JP2011047037A - Induction heating coil, heat treatment device, and heat treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating coil which can improve treatment efficiency, and to provide a heat treatment device, and to provide a heat treatment method. <P>SOLUTION: The induction heating coil has a heating induction part 31 formed in zigzag pattern in which bend sections 34 which are open to one side in the first direction and bend sections 35 which are open to the other side in the first direction are continuously arranged in an alternating manner in the circumferential direction R so as to face each other. The configuration enables the induction heating and quenching device to easily perform the heat treatment of a desired heating region with high treatment efficiency. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an induction heating coil, an induction heating apparatus, a heat treatment apparatus, and a heat treatment method, and for example, relates to an object to be processed while moving a processing object and the induction heating coil relatively.

  In a heat treatment apparatus for performing heat treatment such as induction hardening on a metal member, an induction heating apparatus of a one-shot heating method is known in which treatment is performed using an induction heating coil opposed to the entire area to be treated (see, for example, Patent Document 1). ). In such a single-heating heat treatment apparatus, the induction heating coil is configured in a shape corresponding to the entire area to be processed. For example, when the part to be processed is cylindrical, an annular induction heating coil is used.

  On the other hand, the heating process and the cooling process are sequentially performed while the induction heating coil facing only a part of the processing target part and the cooling jacket following the induction heating coil are moved relative to the processing target part. A heat treatment method of the formula is known (for example, see Patent Document 2). In such a mobile heat treatment method, the induction heating coil is configured in a shape corresponding to a part of the part to be processed.

JP 2002-174251 A JP 60-116724 A

  However, the above technique has the following problems. That is, in the heat treatment apparatus of the one-shot heating method described above, an induction heating coil corresponding to the shape and size of the object to be processed and the part to be processed is used. An induction heating coil is required and high output power is required. In addition, when the processing object is deformed due to thermal expansion or the like during induction heating, it is difficult to properly maintain the dimension between the induction heating coil and the processing object. For this reason, since it is necessary to set the induction heating coil larger in advance, there arises a problem that the heating efficiency is deteriorated.

  On the other hand, in the above-described mobile heat treatment method, when the induction heating coil is configured in a shape corresponding to a part of the processing target, the processing area per unit time is small, the processing time is long, ineffective. In addition, when moving while continuously performing the heat treatment and the cooling treatment, for example, when the annular treatment target portion is targeted, the necessary hardness cannot be obtained at the boundary between the start portion and the end portion of the treatment. There is a problem that a soft zone occurs.

  An object of the present invention is to provide an induction heating coil, a heat treatment apparatus, and a heat treatment method capable of improving the heat treatment efficiency in induction heating even for a large object to be treated.

  An induction heating coil according to an aspect of the present invention is formed of a conductor member, and a curved portion opened on one side in the first direction and a curved portion opened on the other side in the first direction are alternately opposed. And a heating conductor portion having a zigzag shape continuously arranged along a second direction intersecting the first direction.

  In a heat treatment apparatus according to an aspect of the present invention, the induction heating coil, a high-frequency power source connected to the induction heating coil, and the portion to be processed are relative to the induction heating coil along the second direction. And a moving means for moving to.

  In the heat treatment method according to an aspect of the present invention, the induction heating coil may be opposed to a part of the processing target having an endless loop shape continuous along the second direction by induction heating. A heating process for moving the process target part relative to the induction heating coil along the second direction, and a heating process for the entire process of the process target part in the second direction. And a cooling step for cooling the portion to be processed.

  According to the present invention, it is possible to improve the heat treatment efficiency during induction heating even for a large object to be treated.

Explanatory drawing which shows the heat processing apparatus which concerns on 1st Embodiment of this invention. The top view which shows the heat processing apparatus which concerns on the same embodiment. The side view which shows the heat processing apparatus which concerns on the same embodiment. The front view which shows the heat processing apparatus which concerns on the same embodiment. Explanatory drawing which shows the cross-section of the heating coil which concerns on the same embodiment. Explanatory drawing of the heat processing apparatus which concerns on other embodiment of this invention. Explanatory drawing of the heat processing apparatus which concerns on other embodiment of this invention. Explanatory drawing of the heat processing apparatus which concerns on other embodiment of this invention. Explanatory drawing of the heat processing apparatus which concerns on other embodiment of this invention. Explanatory drawing of the heat processing apparatus which concerns on other embodiment of this invention.

  Hereinafter, a heat treatment apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. In the figure, arrows X, Y, and Z indicate three directions orthogonal to each other. In each drawing, the configuration is appropriately enlarged, reduced, or omitted for explanation.

  FIG. 1 is an explanatory diagram schematically showing the overall configuration of a heat treatment apparatus according to the present embodiment. 2 to 4 show a plan view, a side view, and a front view of the heat treatment apparatus, respectively.

  As shown in FIG. 1, the heat treatment apparatus 10 includes a moving support unit 11 that movably supports a workpiece P1 that is a processing target, and a processing target while moving relative to the processing target A1 of the workpiece P1. An induction heating unit 12 that induction-heats A1 and a cooling unit 13 (cooling unit) that cools the workpiece P1 after the heat treatment process of the processing target A1 are configured.

  As shown in FIGS. 2 to 5, the induction heating unit 12 includes a high-frequency power source 21 as power supply means, lead wires 22 and 23 connected to the high-frequency power source 21, and a pair connected to the lead wires 22 and 23. Spacers 28 having conductive plates 24 and 25, an induction heating coil 26 having both ends connected to a pair of conductive plates 24 and 25, and a core 27 (behind the heating conductor portion 31 of the induction heating coil 26). 2 and FIG. 5 only).

  A workpiece P1 as an example of the object to be processed shown in FIG. 1 is a thick part (thick part) having a thickness of 25 mm or more. For example, an outer radius r1 = 250 mm and an inner radius r2 centered on the axis C1. = 200 mm, a wall thickness t 1 = 50 mm, and a cylindrical member having an axial direction (first direction) length l 1 = 100 mm is used. The heating conductor portion 31 is disposed so as to face a portion of the workpiece P1 in the processing target portion A1 and secure a predetermined gap dimension G1.

  In the present embodiment, for example, a case where a circular band-like region in the central portion in the axial direction of the outer peripheral surface of the workpiece P1 is set as the processing target A1, and the processing target A1 that is a thick portion is heat treated over the entire circumference is shown. . In this embodiment, the Z direction that is the axial direction of the workpiece P1 is the first direction, and the circumferential direction R along the outer peripheral surface of the workpiece P1 with the axis C1 as the center is the second direction. Here, the radial dimension in the circumferential direction R is a value obtained by adding the gap dimension G1 to the radial dimension r1 of the outer peripheral surface of the workpiece, and is r1 + G1.

  The part A1 to be processed has an endless loop shape that is continuous along the circumferential direction on the outer peripheral surface of the workpiece P1. The workpiece P1 is rotated about the axis C1 by the movement support portion 11, so that the processing target portion A1 and the heating conductor portion 31 are relatively moved along the circumferential direction R.

  As shown in FIGS. 2 to 4, the induction heating coil 26 includes a zigzag-shaped heating conductor portion 31 facing the processing target A <b> 1 of the workpiece P <b> 1 and a first connection continuous to one end side 31 a of the heating conductor portion 31. The conductor part 32 and the 2nd connection conductor part 33 continuous with the other end side 31b of the heating conductor part 31 are provided continuously and integrally.

  As shown in FIG. 4, the heating conductor portion 31 is formed of a conductor member 31w, and a plurality of U-shaped bent portions 34 and 35 open toward the center C2 in the Z direction and are alternately opposed to each other. A zigzag shape in which a plurality of pieces are continuously arranged along the circumferential direction R is formed. The bent portion 34 has a U-shape opened downward, and the bent portion 35 has a U-shape opened upward.

  The total dimension R2 of the heating conductor 31 in the second direction is not less than 1/10 and not more than 1/2 of the dimension of the entire circumference in the second direction of the processing target A1 facing the heating conductor 31. The cover ratio, which is the ratio of the dimension in the second direction of the heating conductor portion 31 to the processed portion A1, is set to be about 1/10 here.

  In addition, R5 which is the space | interval of the adjacent conductor member 31w is set to 1 time or more of the dimension of R4 which is the width | variety of the conductor member 31w, and 2 times or less. If the distance between the adjacent conductor members 31w is less than or equal to one time the width of the conductor member 31w, the adjacent currents are in opposite directions, so the magnetic fluxes cancel each other. It is. In the present embodiment, the dimensions are set to R4 = 15 mm and R5 = 20 mm in FIG.

  The first connection conductor portion 32 includes a conductor portion 32a extending in the Y direction from the end portion 31a of the heating conductor portion 31, and a width of the conductive plate 24 along the X direction by bending from the end portion of the conductor portion 32a. The conductor portion 32b extending toward the center in the direction, the conductor portion 32c bent toward the Y direction by bending at the center of the conductive plate 24, and the conductor portion 32d extending further in the Z direction continuously integrated. It is configured to prepare for. A coupler 36 for connecting components such as a coolant hose is provided at the end of the first connection conductor portion 32.

  The second connecting conductor portion 33 includes a conductor portion 33a extending in the Y direction from the end portion of the other end side 31b of the heating conductor portion 31, and a bent portion of the conductive plate 25 along the X direction by bending from the end portion of the conductor portion 33a. A conductor portion 33b extending toward the center in the width direction, a conductor portion 33c bent at the center of the conductive plate 25 and extending toward the Y direction, and a conductor portion 33d further bent and extending in the Z direction are continuously provided. It is configured to be integrated. A coupler 37 for connecting components such as a coolant hose is provided at the end of the second connection conductor portion 33.

  The first connection conductor portion 32 and the second connection conductor portion 33 are arranged to be separated from each other in the thickness (Z-axis) direction with the spacer 28 interposed therebetween. The spacer 28 includes a pair of conductive plates 24 and 25 each having a rectangular flat plate shape, and a rectangular flat plate-shaped insulating plate 38 sandwiched between the pair of conductive plates 24 and 25 so as to overlap each other in the Z direction. The conductive plates 24 and 25 and the insulating plate 38 are fixed by bolts 41 and nuts 42 through an insulating bush 39. Each of the conductive plates 24 and 25 is connected to the high frequency power source 21 via the lead wires 22 and 23.

  As shown in a cross section in FIG. 5, the induction heating coil 26 is formed in a rectangular hollow shape from a material such as copper. The hollow portion 26a becomes a passage through which the coolant flows. The width dimension W1 of the induction heating coil 26 was set to 15 mm, and the thickness dimension T1 in the Y direction was set to 10 mm.

  The core 27 is made of a material having a high magnetic permeability such as a silicon steel plate, a polyiron core, or ferroton, and is disposed on the back side of the heating conductor portion 31. The core 27 has a thickness T2 = about 5 mm, and is formed in a U-shaped cross section that integrally includes both side portions of the heating conductor portion 31 and a rear wall portion.

  The movement support unit 11 shown in FIG. 1 rotates the workpiece P1 around the axis C1 with the workpiece P1 set at a predetermined position. At this time, the movement support part 11 controls the gap dimension G1 between the heating conductor part 31 and the workpiece P1 to be maintained at a predetermined value. Furthermore, the movement support unit 11 moves the workpiece P1 to the lower cooling unit 13 along the axial direction after the heat treatment is completed over the entire circumference (the entire stroke) of the processing target A1.

  The cooling unit 13 provided below the heating coil 26 is configured in a cylindrical shape so as to surround the outside of the work P1 moved downward after the heat treatment, and cools the work P1 arranged in the inner space 13a.

  Hereinafter, the heat treatment method according to the present embodiment will be described. The heat treatment method of the present embodiment includes a moving heating process in which the processing target A1 is relatively moved while heating, and a cooling process in which the processing target A1 is cooled after the moving heating process.

  In the moving heating process, when the high frequency power supply 21 is turned on with the heating conductor 31 facing a part of the processing target A1 as shown in FIGS. The first conductive plate 24, the first connection conductor portion 32, the heating conductor portion 31, the second connection conductor portion 33, the second conductive plate 25, and the lead wire 23 are sequentially passed back to the high-frequency power source 21. .

  At this time, the high-frequency current flows in the heating conductor portion 31 from the one end 31a side to the other end 31b side as shown by arrows in FIGS. The to-be-processed part A1 arrange | positioned is heated.

  At this time, the moving support unit 11 rotates the workpiece P1 while maintaining the gap dimension G1 between the surface of the processing target portion A1 of the workpiece P1 and the surface of the heating conductor portion 31 at a predetermined value. The heating conductor portion 31 moves relative to the processing portion A1 in the second direction at a predetermined speed.

  For example, the relative movement is performed at a speed of 200 to 300 mm / sec while maintaining the power of 100 to 150 kW and the gap dimension G1 = 2.5 mm.

  As described above, the entire area A1 to be processed, which is a band-like region on the outer peripheral surface of the work P1 disposed to face the heating conductor 31, is uniformly heated.

  After the heat treatment is completed over the entire periphery of the processing target A1, the moving support unit 11 moves the workpiece P1 to the cooling unit 13 below along the Z direction. The cooling unit 13 cools the workpiece P1 arranged in the space 13a, which is a cooling region surrounded by the cooling jacket, with the coolant.

  Further, the coolant flows through the hollow portion 26 a inside the induction heating coil 26 and through the hollow portion 26 a of the first connection conductor portion 32, the heating conductor portion 31, and the second connection conductor portion 33. Thus, the induction heating coil 26 and the conductive plates 24 and 25 are cooled.

  According to the induction heating coil, the heat treatment apparatus, and the heat treatment method according to the present embodiment, the following effects can be obtained. That is, by forming the heating conductor portion 31 in a zigzag shape having a plurality of curved portions continuously, a strong magnetic field can be secured and a good temperature pattern can be obtained. For this reason, high-speed and uniform heat treatment can be performed with less power.

  For example, when a hairpin coil is used, the coil efficiency is about 30%, whereas when the zigzag shape is used as in this embodiment, a coil efficiency of about 70% can be ensured.

  Further, by setting the interval between the adjacent conductor members 31w to be not less than 1 and not more than twice the width of the conductor member 31w of the heating conductor portion 31, magnetic flux cancellation can be prevented and coil self-loss can be reduced. It is possible.

  When the zigzag-shaped heating conductor 31 according to the present embodiment is used, when the power reaches 100 kW and the surface temperature of the processing target A1 is 850 degrees, the heating time is set to 200 to 300 mm / sec. It can be realized in 300 seconds. That is, by using the induction heating coil 26 having the zigzag-shaped heating conductor portion 31, for example, heat treatment of a large workpiece by moving partial heating that cannot be realized by a flat induction heating coil can be realized.

  Even in the case of partial heating, when the part A1 to be processed has a loop shape, uniform heat treatment without a soft zone at the processing start end and end end is possible.

  For this reason, for example, when the rolling bearing is a workpiece and the raceway surface through which the rolling element passes is the treated portion A1, a uniform hardened layer without a soft zone can be formed, so that particularly good characteristics can be obtained.

  Since the heat treatment is performed while relatively moving while facing only a part of the portion to be processed A1, when the portion to be processed A1 and the workpiece P1 are large, the size of the heating conductor portion 31 is increased by arranging a plurality of portions. The heat treatment apparatus 10 can be reduced in size. For this reason, it is possible to reduce the required power and the manufacturing cost.

  In addition, since the heat treatment is performed while relatively moving while facing only a part of the portion to be treated A1, when a member having a curved portion such as a circle is used as a workpiece, the thermal expansion during induction heating, etc. Even if the workpiece is deformed due to a factor, an appropriate gap dimension can be easily maintained. For example, when heat treatment is performed by a single heating method using an annular induction heating coil corresponding to a circular target part, the workpiece is deformed due to thermal expansion. Therefore, there is a problem that the heating efficiency is deteriorated. However, when the cover ratio is small as in the present embodiment, it is possible to maintain an appropriate gap only by adjusting the arrangement with the workpiece.

  The present invention is not limited to the above-described embodiments, and each configuration can be modified as appropriate. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, the processing conditions and the shapes, materials, materials, dimensions, and the like of each component are not limited to those exemplified in the above embodiment, and can be changed as appropriate. Further, a part having a thickness of 25 mm or more is defined as a thick part (thick part).

  For example, in the above-described embodiment, an example of relative movement by rotating the workpiece P1 has been described. However, the present invention is not limited to this, and the induction heating unit 12 side is moved along a predetermined locus along the second direction. May be moved relative to each other. Although each of the two bent portions 34 and 35 is disposed, the present invention is not limited to this, and the number of the bent portions 34 and the number of the bent portions 35 may be different. .

  In the said embodiment, although the case where the one induction heating part 12 was arrange | positioned only at one place with respect to one to-be-processed part A1, it is not restricted to this, A plurality of along the 2nd direction. An induction heating unit 12 may be disposed. For example, when two induction heating units 12 are installed, two induction heating coils 26 are arranged at positions where the central angles are shifted by 180 degrees so as to face each other as shown in FIG. The angle is 120 degrees. FIG. 10 shows a plan view in which four induction heating coils 26 are arranged with the central angle shifted by 90 degrees. As described above, when a plurality of induction heating units 12 are used, the heat treatment can be completed quickly by shortening the treatment time, which is preferable when the size of the workpiece is large.

  In the above-described embodiment, the heating conductor portion 31 is configured to be curved so that the center protrudes from both ends in plan view, but is not limited to this, and can be appropriately changed according to the shape of the workpiece. For example, as shown in FIG. 7, when the inner peripheral surface of the circular workpiece P2 is the processing target A2, the heating conductor 31 is curved in the opposite direction so that both end portions protrude from the center side. The configuration is as follows. Also, as shown in FIG. 8, when the plane of the workpiece P3 is the processing target A3, the heating conductor portion 31 is configured to be linear in plan view. In this case, the linear X direction is the first direction. In these cases, the same effect as the above embodiment can be obtained.

  In the above-described embodiment, the bent portions 34 and 35 that are bent in a rectangular shape in a U-shape are illustrated as the bent portion, but the present invention is not limited to this. For example, as shown in FIG. 9, it is good also as a structure which has the curved parts 134 and 135 of the shape curved in the semicircular shape. In this case, heating is performed with a temperature pattern concentrated at the center C2 in the first direction. For this reason, for example, it is suitable when it is desired to increase the heating temperature on the center C2 side.

  In the above embodiment, the case where the processing target A1 is an arc-shaped surface having a uniform thickness is exemplified, but the present invention is not limited to this, and the surface of the processing target may be inclined, a concave portion or the like. It may have a step portion.

  In the said embodiment, although illustrated about the case where the radius of a workpiece | work is about 250 mm and a coverage is about 1/10, it is not restricted to this. For example, the range of the coverage can be appropriately changed according to conditions such as the diameter of the workpiece. For example, a coverage of 1/10 times or more and 1/2 times or less and 1/10 to 1/3 is preferable. If it is less than 1/10, sufficient heating cannot be performed. If it exceeds 1/2, it is difficult for the coil to follow the workpiece expansion during heating. In addition, the equipment cost increases.

  As another embodiment of the present invention, for example, when the dimension of the processed part A1 is set such that the outer diameter of the workpiece r1 = φ1000 mm and the height l1 = 110 mm, it is opposed to the processed part A1 at two locations. The heating conductor portion 31 was installed, the total circumferential dimension of the two heating conductor portions 31 was 600 mm, and the cover ratio was about 1/5. In this case, the heat treatment conditions were an electric power of 140 kW, a heating time = 310 s, and a heat treatment could be realized by setting the reached temperature of the surface of the treated portion A1 to 900 degrees.

  Furthermore, as another embodiment of the present invention, for example, when the dimension of the processed part A1 is set to the outer diameter r1 = φ3000 mm of the workpiece and the height l1 = 135 mm, the four parts are opposed to the processed part A1. The heating conductor part 31 was installed in this, and the total circumferential dimension of the four heating conductor parts 31 was 2400 mm, and the coverage was about 1/4. In this case, the heat treatment conditions were as follows: the power was 185 kW, the heating time was 280 s, and the temperature reached on the surface of the treated part A1 was 920 degrees.

  FIG. 10 illustrates, as another embodiment of the present invention, a case where the coverage is 1/3 times and four heating conductor portions 31 are arranged along the second direction. Here, the total coverage of the four heating conductor portions 31 arranged at equal intervals is set to 1/3. By setting the cover rate in this way, it is possible to reduce the size of the induction heating device while maintaining a desired processing time and processing efficiency.

  Moreover, you may delete some components from all the components shown by embodiment. Furthermore, the constituent elements over different embodiments may be combined.

P1 to P4 ... Workpiece (object to be treated), A1 to A4 ... Processed part, C1 ... Axle, R ... Circumferential direction (second direction), C2 ... Center, 10 ... Heat treatment device,
DESCRIPTION OF SYMBOLS 11 ... Movement support part (movement means), 12 ... Induction heating part, 13 ... Cooling part,
21 ... high frequency power source, 26 ... induction heating coil, 26a ... hollow portion, 27 ... core,
31 ... heating conductor part, 34, 35 ... bent part (curved part), 134, 135 ... curved part (curved part).

Claims (8)

  A bent portion formed of a conductive member and opening on one side in the first direction and a bent portion opening on the other side in the first direction alternately intersect each other in the first direction. An induction heating coil comprising a heating conductor portion having a zigzag shape arranged continuously along two directions.   2. The heating conductor portion is characterized in that an interval between conductor members forming adjacent curved portions is not less than 1 time and not more than 2 times a width dimension of a conductor member forming the curved portion. The induction heating coil as described.   The dimension of the said 2nd direction of the said heating conductor part is 1/10 or more and 1/2 or less of the dimension of the said 2nd direction of the to-be-processed part which opposes the said heating conductor part. Induction heating coil.   The induction heating coil according to any one of claims 1 to 3, wherein each of the curved portions is configured to be bent in a U-shape.   The induction heating coil according to claim 1, wherein the portion to be processed is a thick portion. An induction heating coil according to any one of claims 1 to 5,
A high frequency power source connected to the induction heating coil;
A heat treatment apparatus comprising: moving means for moving the processing target portion relative to the induction heating coil along the second direction. The processed portion has an endless loop shape continuous along the second direction,
After heating the entire process in the second direction of the processed part while moving the processed part relative to the induction heating coil along the second direction, the cooling process of the processed part is performed. The heat treatment apparatus according to claim 6, further comprising a cooling unit to perform. The induction heating coil according to any one of claims 1 to 5 is opposed to a part of an endless loop-like processed part continuous along the second direction so that the processed part is induction-heated. A moving heating step of moving the portion to be treated relative to the induction heating coil along the second direction while heating;
And a cooling step of cooling the portion to be processed after the heat treatment for the entire process in the second direction of the portion to be processed.

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