltage application device, a first current flows between the first electrodes, and a second current different from the first current is present between the second electrode and the first electrode adjacent thereto. Current flows.

The figure which shows schematic structure of the electric heating apparatus of Example 1. FIG. The figure which expands and shows the structure of an electrode part. The figure which shows a part of circuit comprised by the electricity heating apparatus of Example 1, and a workpiece | work. The figure which shows schematic structure of the electricity heating apparatus of a modification. The figure which shows the temperature measurement result when a stabilizer is heated with the electricity heating apparatus of Example 1. FIG. The figure which shows the temperature measurement result when a stabilizer is heated with the conventional electricity heating apparatus. The figure which shows the modification of an electrode. The figure which shows schematic structure of the electric heating apparatus of a modification (however, only the one end side of the workpiece | work is shown).

In the energization heating method disclosed in this specification, the pair of first electrodes may be brought into contact with the rod-shaped member with an interval in the axial direction of the rod-shaped member. Further, the pair of second electrodes may be brought into contact with the rod-shaped member so as to sandwich the pair of first electrodes. Next, the second voltage may be applied between the pair of second electrodes simultaneously with the application of the first voltage between the pair of first electrodes.

The electric heating method disclosed in the present specification includes a first portion having a first cross-sectional area, and a rod-like shape having a second portion disposed on both sides of the first portion and having a second cross-sectional area different from the first cross-sectional area. You may apply, when energizing and heating a member. In such a case, the pair of first electrodes may be brought into contact with the first portion, and the pair of second electrodes may be brought into contact with the second portion. According to such a configuration, the first current flows through the first portion, while the second current flows through the second portion. Since the current values of the first current and the second current can be controlled, an appropriate current can be passed through the first portion and the second portion, and the first portion and the second portion can be appropriately heated. .

In the energization heating method disclosed in this specification, the first voltage and the second voltage are the same, and the resistance value of the first electrode and the resistance value of the second electrode may be different. According to such a configuration, since the voltage applied to each electrode pair is the same, current heating can be performed by one power supply device.

The current heating method disclosed in the present specification may further include a step of bringing the pair of third electrodes into contact with the rod-shaped member so as to sandwich the pair of second electrodes. In this case, in the step of energizing and heating, when applying the first voltage between the pair of first electrodes and simultaneously applying the second voltage between the pair of second electrodes, the third voltage is applied between the pair of third electrodes. The rod-shaped member may be heated by applying a third current different from the first current and the second current between the third electrode and the adjacent second electrode. According to such a configuration, the heating amount of the rod-shaped member can be precisely adjusted according to the shape of the rod-shaped member.

Moreover, the electric heating apparatus disclosed in the present specification includes a pair of first electrodes that contact the rod-shaped member with an interval in the axial direction of the rod-shaped member, and a pair that contacts the rod-shaped member so as to sandwich the pair of first electrodes. A voltage applying device that applies the first voltage between the second electrode and the pair of first electrodes and simultaneously applies the second voltage between the pair of second electrodes may be provided. When a voltage is applied between the electrodes by the voltage application device, a first current flows between the first electrodes, and a second current different from the first current is present between the second electrode and the first electrode adjacent thereto. A current may flow.

As one aspect of the above-mentioned current heating device, the resistance value of the first electrode and the resistance value of the second electrode are different, the first voltage and the second voltage are the same, and the voltage application device is One power supply device that applies the same voltage between the electrodes and between the second electrodes may be provided. In this energization heating device, the current value of the current flowing through each part of the rod-shaped member can be controlled by adjusting the resistance values of the first electrode and the second electrode.

As another aspect of the above-described energization heating device, the first voltage and the second voltage are different, and the voltage application device includes a first power supply device that applies the first voltage between the first electrodes, and a second electrode. You may provide the 2nd power supply device which applies a 2nd voltage in between. This energization heating device can control the value of current flowing through each part of the rod-shaped member by using two power supply devices.

Hereinafter, the electric heating apparatus 10 according to the present embodiment will be described with reference to the drawings. First, the workpiece W heated by the energization heating device 10 will be described. The workpiece W is a stabilizer that is mounted on the underbody of the automobile, and is formed of a rod-shaped steel material (for example, SUP9 (Japanese Industrial Standard)). As the steel material used for the stabilizer, a steel material having a solid cross section or a steel material having a hollow cross section (so-called pipe materials (for example, STKM13A, STKM15A, etc. (Japanese Industrial Standard))) can be used. In general, the stabilizer for an automobile can have an outer diameter of φ20 to 30 mm. Further, when a pipe material is used for the stabilizer, the thickness can be set to 4 to 8 mm.

As shown in FIG. 1, a work (stabilizer) W has attachment portions W3 formed at both ends thereof, and a linear portion W1 formed in the middle thereof. Between the attachment part W3 and the linear part W1, a gradual change part W2 whose cross-sectional area (cross-sectional area of a cross section orthogonal to the axis) gradually changes is formed. The attachment portion W3 is processed into a flat plate shape, and a bolt hole W3a is formed at the center thereof. The straight line portion W1 is a portion whose axis is not curved (that is, a straight portion). The cross-sectional area of the straight line portion W1 (the cross-sectional area of the cross section orthogonal to the axis) is larger than the cross-sectional area of the gradual change portion W2 (cross-sectional area of the cross section orthogonal to the axis), and the cross-sectional area of the gradual change portion W2 The cross-sectional area of the cross section) is larger than the cross-sectional area of the attachment portion W3 (the cross-sectional area of the cross section perpendicular to the axis). Therefore, the cross-sectional area of the straight portion W1 is larger than the cross-sectional area of the attachment portion W3.

Next, the energization heating apparatus 10 that energizes and heats the workpiece W described above will be described. As shown in FIG. 1, the energization heating device 10 includes a power source 12,

first electrodes

22 b and 22 b and

second electrodes

20 b and 20 b connected to the power source 12 via wiring 18, a switch 14 and wiring to the power source 12. The

first electrodes

22a and 22a and the

second electrodes

20a and 20a are connected via the 16th line. As the power source 12, either a DC power source or an AC power source can be used. In this embodiment, a DC power source is used. The on / off state of the switch 14 is controlled by a control device (not shown). The

wirings

16 and 18 are made of a low-resistance conductive material (for example, copper). In the present embodiment, the combination of the

first electrodes

22a and 22a disposed on the right end side of the work W and the

first electrodes

22b and 22b disposed on the left end side of the work W is referred to as “a pair of claims”. Corresponds to an example of “first electrode”. The combination of the

second electrodes

20a, 20a disposed on the right end side of the workpiece W and the

second electrodes

20b, 20b disposed on the left end side of the workpiece W is a "pair of second electrodes" in the claims. It corresponds to an example.

The

first electrodes

22a and 22a clamp the right end of the straight portion W1 of the workpiece W, and the

first electrodes

22b and 22b clamp the left end of the straight portion W1 of the workpiece W. When the first electrodes 22a to 22b clamp the workpiece W, the first electrodes 22a to 22b and the workpiece W are electrically connected (contacted). The first electrodes 22a to 22b are made of a conductive material (for example, iron, stainless steel, chromium copper, inconel, etc.), and their resistance values are adjusted as will be described later.

The

second electrodes

20a and 20a clamp the right end of the workpiece W (that is, the mounting portion W3), and the

second electrodes

20b and 20b clamp the left end of the workpiece W (that is, the mounting portion W3). More specifically, the

second electrodes

20a, 20a, 20b, and 20b clamp a portion outside the intermediate position of the bolt hole W3a of the workpiece W. For this reason, the second electrodes 20a to 20b are arranged so as to sandwich the first electrodes 22a to 22b. That is, the first electrodes 22a to 22b are positioned between the

second electrodes

20a and 20a that clamp the right end of the workpiece W and the

second electrodes

20b and 20b that clamp the left end of the workpiece W. When the second electrodes 20a to 20b clamp the workpiece W, the second electrodes 20a to 20b and the workpiece W are electrically connected (contacted). The second electrodes 20a to 20b are formed of a conductive material (for example, chromium copper, aluminum alloy, etc.), and the resistance value thereof is adjusted as will be described later.

In the electric heating apparatus 10 described above, when the switch 14 is turned on with the first electrodes 22a to 22b clamping the workpiece W and the second electrodes 20a to 20b clamping the workpiece W, the power supply 12, the

wiring

16, 18, the switch 14, the first electrodes 22 a to 22 b, the second electrodes 20 a to 20 b, and the work W form an electric circuit. As a result, a current flows through the workpiece W. In the present embodiment, the resistance values of the first electrodes 22a to 22b and the second electrodes 20a to 20a are set so that the temperature of the attachment portion W3 and the gradual change portion W2 of the workpiece W and the temperature of the linear portion W1 of the workpiece W are the same. The resistance value of 20b is adjusted. Hereinafter, an example of the adjustment method will be specifically described. In energization heating, it is difficult to heat a portion in contact with the electrode and a portion outside the pair of electrodes to which a voltage is applied, but a large load does not act on a portion outside the bolt hole of the stabilizer. In the present embodiment, the second electrodes 20a to 20b clamp the bolt holes W3a of the workpiece W or the portions outside the bolt holes W3a, so no problem arises even if these portions are difficult to be heated.

As described above, since the

wirings

16 and 18 are made of a low resistance material, the resistance can be ignored. Then, the power supply voltage of the power supply 12 is applied between the

first electrodes

22a and 22a and the

first electrodes

22b and 22b, and the power supply 12 is also connected between the

second electrodes

20a and 20a and the

second electrodes

20b and 20b. A power supply voltage is applied. That is, the same voltage is applied between the first electrodes 22a to 22b and between the second electrodes 20a to 20b. Here, the second electrode 20a, a current flowing through 20a (20b, 20b) and _{I 2,} the

first electrode

22a, 22a (22b, 22b) the current through the _{I 1,} attachment portion W3 and Xu workpiece W current flowing through the variable section W2 is current flowing next to _{I 2,} the straight portion W1 of the workpiece W becomes _{_I} 1 + _I _2. The

first electrode

22a, 22a (22b, 22b) the resistance of the _{R 1,} the

second electrode

20a, 20a (20b, 20b) the resistance of the _{R 2,} the resistance of the attachment portion W3 and the gradually changing portion W2 Rw23 And the resistance of the straight line portion W1 is Rw1. A circuit diagram at the right end of the workpiece W is as shown in FIG. That is, the resistance R1 (

first electrode

22a, 22a) current _{I 1} flows through the resistor R2 (

second electrode

20a, 20a) and a resistor Rw23 (mounting portion W3 and the gradually changing portion W2) current _{I 2} flows through the resistor Current I ₁ + I ₂ flows through Rw1 (straight line portion W1).

Here, the calorific value per unit volume of the work is obtained by (work resistance value) × (current flowing through the work) ² / volume. For this reason, if the calorific value per unit volume of the attachment part W3 and the gradual change part W2 and the calorific value per unit volume of the linear part W1 are the same, the temperature of the attachment part W3 and the gradual change part W2 and the linear part The temperature of W1 is substantially the same. Therefore, if the following (Formula 1) is satisfied, the entire workpiece W can be heated to a substantially uniform temperature.

Here, the volume V ₂ of the volume V ₁ and the mounting portion W3 and the gradually changing portion W2 of the linear portion W1 are known, also the resistance Rw23 the resistance Rw1 and the mounting portion W3 and the gradually changing portion W2 of the linear portion W1 Known. Therefore, in the above (Formula 1), only the current values I ₁ and I ₂ are variables, and the ratio between them can be determined.

On the other hand, as is clear from FIG. 3, the voltage drop _{R 1} × _{I 1} by resistance _{R 1,} the voltage drop due to the resistance _{R 2} and the resistor _{Rw23 (R 2 + Rw23) ×} I 2 are equal. That is, the following (Formula 2) is established.

Thus, using the value of the resistor Rw23 mounting portion W3 and the gradually changing portion W2, the above equation (1) obtained in relationship between the current value I ₁ and I _2, so as to satisfy (Equation 2), first electrode 22a, and the resistance _{R 1} of the 22a (22b, 22b), the

second electrode

20a, 20a (20b, 20b) may be determined resistance _{R 2} of.

Next, an example of a specific configuration of the electrode part that clamps both ends of the workpiece W will be described with reference to FIG. In addition, since the structure of the electrode part which clamps the left end part of the workpiece | work W and the electrode part which clamps the right end part of the workpiece | work W are the same, here, the structure of the electrode part which clamps the right end part of the workpiece | work W is demonstrated. .

As shown in FIG. 2, the electrode portion 24a includes an upper conductive plate portion 16a, a lower conductive plate portion 16b, and

first electrodes

22a and 22a and

second electrodes

20a and 20a attached to the

conductive plate portions

16a and 16b. It is configured. The upper conductive plate portion 16a and the lower conductive plate portion 16b constitute a part of the wiring 16 shown in FIG. Therefore, the upper conductive plate portion 16 a and the lower conductive plate portion 16 b are connected to the power supply 12 through the switch 14. The upper conductive plate portion 16a and the lower conductive plate portion 16b are formed of a low resistance conductive material (for example, copper). The upper conductive plate portion 16a and the lower conductive plate portion 16a can be moved in the vertical direction by an actuator (not shown). A first electrode 22a and a second electrode 20a are attached to the lower surface of the upper conductive plate portion 16a. A first electrode 22a and a second electrode 20a are attached to the upper surface of the lower conductive plate portion 16b. The surface of the

first electrode

22a, 22a on the workpiece W side is formed in a shape that follows the outer peripheral surface of the linear portion W1 of the workpiece W. The surface on the workpiece W side of the

second electrodes

20a, 20a is formed in a shape that follows the outer peripheral surface of the mounting portion W3 of the workpiece W. In addition, as shown in FIG. 7, an electrode 40 having a V-shaped contact surface with the workpiece W may be used as the second electrode 20a for clamping the workpiece W. When the upper conductive plate portion 16a is lowered toward the workpiece W or the lower conductive plate portion 16b is raised toward the workpiece W, the linear portion W1 of the workpiece W is clamped by the

first electrodes

22a and 22a, and The attachment portion W3 of the workpiece W is clamped by the

second electrodes

20a and 20a. Thus, the

first electrodes

22a and 22a and the

second electrodes

20a and 20a are connected to the power source 12.

When the workpiece W is energized and heated by the energization heating device 10 described above, one end of the workpiece W is clamped by the

electrodes

20a, 20a, 22a, and 22a, and the other end of the workpiece W is clamped by the

electrodes

20b, 20b, 22b, and 22b. . Next, the switch 14 is turned on to pass a current through the work W. As described above, the

first electrode

22a, 22a (22b, 22b) and the resistance value _{R 1} of, the second electrode 20a, the resistance value _{R 2} of 20a (20b, 20b) is adjusted, straight workpiece W The part W1, the attachment part W3 of the workpiece W, and the gradual change part W2 are heated substantially uniformly. As a result, the entire workpiece W has a substantially constant temperature. When the energization heating to the workpiece W is finished, the switch 14 is turned off.

As described above, in the energization heating device 10 of the present embodiment, the first electrodes 22a to 22a are arranged so that the temperature of the attachment portion W3 and the gradual change portion W2 of the workpiece W and the temperature of the linear portion W1 of the workpiece W are the same. and the resistance value _{R 1} of the 22b, the resistance value _{R 2} of the second electrodes 20a ~ 20b are adjusted. For this reason, even if it is a case where the cross-sectional area of the workpiece | work W is not fixed to an axial direction, the whole workpiece | work W can be heated substantially uniformly by one electricity supply process. Further, the resistance value _{R 1} of the first electrodes 22a ~ 22b, since only adjusting the resistance value _{R 2} of the second electrodes 20a ~ 20b, configurations other than the electrodes of the resistance heating apparatus 10 is able to remain in the conventional Can do.

FIG. 5 shows a result of measuring the surface temperature of the stabilizer at that time by heating the stabilizer with the energization heating device 10 according to the example. FIG. 6 shows the result of measuring the surface temperature of the stabilizer at that time by heating the stabilizer with a conventional energization heating device (clamping both ends of the stabilizer only with a pair of electrodes). In FIGS. 5 and 6, the portion having a high surface temperature is white in color, and the portion having a low surface temperature is dark in color. As is clear from FIG. 6, when heated by a conventional energization heating device, the temperature of the small cross-sectional area at both ends of the stabilizer is high, and the temperature of the large cross-sectional area at the center of the stabilizer is low. Yes. On the other hand, as is clear from FIG. 5, when heated by the electric heating device 10 of the example, the entire stabilizer is heated substantially uniformly.

As mentioned above, although the Example was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

In the embodiment described above, the resistance value _{R 1} of the first electrodes 22a ~ 22b, by adjusting the resistance value _{R 2} of the second electrodes 20a ~ 20b, and the temperature of the mounting portion W3 and the gradually changing portion W2, straight portion Although the temperature of W1 is made substantially the same, the technique disclosed in this specification is not limited to such an example. 4, the first power source 32a is connected to the first electrodes 22a to 22b via the

wirings

36 and 38, and the second power source 32b is connected to the second electrodes 20a to 20b via the

wirings

16 and 18. However, the power supply voltages of the first power supply 32a and the second power supply 32b may be adjusted. Also with such a form, the temperature of the attachment part W3 and the gradual change part W2 and the temperature of the linear part W1 can be made substantially the same. When using the first power source 32a and the second power source 32b, for example, the first power source 32a and the second power source 32b are DC power sources, the timing for turning on / off the first power source 32a, and the second power source 32b being turned on. Control is performed to synchronize on / off using a timing synchronization circuit so that the timing of turning off / off does not shift.

Further, in the embodiment described above, the resistance value _{R 1} of the first electrodes 22a ~ 22b, has been adjusting the resistance value _{R 2} of the second electrodes 20a ~ 20b, adjusting the portion of the resistance of the

wiring

16 and 18 Thus, the same effect can be obtained. That is, the resistance of the wiring portion branched from the common portion of the

wirings

16 and 18 and extending to the first electrodes 22a to 22b, and the resistance of the wiring portion branched from the common portion of the

wirings

16 and 18 and extended to the second electrodes 20a to 20b. The same effect can be obtained by adjusting.

Incidentally, the resistance value _{R 1} of the first electrodes 22a ~ 22b, adjustment of the resistance value _{R 2} of the second electrodes 20a ~ 20b are, for example, the material and the second electrode 20a ~ 20b for forming the first electrode 22a ~ 22b This can be done by changing the material to be formed and / or the electrode shape. Alternatively, the adjustment can be performed by interposing another resistor in part of the first electrodes 22a to 22b and / or the second electrodes 20a to 20b.

In the above-described embodiment, the linear portion W1 of the workpiece W is clamped by the

first electrodes

22a and 22a, and the mounting portion W3 of the workpiece W is clamped by the

second electrodes

20a and 20a. However, the technology disclosed in this specification. Is not limited to such an example. For example, as shown in FIG. 8, the linear portion W1 of the workpiece W is clamped by the first electrode 46a, the gradually changing portion W2 of the workpiece W is clamped by the second electrode 44a, and the mounting portion W3 of the workpiece W is clamped by the third electrode. You may clamp by 42a. In this case, current I ₁ + I ₂ + I ₃ flows between the pair of first electrodes, current I ₃ + I ₂ flows between the first electrode 46a and the second electrode 44a, and the second electrode 44a and the third electrode. 42a flows current _{I 3} between. As a result, the current flowing through the workpiece W is precisely controlled according to the change in the cross-sectional area, and the workpiece W can be heated more uniformly. Note that the number of electrode pairs for clamping the workpiece W and the positions thereof can be set to an arbitrary number (for example, four pairs) according to the shape of the workpiece W or the like.

Also, the current heating method disclosed in this specification can be applied to a workpiece whose cross-sectional area changes in three or more locations in the axial direction. In that case, the number of electrode pairs brought into contact with the workpiece can be appropriately increased, and the resistance of these electrode pairs can be adjusted, whereby the entire workpiece can be heated substantially uniformly by a single energization heating.

The above-described embodiment is an example in which the stabilizer is heated. However, the present invention can also be applied to the case where a rod-like member other than the stabilizer (for example, a torsion bar, a leaf spring, etc.) is heated.

Moreover, although the Example mentioned above was an example which energizes and heats the workpiece | work W in which the cross-sectional area changes to an axial direction, the technique disclosed by this specification is applied to the workpiece | work whose cross-sectional area is constant in an axial direction. Then, the temperature distribution in the axial direction of the workpiece may be a desired temperature distribution.

Further, the technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Claims

A method of energizing and heating a rod-shaped member,
A step of bringing the pair of first electrodes into contact with the rod-shaped member at an interval in the axial direction of the rod-shaped member;
Contacting the pair of second electrodes with the rod-shaped member so as to sandwich the pair of first electrodes;
A first voltage is applied between the pair of first electrodes, and simultaneously, a second voltage is applied between the pair of second electrodes so that the first current flows between the first electrodes, and the second electrode and the adjacent first electrode And a step of energizing and heating the rod-shaped member by passing a second current different from the first current between the electrodes.
The rod-shaped member includes a first portion having a first cross-sectional area, and a second portion disposed on both sides of the first portion and having a second cross-sectional area different from the first cross-sectional area,
The energization heating method according to claim 1, wherein the pair of first electrodes are brought into contact with the first part, and the pair of second electrodes are brought into contact with the second part.
The energization heating method according to claim 1 or 2, wherein the first voltage and the second voltage are the same, and the resistance value of the first electrode is different from the resistance value of the second electrode.
A step of bringing the pair of third electrodes into contact with the rod-shaped member so as to sandwich the pair of second electrodes;
In the step of energizing and heating, when applying the first voltage between the pair of first electrodes and simultaneously applying the second voltage between the pair of second electrodes, the third voltage is applied between the pair of third electrodes. The rod-shaped member is heated by further passing a third current different from the first current and the second current between the third electrode and the adjacent second electrode. Electric heating method.
A device for energizing and heating a rod-shaped member,
A pair of first electrodes that are in contact with the rod-shaped member at an interval in the axial direction of the rod-shaped member;
A pair of second electrodes in contact with the rod-shaped member so as to sandwich the pair of first electrodes;
A voltage applying device that applies a first voltage between the pair of first electrodes and simultaneously applies a second voltage between the pair of second electrodes;
When a voltage is applied between the electrodes by the voltage application device, a first current flows between the first electrodes, and a second current different from the first current is generated between the second electrode and the adjacent first electrode. Flowing electric heating device.
The resistance value of the first electrode is different from the resistance value of the second electrode,
The first voltage and the second voltage are the same,
The energization heating apparatus according to claim 5, wherein the voltage application device includes one power supply device that applies the same voltage between the first electrodes and between the second electrodes.
The first voltage and the second voltage are different,
6. The voltage application device according to claim 5, comprising: a first power supply device that applies a first voltage between first electrodes; and a second power supply device that applies a second voltage between second electrodes. Electric heating device.