High-frequency hardening device for stepped shafts, etc., its use, and transformer

Abstract

The first and second hardening coils are supplied with power from a power supply coil that moves relatively within the first and second relay coils, and harden workpieces such as stepped shafts that have a step between the first and second cross sections, achieving "uniform induction hardening." [Solution] An induction hardening device 1 for hardening a workpiece W such as a stepped shaft hardens first and second cross-sectional portions W1 and W2 of the workpiece W using first and second hardening coils C1 and C2 supplied with power from a power supply coil L0 that moves relatively within first and second relay coils L1 and L2 of a transformer 10. The power supply coil L0 and the first and second relay coils L1 and L2 may be air-core coils, and a method of using the hardening device 1 includes a first hardening process P1 in which the power supply coil L0 is inserted into the first relay coil L1 to harden the first cross-sectional portion W1, a moving process PP in which the power supply coil L0 is moved relatively within the first and second relay coils L1 and L2, and a second hardening process P2 in which the power supply coil L0 is inserted into the second relay coil L2 to harden the second cross-sectional portion W2.

Description

[Technical Field]

[0001] The present invention relates to an induction hardening apparatus for hardening a workpiece having an axial direction, such as a stepped shaft, a method for using the same, and a transformer. [Background technology]

[0002] BACKGROUND ART Conventionally, an induction hardening device for a shaft-shaped workpiece is known (Patent Document 1). This high-frequency hardening device is equipped with a high-frequency heating coil that heats the axial workpiece, a cooling jacket that sprays coolant onto the part heated by the high-frequency heating coil, and a moving mechanism that moves the high-frequency heating coil, cooling jacket, and axial workpiece relative to each other, and the cooling jacket sprays coolant from a direction perpendicular to the axis of the axial workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-294933 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] However, the high-frequency hardening device described in Patent Document 1 has only one type of high-frequency heating coil located a predetermined distance away from the convex portion of the shaft-shaped workpiece, even though the shaft-shaped workpiece has unevenness (steps) on its peripheral surface.As a result, the convex portion of the shaft-shaped workpiece is easily heated, while the concave portion is difficult to heat, resulting in the problem that uniform high-frequency hardening cannot be performed on the unevenness of the shaft-shaped workpiece.

[0005] In view of the above, an object of the present invention is to provide an induction hardening device that can achieve "uniform induction hardening" of stepped shafts and the like by hardening a first cross-sectional portion and a second cross-sectional portion of a workpiece with a first quenching coil and a second quenching coil that are supplied with power from a power supply coil that moves relatively within a first relay coil and a second relay coil in a transformer, a method for using the same, and a transformer. [Means for solving the problem]

[0006] The induction hardening apparatus 1 according to the present invention is an induction hardening apparatus for hardening a workpiece W having an axial direction, the workpiece W having at least a first cross-sectional portion W1 having a predetermined cross-section and a second cross-sectional portion W2 having a cross-section different from the first cross-sectional portion W1, the first cross-sectional portion W1 and the second cross-sectional portion W2 having a step portion WD formed therebetween and arranged substantially along the axial direction, the induction hardening apparatus having at least a first hardening coil C1 for hardening the first cross-sectional portion W1 and a second hardening coil C2 for hardening the second cross-sectional portion W2, the first hardening coil C1 and the second hardening coil C2 being supplied with hardening power from a transformer 10, the transformer 10 including a power supply coil L0 capable of supplying the power, a first relay coil L1 capable of relaying power from the power supply coil L0 to the first hardening coil C1, and a second relay coil L2 capable of relaying power from the power supply coil L0 to the first hardening coil C1. a second relay coil L2 capable of relaying power to a second hardened coil C2; and in the transformer 10, the power supply coil L0 is a coil that is movable relatively to the workpiece W in a direction substantially parallel to the axial direction thereof, at least inside the first relay coil L1 and the second relay coil L2, from the first relay coil L1 to the second relay coil L2; the first relay coil L1 is a coil that is movable relatively to the workpiece W together with the first hardened coil C1, across a first cross-sectional portion W1 of the workpiece W, in a direction substantially parallel to the axial direction thereof; and the second relay coil L2 is a coil that is movable relatively to the workpiece W together with the second hardened coil C2, across a second cross-sectional portion W2 of the workpiece W, in a direction substantially parallel to the axial direction thereof.

[0007] A second feature of the induction hardening apparatus 1 according to the present invention is that, in addition to the first feature, at least one of the power supply coil L0, the first relay coil L1, and the second relay coil L2 is an air-core coil.

[0008] A method of using the induction hardening apparatus 1 according to the present invention is a method of using the induction hardening apparatus described above, and includes a first quenching step P1 in which the first cross-sectional portion W1 of the workpiece W is quenched from one end of the first cross-sectional portion W1 to a step portion WD by the first quenching coil C1 in a direction substantially parallel to the axial direction of the workpiece W, with at least a portion of the power supply coil L0 being inside the first relay coil L1; a moving step PP in which the power supply coil L0 moves relatively to the first relay coil L1 and / or the second relay coil L2 substantially along the axial direction thereof until the power supply coil L0 reaches the inside of the second relay coil L2; and a second quenching step P2 in which the second quenching coil C2 quenches the second cross-sectional portion W2 from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 substantially along the axial direction of the workpiece W.

[0009] others, The transformer 10 is a transformer that supplies electric power and includes at least a power supply coil L0 capable of supplying the electric power, a first relay coil L1 capable of relaying the electric power from the power supply coil L0 to the outside, and a second relay coil L2 capable of relaying the electric power from the power supply coil L0 to the outside, and the power supply coil L0 is a coil that is movable relatively to the first relay coil L1 and / or the second relay coil L2 substantially along its axial direction, at least inside the first relay coil L1 and inside the second relay coil L2, from the first relay coil L1 to the second relay coil L2. It's okay .

[0010] Due to these features, in the transformer 10, within the first and second relay coils L1 and L2 that relay power to the first and second hardening coils, the power supply coil L0 is moved relatively along a direction substantially parallel to the axial direction of the workpiece W, and the first cross-sectional portion W1 is hardened by the first hardening coil C1, and the second cross-sectional portion W2, which has a different cross-sectional shape and size (cross-sectional area), is hardened by the second hardening coil C2.Unlike Patent Document 1, even if there is a step between the first cross-sectional portion W1 and the second cross-sectional portion W2, which have different cross-sectional shapes and sizes, hardening can be performed by the corresponding first hardening coil C1 and second hardening coil C2, making it possible to ``uniformly harden'' a stepped shaft, etc. In addition, the first and second hardening coils can be hardened using power from one power supply coil L0 via the first and second relay coils L1 and L2, so only one power supply source is required, which can lead to cost reductions and a more compact device.

[0011] Furthermore, by using air-core coils for the power supply coil L0 and the first and second relay coils L1 and L2, a heavy iron core is not required, which allows for a lighter device.

[0012] Furthermore, the method of using the induction hardening device 1 includes a first hardening process P1 in which the power supply coil L0 is placed inside the first relay coil L1 and the first cross-sectional portion W1 is hardened, a moving process PP in which the power supply coil L0 is moved relatively inside the first relay coil L1 and the second relay coil L2, and a second hardening process P2 in which the power supply coil L0 is placed inside the second relay coil L2 and the second cross-sectional portion W2 is hardened. As a result, even if there is a step between the first cross-sectional portion W1 and the second cross-sectional portion W2 in the workpiece W, it is possible to harden the workpiece W evenly from one end to the other (realizing "uniform induction hardening" of a stepped shaft, etc.).

[0013] Furthermore, in the transformer 10, power from one power supply coil L0 can be relayed to different external devices via the first and second relay coils L1 and L2, so the power supply source only needs to be in one place, which means that the transformer 10 can be made smaller. [Effects of the Invention]

[0014] The induction hardening device, method of use thereof, and transformer according to the present invention enable "uniform induction hardening" of a stepped shaft or the like to be achieved by hardening the first cross-sectional portion and the second cross-sectional portion of the workpiece with the first hardening coil and the second hardening coil, which are supplied with power from a power supply coil that moves relatively within the first relay coil and the second relay coil of the transformer. [Brief explanation of the drawings]

[0015] [Figure 1] 1A to 1G are schematic diagrams showing an induction hardening apparatus, a method for using the same, and a transformer according to the present invention, in which (a) shows the workpiece mounting process, (b) shows the first hardening process (starting state), (c) shows the first hardening process (finished state), (d) shows the moving process, (e) shows the second hardening process (starting state), (f) shows the second hardening process (finished state), and (g) shows the workpiece removal process. The arrows on the workpiece and each coil in Figs. 1A to 1G indicate the movement of the workpiece and each coil. Also, the hardened portions of the workpiece surface are shaded in Figs. 1A to 1G. [Figure 2] The workpiece is illustrated in Fig. 2(a), where (a) is a photograph showing the cross section of a stepped shaft (after it has been hardened and cut in the axial direction), (b) is a schematic diagram showing the cross section of a bearing and the first and second hardening coils, and (c) is a photograph showing a drill. The arrows in Fig. 2(b) on the power supply coil indicate the movement of the power supply coil. The arrows are also shown as dark-colored areas on the workpiece surface in Fig. 2(a) and (b). [Figure 3] 3A and 3B are diagrams illustrating an example of an entire induction hardening apparatus, in which (a) is a left side view, (b) is a front view, (c) is a rear view, and (d) is a plan view. Note that the arrows in Fig. 3A indicate the movement of the power supply coil. [Figure 4]4(a) and 4(b) are diagrams illustrating a power supply coil and its movement mechanism in an induction hardening apparatus, where (a) is a rear view, (b) is a left side view, (c) is a left side view of the relationship between the power supply coil and a second relay coil, and (d) is a plan view. Note that the arrows in Fig. 4(c) can be said to indicate the movement of the power supply coil. [Figure 5] 1A to 1C are diagrams illustrating a first relay coil and a second relay coil in an induction hardening device and a mechanism for moving them, where FIG. 1A is a left side view, FIG. 1B is a rear view, and FIG. 1C is a plan view. [Figure 6] 10A, 10B, and 10C are diagrams illustrating a second relay coil and its moving mechanism in an induction hardening device, in which FIG. 10A shows a left side view, FIG. 10B shows a front view, and FIG. 10C shows a plan view. [Figure 7] 1A and 1B are diagrams illustrating a workpiece holding and moving mechanism in an induction hardening device, in which FIG. 1A is a left side view and FIG. 1B is a plan view. [Figure 8] 10A and 10B are diagrams illustrating the up-and-down drive unit in the work holding and moving mechanism, where (a) is a right side view, (b) is a front view, (c) is a rear view, (d) is a plan view, and (e) is a bottom view. [Figure 9] 10A and 10B are photographs showing the first and second relay coils of a transformer, in which FIG. 10A shows the exterior and FIG. 10B shows the interior. [Figure 10] Photographs in place of drawings showing a first relay coil, a second relay coil, and a power supply coil in a transformer, where (a) shows a state in which the power supply coil is located inside the second relay coil, and (b) shows a state in which the power supply coil is located inside the first relay coil. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Overall configuration of induction hardening device 1> 1 to 10 show an induction hardening device (hereinafter also referred to as "hardening device") 1 according to the present invention. The quenching device 1 is a device for quenching a workpiece W, which will be described later. The quenching device 1 has at least a first quenching coil C1 and a second quenching coil C2, which will be described later, and may also have a third quenching coil, which will be described later, and so on. Using these multiple quenching coils C1, C2, etc., the quenching device 1 quenches the workpiece W by induction heating (IH). More specifically, the workpiece W, which will be described later, is quenched by induction heating via the first quenching coil C1, the second quenching coil C2, etc.

[0017] It can be said that the quenching device 1 has a transformer 10, which will be described later, and that this transformer 10 is included in a current supply mechanism 20, which will be described later. In addition, the hardening device 1 may have a workpiece holding and moving mechanism 30 that holds the workpiece W, or a coil moving mechanism 40 that moves (relatively moves) the first and second hardening coils C1 and C2, etc., the power supply coil L0 in the transformer 10, the first and second relay coils L1 and L2, etc., or a housing 50 that supports the first and second hardening coils C1 and C2, etc., the current supply mechanism 20 including the transformer 10, the workpiece holding and moving mechanism 30 that holds the workpiece W, and the coil moving mechanism 40. The quenching device 1 may also include a control unit for controlling the above-mentioned mechanisms 20, 30, 40, a hydraulic pump for quenching, a hydraulic circuit such as a drain, a switching device (not shown), and the like. Next, the workpiece W to be hardened by the hardening apparatus 1 will be described.

[0018] <Work W> As shown in Figures 1 to 3, 5, and 7, the workpiece W has an axial direction (or axial direction, or axis) WJ, and at least a first cross-sectional portion W1 (described below) having a predetermined cross-section, and a second cross-sectional portion W2 (described below) having a cross-section different from the first cross-sectional portion W1, and the first cross-sectional portion W1 and the second cross-sectional portion W2 are arranged approximately along the axial direction WJ, with a step portion WD formed between them. In addition, the workpiece W may have a third cross-sectional portion W3 or the like having a cross section different from at least one of the first cross-sectional portion W1 and the second cross-sectional portion described above.

[0019] The workpiece W is, for example, <1> Like a stepped shaft, the cross-sectional shape (shape of a cross section perpendicular to the axial direction WJ) is approximately circular, and the first cross-sectional portion W1 (so-called large diameter portion) and the second cross-sectional portion W2 (so-called small diameter portion) are located at approximately the same cross-sectional position in the axial direction (axis) WJ but have different diameters (see Figures 1 and 2(a)), <2> A bearing or the like has a substantially ring-shaped cross section, and the first cross section W1 and the second cross section W2 are located at substantially the same cross-sectional position in the axial direction WJ, but have different diameters (strictly speaking, outer diameter and inner diameter) (see Figure 2(b)). <3> The following mainly describes a drill or the like, in which the cross-sectional shape is a drill cross-sectional shape (a shape in which two or three grooves are cut out from an approximately circular outer shape) and the grooves are formed spirally, and the first cross-sectional portion W1 of the drill part and the second cross-sectional portion W2 of the tip part are at approximately the same cross-sectional position in the axial direction WJ (see Figure 2(c)). Here, in Fig. 2(b), <2> Like a bearing, a third cross-sectional portion W3 may be disposed between the first cross-sectional portion W1 and the second cross-sectional portion W2, and in this case, it can be said that there are two step portions WD formed between the first cross-sectional portion W1 and the second cross-sectional portion W2: one step portion WD between the first cross-sectional portion W1 and the third cross-sectional portion W3, and one step portion WD between the first cross-sectional portion W1 and the second cross-sectional portion W2. Note that even when two step portions WD are formed between the first cross-sectional portion W1 and the second cross-sectional portion W2, it can be said that the first cross-sectional portion W1 and the second cross-sectional portion W2 are disposed substantially along the axial direction WJ with the step portion WD formed therebetween.

[0020] <First hardened coil C1> As shown in Figures 1 to 5, the first hardening coil C1 is a coil (inductor) that hardens the first cross-sectional portion W1 in the workpiece W described above, and its cross-sectional shape (shape of a cross section perpendicular to the axial direction (or axial direction) CJ) and size (cross-sectional area) correspond to the cross-sectional shape and size of the first cross-sectional portion W1. The first hardening coil C1 is <1> or <3> In the case of a stepped shaft or drill, the workpiece W is surrounded by the first cross-sectional portion W1 (in other words, the diameter is larger than the first cross-sectional portion W1), and the workpiece W is <2> In the case of a bearing or the like, it can be said that it surrounds the outer periphery of the first cross-sectional portion W1 of the workpiece W (in other words, it has a larger diameter than the first cross-sectional portion W1) or penetrates into the inner periphery of the first cross-sectional portion W1 (in other words, it has a smaller diameter than the first cross-sectional portion W1).

[0021] The first hardened coil C1 is not particularly limited in its configuration, but may be a copper pipe, copper wire, copper plate (having a predetermined thickness as described below), or the like wound in an approximately ring shape. In the first hardened coil C1, the copper pipe or copper wire wound around it may be a copper pipe or copper wire coated with enamel resin (enamel paint) (such as an enameled wire), or may be coated with polyurethane resin, polyester resin, polyesterimide resin, or other insulator (such as a magnet wire), or it may be a bare copper pipe or copper wire. The first hardened coil C1 may be made of a material other than copper, such as aluminum, silver, gold, or iron, and these materials may be in a pipe or wire shape.In addition, the first hardened coil C1 may be hollow, such as a pipe, or may be solid (i.e., approximately cylindrical or rectangular).

[0022] The number of turns of the copper pipe or copper wire wound around the first hardened coil C1 is not particularly limited, but may be, for example, one or two turns, or three or more turns, or even 20 or less turns (one turn (see Figure 1, etc.) or two turns (see Figure 2(c))). The thickness (diameter) of the copper pipe or copper wire in the first hardened coil C1 is not particularly limited, but for example, in the case of a copper pipe, it may be 2 mm or more and 20 mm or less, and more specifically, the lower limit may be 2 mm or more, preferably 4 mm or more, and more preferably 6 mm or more, and the upper limit may be 20 mm or less, preferably 16 mm or less, and more preferably 12 mm or less. Note that each lower limit of the thickness may be combined with any of the upper limits. The length in the axial direction CJ of the first hardened coil C1 as a whole (regardless of the number of turns or the thickness of the copper pipe, etc.) (i.e., the axial length in the CJ (axial length) or thickness) is not particularly limited, but may be, for example, 5 mm or more and 100 mm or less. More specifically, the lower limit may be 5 mm or more, preferably 10 mm or more, and more preferably 15 mm or more, and the upper limit may be 100 mm or less, preferably 50 mm or less, and more preferably 30 mm or less. Note that each lower limit of the axial length in the CJ may be combined with any of the upper limits.

[0023] The first hardened coil C1 may be arranged approximately coaxially (approximately coaxially) with the workpiece W (particularly, the first cross-sectional portion W1) having the axial direction WJ, and in more detail, the axial direction CJ of the first hardened coil C1 may be arranged so that its position (position as viewed from the axial direction CJ (position as viewed from the axial direction)) is approximately the same as the axial direction WJ of the workpiece W (first cross-sectional portion W1). As described above, the first hardened coil C1 is approximately ring-shaped, and therefore has an axial direction CJ. There are no particular limitations on the shape as viewed in the axial direction CJ (shape as viewed in the axial direction; if the axial direction CJ is the up-down direction (vertical direction), shape as viewed in a plane) but it may be, for example, approximately circular. In this case, the axis (axis) of the first hardened coil C1 can also be said to be the axis of a rotating body. Alternatively, the shape as viewed in the axial direction CJ of the first hardened coil C1 may be approximately C-shaped (a shape with one portion missing in the circumferential direction, see symbol "C2" in Figure 2(c)) or a shape with two portions missing in the circumferential direction (a roughly parenthetical shape, so to speak). The portion hardened by such a first hardening coil C1 may not only be the peripheral surface of the first cross-sectional portion W1 of the workpiece W (the portion extending from one end to the other in the axial direction WJ), but may also be the end face (the surface rising from the peripheral surface of the small diameter portion to the peripheral surface of the large diameter portion, i.e., the step surface) of the step portion WD between the first cross-sectional portion W1 and an adjacent cross-sectional portion (for example, the second cross-sectional portion W2 in Figures 2(a) and (c) or the third cross-sectional portion W3 in Figure 2(b)).

[0024] The first hardened coil C1 does not have to have an iron core (it may be an air-core coil). Here, the term "air-core coil" in the present invention means a coil that does not have an iron core, and is also called an air-core coil. In addition, when the first hardened coil C1 is an air-core coil and is arranged approximately coaxially with the workpiece W, the workpiece W can also be said to be an iron core. In addition, the work W is <2> In the case of a bearing or the like, the first hardened coil C1 may have an iron core. Additionally, the first hardened coil C1 may be provided with a cooling device (such as a cooling jacket) for cooling the first hardened coil C1.

[0025] The first hardening coil C1 described above is supplied with hardening power from a transformer 10, which will be described later. The first hardened coil C1, together with a first relay coil L1 in the transformer 10 (described later), is movable relative to the workpiece W substantially along a direction parallel to the axial direction WJ thereof. The coil moving mechanism 40 (strictly speaking, the first coil mechanism 40-1) that moves the first hardened coil C1 relatively together with the first relay coil L1 will be described later.

[0026] <Second hardened coil C2> As shown in Figures 1 to 6, the second hardening coil C2 is most different from the first hardening coil C1 in that it is a coil (inductor) that hardens the second cross-sectional portion W2 of the workpiece W described above, and its cross-sectional shape and size correspond to the cross-sectional shape and size of the second cross-sectional portion W2. To explain this in more detail, for example, as in Figures 1 and 2(a), if the second cross-sectional portion W2 has a cross-section different from that of the first cross-sectional portion W1 (both cross-sectional shapes are approximately circular, and the diameter of the second cross-sectional portion W2 is smaller (smaller) than the diameter of the first cross-sectional portion W1), then similarly, the second hardened coil C2 may also have a cross-section different from that of the first hardened coil C1 (for example, both cross-sectional shapes may be approximately circular, and the diameter of the second hardened coil C2 may be smaller (smaller) than the diameter of the first hardened coil C1). On the other hand, for example, as shown in Figure 2(b), although the second cross-sectional portion W2 has a cross-section different from that of the first cross-sectional portion W1 (or has a cross-sectional shape and size almost the same as that of the first cross-sectional portion W1), the cross-sectional shape and size of the second hardened coil C2 may be approximately the same as that of the first hardened coil C1.

[0027] The second hardening coil C2 may also be arranged substantially coaxially with the workpiece W (particularly the second cross-sectional portion W2) having the axial direction WJ, and more specifically, the second hardening coil C2 may be arranged so that the axial direction (or axial direction) CJ of the second hardening coil C2 is approximately the same as the axial direction WJ of the workpiece W (second cross-sectional portion W2) when viewed from the axial direction CJ. Therefore, it can be said that the second hardening coil C2 has a different axial direction WJ position (axial position, or axial direction CJ position (axial position) of each hardening coil) on the workpiece W (e.g., vertically shifted) from the first hardening coil C1. Another difference between the second hardened coil C2 and the first hardened coil C1 is that the second hardened coil C2, together with a second relay coil L2 in the transformer 10 (described later), is movable relative to the workpiece W across the second cross-sectional portion W2 in the workpiece W (from one end to the other end in the axial direction WJ), approximately along a direction parallel to the axial direction WJ. A coil moving mechanism 40 (strictly speaking, a second coil moving mechanism 40-2) that moves the second hardened coil C2 relative to the workpiece W together with the second relay coil L2 will also be described later. The second hardening coil C2 is similar to the first hardening coil C1 in that it receives hardening power from a transformer 10, which will be described later. Other than these, the configuration of the second hardened coil C2, the number of turns and its numerical range, the thickness of the wound copper pipe or copper wire, the length in the axial direction CJ, the part to be hardened (the part to be hardened in the second cross-sectional portion W2), and the presence or absence of an iron core or cooling equipment may be the same as or different from the first hardened coil C1. Other configurations, effects, and modes of use of the second hardened coil C2 are the same as those of the first hardened coil C1.

[0028] <Third hardened coil...nth hardened coil, etc.> If the hardening device 1 also has a third hardening coil (not shown), the biggest difference between the third hardening coil and the first and second hardening coils C1 and C2 is that the third hardening coil is a coil (inductor) that hardens the third cross-sectional portion W3 of the workpiece W described above, and its cross-sectional shape and size correspond to the cross-sectional shape and size of the third cross-sectional portion W3. To explain this in more detail, for example, as shown in FIG. 2(b), if the third cross-sectional portion W3 has a cross-section different from those of the first and second cross-sectional portions W1 and W2 (for example, the cross-sectional shapes are all approximately circular and the inner diameter of the third cross-sectional portion W3 is smaller (smaller) than those of the first and second cross-sectional portions W1 and W2), then similarly, the third hardened coil may have a cross-section different from those of the first and second hardened coils C1 and C2 (for example, the cross-sectional shapes are all approximately circular and the inner diameter of the third hardened coil is smaller (smaller) than those of the first and second hardened coils C1 and C2). On the other hand, for example, the third cross-sectional portion W3 may have a cross section different from the first and second cross-sectional portions W1 and W2 (or may have a cross-sectional shape and size almost the same as the first and second cross-sectional portions W1 and W2), but the cross-sectional shape and size of the third hardened coil may be approximately the same as the cross-sectional shape and size of the first and second hardened coils C1 and C2.

[0029] Furthermore, the third hardening coil may also be arranged approximately coaxially (substantially coaxially) with the workpiece W (particularly the third cross-sectional portion W3) having the axial direction WJ, and more specifically, the third hardening coil may be arranged so that the axial (or axial) direction CJ of the third hardening coil is approximately the same as the axial WJ of the workpiece W (third cross-sectional portion W3) when viewed from the axial direction CJ. Therefore, it can be said that the third hardening coil has a different axial WJ position on the workpiece W (or the axial CJ ​​position of each hardening coil) from the first and second hardening coils C1 and C2 (for example, shifted up and down). Another difference between the third hardened coil and the first and second hardened coils C1 and C2 is that, when the transformer 10 has a third relay coil described below, the third hardened coil can be moved together with the third relay coil across the third cross-sectional portion W3 of the workpiece W (from one end to the other end in the axial direction WJ) in a direction substantially parallel to the axial direction WJ, and a coil moving mechanism 40 (strictly speaking, a third coil moving mechanism (not shown)) that moves the third hardened coil together with the third relay coil will also be described later. The third hardening coil is supplied with hardening power from a transformer 10, which will be described later, just like the first and second hardening coils C1 and C2. Other than these, the configuration of the third hardening coil, the number of turns and its numerical range, the thickness of the copper pipe or copper wire to be wound, the length in the axial direction CJ, the part to be hardened (the part to be hardened in the third cross-sectional portion), and the presence or absence of an iron core or cooling device may be the same as or different from the first and second hardening coils C1 and C2. Other configurations, effects, and modes of use of the third hardened coil are the same as those of the first and second hardened coils C1 and C2.

[0030] In addition, the hardening device 1 may have a fourth hardening coil, a fifth hardening coil, a sixth hardening coil, and so on, up to an nth hardening coil (n is a natural number) (not shown), and in these cases, as will be described later, the workpiece W will also have a fourth cross-sectional portion through an nth cross-sectional portion. In this way, when the hardening device 1 has the fourth hardening coil...nth hardening coil, the biggest difference between the fourth hardening coil...nth hardening coil and the first to third hardening coils C1...C2, etc. is that the fourth hardening coil...nth hardening coil is a coil (inductor) that hardens the fourth cross-sectional portion...nth cross-sectional portion of the workpiece W described above, and the cross-sectional shape and size thereof correspond to the cross-sectional shape and size of the fourth cross-sectional portion...nth cross-sectional portion, respectively. Furthermore, the fourth hardening coil...nth hardening coil may also be arranged approximately coaxially (approximately coaxially) with the workpiece W having the axial direction WJ (particularly, the fourth cross-sectional portion...nth cross-sectional portion), and it can also be said that the fourth hardening coil...nth hardening coil have different axial WJ positions on the workpiece W (or the axial CJ ​​positions of each hardening coil) from the first to third hardening coils C1, C2, etc. (for example, shifted up or down). Another difference between the fourth hardened coil...the nth hardened coil and the first to third hardened coils C1...C2, etc. is that when the transformer 10 has a fourth relay coil...the nth relay coil, which will be described later, the fourth hardened coil...the nth hardened coil, together with the fourth relay coil...the nth relay coil, are movable relative to the workpiece W across the fourth cross-sectional portion...the nth cross-sectional portion (from one end to the other end in the axial direction WJ) of the workpiece W, approximately along a direction parallel to the axial direction WJ. A coil moving mechanism 40 (strictly speaking, a fourth coil...nth coil moving mechanism (not shown)) that moves the fourth hardened coil...the nth hardened coil relative to the workpiece W together with the fourth relay coil...the nth relay coil, will also be described later. The fourth hardening coil, the n-th hardening coil, and the like are similar to the first to third hardening coils C1, C2, and the like in that they are supplied with hardening power from a transformer 10, which will be described later. Other than these, the configuration of the 4th hardened coil...nth hardened coil, the number of turns and its numerical range, the thickness of the wound copper pipe or copper wire, the part to be hardened (the part to be hardened in the 4th cross-sectional portion...nth cross-sectional portion), the presence or absence of an iron core or cooling device, etc. may be the same as or different from the 1st to 3rd hardened coils C1, C2, etc. The configurations, effects, and modes of use of the other fourth hardened coils...nth hardened coils are the same as those of the first to third hardened coils C1, C2, etc.

[0031] <Transformer 10> 1, 3 to 6, 9, and 10, the transformer 10 is a device that supplies power to the first and second quenching coils C1 and C2 in the above-described quenching apparatus 1. Note that the transformer 10 may also supply power to devices other than the above-described quenching apparatus 1. The transformer 10 includes at least a power supply coil L0, a first relay coil L1, and a second relay coil L2, which will be described later, and may also include a third relay coil, etc., which will be described later. The current supplied by the transformer 10 is an alternating current, and its frequency may be high frequency (i.e., it may be called high frequency current). There is no particular restriction on the specific value of the frequency, but it may be, for example, 1 kHz or more and 500 kHz or less. The power source of the transformer 10 itself is not particularly limited, and may be, for example, a household power source (household outlet).

[0032] <Power supply coil L0> 1, 3, 4, and 10, the power supply coil L0 is a coil capable of supplying power for hardening to the above-mentioned first and second hardening coils C1, C2, etc. The power supply coil L0 may also supply power to devices other than the above-mentioned first and second hardening coils C1, C2, etc. The power supply coil L0 is also a coil that can move relatively to the workpiece W in a direction substantially parallel to its axial direction WJ, at least within the first relay coil L1 described later and the second relay coil L2 described later, from the first relay coil L1 to the second relay coil L2. In other words, when the transformer 10 includes only the first and second relay coils L1 and L2, the power supply coil L0 is movable within the first and second relay coils L1 and L2 over the first to second relay coils L1 to L2 relative to the workpiece W in a direction substantially parallel to the axial direction WJ; when the transformer 10 includes the first to third relay coils L1, L2, etc., the power supply coil L0 is movable within the first to third relay coils L1, L2, etc. over the first to third relay coils L1 to L2, etc. relative to the workpiece W in a direction substantially parallel to the axial direction WJ; and when the transformer 10 includes the first to nth relay coils L1, L2, etc., the power supply coil L0 is movable within the first to nth relay coils L1, L2, etc. over the first to nth relay coils L1, L2, etc. (from one end to the other end in the axial direction (or axial direction) LJ) relative to the workpiece W in a direction substantially parallel to the axial direction WJ. Therefore, it can be said that the power supply coil L0 is surrounded by the first relay coil L1 from the outer periphery (its diameter is smaller than that of the first relay coil L1), and it can also be said that the axial direction LJ of the power supply coil L0 is approximately parallel to the axial direction WJ of the workpiece W. The shape of the power supply coil L0 as viewed in the axial direction LJ (shape as viewed in the axial direction) is not particularly limited, but may be, for example, an approximately circular shape, an approximately C-shape (a shape with one portion missing in the circumferential direction), or a shape with two portions missing in the circumferential direction (in other words, an approximately parenthetical shape).

[0033] The power supply coil L0 may also be an air-core coil, or may have an iron core. If the power supply coil L0 has an iron core, the iron core may be shared with the first and second relay coils L1 and L2, which will be described later. The number of turns of the copper pipe, copper wire, copper plate (having a predetermined thickness, described below) wound around the power supply coil L0 is not particularly limited, but may be, for example, 2 or more turns, 10 or more turns, or 30 or less turns (11 turns, 12 turns, 16 turns, etc.). The axial length LJ of the entire power supply coil L0 (regardless of the number of turns or the thickness of the copper pipe, etc.) is not particularly limited, but may be, for example, 10 mm or more and 300 mm or less. More specifically, the lower limit may be 10 mm or more, preferably 20 mm or more, and more preferably 30 mm or more, and the upper limit may be 300 mm or less, preferably 200 mm or less, and more preferably 150 mm or less. Each lower limit of the axial length LJ may be combined with any of the upper limits. Unlike the first and second relay coils L1 and L2, which will be described later, the power supply coil L0 does not move together with the first and second hardened coils C1 and C2, but is moved (moved relatively to the first relay coil L1 and / or the second relay coil L2 substantially along the axial direction LJ) by a separate coil movement mechanism 40 (strictly speaking, a power supply coil movement mechanism 40-0). This power supply coil movement mechanism 40-0 will also be described later. Other factors such as the configuration of the power supply coil L0, the thickness of the copper pipe or copper wire wound around it, and the presence or absence of an iron core or cooling device may be the same as or different from those of the first to third hardened coils C1 and C2.

[0034] <First relay coil L1> 1, 3, 5, 9, and 10, the first relay coil L1 is a coil that can relay power from the power supply coil L0 to the first hardened coil C1. Note that the first relay coil L1 may also relay power from the power supply coil L0 to an external device (outside the transformer 10) other than the first hardened coil C1. The first relay coil L1, together with the first hardened coil C1, is also a coil that can move relative to the workpiece W in a direction approximately parallel to the axial direction WJ across the first cross-sectional portion W1 of the workpiece W described above (from one end to the other end in the axial direction WJ). The coil moving mechanism 40 (strictly speaking, the first coil mechanism 40-1) that moves the first relay coil L1 relatively together with the first hardened coil C1 will be described later. The first relay coil L1 is also a coil in which the above-described power supply coil L0 can move relatively to the first relay coil L1 substantially along the axial direction LJ thereof. Therefore, it can be said that the first relay coil L1 surrounds the power supply coil L0 from the outer periphery (its diameter is larger than that of the power supply coil L0), and it can also be said that the axial direction (or axial direction) LJ of the first relay coil L1 is approximately parallel to the axial direction WJ of the workpiece W. The shape of the first relay coil L1 as viewed in the axial direction LJ is not particularly limited, but may be, for example, substantially the same as (similar to) the shape of the power supply coil L0 as viewed in the axial direction LJ, but may be different in size. Specifically, the shape may be substantially circular, C-shaped, or parenthesized.

[0035] The first relay coil L1 may be arranged substantially coaxially with the power supply coil L0, and more specifically, the first relay coil L1 may be arranged so that the axial direction LJ of the first relay coil L1 is substantially the same as the axial direction LJ of the power supply coil L0 when viewed from the axial direction LJ (axial position). In this case, the axial direction LJ of the first relay coil L1 can also be said to be substantially parallel to the axial direction WJ of the workpiece W. The first relay coil L1 is not particularly limited in its configuration, but may be a copper plate wound into a generally cylindrical shape, or a copper pipe or copper wire wound around the outer periphery of a wound copper plate, or may be a copper pipe (copper tube) or copper wire wound into a generally ring shape. In the first relay coil L1, the copper plate or the like around which the coil is wound may be in a bare state, or may be coated with enamel resin (enamel paint), polyurethane resin, polyester resin, polyesterimide resin, or other insulators. The number of turns of the copper plate wound around the first relay coil L1 is not particularly limited, but may be, for example, 1 turn or more and 10 turns or less (such as 1 turn). The thickness of the copper plate in the first relay coil L1 is not particularly limited, and may be, for example, 1 mm or more and 10 mm or less. More specifically, the lower limit may be 1 mm or more, preferably 2 mm or more, and more preferably 3 mm or more, and the upper limit may be 10 mm or less, preferably 8 mm or less, and more preferably 6 mm or less. Note that each lower limit value for the thickness may be combined with any of the upper limits. The overall axial direction LJ length of the first relay coil L1 (copper plate or the like) is not particularly limited, but may correspond to, for example, the axial direction WJ length of the first cross-sectional portion W1 of the workpiece W described above, and specifically may be 20 mm or more and 600 mm or less, or more specifically, the lower limit may be 20 mm or more, preferably 40 mm or more, and more preferably 60 mm or more, and the upper limit may be 600 mm or less, preferably 500 mm or less, and more preferably 400 mm or less. Note that each lower limit of the axial direction LJ length may be combined with any of the upper limits. The first relay coil L1 may also be an air-core coil, or may have an iron core. If the first relay coil L1 has an iron core, the iron core may be shared with the above-mentioned power supply coil L0 or the second relay coil L2 (described later). Other aspects of the first relay coil L1, such as the configuration, the number of turns and the numerical range, the thickness of the copper pipe or copper wire when it is wound around the coil, and the presence or absence of an iron core or cooling device, may be the same as or different from those of the power supply coil L0 and the first to third hardened coils C1 and C2.

[0036] <Second relay coil L2> 1, 3, 5, 6, 9, and 10, the second relay coil L2 is a coil that can relay power from the power supply coil L0 to the second hardened coil C2. Note that the second relay coil L2 may also relay power from the power supply coil L0 to an external device (outside the transformer 10) other than the second hardened coil C2. The second relay coil L2, together with the second hardened coil C2, is also a coil that can move relative to the workpiece W in a direction approximately parallel to the axial direction WJ across the second cross-sectional portion W2 of the workpiece W described above (from one end to the other end in the axial direction WJ). The coil moving mechanism 40 (strictly speaking, the second coil moving mechanism 40-2) that moves the second relay coil L2 relatively together with the second hardened coil C2 will be described later. The second relay coil L2 is also a coil in which the above-described power supply coil L0 can move relatively to the second relay coil L2 substantially along the axial direction LJ thereof. Therefore, it can be said that the second relay coil L2 also surrounds the power supply coil L0 from the outer periphery (its diameter is larger than that of the power supply coil L0), and it can also be said that the axial direction (or axial direction) LJ of the second relay coil L2 is approximately parallel to the axial direction WJ of the workpiece W. The shape of the second relay coil L2 as viewed in the axial direction LJ is not particularly limited, and may be, for example, substantially the same as the first relay coil L1 described above (that is, substantially the same in shape and size), or may be different. Specifically, the second relay coil L2 may be substantially circular, C-shaped, or parenthesized.

[0037] The second relay coil L2 may be arranged substantially coaxially with the power supply coil L0 and the first relay coil L1, and more specifically, the second relay coil L2 may be arranged so that the axial direction LJ of the second relay coil L2 is substantially the same as the axial direction LJ of the power supply coil L0 and the first relay coil L1 when viewed from the axial direction LJ. In this case, it can also be said that the axial direction LJ of the second relay coil L2 is also substantially parallel to the axial direction WJ of the workpiece W. The overall axial direction LJ length of the second relay coil L2 (copper plate or the like) is not particularly limited, and may be, for example, approximately the same as or different from that of the first relay coil L1 described above, or may correspond to the axial direction WJ length of the second cross-sectional portion W2 of the workpiece W described above, specifically, 20 mm or more and 600 mm or less, or, more specifically, the lower limit may be 20 mm or more, preferably 40 mm or more, and more preferably 60 mm or more, and the upper limit may be 600 mm or less, preferably 500 mm or less, and more preferably 400 mm or less. Each lower limit of the axial direction LJ length may be combined with any of the upper limits. Other aspects of the second relay coil L2, such as the configuration, the number of turns and its numerical range, the thickness when the wound object is a copper plate or the like, the numerical range of the length in the axial direction LJ, and the presence or absence of an iron core or cooling device, may be the same as or different from those of the first relay coil L1, the power supply coil L0, and the first to third hardened coils C1 and C2.

[0038] <Third relay coil...nth relay coil, etc.> When the quenching apparatus 1 (particularly the transformer 10) also has a third relay coil (not shown), the third relay coil is a coil that can relay power from the power supply coil L0 to the third quenching coil. Note that the third relay coil may also relay power from the power supply coil L0 to an external device (outside the transformer 10) other than the third quenching coil. The third relay coil, together with the third hardened coil, is also a coil that can move relative to the workpiece W in a direction approximately parallel to the axial direction WJ across the third cross-sectional portion W3 of the workpiece W described above (from one end to the other end in the axial direction WJ). A coil moving mechanism 40 (strictly speaking, a third coil moving mechanism (not shown)) that moves the third relay coil relatively together with the third hardened coil will be described later. The third relay coil is also a coil in which the above-described power supply coil L0 can move relatively to the third relay coil substantially along the axial direction LJ thereof. Therefore, it can be said that the third relay coil also surrounds the power supply coil L0 from the outer periphery (its diameter is larger than that of the power supply coil L0), and it can also be said that the axial direction (or axial direction) LJ of the third relay coil is approximately parallel to the axial direction WJ of the workpiece W. The shape of the third relay coil as viewed in the axial direction LJ is not particularly limited, and may be, for example, substantially the same as the first and second relay coils L1 and L2 described above (i.e., substantially the same shape and size), or may be different. Specifically, the third relay coil may be substantially circular, C-shaped, or parenthesized. This third relay coil may be arranged substantially coaxially with the power supply coil L0 and the first and second relay coils L1 and L2, and more specifically, the third relay coil may be arranged so that the axial direction LJ of the third relay coil is substantially the same as the axial direction LJ of the power supply coil L0 and the first and second relay coils L1 and L2 when viewed from the axial direction LJ. In this case, it can also be said that the axial direction LJ of the third relay coil is also substantially parallel to the axial direction WJ of the workpiece W. The overall length of the third relay coil (copper plate or the like) in the axial direction LJ is not particularly limited, and may be, for example, approximately the same as or different from the length of the first and second relay coils L1 and L2 described above, or may correspond to the length of the third cross-sectional portion W3 of the workpiece W in the axial direction WJ. Other details of the third relay coil, such as its configuration, number of turns and its numerical range, thickness when the wound object is a copper plate or the like, numerical range of the length in the axial direction LJ, and the presence or absence of an iron core or cooling device, may be the same as or different from those of the first and second relay coils L1 and L2, the power supply coil L0, and the first to third hardened coils C1 and C2, etc.

[0039] Additionally, the hardening device 1 (particularly, the transformer 10) may have a fourth relay coil, a fifth relay coil, a sixth relay coil,... an nth relay coil (n is a natural number) (not shown), and in this case, as will be described later, the hardening device 1 also has a fourth quenching coil... an nth quenching coil, and the workpiece W also has a fourth cross-sectional portion... an nth cross-sectional portion. In this way, when the quenching apparatus 1 has the fourth relay coil...n-th relay coil, the fourth relay coil...n-th relay coil are coils that can relay power from the above-mentioned power supply coil L0 to the above-mentioned fourth quenching coil...n-th quenching coil, respectively. Note that the fourth relay coil...n-th relay coil may also relay power from the power supply coil L0 to an external device (outside the transformer 10) other than the fourth quenching coil...n-th quenching coil. The fourth relay coil...the nth relay coil, together with the fourth hardened coil...the nth hardened coil, respectively, are also coils that are movable relative to the workpiece W in a direction substantially parallel to the axial direction WJ across the fourth cross-sectional portion...the nth cross-sectional portion of the workpiece W described above (from one end to the other end in the axial direction WJ). The coil moving mechanism 40 (strictly speaking, the fourth coil moving mechanism...nth coil moving mechanism (not shown)) that moves the fourth relay coil...nth relay coil relatively together with the fourth hardened coil...nth hardened coil, respectively, will be described later. Furthermore, the fourth relay coil to the nth relay coil are also coils in which the above-described power supply coil L0 can move relatively to the fourth relay coil to the nth relay coil substantially along the axial direction LJ of each coil. Therefore, it can be said that the fourth relay coil to the nth relay coil each surround the power supply coil L0 from the outer periphery (each has a larger diameter than the power supply coil L0), and it can also be said that the axial direction (or axial direction) LJ of the fourth relay coil to the nth relay coil each is approximately parallel to the axial direction WJ of the workpiece W. The shape of the fourth relay coil through the nth relay coil as viewed in the axial direction LJ is not particularly limited, and may be, for example, substantially the same as the first to third relay coils L1, L2, etc. described above (that is, substantially the same in shape and size), or may be different. Specifically, the shape may be substantially circular, C-shaped, or parenthesized. Each of the fourth relay coil through the nth relay coil may be arranged substantially coaxially with the power supply coil L0 and the first to third relay coils L1 and L2, etc. In more detail, the fourth relay coil through the nth relay coil may be arranged so that the axial direction LJ of each of the fourth relay coil through the nth relay coil is substantially the same as the axial direction LJ of the power supply coil L0 and the first to third relay coils L1 and L2, etc. In this case, it can also be said that the axial direction LJ of each of the fourth relay coil through the nth relay coil is substantially parallel to the axial direction WJ of the workpiece W. The overall length in the axial direction LJ of the fourth relay coil through the nth relay coil (copper plates, etc.) is not particularly limited, and may be, for example, approximately the same as or different from the lengths of the first to third relay coils L1, L2, etc. described above, or may correspond to the lengths in the axial direction WJ of the fourth cross-sectional portion through the nth cross-sectional portion of the workpiece W described above. In addition, the configuration of the fourth relay coil through the nth relay coil, the number of turns and its numerical range, the thickness when the wound material is a copper plate or the like, the numerical range of the length in the axial direction LJ, the presence or absence of an iron core or cooling device, etc. may be the same as or different from the first to third relay coils L1 and L2, etc., the power supply coil L0, and the first to third hardened coils C1 and C2, etc.

[0040] <Current supply mechanism 20> As shown in FIGS. 3 to 6, 9 and 10, the current supply mechanism 20 includes the above-mentioned transformer 10, and is a mechanism for supplying current to the above-mentioned first and second hardened coils C1, C2, etc. As described above, the current supplied by the current supply mechanism 20 is an alternating current, and its frequency may be high (i.e., it may be called a high-frequency current). There are no particular restrictions on the specific value of the frequency, but it may be, for example, 1 kHz or more and 500 kHz or less (e.g., 20 kHz). The configuration of the current supply mechanism 20 (including the transformer 10) is not particularly limited, but for example, its power supply may be 50V or more and 300V or less (100V (commercial power outlet, single phase), 200V (single phase, three phase (for power)), etc.). The current (AC current) from such a power source may be converted into an AC current of 3000V or more and 5000V or less by a switching device (or an oscillator (also called a high-frequency oscillator), not shown) in the current supply mechanism 20, and this voltage (potential) becomes the voltage of the power supply coil L0 in the transformer 10.

[0041] The voltage ratio between the primary side (power supply coil L0) and the secondary side (first and second relay coils L1 and L2, etc.) of the transformer 10 is not particularly limited, but may be, for example, 3000V to 5000V:200V to 300V (in other words, 1:10 to 1:25).The turns ratio between the primary side and the secondary side is also not particularly limited, but may be, for example, the number of turns on the primary side > the number of turns on the secondary side, and may be 2 turns to 20 turns to 1 turn to 10 turns (in other words, 2:1 to 20:1). Furthermore, the voltage (potential) at the first and second hardened coils C1, C2, etc., to which current is supplied from the current supply mechanism 20 including such a transformer 10, is not particularly limited, but may be, for example, 50V or more and 100V or less. The frequency of the current supplied from such a current supply mechanism 20 may be changed between 1 kHz (1000 Hz) and 50 kHz, and it can be said that the depth of hardening of the workpiece W can be adjusted by changing this frequency. In addition, the current supply mechanism 20 may have an oscillator (high frequency oscillator, not shown), and the power source of the current supply mechanism 20 itself is not particularly limited, but may be, for example, a household power source (household outlet).

[0042] <Workpiece holding and moving mechanism 30> As shown in FIGS. 3, 7, 8, etc., the workpiece holding and moving mechanism 30 is a mechanism for holding the above-mentioned workpiece W in the hardening apparatus 1 and moving it. The workpiece holding / moving mechanism 30 is not particularly limited in its configuration, but for example, when holding the workpiece W relative to the hardening apparatus 1 so that the axial direction WJ of the workpiece W is aligned with the vertical direction of the hardening apparatus 1, the mechanism may include a workpiece lower holding portion 30a that supports the workpiece W from below, a workpiece upper holding portion 30b that supports the workpiece W from above, a biasing portion (e.g., a rotary motor, etc.) 30c that biases (presses) the workpiece upper holding portion 30b downward to bias the workpiece W from above (or biases the workpiece W from below), and a workpiece moving cylinder (e.g., an electric cylinder (electric actuator) with a servo motor, etc.) 30d that can move the entire workpiece lower holding portion 30a, workpiece upper holding portion 30b, and upper biasing portion 30c described above approximately along the axial direction WJ (e.g., vertical direction) of the workpiece W. Here, since the workpiece holding / moving mechanism 30 has the workpiece moving cylinder 30d, it is possible to change the position (relative position) of the workpiece W with respect to the first and second hardening coils C1, C2, etc. and the first and second relay coils L1, L2, etc. from one side to the other (from below to above) by moving only the workpiece W held by the mechanism 30 approximately along its axial direction WJ without moving the positions of the above-mentioned first and second hardening coils C1, C2, etc. by the coil moving mechanism 40 described later.

[0043] Furthermore, the workpiece lower holding portion 30a and the workpiece upper holding portion 30b in the workpiece holding / moving mechanism 30 may have a shape and configuration that corresponds to the workpiece W to be held. For example, if the axial length WJ (axial length, vertical length) of the workpiece W is short (for example, if the workpiece W is a bearing, etc.), the vertical lengths of the workpiece lower holding portion 30a and the workpiece upper holding portion 30b may be made longer, and a configuration may be adopted in which the housing 50 described below and other mechanisms 20, 40, etc. do not need to be changed. The workpiece holding and moving mechanism 30 may hold the workpiece W so that its axial direction WJ is aligned with the horizontal direction of the hardening apparatus 1 (left-right direction or front-rear direction). In addition, the workpiece holding / moving mechanism 30 may also have a lower biasing portion (e.g., a rotary motor (stepping motor), not shown) that biases (presses) the above-mentioned lower workpiece holding portion 30a upward to hold the workpiece W from below.In this case, too, it can be said that the relative position of the workpiece W to the first and second hardening coils C1, C2, etc. can be changed by moving only the workpiece W held by the mechanism 30 approximately along its axial direction WJ without moving the positions of the first and second hardening coils C1, C2, etc. with the coil moving mechanism 40.

[0044] <Coil moving mechanism 40> As shown in FIGS. 3 to 6, 9 and 10, the coil moving mechanism 40 is a mechanism for moving coils such as the first and second hardened coils C1 and C2, the power supply coil L0, and the first and second relay coils L1 and L2. The coil moving mechanism 40 is not particularly limited in its configuration, but may have, for example, as described above, a power supply coil moving mechanism 40-0, a first coil mechanism 40-1, a second coil moving mechanism 40-2, a third coil moving mechanism (not shown), a fourth coil moving mechanism,... an nth coil moving mechanism (not shown) depending on the coil to be moved, which will be explained in detail below. The detailed explanation will be given in the following order: first, the power supply coil moving mechanism 40-0 and the second coil moving mechanism 40-2 will be described, and then the first coil mechanism 40-1, the third coil moving mechanism, and so on to the n-th coil moving mechanism. Furthermore, these coil moving mechanisms 40 may also move the coils relatively so that the axial directions CJ and LJ of the coils are aligned with the horizontal direction of the quenching apparatus 1 (left-right direction or front-rear direction).

[0045] As shown in FIGS. 3, 4, 9, 10, etc., the power supply coil moving mechanism 40-0 is a mechanism that moves the power supply coil L0 relatively to the workpiece W in a direction substantially parallel to the axial direction WJ of the workpiece W, at least inside the first relay coil L1 and the second relay coil L2, from the first relay coil L1 to the second relay coil L2 (in other words, moves the power supply coil L0 relatively to the first relay coil L1 and / or the second relay coil L2 substantially along the axial direction LJ of the workpiece W). The power supply coil moving mechanism 40-0 is not particularly limited in its configuration, but for example, when the power supply coil L0 is attached to the quenching device 1 (particularly the housing 50 described below) so that the axial direction LJ of the power supply coil L0 is in the vertical direction of the quenching device 1, the mechanism may have a power supply coil moving cylinder (for example, an electric cylinder (electric actuator) with a servo motor, etc.) 40-0a that can move the power supply coil L0 approximately along the axial direction (vertical direction, etc.) WJ of the workpiece W. In addition, the power supply coil moving mechanism 40-0 may have the above-mentioned power supply coil moving cylinder 40-0a and a connecting member (power supply coil connecting member 40-0b) that connects the power supply coil L0 itself, and this connecting member can also be said to be part of the housing 50 described later.

[0046] As shown in Figures 3, 5, 9, 10, etc., the second coil moving mechanism 40-2 is a mechanism that moves both the second hardened coil C2 and the second relay coil L2 relative to the workpiece W across the second cross-sectional portion W2 of the workpiece W in a direction approximately parallel to its axial direction WJ. The second coil moving mechanism 40-2 is also not particularly limited in its configuration, but for example, when the second quenching coil C2 and the second relay coil L2 are attached to the quenching device 1 (particularly, to the housing 50 described later) so that the axial directions CJ of the second quenching coil C2 and the second relay coil L2 are aligned in the vertical direction of the quenching device 1, the second coil moving mechanism 40-2 may include a second coil moving cylinder (for example, an electric cylinder (electric actuator) with a servo motor) 40-2a that can move the second quenching coil C2 and the second relay coil L2 substantially along the axial direction (e.g., the vertical direction) WJ of the workpiece W, and a second coil connecting member 40-2b that connects the second quenching coil C2 and the second relay coil L2; the second coil connecting member 40-2b will be described later in particular. In addition, the second coil moving mechanism 40-2 may also have the above-mentioned second coil moving cylinder 40-2a and a connecting member that connects the second hardened coil C2 and the second relay coil L2 themselves, and this connecting member can also be considered part of the housing 50 described later.

[0047] As shown in Figures 3, 5, 6, 9, 10, etc., the first coil mechanism 40-1 is a mechanism that moves both the first hardened coil C1 and the first relay coil L1 relative to the workpiece W across the first cross-sectional portion W1 of the workpiece W in a direction approximately parallel to its axial direction WJ. The first coil mechanism 40-1 is also not particularly limited in its configuration, but the biggest difference between it and the second coil moving mechanism 40-2 described above is that, when the first quenching coil C1 and the first relay coil L1 are attached to the quenching device 1 (particularly the housing 50 described below) so that the axial directions CJ of the first quenching coil C1 and the first relay coil L1 are aligned in the vertical direction of the quenching device 1, the first coil mechanism 40-1 does not have a (so-called) coil moving cylinder (for example, an electric cylinder (electric actuator) with a servo motor) that can move the first quenching coil C1 and the first relay coil L1 approximately along the axial direction WJ (e.g., the vertical direction) of the workpiece W. Here, although the first coil mechanism 40-1 does not have a first coil moving cylinder, the work holding / moving mechanism 30, the power supply coil moving mechanism 40-0, and the second coil moving mechanism 40-2 have moving cylinders 30d, 40-0a, and 40-2b, respectively, and therefore it can be said that the first hardened coil C1 and the first relay coil L1 can move relative to the workpiece W across the first cross-sectional portion W1 of the workpiece W in a direction substantially parallel to its axial direction WJ. It should be noted that the first coil mechanism 40-1 may have a first coil moving cylinder, in which case it can be said that the first coil mechanism 40-1 is the first coil moving mechanism 40-1. In summary, it can also be said that if at least three of the four mechanisms, the work holding / moving mechanism 30, the power supply coil moving mechanism 40-0, the second coil moving mechanism 40-2, and the first coil (moving) mechanism 40-1, have the above-mentioned moving cylinders, relative movement between them is possible. Furthermore, when the first coil mechanism 40-1 has a first coil moving cylinder, it may also have a connecting member that connects the first coil moving cylinder with the first hardened coil C1 and the first relay coil L1 themselves, and this connecting member can also be considered part of the housing 50 described later. The first coil mechanism 40-1 also includes a first coil connecting member 40-1b that connects the first hardened coil C1 and the first relay coil L1, and this first coil connecting member 40-1b will be described later. Alternatively, the first coil mechanism 40-1 may have a rod-shaped member 40-1c that stands upright at the axial position of the first relay coil L1 (see FIG. 5, etc.). If this rod-shaped member 40-1c is made of iron or the like (iron core material), the first relay coil L1 can also be said to have an iron core. In this case, if the second relay coil L2 and the power supply coil L0 are arranged approximately coaxially with the first relay coil L1, the second relay coil L2 and the power supply coil L0 can also be said to have an iron core.

[0048] In the case where the hardening device 1 also has the third hardening coil...nth hardening coil and the third relay coil...nth relay coil, the hardening device 1 may also have a third coil moving mechanism...nth coil moving mechanism that moves the third hardening coil...nth hardening coil and the third relay coil...nth relay coil together relative to the workpiece W across the third cross-sectional portion W3...nth cross-sectional portion of the workpiece W in a direction approximately parallel to its axial direction WJ. The third coil moving mechanism...nth coil moving mechanism is not particularly limited in its configuration, but for example, when the third quenching coil...nth quenching coil and the third relay coil...nth relay coil are attached to the quenching device 1 (particularly, to the housing 50 described later) so that the axial directions LJ of the third quenching coil...nth quenching coil and the third relay coil...nth relay coil are aligned in the up-down direction of the quenching device 1, at least the third quenching coil...nth quenching coil and The third relay coil...n-th relay coil may have a 3...n-th coil connecting member (not shown) connecting the third relay coil...n-th relay coil, and may also have a 3...n-th coil moving cylinder (for example, an electric cylinder (electric actuator) with a servo motor) that can move the third hardened coil...n-th hardened coil and the third relay coil...n-th relay coil substantially along the axial direction WJ (up and down direction, etc.) of the workpiece W, and the 3...n-th coil connecting member in particular will be described later. Additionally, when the third coil moving mechanism...nth coil moving mechanism has the above-mentioned 3rd...nth coil moving cylinder, it may have a connecting member that connects the 3rd...nth coil moving cylinder with the 3rd hardened coil...nth hardened coil and the 3rd relay coil...nth relay coil itself, and this connecting member can be said to be part of the housing 50 described later.

[0049] <1st to nth coil connecting members 40-1b, 40-2b, etc.> As shown in FIGS. 1 to 6 (particularly FIGS. 1, 2(b), and 2(c)), the first and second coil connecting members 40-1b and 40-2b are members that connect the first and second hardened coils C1 and C2 to the first and second relay coils L1 and L2, respectively, as described above. There are no particular limitations on the configuration of the first and second coil connecting members 40-1b, 2b. For example, when the first and second quenching coils C1, C2 and the first and second relay coils L1, L2 are attached to the hardening apparatus 1 (particularly, to the housing 50 described below) so that the axial direction LJ of the first and second quenching coils C1, C2 and the first and second relay coils L1, L2 is aligned in the vertical direction of the hardening apparatus 1, if the workpiece W is a stepped shaft, a drill, or the like, as shown in FIG. 1 or FIG. 2(b), the first coil connecting member 40-1b connects the first quenching coil C1 to the first relay coil L1 so that the first quenching coil C1 is positioned upward, and the second coil connecting member 40-2b connects the second relay coil L2 so that the second quenching coil C2 is positioned downward. Conversely, as shown in FIG. 2(c), if the workpiece W is a bearing or the like, the first coil connecting member 40-1b may connect the first relay coil L1 so that the first hardened coil C1 is positioned downward, and the second coil connecting member 40-2b may connect the second relay coil L2 so that the second hardened coil C2 is positioned upward. As a result, even if the axial length CJ (vertical length, etc.) of the first and second hardening coils C1 and C2 is shorter than the axial length LJ (vertical length) of the first and second relay coils L1 and L2, if the first relay coil L1 and the second relay coil L2 are close to each other, the first hardening coil C1 and the second hardening coil C2 will also be close to each other. Even if the workpiece W is a stepped shaft, drill, bearing, or other workpiece that has a step WD between the first and second cross-sectional portions W1 and W2, it is possible to harden each cross-sectional portion W1 and W2 and the step WD between them without any gaps even at the step WD. There are no particular limitations on the relationship between the axial length LJ (vertical length) of the power supply coil L0 and the axial length LJ (vertical length) of the first and second relay coils L1 and L2. For example, the axial length LJ of the power supply coil L0 may be shorter than the axial length LJ of the first and second relay coils L1 and L2 (see FIG. 1, etc.), or conversely, the axial length LJ of the power supply coil L0 may be longer than the axial length LJ of the first and second relay coils L1 and L2 (see FIG. 2(b)), or they may be approximately the same. Furthermore, the relationship in length between the axial direction LJ of the first relay coil L1 and the axial direction LJ of the second relay coil L2 is not particularly limited. For example, the axial direction LJ length of the first relay coil L1 may be approximately the same as the axial direction LJ length of the second relay coil L2 (see FIG. 1, etc.), may be shorter than the axial direction LJ length of the second relay coil L2 (see FIG. 2(b)), or may be longer.

[0050] In addition, when the quenching device 1 has first to third quenching coils C1, C2, etc. and first to third relay coils L1, L2, etc., and has first to third coil connection members 40-1b, 2b, etc. that connect these coils, the first to third coil connection members 40-1b, 2b, etc. may be configured as follows: for example, the first coil connection member 40-1b connects the first quenching coil C1 to the first relay coil L1 so that the first quenching coil C1 is located upward, the second coil connection member 40-2b connects the second relay coil L2 so that the second quenching coil C2 is located toward the center in the up-down direction, and the third coil connection member connects the third relay coil so that the third quenching coil is located downward. Similarly, when the quenching apparatus 1 has 1...n-th quenching coils C1...C2 etc. and 1...n-th relay coils L1...L2 etc. (n is a natural number of 4 or more) and has 1...n-th coil connection members 40-1b, 2b etc. connecting these coils, the 1...n-th coil connection members 40-1b, 2b etc. may be connected such that each quenching coil is arranged closer to the coil connection member in the order of approximately the center with respect to each relay coil, so that the cross-sectional portions W1...W2 etc. and the step portions WD of the workpiece W can be hardened without any gaps, for example, even at step portions WD etc. Furthermore, the first to nth coil connecting members 40-1b, 40-2b, etc. may also be connected so that the axial directions CJ, LJ of the coils are aligned with the horizontal direction (left-right direction or front-rear direction) of the quenching apparatus 1.

[0051] <Case 50> As shown in Figures 3 to 8, the housing 50 supports the above-mentioned workpiece W, the first and second hardened coils C1 and C2, the current supply mechanism 20 including the transformer 10, the workpiece holding and moving mechanism 30, the coil moving mechanism 40, etc. The housing 50 is not particularly limited in its configuration, but may have, for example, a frame member 50a to which the mechanisms 20, 30, 40, etc. are attached, a bottom 50b attached to the lower end side of the frame member 50a, and legs 50c protruding downward from the bottom 50b and whose height can be adjusted freely. In addition, in the housing 50, a control unit (control panel, operation panel) for controlling the above-mentioned current supply mechanism 20, workpiece holding / moving mechanism 30, coil moving mechanism 40, etc. may be provided on an outer wall member (not shown) so that these mechanisms 20, 30, 40, etc. can be operated, and the outer wall member may be provided with an openable and closable door.

[0052] <How to use induction hardening device 1> As shown in Figures 1 and 2, the method of using the induction hardening apparatus 1 described above (hereinafter also referred to as "the method of use") includes at least a first hardening process P1, a moving process PP, and a second hardening process P2, which will be described later. The method of use may include a workpiece mounting step and a workpiece removal step, which will be described later. Here, in this usage method, the workpiece W is <1> The cross-sectional shape is generally circular, such as a stepped shaft, and the first cross-sectional portion W1 and the second cross-sectional portion W2 are located at generally the same cross-sectional position in the axial direction WJ but have different diameters (see Figures 1 and 2(a)). <2> The cross-sectional shape is generally ring-shaped, such as a bearing, and the first cross-sectional portion W1 and the second cross-sectional portion W2 are located at generally the same cross-sectional position in the axial direction WJ but have different diameters (see FIG. 2(b)). <3> The following description will be divided into drills and the like, in which the first cross-sectional portion W1 of the drill part has a cross-sectional shape similar to that of a drill and has spiral grooves, and the second cross-sectional portion W2 of the tip part are located at approximately the same cross-sectional position in the axial direction WJ (see Figure 2(c)).

[0053] <First quenching process P1> As shown in Figures 1 and 2 (particularly Figures 1(b) and 1(c) and Figures 2(b) and 2(c)), the first quenching process P1 is basically a process of quenching the first cross-sectional portion W1 of the workpiece W. In more detail, the basic first quenching process P1 is a process of quenching the first cross-sectional portion W1 of the workpiece W from one end to the step portion WD using the first quenching coil C1 in a direction approximately parallel to the axial direction WJ of the workpiece W, with at least a portion of the power supply coil L0 inside the first relay coil L1. As shown in Figure 1(b) and (c), when the workpiece W is <1> In the case of a stepped shaft or the like, the first quenching step P1 may be a step in which, with the entire power supply coil L0 inside the first relay coil L1, the first relay coil L1, the first quenching coil C1, and the power supply coil L0 are moved relative to the workpiece W from one end of the first cross-sectional portion W1 to the stepped portion WD in a direction substantially parallel to the axial direction WJ of the workpiece W to quench the first cross-sectional portion W1, and during this time, the second relay coil L2 and the second quenching coil C2 are kept stopped at the stepped portion WD of the workpiece W. <1> In this case, the first quenching process P1 is as follows, in comparison with the basic first quenching process P1 described above: <1-1> The power supply coil L0, which is entirely inside the first relay coil L1, moves relatively with the first relay coil L1 and the first hardening coil C1, and hardens the first cross-sectional portion W1; and <1-2> It can also be said that the second relay coil L2 and the second hardening coil C2 continue to stop at the stepped portion WD of the workpiece W while the first cross-sectional portion W1 is being hardened. Also, as shown in Figure 2(b), when the workpiece W is <2> In the case of a bearing or the like, the first quenching step P1 may be a step in which, with at least a portion of the power supply coil L0 inside the first relay coil L1, the power supply coil L0, together with the first relay coil L1 and the first quenching coil C1, moves relatively with respect to the workpiece W from one end of the first cross-sectional portion W1 of the workpiece W to the stepped portion WD in a direction substantially parallel to the axial direction WJ (and stops) to quench the first cross-sectional portion W1; or, with at least a portion of the power supply coil L0 inside the first relay coil L1, the power supply coil L0 alone moves relatively with respect to the workpiece W from one end of the first cross-sectional portion W1 of the workpiece W to the stepped portion WD in a direction substantially parallel to the axial direction WJ to quench the first cross-sectional portion W1, while the first relay coil L1 and the first quenching coil C1 are stopped. <2> In this case, the first quenching process P1 is as follows, in comparison with the basic first quenching process P1 described above: <2-1> The power supply coil L0, at least a portion of which is inside the first relay coil L1, moves relatively together with the first relay coil L1 and the first hardening coil C1, and stops while hardening the first cross-sectional portion W1; or <2-2> It can be said that an additional feature is that the first cross-sectional portion W1 is hardened while only the power supply coil L0, at least a portion of which is inside the first relay coil L1, moves relative to the first relay coil L1 (conversely, the first relay coil L1 and the first hardening coil C1 are stationary). On the other hand, as shown in Figure 2(c), when the workpiece W is <3> In the case of a drill or the like, the first quenching step P1 is <1> As in the case of a stepped shaft or the like, the power supply coil L0 may be entirely inside the first relay coil L1, and the power supply coil L0, together with the first relay coil L1 and the first quenching coil C1, may be moved relative to the workpiece W from one end of the first cross-sectional portion W1 of the workpiece W to the stepped portion WD in a direction substantially parallel to the axial direction WJ of the workpiece W to quench the first cross-sectional portion W1, while the second relay coil L2 and the second quenching coil C2 remain stopped at the stepped portion WD of the workpiece W. <3> In the first quenching process P1 in this case, the content of the basic first quenching process P1 described above is as follows: <3-1> The power supply coil L0, which is entirely inside the first relay coil L1, moves relatively with the first relay coil L1 and the first hardening coil C1, and hardens the first cross-sectional portion W1; and <3-2> It can also be said that the second relay coil L2 and the second hardening coil C2 continue to stop at the stepped portion WD of the workpiece W while the first cross-sectional portion W1 is being hardened.

[0054] <Moving process PP> As shown in FIGS. 1 and 2 (particularly, FIG. 1(d) and FIGS. 2(b) and 2(c)), the moving step PP is basically a step of moving (relatively moving) the power supply coil L0. In more detail, the moving step PP is a step of moving at least a part of the power supply coil L0 from the inside of the first relay coil L1 to the inside of the second relay coil L2, relatively to the first relay coil L1 and / or the second relay coil L2 substantially along the axial direction LJ thereof. As shown in Figure 1(d), the workpiece W <1> In the case of a stepped shaft or the like, the moving step PP may be a step in which the power supply coil L0, together with the first relay coil L1 and the first hardened coil C1, moves relatively to the workpiece W in a direction substantially parallel to the axial direction WJ thereof to the stepped portion WD of the workpiece W, and then the power supply coil L0 alone moves relatively to the workpiece W in a direction substantially parallel to the axial direction WJ thereof from the inside of the first relay coil L1 to the inside of the second relay coil L2. <1> In this case, the transfer process PP is as follows, in relation to the contents of the basic transfer process PP described above: <1-1> After the power supply coil L0, the first relay coil L1, and the first hardened coil C1 move relatively to the stepped portion WD of the workpiece W in a direction substantially parallel to the axial direction WJ of the workpiece W, only the power supply coil L0 moves relatively; and <1-2> It can also be said that the entire power supply coil L0 moves relatively from the inside of the first relay coil L1 to the inside of the second relay coil L2 substantially in a direction parallel to the axial direction WJ of the workpiece W. Also, as shown in Figure 2(b), when the workpiece W is <2> In the case of a bearing or the like, the moving step PP may be a step in which at least a part of the power supply coil L0 straddles the inside of the first relay coil L1 and the inside of the second relay coil L2 and moves relatively to the first relay coil L1 and the second relay coil L2 substantially along the axial direction LJ thereof. <2> In this case, the transfer process PP is as follows, in relation to the contents of the basic transfer process PP described above: <2-1> At least a portion of the power supply coil L0 is located inside the first relay coil L1 and at least a portion of the power supply coil L0 is located inside the second relay coil L2, and <2-2> It can also be said that only the power supply coil L0, at least a portion of which is inside the first relay coil L1 and at least a portion of which is inside the second relay coil L2, moves relatively (conversely, the first relay coil L1 and the first hardened coil C1 are stationary). On the other hand, as shown in Figure 2(c), when the workpiece W is <3> In the case of a drill or the like, the moving step PP is <2> As in the case of a bearing or the like, a step may be adopted in which at least a portion of the power supply coil L0 straddles the inside of the first relay coil L1 and the inside of the second relay coil L2 and moves relatively to the first relay coil L1 and the second relay coil L2 substantially along the axial direction LJ thereof. <3> In this case, the transfer process PP is also as follows, in relation to the contents of the basic transfer process PP described above: <3-1> At least a portion of the power supply coil L0 is located inside the first relay coil L1 and at least a portion of the power supply coil L0 is located inside the second relay coil L2, and <3-2> It can also be said that only the power supply coil L0, at least a portion of which is inside the first relay coil L1 and at least a portion of which is inside the second relay coil L2, moves relative to each other (conversely, the first relay coil L1 and the first hardened coil C1 are stationary).

[0055] <Second quenching process P2> As shown in Figures 1 and 2 (particularly Figures 1(e) and (f) and Figures 2(b) and (c)), the second quenching process P2 is basically a process of quenching the second cross-sectional portion W2 of the workpiece W. In more detail, the basic second quenching process P2 is a process of quenching the second cross-sectional portion W2 from the step portion WD of the workpiece W to the other end of the second cross-sectional portion W2 using the second quenching coil C2 in a direction approximately parallel to the axial direction WJ of the workpiece W, with at least a portion of the power supply coil L0 inside the second relay coil L2. As shown in Fig. 1(e) and (f), when the workpiece W is <1> In the case of a stepped shaft or the like, the second quenching process P2 may be a process in which, with the entire power supply coil L0 inside the second relay coil L2, the power supply coil L0, together with the second relay coil L2 and the second quenching coil C2, moves relatively to the workpiece W from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 in a direction substantially parallel to the axial direction WJ of the workpiece W to quench the second cross-sectional portion W2, and during this time, the first relay coil L1 and the first quenching coil C1 continue to stop at the stepped portion WD of the workpiece W. <1> In this case, the second quenching process P2 is as follows, in comparison with the basic second quenching process P2 described above: <1-1> The power supply coil L0, which is entirely inside the second relay coil L2, moves relatively with the second relay coil L2 and the second hardening coil C2, and hardens the second cross-sectional portion W2; and <1-2> It can also be said that the first relay coil L1 and the first hardening coil C1 continue to stop at the stepped portion WD of the workpiece W while the second cross-sectional portion W2 is being hardened. Also, as shown in Figure 2(b), when the workpiece W is <2> In the case of a bearing or the like, the second quenching step P2 may be a step in which, with at least a portion of the power supply coil L0 inside the second relay coil L2, the power supply coil L0, together with the second relay coil L2 and the second quenching coil C2, moves relatively with respect to the workpiece W from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 substantially along a direction parallel to the axial direction WJ (and stops) to quench the second cross-sectional portion W2; or, with at least a portion of the power supply coil L0 inside the second relay coil L2, the power supply coil L0 alone moves relatively with respect to the workpiece W from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 substantially along a direction parallel to the axial direction WJ to quench the second cross-sectional portion W2, while the second relay coil L2 and the second quenching coil C2 are stopped. <2> In this case, the second quenching process P2 is as follows, in comparison with the basic second quenching process P2 described above: <2-1> The power supply coil L0, at least a portion of which is inside the second relay coil L2, moves relatively together with the second relay coil L2 and the second hardening coil C2, and stops while hardening the second cross-sectional portion W2, or <2-2> It can be said that an additional feature is that the second cross-sectional portion W2 is hardened while only the power supply coil L0, at least a portion of which is inside the second relay coil L2, moves relatively (conversely, the second relay coil L2 and the second hardening coil C2 are stopped). On the other hand, as shown in Figure 2(c), when the workpiece W is <3> In the case of a drill or the like, the second quenching step P2 is <2> As in the case of bearings, etc., the second cross-sectional portion W2 may be hardened by moving (and stopping) the power supply coil L0 together with the second relay coil L2 and the second quenching coil C2 relative to the workpiece W from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 substantially along the direction parallel to the axial direction WJ of the workpiece W, with at least a portion of the power supply coil L0 inside the second relay coil L2, or by moving only the power supply coil L0 relative to the workpiece W from the stepped portion WD of the workpiece W to the other end of the second cross-sectional portion W2 substantially along the direction parallel to the axial direction WJ of the workpiece W, with the second relay coil L2 and the second quenching coil C2 stopped. <3> In the case of the second quenching process P2, the following is true for the basic second quenching process P2 described above: <3-1> The power supply coil L0, at least a portion of which is inside the second relay coil L2, moves relatively together with the second relay coil L2 and the second hardening coil C2, and stops while hardening the second cross-sectional portion W2, or <3-2> It can be said that an additional feature is that the second cross-sectional portion W2 is hardened while only the power supply coil L0, at least a portion of which is inside the second relay coil L2, moves relative to the second relay coil L2 (conversely, the second relay coil L2 and the second hardening coil C2 are stationary).

[0056] <Workpiece mounting process> As shown in Figures 1 and 2 (particularly Figure 1(a) and Figures 2(b) and (c)), the workpiece mounting process is basically a process of mounting the workpiece W to the hardening apparatus 1. In more detail, the basic workpiece mounting process is a process in which the workpiece W is mounted to the hardening apparatus 1 (particularly the above-mentioned workpiece holding / moving mechanism 30) so that the axial direction WJ of the workpiece W is aligned with the vertical direction of the hardening apparatus 1, and the workpiece W supported from below by the lower workpiece holding portion 30a is supported from above by the upper workpiece holding portion 30b, which is biased downward by the upper biasing portion 30c, thereby mounting the workpiece W to the induction hardening apparatus 1. As shown in Figure 1(a), the workpiece W is <1> In the case of a stepped shaft or the like, the workpiece mounting step may be a step of supporting the workpiece W from below by the workpiece lower holding part 30a from above by the workpiece upper holding part 30b, which is biased downward by the upper biasing part 30c, and then positioning the first relay coil L1 and the first quenching coil C1 at one end (lower end) of the workpiece W, and positioning the second relay coil L2 and the second quenching coil C2 at the stepped part WD of the workpiece W, with the entire power supply coil L0 inside the first relay coil L1, and mounting the workpiece W to the induction hardening apparatus 1. <1> In this case, the workpiece mounting process is as follows, in comparison with the basic workpiece mounting process described above: <1-1> The workpiece W has been supported by the lower workpiece holding portion 30a, the upper workpiece holding portion 30b, and the upper biasing portion 30c, and <1-2> The power supply coil L0 is entirely inside the first relay coil L1, and the first relay coil L1 and the first hardened coil C1 are positioned at one end of the workpiece W, and <1-3> It can also be said that the second relay coil L2 and the second hardened coil C2 are positioned at the stepped portion WD of the workpiece W. Also, as shown in Figure 2(b), when the workpiece W is <2> In the case of a bearing or the like, the workpiece mounting step may be a step of supporting the workpiece W from below by the workpiece lower holding part 30a from above by the workpiece upper holding part 30b, which is biased downward by the upper biasing part 30c, and then positioning the first relay coil L1 and the first quenching coil C1 near one end (lower end) of the stepped part WD of the workpiece W and positioning the second relay coil L2 and the second quenching coil C2 near the other end (upper end) of the stepped part WD of the workpiece W, with at least a part of the power supply coil L0 spanning the inside of the first relay coil L1 and the inside of the second relay coil L2, and mounting the workpiece W to the induction hardening apparatus 1. <2> In this case, the workpiece mounting process is as follows, in comparison with the basic workpiece mounting process described above: <2-1> The workpiece W has been supported by the lower workpiece holding portion 30a, the upper workpiece holding portion 30b, and the upper biasing portion 30c, and <2-2> At least a portion of the power supply coil L0 straddles the inside of the first relay coil L1 and the inside of the second relay coil L2, and <2-3> The first relay coil L1 and the first hardened coil C1 are positioned near one end of the stepped portion WD of the workpiece W, and <2-4> It can also be said that the second relay coil L2 and the second hardened coil C2 are positioned near the other end of the stepped portion WD of the workpiece W. On the other hand, as shown in Figure 2(c), when the workpiece W is <3> In the case of a drill or the like, the workpiece mounting step is the same as that described above. <1> As in the case of a stepped shaft or the like, the workpiece W may be supported from below by the workpiece lower holding part 30a, and then supported from above by the workpiece upper holding part 30b, which is biased downward by the upper biasing part 30c. Then, with the entire power supply coil L0 inside the first relay coil L1, the first relay coil L1 and the first quenching coil C1 are positioned at one end (lower end) of the workpiece W, and the second relay coil L2 and the second quenching coil C2 are positioned at the stepped part WD of the workpiece W, and the workpiece W is attached to the induction hardening apparatus 1. <3> In this case, the workpiece mounting process is also different from the basic workpiece mounting process described above. <3-1> The workpiece W has been supported by the lower workpiece holding portion 30a, the upper workpiece holding portion 30b, and the upper biasing portion 30c, and <3-2> The power supply coil L0 is entirely inside the first relay coil L1, and the first relay coil L1 and the first hardened coil C1 are positioned at one end of the workpiece W, and <3-3> It can be said that the second relay coil L2 and the second hardened coil C2 are positioned at the stepped portion WD of the workpiece W.

[0057] <Work removal process> As shown in Figures 1 and 2 (particularly Figure 1(g) and Figures 2(b) and (c)), the workpiece removal process is basically a process of removing the workpiece W from the hardening apparatus 1. In more detail, the basic workpiece removal process is a process in which, when the workpiece W is attached to the hardening apparatus 1 (particularly the workpiece holding and moving mechanism 30 described above) so that the axial direction WJ of the workpiece W is aligned with the vertical direction of the hardening apparatus 1, the workpiece W is moved upward by the upper workpiece holding portion 30b using the upper biasing portion 30c, and the workpiece W, which is supported from below by the lower workpiece holding portion 30a, is removed from the induction hardening apparatus 1. In addition, the workpiece W shown in Figure 1(g) <1> Not only in the case of stepped shafts, but also in the case of workpiece W shown in Figure 2(b), <2> In the case of bearings, the workpiece W shown in Figure 2(c) is <3> Similarly, in the case of a drill or the like, the workpiece removal step may be a step of moving the first relay coil L1 and the first quenching coil C1 relatively outward from one end of the workpiece W (downward from the lower end) and moving the second relay coil L2 and the second quenching coil C2 relatively outward from the other end of the workpiece W (upward from the upper end) (regardless of the position of the power supply coil L0), and then moving the workpiece W above the workpiece upper holding part 30b by the upper biasing part 30c, and removing the workpiece W supported from below by the workpiece lower holding part 30a from the induction hardening apparatus 1. <1> ~ <3> In this case, the workpiece removal process is as follows, in comparison with the basic workpiece removal process described above: <1-3-1> It can also be said that the first relay coil L1 and the first hardened coil C1 are moved relatively outward from one end of the workpiece W, and the second relay coil L2 and the second hardened coil C2 are moved relatively outward from the other end of the workpiece W (the position of the power supply coil L0 does not matter).

[0058] <Other processes> The method of use may include a step of simultaneously performing the first quenching step P1 and the moving step PP (i.e., a first quenching moving step), a step of simultaneously performing the second quenching step P2 and the moving step PP (i.e., a second quenching moving step), or a step of simultaneously performing the first quenching step P1, the second quenching step P2, and the moving step PP (i.e., a first and second quenching moving step). Furthermore, in this method of use, the order in which the first quenching process P1, the moving process PP, and the second quenching process P2 are performed is not particularly limited, and may be, for example, the order first quenching process P1 → moving process PP → second quenching process P2, or conversely, the order second quenching process P2 → moving process PP → first quenching process P1. In addition, if the workpiece W also has a third cross-sectional portion W3.....nth cross-sectional portion, and the quenching device 1 also has a third quenching coil....nth quenching coil and a third relay coil....nth relay coil, etc., the method of use may include a third quenching process for quenching the third cross-sectional portion W3 of the workpiece W, and an nth quenching process for quenching the nth cross-sectional portion of the workpiece W, etc. The configuration, effects, and modes of use of the third quenching process through the nth quenching process are the same as those of the first and second quenching processes P1 and P2. The method may also include a step of simultaneously performing each of the third quenching step through the nth quenching step and the moving step PP. Furthermore, in this method of use, the order in which the first quenching process...nth quenching process and the moving process PP are performed is not particularly limited, and for example, the order may be first quenching process P1 → moving process PP → second quenching process P2 →... → moving process PP → nth quenching process, or conversely, the order may be nth quenching process → moving process PP →... second quenching process P2 → moving process PP → first quenching process P1.

[0059] <Other> The present invention is not limited to the above-described embodiment. The induction hardening apparatus 1, its usage, and the individual components or overall structure, shape, and dimensions of the transformer 10 and the like can be modified as appropriate within the spirit of the present invention. Any of the power supply coil L0, the first relay coil L1, and the second relay coil L2 does not have to be an air-core coil (it may have an iron core). The workpiece holding / moving mechanism 30 does not have to have the workpiece moving cylinder 30d. In this case, it can be said that the position (relative position) of the workpiece W with respect to the first and second hardening coils C1, C2, etc. cannot be changed unless the positions of the above-mentioned first and second hardening coils C1, C2, etc. and the first and second relay coils L1, L2, etc. are moved by the coil moving mechanism 40. However, as mentioned above, if the first coil mechanism 40-1 in the coil moving mechanism 40 has a first coil moving cylinder, it can also be said that the position (relative position) of the workpiece W with respect to the first and second hardening coils C1, C2, etc. can be changed. The following will provide a detailed explanation of the induction hardening apparatus 1 described above and the workpiece W to be hardened using the method of using the apparatus.

[0060] <Details of Work W> 1 to 3, 7, and 8, the workpiece W has an axial direction (or axial direction or axis) WJ, and the workpiece W has a predetermined length along this axial direction WJ (predetermined axial direction WJ length). The material of the workpiece W is not particularly limited, and may be, for example, carbon steel, alloy steel, stainless steel, carbon tool steel, alloy tool steel, or the like. In one workpiece W having such an axial direction WJ, at least a portion (for example, a first cross-sectional portion W1 or a second cross-sectional portion W2 described below) may have a cross-sectional shape (the shape of a cross section perpendicular to the axial direction WJ) that is approximately circular, approximately ring-shaped (approximately circular annular), or drill-shaped (a shape with two or three grooves cut out from an approximately circular outer shape). Note that in at least a portion of one workpiece W having a cross-sectional shape that is approximately circular or the like, the axial direction (axis) WJ of the workpiece W passes through the center of the cross-section of the approximately circular or the like (the axial direction WJ of the workpiece W is located at the center of the cross-sectional shape), and the axis in at least a portion having a cross-sectional shape that is approximately circular or the like can also be said to be the axis of a rotating body. In addition, at least a portion of the workpiece W may have a cross-sectional shape other than an approximately circular or ring-shaped shape, or a shape other than a drill cross-sectional shape (for example, a gear-shaped or pulley-shaped portion (the axial WJ position can be said to be a portion that coincides with a portion of another cross-sectional shape (gear portion or pulley portion)), or a crank-shaped portion (the axial WJ position can be said to be a portion that does not coincide with a portion of another cross-sectional shape (crank portion))).In this case, it can be said that a step portion WD, which will be described later, exists between the gear portion, pulley portion, crank portion, etc. and the portion whose cross-sectional shape is approximately circular or ring-shaped.

[0061] When the workpiece W includes a portion whose cross section is substantially circular, the workpiece W can be said to be an axial member (shaft material, shaft body) such as a shaft, or a substantially cylindrical member. In this case, if the workpiece W is a shaft, it may be, for example, a camshaft, drive shaft, pinion shaft, crankshaft, input shaft, main shaft, countershaft, control shaft, pulley shaft, stator shaft, drive shaft, half shaft, propeller shaft, rotor shaft, rack shaft, hub shaft, etc. These shafts may be stepped shafts having a stepped portion WD, which will be described later, or other workpieces W other than shafts such as spindles or splines, and may have a portion whose thickness changes midway or a tapered shape; in other words, the portion whose thickness changes midway or the tapered shape can be said to be the stepped portion WD. If the workpiece W includes a portion whose cross-sectional shape is approximately ring-shaped, the workpiece W may be, for example, a bearing (a bearing, more specifically, a raceway ring (inner ring, outer ring) or a retainer in a bearing), or if the workpiece W includes a portion whose cross-sectional shape is approximately ring-shaped, the workpiece W may be approximately pipe-shaped (approximately cylindrical, pipe-shaped member). Furthermore, if the workpiece W includes a portion whose cross-sectional shape is that of a drill, the workpiece W can naturally be said to be a drill. When the workpiece W is a shaft-shaped member, a pipe-shaped member, a drill, etc., the axial direction WJ length can be said to be longer than the diameter or outer diameter of a substantially circular or ring-shaped cross section, in which case the axial direction WJ is also the longitudinal direction and can also be said to simply be the length. When the workpiece W is a bearing, etc., the axial direction WJ length can be said to be shorter than the diameter of a substantially ring-shaped cross section, in which case the axial direction WJ length can also be said to be the height or thickness.

[0062] The workpiece W has at least a first cross-sectional portion W1 described later and a second cross-sectional portion W2 described later, and may also have a third cross-sectional portion W3, etc., and each of these cross-sectional portions can be said to have a predetermined axial WJ length. The axial length WJ of the workpiece W is not particularly limited, but may be, for example, 10 mm or more and 1000 mm or less, and more specifically, the lower limit may be 10 mm or more, preferably 50 mm or more, and more preferably 100 mm or more, and the upper limit may be 1000 mm or less, preferably 500 mm or less, and more preferably 300 mm or less. Note that each lower limit value of the axial length WJ of the workpiece W may be combined with any of the upper limits. The axial length WJ of each cross-sectional portion, such as the first and second cross-sectional portions W1 and W2, is not particularly limited, and may be, for example, 5 mm or more and 500 mm or less. More specifically, the lower limit may be 5 mm or more, preferably 20 mm or more, and more preferably 50 mm or more, and the upper limit may be 500 mm or less, preferably 300 mm or less, and more preferably 200 mm or less. Note that each lower limit of the axial length WJ of each cross-sectional portion may be combined with any of the upper limits. Such a workpiece W has a step portion WD, which will be described later, at least between the first cross-sectional portion W1 and the second cross-sectional portion W2.

[0063] <1st and 2nd cross section W1 and W2> As shown in FIGS. 1 to 3, 7 and 8, the first cross-sectional portion W1 is a part of the workpiece W described above, and has a predetermined cross section. Here, the "predetermined cross section" in the present invention refers to a surface (cut surface) perpendicular to the axial direction WJ, and has a predetermined cross-sectional shape and a predetermined size (cross-sectional area). As described above, the "predetermined cross-sectional shape" in the present invention includes a substantially circular shape, a substantially ring shape, a drill cross-sectional shape, and also other shapes such as a gear shape, a pulley shape, and a crank shape.

[0064] As shown in FIGS. 1 to 3, 7 and 8, the second cross-sectional portion W2 is also a part of the workpiece W described above, but has (has) a cross section different from the first cross-sectional portion W1 described above. Here, in the present invention, "the second cross-sectional portion W2 has a cross-section different from that of the first cross-sectional portion W1" means that the cross-section of the second cross-sectional portion W2 and the cross-section of the first cross-sectional portion W1 are different in cross-sectional shape and / or size. More specifically, this includes the cases where the cross-section of the second cross-sectional portion W2 and the cross-section of the first cross-sectional portion W1 are different in cross-sectional shape but the same in size, the cases where the cross-sectional shapes are the same but different in size, and the cases where the cross-sectional shapes are different but different in size. Furthermore, in the present invention, "the cross-sectional shapes are the same" includes not only the cases where the cross-sections of the second cross-sectional portion W2 and the first cross-sectional portion W1 are the same in shape (such as the case where two substantially circular shapes are the same, or the case where two substantially ring shapes are the same, or the case where two drill cross-sectional shapes are the same) and the same size, but also the cases where the cross-sections of the second cross-sectional portion W2 and the first cross-sectional portion W1 are the same in shape but different in size (i.e., the cross-sections of the second cross-sectional portion W2 and the first cross-sectional portion W1 are similar).

[0065] It can be said that the first cross-sectional portion W1 and the second cross-sectional portion W2 described above are arranged (exist) substantially along the axial direction WJ throughout the workpiece W. In this way, the first cross-sectional portion W1 and the second cross-sectional portion W2, which are arranged substantially along the axial direction WJ, may have substantially the same or different positions (cross-sectional positions) of the axis (axial direction) WJ of each cross-sectional portion in a cross-sectional view. If the positions of the axes of each cross-sectional portion are different in a cross-sectional view, it can be said that the axes are eccentric, or that a crank portion is formed. Furthermore, when the cross-sectional positions of the axis in the first cross-sectional portion W1 and the second cross-sectional portion W2 are different in one workpiece W, it can be said that the axial direction (axis) WJ of either the longer cross-sectional portion, between the axial WJ length of the first cross-sectional portion W1 and the axial WJ length of the second cross-sectional portion W2, is the axial direction WJ of the entire workpiece W, and when the axial WJ length of the first cross-sectional portion W1 and the axial WJ length of the second cross-sectional portion W2 are approximately the same, it can be said that the axial direction WJ of either cross-sectional portion is the axial WJ of the entire workpiece W.

[0066] <Stepped section WD> As shown in Figures 1 to 3, 7 and 8, the step portion WD is formed between the first cross-sectional portion W1 and the second cross-sectional portion W2 described above, which can be said to arise from the difference between the cross-section of the first cross-sectional portion W1 and the cross-section of the second cross-sectional portion W2. The step height of the step portion WD (for example, the height from the peripheral surface of the small diameter portion to the peripheral surface of the large diameter portion) is not particularly limited, but may be, for example, 1 mm or more and 20 mm or less, and more specifically, the lower limit may be 1 mm or more, preferably 2 mm or more, and more preferably 3 mm or more, and the upper limit may be 20 mm or less, preferably 10 mm or less, and more preferably 5 mm or less. Note that each lower limit of the step height may be combined with any of the upper limits. Furthermore, the height of the step portion WD may be constant over the entire circumference of the workpiece W, or may vary midway along the circumference.

[0067] The rising angle of the step portion WD (for example, the angle between the peripheral surface of the small diameter portion and the step portion WD) is not particularly limited, but may be, for example, a right angle or a nearly right angle in side view, such as 90° or nearly 90°, or may be oblique in side view. More specifically, the rising angle may have a lower limit greater than 0°, preferably 30° or more, and more preferably 45° or more, or an upper limit less than 90°, preferably 80° or less, and more preferably 70° or less. Note that each lower limit of the rising angle may be combined with any of the upper limits. The step portion WD may be formed (only one) around the entire circumference of the workpiece W in the circumferential direction, or may be formed (one or more) only on a portion in the circumferential direction.

[0068] <Third cross section W3...nth cross section, etc.> The third cross-sectional portion W3 is also a part of the workpiece W described above, and has a cross section different from at least one of the first cross-sectional portion W1 and the second cross-sectional portion described above. Here, in the present invention, "the third cross-sectional portion W3 has a cross-section different from at least one of the first cross-sectional portion W1 and the second cross-sectional portion W2" means that the cross-section of the third cross-sectional portion W3 and at least one of the first cross-sectional portion W1 and the second cross-sectional portion W2 have different cross-sectional shapes and / or sizes, and the details of the third cross-sectional portion W3 having a cross-section different from the first cross-sectional portion W1 and the second cross-sectional portion W2 are the same as those in the case of the second cross-sectional portion W2 and the first cross-sectional portion W1 described above. In addition, the workpiece W may have a fourth cross-sectional portion, a fifth cross-sectional portion, a sixth cross-sectional portion,... an nth cross-sectional portion (n is a natural number) (these are not shown), and among the cross sections of the first cross-sectional portion W1... the nth cross-sectional portion described so far, at least two adjacent cross-sectional portions may have different cross sections. Here, in the present invention, "among the cross sections of the first cross section to the nth cross section, at least two adjacent cross sections have different cross sections" means the same as the first cross section W1, the second cross section W2, and the third cross section W3 described above having different cross sections.

[0069] It can be said that the first cross-sectional portion W1 to the n-th cross-sectional portion described so far are arranged in the entire workpiece W substantially along the axial direction WJ. In this way, the first cross-sectional portion W1 to the nth cross-sectional portion arranged approximately along the axial direction WJ may have the positions of the axes of each cross-sectional portion in a cross-sectional view (cross-sectional view positions) all approximately identical, at least two of them approximately identical, at least two of them different, or all different. As in the case of the first cross-sectional portion W1 and the second cross-sectional portion W2 described above, when the cross-sectional view positions of the axes of at least two cross-sectional portions are different, it can be said that the axes are eccentric, or that a crank portion is formed, so to speak. Furthermore, in one workpiece W, if at least two of the cross-sectional positions of the axis in the first cross-sectional portion W1 to the nth cross-sectional portion are different, the axial direction (axis) WJ of the longest cross-sectional portion among the axial WJ lengths of each cross-sectional portion where the cross-sectional position of the axis is different can be said to be the axial direction WJ of the entire workpiece W, and if the axial WJ lengths of each cross-sectional portion where the cross-sectional position of the axis is different are approximately the same, it can also be said that the axial direction WJ of any of the cross-sectional portions is the axial direction WJ of the entire workpiece W. Furthermore, in one workpiece W, if at least two of the cross-sectional view positions of the axis at the first cross-sectional portion W1 to the nth cross-sectional portion are different and at the same time at least two are approximately identical, then the axial direction WJ of the cross-sectional portion with the longest total length among the total lengths of the axial direction WJ lengths at each cross-sectional portion where the cross-sectional view position of the axis is approximately identical can be said to be the axial direction WJ of the entire workpiece W, and if the total lengths of the axial direction WJ lengths at each cross-sectional portion where the cross-sectional view position of the axis is approximately identical are approximately identical, then the axial direction WJ of any of the cross-sectional portions can be said to be the axial direction WJ of the entire workpiece W.

[0070] When a portion of one workpiece W has a cross-sectional shape other than a substantially circular shape, the cross-sectional position in the axial direction WJ of the portion having a cross-sectional shape other than a substantially circular shape may be substantially the same as the cross-sectional position in the axial direction WJ of the portion having a cross-sectional shape other than a substantially circular shape, etc. Additionally, when the entirety of one workpiece W has a cross-sectional shape other than a substantially circular shape, the cross-sectional position in the axial direction WJ of the portion having a cross-sectional shape other than a substantially circular shape, etc. may be the position of the center of gravity of the cross-sectional shape. If the first cross-sectional portion W1 and the second cross-sectional portion W2 described above are all approximately circular in cross-sectional shape and differ only in diameter, then one of the first and second cross-sectional portions W1, W2 can be said to be a large diameter portion and the other a small diameter portion. Also, if the first cross-sectional portion W1 to the nth cross-sectional portion are all approximately circular in cross-sectional shape and differ only in diameter, then the cross-sectional portion with the largest diameter can be said to be the large diameter portion (largest diameter portion), and the cross-sectional portion with the smallest diameter can be said to be the small diameter portion (smallest diameter portion). The thickness of each of the first cross-sectional portion W1 to the nth cross-sectional portion of the workpiece W is not particularly limited, but may be, for example, 10 mm or more and 100 mm or less, and more specifically, the lower limit may be 10 mm or more, preferably 20 mm or more, and more preferably 30 mm or more, and the upper limit may be 100 mm or less, preferably 80 mm or less, and more preferably 50 mm or less. Note that each lower limit value of the thickness may be combined with any of the upper limits.

[0071] In one workpiece W, the first cross-sectional portion W1, the second cross-sectional portion W2, the third cross-sectional portion W3, ..., the n-th cross-sectional portion do not have to be arranged in that order substantially along the axial direction WJ of the workpiece W, and the first cross-sectional portion W1, the second cross-sectional portion W2, the third cross-sectional portion W3, ..., the n-th cross-sectional portion may be arranged in that order substantially along the axial direction WJ of the workpiece W, and the first <2> Like a bearing or the like, the first cross-sectional portion W1, the third cross-sectional portion W3, and the second cross-sectional portion W2 may be arranged in this order substantially along the axial direction WJ of the workpiece W. In other words, the first cross-sectional portion W1, the second cross-sectional portion W2, etc. in the workpiece W can be said to be the cross-sectional portion that is hardened by the first quenching coil C1 in the quenching device 1 as the first cross-sectional portion W1, and the cross-sectional portion that is hardened by the second quenching coil C2 as the second cross-sectional portion W2, and the same can be said for the third cross-sectional portion W3,..., the n-th cross-sectional portion. In addition, in Fig. 2(b), <2> When the first cross-sectional portion W1, the third cross-sectional portion W3, and the second cross-sectional portion W2 are arranged in this order, approximately along the axial direction WJ of the workpiece W, as in a bearing or the like, the axial length WJ of the third cross-sectional portion W3 sandwiched between them is short (in other words, thin), so it can be said that if the first cross-sectional portion W1 is hardened with the first quenching coil C1 and the second cross-sectional portion W2 is hardened with the second quenching coil C2, the third cross-sectional portion W3 can also be hardened. Also, in Fig. 2(b), <2> Like a bearing or the like, two or more step portions WD may be formed between the first cross-sectional portion W1, the second cross-sectional portion W2, the third cross-sectional portion W3, . . . the n-th cross-sectional portion. In addition, the corners of the workpiece W may be chamfered or rounded at both ends or at either end in the axial direction WJ, and in this case, the corners of the step portion WD (for example, the corner between the large diameter portion and the end face of the step portion WD) may also be chamfered or rounded. Furthermore, the base end of the stepped portion WD (for example, the portion between the small diameter portion and the end face of the stepped portion WD) may also be rounded or chamfered. The peripheral surfaces (inner peripheral surface or outer peripheral surface) of the first cross-sectional portion W1 to the nth cross-sectional portion may each have a recess formed along the circumferential direction (for example, a receiving recess for a steel ball or roller of a bearing, see FIG. 2(b)), or a curved surface when viewed from the side. [Industrial Applicability]

[0072] The induction hardening device and its method of use according to the present invention can be used not only for hardening workpieces such as stepped shafts, bearings, and drills, but also for hardening any workpiece that has an axial direction, such as spindles, splines, and other parts whose thickness changes midway or has a tapered shape, and pipe-shaped components. others, The transformer not only supplies power for hardening to an induction hardening device that hardens workpieces having an axial direction, such as stepped shafts, bearings, and drills, and that has at least the first and second hardening coils described above, but can also supply power to an induction hardening device that hardens workpieces having the first and second hardening coils described above but that do not have an axial direction, an induction hardening device that does not have the first and second hardening coils, etc., and can also be used for devices that require power other than induction hardening devices. It's okay . [Explanation of symbols]

[0073] 1. High-frequency hardening equipment 10. Transformers double work W1 First cross section of workpiece W2 Second cross section of workpiece WD Stepped part of workpiece WJ Axial direction of workpiece C1 First hardened coil C2 Second hardened coil CJ Axial direction of hardened coil L0 power supply coil L1 First relay coil L2 Second relay coil LJ Axial direction of power supply coil and relay coil P1 First hardening process PP moving process P2 Second hardening process

Claims

1. An induction hardening apparatus for hardening a workpiece (W) having an axial direction, The work (W) has at least a first cross-sectional portion (W1) having a predetermined cross-section and a second cross-sectional portion (W2) having a cross-section different from the first cross-sectional portion (W1), and the first cross-sectional portion (W1) and the second cross-sectional portion (W2) are arranged substantially along the axial direction with a step portion (WD) formed therebetween; The induction hardening device has at least a first hardening coil (C1) that hardens the first cross-sectional portion (W1) and a second hardening coil (C2) that hardens the second cross-sectional portion (W2), The first hardening coil (C1) and the second hardening coil (C2) are supplied with hardening power from a transformer (10), The transformer (10) includes at least a power supply coil (L0) capable of supplying the power, a first relay coil (L1) capable of relaying the power from the power supply coil (L0) to a first hardened coil (C1), and a second relay coil (L2) capable of relaying the power from the power supply coil (L0) to a second hardened coil (C2), In the transformer (10), the power supply coil (L0) is a coil that is movable relatively to the workpiece (W) in a direction substantially parallel to the axial direction of the workpiece (W), from the first relay coil (L1) to the second relay coil (L2), at least inside the first relay coil (L1) and the second relay coil (L2); the first relay coil (L1), together with the first hardened coil (C1), is a coil that is movable relative to the workpiece (W) across a first cross-sectional portion (W1) of the workpiece (W) in a direction substantially parallel to the axial direction of the workpiece (W), the second relay coil (L2), together with the second hardening coil (C2), is a coil that is movable relative to the workpiece (W) across a second cross-sectional portion (W2) of the workpiece (W) in a direction substantially parallel to the axial direction of the workpiece (W).

2. 2. The induction hardening device according to claim 1, wherein at least one of the power supply coil (L0), the first relay coil (L1), and the second relay coil (L2) is an air-core coil.

3. A method for using the induction hardening device according to claim 1 or 2, a first quenching step (P1) of quenching the first cross-sectional portion (W1) of the workpiece (W) from one end of the first cross-sectional portion (W1) to a step portion (WD) by the first quenching coil (C1) substantially along a direction parallel to the axial direction of the workpiece (W), with at least a portion of the power supply coil (L0) located inside the first relay coil (L1); a moving step (PP) in which at least a part of the power supply coil (L0) moves relatively to the first relay coil (L1) and / or the second relay coil (L2) substantially along the axial direction thereof from the inside of the first relay coil (L1) to the inside of the second relay coil (L2); a second quenching step (P2) of quenching the second cross-sectional portion (W2) by the second quenching coil (C2) from the step portion (WD) of the workpiece (W) to the other end of the second cross-sectional portion (W2) substantially along a direction parallel to the axial direction of the workpiece (W), with at least a portion of the power supply coil (L0) inside the second relay coil (L2).

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