JP4354975B2 - High frequency induction heating device for tempering crankshaft - Google Patents

Description

  The present invention relates to a high-frequency induction heating apparatus for tempering a hardened portion that has been hardened with a fillet R after the journal portion or pin portion constituting the main portion of the crankshaft has been hardened with the fillet R.

  FIG. 4 shows the structure of a four-cylinder medium-sized crankshaft 1 that is an example of a crankshaft. The four-cylinder medium-sized crankshaft 1 is provided integrally with five journal portions 1J to 5J arranged along the same axis line (rotation axis line of the crankshaft 1) X, and these journal portions 1J to 5J, respectively. Eight counterweight portions CW1 to CW8, and counterweight portions CW1 and CW2, CW3 and CW4, CW5 and CW6, CW7 and CW8, which are adjacently arranged opposite to each other, are respectively constructed, and the journal portion 1J Four pin portions 1P to 4P respectively disposed at positions deviated from the axis of ˜5J, shaft portions S1 and S2 coaxially formed integrally with the journal portion 1J on one end side, and the journal portion on the other end side The flange portion F is integrally formed with the 5J coaxially.

  Among the pin portions 1P to 4P described above, the pin portions 1P and 2P adjacent to each other in the rotation axis X direction are arranged at positions shifted from each other by 180 °, and the pin portions 3P adjacent to each other in the rotation axis X direction. And 4P are arranged at positions that are 180 ° out of phase with each other, and the pin portions 1P and 4P at the left and right ends are arranged at the same position as each other and are adjacent to each other in the rotation axis X direction. Are arranged at the same phase. Further, as shown in FIG. 4, the flanges F at both ends of the crankshaft 1 and the axes of the shafts S1 and S2 are aligned with the extension line of the rotation axis X of the journals 1J to 5J. It is configured to be driven to rotate about a linear rotation axis X. In FIG. 4, Y is a linear axis of the pin portions 1P and 4P arranged at the same phase position, and Z is a linear axis of the pin portions 2P and 3P arranged at the same phase position.

  In such a crankshaft 1, the cylindrical outer peripheral surfaces of the journal portions 1J to 5J are usually subjected to a quenching process, and the pin portions 1P to 4P are also subjected to a quenching process in a separate process. I'm trying to rub. In addition, there are roughly two ways of quenching treatment of the pin portions 1P to 4P, that is, there are two ways of flat quenching and fillet R quenching. Here, it is as follows when the method of two hardening processes about pin part 1P-4P is described briefly.

  First, each of the pin portions 1P to 4P is formed following a cylindrical portion A having a cylindrical outer peripheral surface α, an R portion (corner or corner) B following the cylindrical portion A, and the R portion B. And it is comprised from the fillet part C formed so that it might extend at right angles with respect to the axis line X of the crankshaft 1 (refer FIG. 5). Thus, the quenching method for quenching only the cylindrical outer peripheral surface α of the columnar portion A of the pin portions 1P to 4P is referred to as flat quenching, and the cylindrical outer peripheral surface α, the bay-shaped surface β of the R portion B, and A quenching method in which all of the continuous surface portions (portions indicated by a large number of points in FIG. 5) each including the side surface γ of the fillet portion C are referred to as fillet R quenching.

  FIG. 5 shows an example of a hardened and hardened layer pattern when performing fillet R hardening (only the hardened and hardened layer pattern of the pin portion 1P and the journal portions 1J and 5J is shown in FIG. 5). In this case, not only the cylindrical outer peripheral portion δ of the journal portions 5J and 5J and the cylindrical outer peripheral portion α of the pin portions 1P to 4P, but also from the cylindrical outer peripheral portion α via the curved surface β of the R portion B at the corner. The hardened and hardened layer 6 is formed in a region that continues to the side surface γ of the fillet portion C in a perpendicular direction that continues to this. On the other hand, with respect to the journal portions 1J and 5J at the left and right ends, as shown in FIG. 5, the cylindrical outer peripheral portion δ of the column portion D and the side surface ε of the fillet portion C adjacent to the journal portions 1J and 5J, respectively. It is common to form a hardened and hardened layer pattern 7 (however, the other journal portions 2J to 4J are not subjected to a quenching treatment. In other embodiments, the journal portions 1J to 5J) All may be quenched.) When forming different hardened and hardened layer patterns 6 and 7 by induction hardening as shown in FIG. 5, each of them is heated to a required hardening temperature by using a separate high frequency induction heating coil and rapidly cooled. Thus, the desired hardened and hardened layer patterns 6 and 7 are formed.

  The crankshaft 1 subjected to the quenching process in this way is usually subjected to a tempering process for the purpose of improving toughness and removing internal strain. By the way, conventionally, when tempering the crankshaft 1, an electric furnace is generally used as a heating means.

  However, in the conventional tempering apparatus in which the crankshaft 1 after quenching is heated to a required temperature by an electric furnace and cooled, a uniform and stable tempering quality can be obtained, but a relatively long heating time is required. Therefore, there is a problem that the compressive residual stress obtained by induction hardening is reduced during heating, and as a result, the fatigue strength is significantly reduced. Moreover, heating by the electric furnace is indirect heating, and the crankshaft as the tempered body is heated by radiant heat from the heating element or heat conduction from the atmosphere, so it takes time to raise the temperature, There is a problem that the processing efficiency of tempering is poor. Incidentally, although it depends on the size and mass of the crankshaft to be tempered, generally a heating time of about 0.5 to 1.5 hours is required. Since 1.5 hours are required and the total tempering time is 1.5 to 3 hours, this is a major obstacle to incorporating the induction tempering device into the crankshaft quenching line. This is the actual situation.

  Thus, as an alternative to the tempering apparatus using the electric furnace as described above, an induction tempering apparatus in which heating is performed by a high frequency induction heating coil has been proposed. In the case of this induction tempering apparatus, the semi-open saddle type induction induction coil is placed on the journal parts 1J and 5J of the crankshaft 1 to be tempered and the heated parts of the pin parts 1P to 4P. The crankshaft 1 is individually induction-heated while rotating the crankshaft 1 about the axis X to perform the tempering process. More specifically, first, as shown in FIG. 5, a semi-open saddle type follow-up type high frequency induction heating coil (so-called flat heating coil) is located above the journal portions 1J and 5J or the pin portions 1P to 4P of the crankshaft 1. , While rotating the crankshaft 1 about the axis X, the journal portions 1J and 5J are simultaneously subjected to high-frequency induction heating, and then the pins 1P to 4P are simultaneously subjected to high-frequency induction heating, followed by cooling treatment. By tempering.

  However, in the conventional induction tempering apparatus as described above, only the cylindrical peripheral surface α of the columnar portion A of the journal portions 1J and 5J and the pin portions 1P to 4P quenched with the fillet R is heated by the flat heating coil. Therefore, the R part B and the fillet part C following the cylindrical part A are heated only by heat conduction from the cylindrical part A. Therefore, a relatively large temperature difference is generated between the heating temperature of the cylindrical portion A and the heating temperature of the R portion B and the fillet portion C, and there is a possibility that a relatively large temperature variation occurs in each of these portions. If such temperature difference and temperature variation are remarkably generated, there is a problem that the tempering quality is deteriorated and a non-standard product (defective product) is easily generated.

  In addition, in order to use the conventional induction tempering apparatus, it is necessary to prepare two types of heating coils, a high frequency induction heating coil for heating the journal part and a high frequency induction heating coil for heating the pin part. Is expensive. Moreover, since it is necessary to perform the tempering process of the journal parts 1J and 5J and the pin parts 1P to 4P in separate tempering processes (two processes) using separate high-frequency induction heating coils, two tempering processes are performed. There is also a problem that it takes time and effort to perform processing, and processing efficiency is poor.

  In short, in the conventional tempering apparatus using an electric furnace, the time required for the tempering process is long, which is a major obstacle in incorporating the equipment into the tempering processing line, and in the conventional tempering apparatus using high-frequency induction heating, The reality is that there are difficulties in quality and equipment prices.

  The present invention has been made in view of such a situation, and quenching of a journal portion and a pin portion of a crankshaft with a substantially circular solenoid type high frequency induction heating coil formed by winding a conducting wire in a spiral shape. By tempering all the parts at once (in one step), the R part and the fillet part of the quenched part can be heated in the same manner as the other parts, so that they can be heated uniformly. To temper crankshafts that can achieve excellent uniform and stable tempering quality while keeping the compressive residual stress, which is one of the advantages of insertion, and that requires low equipment costs. It is to provide an induction tempering apparatus.

In order to achieve the above-described object, in the present invention, high frequency induction heating for tempering a hardened portion that has been hardened by fillet R after the journal portion or pin portion constituting the main portion of the crankshaft has been hardened by fillet R. In the apparatus, the entire crankshaft including not only the hardened portion but also the non-hardened portion is completely surrounded by a substantially circular solenoid type high frequency induction heating coil formed by winding a conductive wire in a spiral shape. The entire crankshaft is collectively subjected to high-frequency induction heating in response to energizing the high-frequency induction heating coil, and the hardened portion of the crankshaft is subjected to high-frequency induction heating. The counterweight part of the crankshaft that is easy and has a large heat capacity is also induction-heated at the same time, and the heat is transferred to the R part of the quenched part By heat conduction, so that they comprise a crankshaft high-frequency induction heating means for high-frequency induction heating hardly heated the R unit to the required tempering temperature with quenching the other portion.
In the present invention, the winding interval of the coil portion corresponding to the flange portion on one end side of the crankshaft of the substantially circular solenoid type high frequency induction heating coil is wound so as to be relatively dense. I try to turn.

  According to the present invention as described above, in the high-frequency induction heating apparatus for tempering the hardened portion that has been hardened by the fillet R after the journal portion or the pin portion constituting the main portion of the crankshaft has been hardened, The entire crankshaft, including not only the hardened part but also the non-hardened part, is placed at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil that is formed by winding a conducting wire in a spiral. In response to energization of the induction heating coil, the entire crankshaft is heated by high frequency induction to collectively heat the hardened portion of the crankshaft, and the crankshaft counter that is easily subjected to high frequency induction heating and has a large heat capacity. At the same time, the weight portion is also heated by high frequency induction, and the heat is conducted to the R portion of the quenching portion, so that it is difficult to be heated. The crankshaft high-frequency induction heating means for high-frequency induction heating to the required tempering temperature together with the other quenching portions is provided, so that the counterweight of the crankshaft is easy to be induction-heated and has a large heat capacity. The corner on the outer diameter side of the part becomes overheated, and the heat is conducted to the R part of the quenching part and the fillet part. The temperature can be raised together with the portion, and the entire fillet R quenching portion can be uniformly heated. As a result, a simple structure using only one substantially circular solenoid type high-frequency induction heating coil and a low-cost facility ensure uniform retention of compressive residual stress, which is one of the advantages of induction hardening. Stable and excellent tempering quality can be obtained.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4, the same parts as those in FIG. 5 are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows an induction tempering apparatus 10 using an induction tempering apparatus for a crankshaft according to an embodiment of the present invention. This apparatus 10 is filled with an induction hardening apparatus 11 as shown in FIG. This is for tempering the hardened journal 1J, 5J and pins 1P to 4P of the crankshaft 1 using one high frequency induction heating coil 12.

  A heat treatment mechanism 13 shown in FIG. 1 includes an induction hardening device 11 that hardens the journal portions 1J and 5J of the crankshaft 1 and the pins 1P to 4P, and a journal that has undergone fillet R hardening in the induction hardening device 11. The parts 1J and 5J and the pin parts 1P to 4P are composed of a tempering device 10 that collectively performs a tempering process. Then, when the crankshaft 1 is inserted from the leftmost inlet of the induction hardening device 11, the transfer device 14 thereafter intermittently passes through the stations in the quenching device 11 and the tempering device 10 sequentially. It is automatically discharged to the outlet OUT at the right end while being horizontally moved. However, the conveying device 14 in the quenching device 11 is not shown.

  The tempering apparatus 10 described above includes a heating station 21 that performs high-frequency induction heating (temperature increase heating) of the entire crankshaft 1 that is an object to be tempered (work) to a required tempering temperature by a high-frequency induction heating coil 12; The crankshaft 1 that has been induction-heated by induction heating is allowed to cool by heat conduction of the crankshaft 1 itself (the quenching part and the part to be hardened) and soaking, and the tempering process. A cooling station 24 that cools the crankshaft 1 by injecting a coolant onto the crankshaft 1 to perform subsequent polishing at room temperature, and an air blow station 25 that removes the coolant adhering in the cooling process from the crankshaft 1. The crankshaft 1 is provided with each of the stations 21 to 2 along the horizontal direction by the transport device 14 described above. The via sequentially is configured to be intermittently automatic transfer.

  The heating station 21 is provided with equipment such as a furnace body 30 in which the high-frequency induction heating coil 12 for heating the crankshaft 1 is housed. As shown in FIGS. 1 and 2, the furnace body 30 is attached to the lower part of the power supply matching unit 33. Note that the high frequency induction heating coil 12 shown in FIG. 3 used in the present embodiment is formed by spirally winding a conductive wire so that the winding interval of the coil portion corresponding to the flange portion F of the crankshaft 1 is relatively dense. This is a substantially circular solenoid type coil comprising a single-layer multi-winding, and both terminals 34a and 34b of the high-frequency induction heating coil 12 are disposed below a power supply matching unit 33 for supplying a high-frequency current (power source). Connected to a terminal (not shown). Further, when the crankshaft 1 is conveyed to the heating station 21, the power supply aligning portion 33 is urged by the cylinder 35 and moved along the guide rail 36. Accordingly, the furnace body 30 is indicated by a broken line in FIG. It is configured to move horizontally from the indicated standby position M to the heating position N indicated by the solid line. In addition, after completion | finish of a heating, it returns to the standby position M again.

  The soaking stations 22 and 23 are provided with only the crankshaft supports 63 and 64, respectively. The cooling station 24 cools the entire heated crankshaft 1 with a coolant such as water. Equipment such as an injection cooling ring 41 is provided (see FIG. 1).

  Further, the air blow station 25 is provided with equipment such as an air nozzle 42 for removing coolant particles (water droplets or the like) adhering to the crankshaft 1 after cooling (see FIG. 1).

  As shown in FIG. 1, the mechanism (conveying device 14) that conveys and supports the crankshaft 1 is laid so as to extend from the left end crankshaft input side position of the induction tempering device 10 to the right end discharge side. The moving beam 50 and a fixed beam 60 fixedly disposed between the moving beam 50 and the induction hardening apparatus 11 are provided. Both of these beams 50 and 60 are respectively composed of a pair of beam members laid parallel to each other along the crankshaft transport direction, with the moving beam 50 on the inside and the fixed beam 60 on the outside, Each is arranged. A pair of supporters are attached to the beams 50 and 60 at positions opposite to each other of the pair of beam members at intervals corresponding to the adjacent intervals of the stations 21 to 25 along the crankshaft transport direction. Yes. That is, on the moving beam 50 that conveys the crankshaft 1, six pairs of supporters 51 to 56 each including a V-shaped block are fixedly arranged between the crankshaft input side and the discharge side, and the crankshaft 1 is placed thereon. On the fixed beam 60 to be supported, seven pairs of supporters 61 to 67 each consisting of a V-shaped block are fixedly arranged between the crankshaft input side and the discharge side.

  The supports 51 to 56 on the moving beam 50 and the supports 61 to 67 (except 62) on the fixed beam 60 are made of metal. Further, the support device 62 disposed in the heating station 21 is made of a ceramic heat resistant material. The supports 51 to 56 of the moving beam 50 all support the journal portions 2J and 4J of the crankshaft 1, and the support 62 of the fixed beam 60 disposed in the heating station 21 is connected to the flange portion F and the crankshaft 1. The support portions 61 and 63 to 67 of the other fixed beam 60 support the shaft portion S1, and support the journal portions 1J and 5J of the crankshaft 1.

  Further, as shown in FIG. 2, the pair of ceramic supports 62 fixedly arranged in the heating station 21 is horizontally attached to the fixed beam 60 so as to face each other along the same axis. A pair of non-magnetic metal crankshaft support shafts 68 and 69 are fixed to the tip of one of the shafts 68, 69, and the tip of one of the shafts 68 is provided with a disk-shaped induction assist made of a magnetic material having a water passage inside. A member (induction adjusting member) 38 is provided to assist heating of the crankshaft portion on the flange portion F side. In addition, a coolant is supplied to the water flow path of the guidance assisting member 38 from a cooling facility (not shown). The other shaft 69 is arranged such that the high-frequency induction heating coil 12 at the standby position M is coaxially surrounding the periphery thereof. Thus, the pair of crankshaft support shafts 68 and 69 are arranged coaxially so as to extend along the extending direction of the axis of the high frequency induction heating coil 12.

  Further, the moving beam 50 is configured to be moved by the transport device 14 along a circulation path in which four cycles of ascending, advancing, descending, and retreating are one cycle from a low position before the operation. Thus, the crankshaft 1 mounted on the supporters 61 to 67 of the fixed beam 60 is received by the supporters 51 to 56 as the moving beam 50 moves upward, and is moved forward. By returning to the supporters 61 to 67 of the fixed beam 60 with the downward movement of the fixed beam 60, the fixed beam 60 is transported step by step along the downstream side in the crankshaft transport direction. Then, after one step of conveyance, the moving beam 50 is moved backward to return to the initial standby position. The moving beam 50 is lifted, lowered, moved forward, and moved backward on an arc drawn by the operating arm 71 of the lifting mechanism of the transport device 14 driven by a cylinder (not shown) and the operating arm 72 of the front / rear moving device. Is converted into a vertical motion and a linear motion in the front-rear direction (see FIG. 1). The moving beam 50 shown in FIG. 1 shows a state in which the tips of the supporters 51 to 56 of the moving beam 50 are substantially at the same height as the tips of the supports 61 to 67 of the fixed beam 60.

  The phase of the crankshaft 1 is such that the axis Y of the pin portions 1P and 4P is arranged at the uppermost position (top dead center position) with respect to the axis X of the crankshaft 1 from when the crankshaft 1 is inserted to when it is discharged. The axis Z of the pin portions 2P and 3P is set so as to be arranged at the lowest position (bottom dead center).

  Next, a procedure for tempering the crankshaft 1 using the above-described induction tempering apparatus 10 will be described as follows. First, the crankshaft 1 that has been subjected to a predetermined quenching process by the induction hardening device 11 in the previous process is put into the insertion port indicated by the arrow on the left side of the induction tempering device 10, and the journal portions 1J and 5J of the crankshaft 1 are placed. Is mounted on and supported by the support 61 of the fixed beam 60, the moving beam 50 is moved up immediately after that. Accordingly, the journal portions 2J and 4J of the crankshaft 1 supported by the support 61 of the fixed beam 60 are received by the support 51 on the moving beam 50, and the crankshaft 1 is supported by the support 51. Under this condition, the moving beam 50 is advanced by a distance corresponding to one span length between the supports 61 and 62 of the fixed beam 60 and then lowered. At this time, the flange portion F and the shaft portion of the crankshaft 1 are placed on the ceramic support 62 at the tip of the shafts 68 and 69 (see FIG. 2) fixedly disposed in the heating station 21 and attached to the fixed beam 60. S1 is placed and delivered to the supporter 62.

  The moving beam 50 is further moved downward and then moved backward to complete one cycle of the moving operation, and is placed at the standby position in preparation for the next cycle. On the other hand, on the support 61 of the fixed beam 60, the next crankshaft 1 that is subsequently introduced from the induction hardening apparatus 11 in the previous process is placed.

  When the crankshaft 1 is conveyed to the heating station 21 and placed on the supporter 62 as described above, the furnace body 30 containing the high-frequency induction heating coil 12 is moved from the standby position M indicated by a broken line in FIG. , Horizontally moved to the heating position N indicated by the solid line. At this time, the axis of the high-frequency induction heating coil 12 held in the furnace body 30 is moved substantially along the axis of the horizontal shaft 69, and the crankshaft 1 supported by the support 62 is high-frequency induction heated. The coil 12 is disposed at a position that passes through the opening 32 of the coil 12 and is completely surrounded by the high-frequency induction heating coil 12, that is, a heating position N (see FIG. 2). In synchronism with this, a high-frequency induction heating coil 12 is supplied with a required high-frequency current from a high-frequency power source (not shown) via a power matching unit 33, whereby the crankshaft 1 is not only a hardened portion but also a non-hardened portion. The whole including the above is collectively subjected to high-frequency induction heating (heating heating).

  At this time, the fillet R quenching treatment is arranged at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil to perform tempering heating. The counterweight portions CW1 to CW8 of the crankshaft 1 that are easily subjected to high-frequency induction heating and have a large heat capacity are heated at the same time by high-frequency induction heating, as well as the portion (that is, the R portion B). It will be heated uniformly together with its peripheral parts. This will be described in more detail. The counterweight portions CW1 to CW8 of the crankshaft 1 are portions having the largest heat capacity, and the outer diameter side tip corner portion H (see FIGS. 4 and 5) is a journal. Since the portion 1J to 5J and the pin portion 1P to 4P protrude to the outer diameter side and are most easily heated due to the characteristics of high-frequency induction heating, the outer end-side corners of the counterweight portions CW1 to CW8 described above H becomes a so-called “overheated” state, that is, a heating state at an extremely higher temperature than the surrounding portion. Therefore, the heat at the outer diameter side tip corner portion H in the “overheated” state is immediately conducted to the pin portions 1P to 4P of the crankshaft or the R portion B of the journal portions 1J to 5J. In addition to heating by the induction heating action of the high-frequency induction heating coil, the R part B, which has been recognized as being difficult to heat back, is a heat conduction action from the outer diameter side tip corner H of the counterweight part that is in an “overheating” state. Together, the R part B can be efficiently heated together with its peripheral part to be heated uniformly.

  Since the high frequency induction heating coil 12 used in this embodiment has a relatively close winding interval on the flange portion F side of the crankshaft 1 as described above, In addition, the portion on the flange portion F side having a large heat capacity is induction-heated with a larger heating energy than the other portions. Further, the induction heating of the crankshaft portion on the flange portion F side is assisted (adjusted) by the presence of the induction assisting member 38 attached to the tip of the horizontal shaft 68. As a result, the entire crankshaft 1 is heated and heated uniformly. Then, after heating for a predetermined time, the furnace body 30 is returned to the standby position M together with the high-frequency induction heating coil 12, and the crankshaft 1 is transported by the transport device 14 to the soaking stations 22 and 23 of the next process. .

  In the soaking stations 22 and 23, the crankshaft 1 is cooled to a predetermined tempering temperature while being mounted on and supported by the supporters 63 and 64 of the fixed beam 60, and soaking is performed. . Then, after the temperature is equalized over a predetermined time, the crankshaft 1 is conveyed to the cooling station 24 by the conveying device 14.

  In the cooling station 24, when the crankshaft 1 is placed on the pair of supports 65 of the fixed beam 60, the plurality of injection cooling rings 41 are moved downward from the upper side to the lower side by the cylinder 43, so that the crankshaft The cooling liquid (for example, cooling water) is injected toward the crankshaft 1 from a number of cooling liquid injection holes (not shown) provided in these injection cooling rings 41. . Thereby, the crankshaft 1 is cooled and tempered. After the cooling is completed, the injection cooling ring 41 is returned to the initial standby position, and the crankshaft 1 is transported to the air blow station 25 by the transport device 14.

  In the air blow station 25, when the crankshaft 1 is placed on the support 66 of the fixed beam 60, a plurality of air nozzles 42 corresponding to the size and shape of the crankshaft 1 are integrated with the injection cooling ring 41. The drive mechanism moves down to a predetermined distance with respect to the crankshaft 1, and compressed air is ejected from the air nozzle 42 toward the crankshaft 1 through an air introduction pipe from an air compressor (not shown). At this time, the air nozzle 42 is swung back and forth and left and right by a rocking mechanism (not shown). As a result, the cooling liquid (for example, water droplets) remaining on the surface of the crankshaft 1 in the cooling station 24 in the previous process is blown off from the surface of the crankshaft 1 and removed. After the air blow is completed, the air nozzle 42 is returned to the initial standby position, and the crankshaft 1 is transported by the transport device 14 onto the support 67 of the fixed beam 60 on the discharge side.

  All steps of the tempering process are completed by the series of operations as described above, and the subsequent steps are subsequently taken over. Under continuous operation, each time the movement of the moving beam 50 is cycled, a new crankshaft 1 is continuously input, and the processed crankshaft 1 is continuously discharged, for example, with a cycle time of 42 seconds.

Here, a specific example of the operating conditions of the induction tempering apparatus 10 will be described as follows.
Specific Example (1) Crankshaft Material Steel Type: S48CL
(2) High frequency induction heating coil Frequency: About 2 kHz
Electric power: 40kW
(3) High frequency induction heating time: 28 seconds (4) Soaking time: about 90 seconds Soaking temperature: about 200 ° C
(5) Cooling Coolant temperature: 35 ° C or less Work temperature: 40 ° C or less

  When the crankshaft 1 was tempered using the induction tempering apparatus 10 under the conditions as described above, when the quenching hardness was Hv800, the hardness specification after the tempering was Hv513- The tempering hardness was Hv650-700 while it was 830.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, the present invention is not limited to the crankshaft 1 having the shape as shown in FIG. 5, but can be applied to tempering processing of various shapes of the crankshaft.

It is a side view which shows the structure of the induction tempering apparatus of the crankshaft which concerns on one Embodiment of this invention. It is a side view of the heating station in the above-mentioned induction tempering apparatus. FIG. 3A shows a front view of the high-frequency induction heating coil, and FIG. 3B is a side view of the high-frequency induction heating coil. It is a side view of the crankshaft which is a to-be-tempered body. It is explanatory drawing which shows the hardening hardening layer pattern formed in the crankshaft.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crankshaft 1P-4P Pin part 1J-5J Journal part 10 Induction tempering apparatus 11 Induction hardening apparatus 12 Induction induction heating coil 13 Heat processing mechanism 14 Conveying apparatus 21 Heating station 22, 23 Soaking | uniform-heating station 24 Cooling station 25 Air blow station 30 furnace body 38 guidance auxiliary member (guidance adjustment member)
41 Cooling Water Injection Cooling Ring 42 Air Nozzle 50 Moving Beam 51-56 Supporting Device 60 Fixed Beam 61-67 Supporting Device 68, 69 Crankshaft Support Shaft A A Cylinder Part BR Part (Corner or Corner)
C Fillet portion CW1 to CW8 Counterweight portion F Flange portion H Outer diameter side tip corner portion M Standby position N Heating position S1, S2 Shaft portion X Crankshaft rotation axis Y Pin portions 1P, 4P axis Z Pin portions 2P, 3P Axis

Claims (2)

  In a high-frequency induction heating apparatus for tempering a hardened part that has been hardened by fillet R after the journal part or pin part constituting the main part of the crankshaft has been hardened, not only the hardened part but also non-hardened The entire crankshaft including the portion is arranged at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil formed by spirally winding a conducting wire, and the high frequency induction heating coil is energized. In response to the above, the entire crankshaft is collectively induction-heated to inductively heat the quenching portion of the crankshaft, and the counterweight portion of the crankshaft that is easily induction-heated and has a large heat capacity is provided. At the same time, high-frequency induction heating is performed, and the heat is conducted to the R portion of the quenching portion, so that it is difficult to be heated. High-frequency induction heating for high-frequency tempering of the crankshaft characterized by comprising high-frequency induction heating means for high-frequency induction heating of the R section together with the other quenching portions to a required tempering temperature apparatus.   Of the substantially circular solenoid type high-frequency induction heating coil, the winding interval of the coil portion corresponding to the flange portion on one end side of the crankshaft is wound so as to be relatively dense. The high frequency induction heating apparatus for induction tempering of the crankshaft according to claim 1.

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