JP2020035649A - Induction heating apparatus - Google Patents

Abstract

To perform induction heating of a shaft member having a step, without adjusting a current being fed to an induction coil.SOLUTION: An induction heating apparatus for induction-heating a shaft member 4, having a step on the lateral face, by inserting into an annular induction coil 2, includes: a rolling mechanism 7 for rotating the shaft member 4 with a medial axis A thereof as the rotational axis; an axial direction movement mechanism 8 for translating at least one of the induction coil 2 and the shaft member 4 in the medial axis A direction; a radial direction movement mechanism 9 for moving at least one of the induction coil 2 and the shaft member 4 in the radial direction of the shaft member 4; and a guide member 3 attached to the induction coil 2 and keeping a gap of the shaft member 4 and the induction coil 2 constant. When induction-heating the shaft member 4, the shaft member 4 is brought into contact with the guide member 3 by using the radial direction movement mechanism 9, and while keeping the gap of the shaft member 4 and the induction coil 2 constant, the rolling mechanism 7 and the axial direction movement mechanism 8 are operated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an induction heating device.

2. Description of the Related Art A device for inductively heating a metal workpiece using an induction coil is known.
For example, Patent Literature 1 discloses an apparatus for inductively heating a shaft member having a step using an annular induction coil.

JP 2017-106050 A

The inventors have found the following problems with respect to an induction heating device.
When the shaft member is induction-heated using the annular induction coil, the shaft member is inserted into the induction coil, and at least one of the induction coil and the shaft member is moved in parallel in the central axis direction of the shaft member. Apply current.

  The shaft member having a step includes a portion having a large diameter and a portion having a small diameter. When induction heating is performed on a portion having a small diameter, the gap between the shaft member and the induction coil is larger than when induction heating is performed on a portion having a large diameter. The efficiency of induction heating decreases as the gap between the shaft member and the induction coil increases. Therefore, it is necessary to increase the current flowing through the induction coil when induction heating a portion having a small diameter compared to when induction heating a portion having a large diameter. Therefore, it is necessary to adjust the current flowing through the induction coil according to the diameter of the shaft member.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an induction heating device capable of induction heating a shaft member having a step without adjusting a current flowing through an induction coil. .

  One aspect for achieving the above object is an induction heating device for performing induction heating by inserting a shaft member having a step on a side surface into an annular induction coil, wherein the shaft member is provided with a central shaft of the shaft member. A rotation mechanism that rotates the rotation axis as a rotation axis, an axial movement mechanism that translates at least one of the induction coil and the shaft member in the central axis direction, and at least one of the induction coil and the shaft member, A radial moving mechanism for moving the member in the radial direction, and a guide member attached to the induction coil to keep a constant gap between the shaft member and the induction coil, and when the shaft member is induction-heated, The rotating machine while maintaining a constant gap between the shaft member and the induction coil on the guide member side by using the radial moving mechanism to contact the shaft member with the guide member. With rotating the shaft member about said rotation axis with, to translate at least one of said induction coil and the shaft member with the axial direction moving mechanism to said central axis.

  In the induction heating apparatus according to the present invention, when the shaft member is induction-heated, the gap between the shaft member and the induction coil on the guide member side is kept constant by contacting the shaft member with the guide member by using the radial movement mechanism. While rotating the shaft member about the rotation axis using the rotation mechanism, at least one of the induction coil and the shaft member is translated in the center axis direction using the axial movement mechanism. Therefore, there is no need to adjust the current flowing through the induction coil 2 according to the diameter of the shaft member.

  ADVANTAGE OF THE INVENTION According to this invention, the induction heating apparatus which can induction-heat the shaft member which has a level | step difference, without adjusting the electric current which flows into an induction coil can be provided.

1 is an overall view of an induction heating device according to the present embodiment. It is a top view of an induction coil. It is a front view of an induction coil. It is a perspective view of a shaft member. It is sectional drawing of an induction coil and a shaft member at the time of induction heating. It is a graph which shows the measurement result of heating efficiency.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. In addition, in order to clarify the description, the following description and drawings are simplified as appropriate.

  First, the configuration of the induction heating device according to the present embodiment will be described with reference to FIGS. FIG. 1 is an overall view of an induction heating device according to the present embodiment. FIG. 2 is a plan view of the induction coil. FIG. 3 is a front view of the induction coil. FIG. 4 is a perspective view of the shaft member.

  As shown in FIG. 1, the induction heating device 1 includes an induction coil 2, a guide member 3, an oscillator 5, a control unit 6, a rotating mechanism 7, an axial moving mechanism 8, and a radial moving mechanism 9. FIG. 1 also shows the shaft member 4. The guide member 3 has chips 31a to 31c and 32a to 32c as shown in FIG. The shaft member 4 has an end 41, a middle part 42, and an end 43, as shown in FIG. The center axis A shown in FIG. 4 is the center axis of the shaft member 4.

  It should be noted that the right-handed xyz rectangular coordinates shown in FIG. 2 and other drawings are for convenience in describing the positional relationship of the components. Usually, the positive direction of the z-axis is vertically upward and the xy plane is the horizontal plane, which is common between the drawings.

  The induction heating device 1 is a device for induction heating the shaft member 4 using the induction coil 2. The induction coil 2 is an annular metal member as shown in FIG. The induction coil 2 is made of, for example, copper or a copper alloy. A guide member 3 is attached to the induction coil 2. The guide member 3 is attached to a part of the induction coil 2. The guide member 3 is attached, for example, on the z-axis positive direction side of the guide member 3, that is, on the upper side, as shown in FIG.

  The guide member 3 has chips 31a to 31c and 32a to 32c as shown in FIG. The chips 31a to 31c and 32a to 32c are substantially trapezoidal members as shown in FIG. The tips of the tips 31a to 31c and 32a to 32c are thinner than the tip on the base side. The chips 31a to 31c and 32a to 32c are made of a material that is not affected by induction heating. The chips 31a to 31c and 32a to 32c are made of, for example, ceramic.

  The chips 31a to 31c are attached to the surface of the induction coil 2 on the x-axis positive direction side, as shown in FIG. The chips 32a to 32c are attached to the surface of the induction coil 2 on the negative side in the x-axis direction. The tip 31b is attached to the upper vertex of the induction coil 2 so that the tip is directed toward the center of the induction coil 2 as shown in FIG. The tip 31b is attached to the center of the induction coil 2 with respect to the inner peripheral surface of the induction coil 2 so that the tip protrudes.

  As shown in FIG. 3, the tip 31a is attached to the y-axis negative direction side of the tip 31b such that the tip is directed toward the center of the induction coil 2. The tip 31c is attached to the y-axis positive direction side of the tip 31b such that the tip is directed toward the center of the induction coil 2. The tip 31b and the tip 31c are attached to the center side of the induction coil 2 with respect to the inner peripheral surface of the induction coil 2 so that the tips protrude.

  The tip 32b is attached to the upper vertex of the induction coil 2 so that the tip is directed toward the center of the induction coil 2. As shown in FIG. 2, the tip 32a is attached to the y-axis negative direction side of the tip 32b so that the tip is directed toward the center of the induction coil 2. The tip 32c is attached to the y-axis positive direction side of the tip 32b such that the tip is directed toward the center of the induction coil 2. The chips 32 a to 32 c are attached so that the tips project from the inner peripheral surface of the induction coil 2 toward the center of the induction coil 2.

  The chips 31a to 31c and 32a to 32c are attached so that the distances from the respective tips to the center of the induction coil 2 are equal. The gap between the chip 31a and the chip 31b, the gap between the chip 31b and the chip 31c, the gap between the chip 32a and the chip 32b, and the gap between the chip 32b and the chip 32c are so large that the shaft member 4 cannot enter. is there.

  Although details will be described later, when the shaft member 4 is induction-heated, the shaft member 4 is brought into contact with the tip of the tip 31b and the tip of the tip 32b. Since the distances from the tips of the tip 31b and the tip 32b to the center of the induction coil 2 are equal, by bringing the shaft member 4 into contact with the tip of the tip 31b and the tip of the tip 32b, the induction coil 2 is moved to the center axis A of the shaft member 4. Can be arranged in a direction perpendicular to the direction.

  Further, since the shaft member 4 cannot enter the inner peripheral surface side of the induction coil 2 beyond the tips of the chips 31a to 31c and 32a to 32c, the gap between the shaft member 4 and the induction coil 2 is maintained at a predetermined value or more. That is, by attaching the guide member 3 to the induction coil 2, the gap between the shaft member 4 and the induction coil 2 can be maintained at a predetermined value or more.

  The induction coil 2 can insert the shaft member 4 as shown in FIG. The induction coil 2 can induction heat the inserted shaft member 4. The shaft member 4 is a metal columnar member. The shaft member 4 includes an end 41, a middle part 42, and an end 43, as shown in FIG. The diameter of the shaft member 4 is larger in the order of the end portion 41, the middle portion 42, and the end portion 43. Therefore, the shaft member 4 has steps at the boundary between the end portion 41 and the middle portion 42 and at the boundary between the middle portion 42 and the end portion 43.

  When the shaft member 4 is induction-heated using the induction coil 2, an alternating current is passed through the induction coil 2. The induction coil 2 is connected to an oscillator 5, as shown in FIG. The oscillator 5 can supply an alternating current to the induction coil 2. The oscillator 5 is connected to the control unit 6, as shown in FIG. The control section 6 controls the output of the oscillator 5.

  The control unit 6 is connected to a rotating mechanism 7, an axial moving mechanism 8, and a radial moving mechanism 9. The rotation mechanism 7 is connected to the shaft member 4. The radial moving mechanism 9 and the axial moving mechanism 8 are connected to at least one of the induction coil 2 and the shaft member 4, respectively. The control unit 6 controls the relative position between the induction coil 2 and the shaft member 4 by operating the rotation mechanism 7, the axial movement mechanism 8, and the radial movement mechanism 9.

  The rotation mechanism 7 can rotate the shaft member 4 around the center axis A. A magnetic flux is generated around the induction coil 2 through which an alternating current according to the output of the oscillator 5 flows. The direction of the magnetic flux generated around the induction coil 2 is always switched according to the frequency of the alternating current flowing through the induction coil 2. Therefore, when the shaft member 4 is inserted into the induction coil 2 around which the magnetic flux is generated, the vicinity of the portion of the shaft member 4 inserted into the induction coil 2 is induction-heated.

  The efficiency of induction heating increases as the gap between the shaft member 4 and the induction coil 2 decreases. Although details will be described later, in the induction heating device 1 according to the present embodiment, the shaft member 4 is induction-heated in a state where the shaft member 4 is always in contact with the tip of the tip 31b and the tip of the tip 32b.

  Therefore, for example, when the diameter of the shaft member 4 is smaller than the diameter of the inner peripheral surface of the induction coil 2 such as the end portion 41, the gap between the shaft member 4 and the induction coil 2 on the lower side of the shaft member 4 is: It is larger than the upper side of the shaft member 4. Therefore, the efficiency of induction heating on the lower side of the shaft member 4 is lower than that on the upper side of the shaft member 4. That is, when the diameter of the shaft member 4 is smaller than the diameter of the inner peripheral surface of the induction coil 2 as in the end portion 41, there is a possibility that uneven heating may occur.

  Therefore, when the shaft member 4 is induction-heated, the rotation mechanism 7 is used to rotate the shaft member 4 about the central axis A as the rotation axis. When induction heating is performed while rotating the shaft member 4 about the central axis A using the rotation mechanism 7 as the rotation axis, uneven heating due to the size of the gap between the shaft member 4 and the induction coil 2 can be suppressed. .

  The axial movement mechanism 8 can move at least one of the induction coil 2 and the shaft member 4 in parallel in the direction of the central axis A of the shaft member 4. The axial movement mechanism 8 is connected to the shaft member 4 in the example shown in FIG. The axial moving mechanism 8 shown in FIG. 1 can move the shaft member 4 in parallel with the direction of the central axis A. When the shaft member 4 inserted in the induction coil 2 through which the alternating current is passed is moved in parallel in the direction of the central axis A, the entire side surface of the shaft member 4 can be induction-heated.

  The example shown in FIG. 1 shows a case where the axial moving mechanism 8 is connected to the shaft member 4. However, the axial movement mechanism 8 may be connected to the induction coil 2. The axial movement mechanism 8 connected to the induction coil 2 can move the induction coil 2 parallel to the center axis A.

  The radial moving mechanism 9 can move at least one of the induction coil 2 and the shaft member 4 in a direction perpendicular to the center axis A, that is, in a radial direction of the shaft member 4. The radial movement mechanism 9 is connected to the induction coil 2 in the example shown in FIG. The radial moving mechanism 9 shown in FIG. 1 can move the induction coil 2 in the radial direction of the shaft member 4. Specifically, the radial moving mechanism 9 shown in FIG. 1 can move the induction coil 2 downward while applying a load.

  When the induction coil 2 moves downward with the shaft member 4 inserted, the tip of the tip 31b and the tip of the tip 32b contact the shaft member 4. By keeping the shaft member 4 in contact with the tip of the tip 31b and the tip of the tip 32b using the radial movement mechanism 9, the gap between the shaft member 4 and the induction coil 2 on the guide member 3 side is kept constant. Can be.

  The example shown in FIG. 1 shows a case where the radial movement mechanism 9 is connected to the induction coil 2. However, the radial movement mechanism 9 may be connected to the shaft member 4. When connecting the radial movement mechanism 9 to the shaft member 4, for example, the guide member 3 is attached to the lower side of the induction coil 2.

  When the shaft member 4 is moved downward by using the radial movement mechanism 9, the shaft member 4 comes into contact with the tip of the guide member 3 attached below the induction coil 2. By keeping the shaft member 4 in contact with the tip of the guide member 3, the gap between the shaft member 4 and the induction coil 2 on the guide member 3 side can be kept constant.

  Next, an operation when heating the shaft member using the induction heating device according to the present embodiment will be described with reference to FIG. FIG. 5 is a cross-sectional view of the induction coil and the shaft member during induction heating.

  In the example illustrated in FIG. 5, the parallel movement of the shaft member 4 is performed in the positive x-axis direction, that is, in the direction from the end 41 to the end 43. Therefore, the shaft member 4 is induction-heated in the order of the end 43, the middle 42, and the end 41. The diameter of the end portion 41 is a diameter φD1. The diameter of the intermediate portion 42 is set to a diameter φD2. The diameter of the end 43 is assumed to be a diameter φD3.

  As shown in FIG. 5, a gap between the end portion 41 and the induction coil 2 on the guide member 3 side is defined as a gap L1. The gap between the intermediate portion 42 and the induction coil 2 on the guide member 3 side is defined as a gap L2. The gap between the end portion 43 and the induction coil 2 on the guide member 3 side is defined as a gap L3.

  When the shaft member 4 is induction-heated, first, the end portion 43 is inserted into the induction coil 2 using the axial movement mechanism 8, and the end portion 43 is induction-heated. When the end 43 is induction-heated, the induction coil 2 is moved by using the radial moving mechanism 9 so that the tip of the tip 31b and the tip of the tip 32b always contact the end 43 as shown in FIG. Deploy. That is, when the end portion 43 is induction-heated, the state where the distance from the inner peripheral surface of the induction coil 2 to the tip of the tip 31b is equal to the size of the gap L3 is maintained.

  Further, when the end portion 43 is induction-heated, the shaft member 4 is rotated around the center axis A using the rotation mechanism 7 and the shaft member 4 is moved in the positive x-axis direction using the axial movement mechanism 8. To translate. With such a configuration, the entire side surface of the end portion 43 is induction-heated.

  Next, the middle part 42 is induction-heated. After the entire side surface of the end portion 43 is induction-heated, the middle portion 42 is inserted into the induction coil 2 by using the axial moving mechanism 8, and the middle portion 42 is induction-heated. When the intermediate portion 42 is induction-heated, the induction coil 2 is moved by using the radial moving mechanism 9 so that the tip of the tip 31b and the tip of the chip 32b always contact the intermediate portion 42 as shown in FIG. Deploy. That is, when the intermediate portion 42 is induction-heated, the state where the distance from the inner peripheral surface of the induction coil 2 to the tip of the tip 31b is equal to the size of the gap L2 is maintained.

  Further, when the intermediate portion 42 is induction-heated, the shaft member 4 is rotated around the central axis A using the rotation mechanism 7 and the shaft member 4 is moved in the positive x-axis direction using the axial movement mechanism 8. To translate. With such a configuration, the entire side surface of the intermediate portion 42 is induction-heated.

  Next, the end 41 is induction-heated. After the entire side surface of the middle portion 42 is induction-heated, the end portion 41 is inserted into the induction coil 2 using the axial movement mechanism 8, and the end portion 41 is induction-heated. When the end 41 is induction-heated, the induction coil 2 is moved by using the radial moving mechanism 9 so that the tip of the tip 31b and the tip of the tip 32b always contact the end 41 as shown in FIG. Deploy. That is, when the end portion 41 is induction-heated, the state where the distance from the inner peripheral surface of the induction coil 2 to the tip of the tip 31b is equal to the size of the gap L1 is maintained.

  Further, when the end portion 41 is induction-heated, the shaft member 4 is rotated around the central axis A using the rotation mechanism 7, and the shaft member 4 is moved in the positive x-axis direction using the axial movement mechanism 8. To translate. With such a configuration, the entire side surface of the end portion 41 is induction-heated.

  As described above, the induction heating device 1 according to the present embodiment can induction heat the shaft member 4. When the shaft member 4 is induction-heated using the induction heating device 1, as described above, the size of the gap between the induction coil 2 and the shaft member 4 on the guide member 3 side is always kept constant. The shaft member 4 is rotated around the center axis A using the rotation mechanism 7. Therefore, it is not necessary to adjust the output of the oscillator 5 according to the diameter of the shaft member 4. Therefore, the induction heating device 1 can induction-heat the shaft member 4 having the step without adjusting the current flowing through the induction coil 2.

  Hereinafter, the present invention will be described specifically with reference to examples. Note that these descriptions do not limit the present invention.

[Example 1]
In Example 1, the shaft member 4 was induction-heated using the induction heating device 1 having the configuration shown in FIG. The shaft member 4 used in Example 1 had φD1: φD2: φD3 = 1: 2: 3. Further, during induction heating, the distance between the induction coil 2 and the shaft member 4 on the guide member 3 side was constant (L1 = L2 = L3).

[Comparative Example 1]
In Comparative Example 1, the induction heating of the shaft member 4 was performed in the same manner as in Example 1 except that the shaft member 4 was induction-heated while the center axis A of the shaft member 4 was always arranged at the center of the induction coil 2. went. In Comparative Example 1, L1: L2: L3 = 3: 2: 1. Note that the distance between the induction coil 2 and the shaft member 4 on the guide member 3 side in Example 1 was equal to the gap L3 in Comparative Example 1.

(Calculation of heating efficiency)
The heating efficiency in Example 1 and Comparative Example 1 was calculated by dividing the temperature of the shaft member 4 after induction heating by the amount of heat input. The amount of heat input was calculated from the amount of power input to the induction heating device 1. FIG. 6 shows the calculation results of the heating efficiency.

  The diamond (◇) in FIG. 6 indicates the heating efficiency at the end 41. A square (□) indicates the heating efficiency in the middle part 42. The triangle (△) indicates the heating efficiency at the end 43. As shown in FIG. 6, the heating efficiency of Example 1 was improved as compared with Comparative Example 1. In particular, the heating efficiency at the end 41 was improved by about 30%.

  According to the invention according to the present embodiment described above, it is possible to provide an induction heating device that can induction heat a shaft member having a step without adjusting the current flowing through the induction coil.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist.

DESCRIPTION OF SYMBOLS 1 Induction heating apparatus 2 Induction coil 3 Guide member 31a-31c, 32a-32c Chip 4 Shaft member 41 End part 42 Intermediate part 43 End part 5 Oscillator 6 Control part 7 Rotation mechanism 8 Axial movement mechanism 9 Radial movement mechanism

Claims (1)

An induction heating device that performs induction heating by inserting a shaft member having a step on a side surface into an annular induction coil,
A rotation mechanism that rotates the shaft member around a center axis of the shaft member as a rotation axis,
An axial moving mechanism that translates at least one of the induction coil and the shaft member in the central axis direction;
A radial moving mechanism that moves at least one of the induction coil and the shaft member in a radial direction of the shaft member;
A guide member attached to the induction coil and keeping a constant gap between the shaft member and the induction coil,
When the shaft member is induction-heated, the radial member is used to contact the guide member with the shaft member so that the gap between the shaft member and the induction coil on the guide member side is kept constant. Rotating the shaft member around the rotation axis using the rotation mechanism, and moving at least one of the induction coil and the shaft member in the central axis direction using the axial movement mechanism.
Induction heating device.

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