JP5089109B2 - Induction tempering method of crankshaft and induction induction apparatus used in this method - Google Patents

Description

The present invention relates to an induction tempering method for a crankshaft for induction tempering a crankshaft in which induction hardening has been applied to a pin portion of a crankshaft of an engine or the like and a fillet R portion of a journal portion, and to the induction tempering method. The present invention relates to a high-frequency induction heating device to be used.

  FIG. 5 shows a crankshaft 1 used in an inline engine. This crankshaft 1 is No. 1 to No. No. 5 arranged up to five journal parts 2 through the counterweight 3 between these journal parts 2 and 2. 1 to No. 4 pin portions 4 up to 4 are provided. As shown in FIG. 5, a flange portion 5 is formed at the right end of the crankshaft 1, and a shaft portion 6 is formed at the left end thereof.

  The journal portion 2 and the pin portion 4 of the crankshaft 1 having the above structure are usually subjected to induction hardening to form a hardened and hardened layer S. The column portion 7a of the journal portion 2 and the pin portion 4 The quenching method in which only the cylindrical outer peripheral portions α and β of 7b are quenched is called flat quenching, and is connected to the cylindrical outer peripheral surfaces α and β and the cylindrical outer peripheral portions α and β as shown in FIG. A quenching method for quenching all of a series of continuous portions including a fillet R portion (curved R portion, corner portion or corner portion) 8 and a fillet portion 9 connected to the fillet R portion 8. This is called Fillet R quenching. The tempering treatment is performed for the purpose of improving toughness and removing internal strain in the induction-quenched portion. Conventionally, heating for this tempering treatment (tempering heating) is performed. An electric furnace was generally used.

  Tempering with an electric furnace provides uniform and stable tempering quality, but on the other hand, it requires a long heating time, and accordingly, the compressive residual stress obtained by induction hardening is reduced. As a result, there arises a problem that the fatigue strength is greatly reduced. Moreover, since the heating by the electric furnace is indirect heating, there is a problem that it takes time to raise the temperature and the tempering efficiency is poor.

In order to solve such problems, there has been proposed an induction tempering method and apparatus in which heating for tempering is performed using a high frequency induction heating coil body without using an electric furnace. Various methods and apparatuses have been proposed, and JP-A-2001-303134 (Japanese Patent No. 3524037) by the applicant of the present application is an effective example. In the crankshaft induction tempering method and apparatus described in JP-A-2001-303134, the entire crankshaft is completely surrounded by a substantially circular solenoid type high-frequency induction heating coil body. The crankshaft pin portion and the journal portion are simultaneously tempered at the same time.
JP 2001-303134 A

  Although the above-described induction tempering method and apparatus described in JP-A-2001-303134 is effective, it is preferable that the crankshaft is relatively small. A high-frequency induction heating coil having an extremely large size that can completely surround the crankshaft is required. In this case, there is a problem that handling is poor and extremely expensive. Furthermore, it is necessary to prepare a dedicated high-frequency induction heating coil according to the length and shape of the crankshaft, which is a workpiece, and heat treatment specifications, and there is a facility problem regarding versatility for a wide variety of workpieces. .

The present invention has been made in view of such a situation, and its purpose is to satisfactorily temper the fillet R portion of the crankshaft and to cope with a large crankshaft. An object of the present invention is to provide an induction tempering method and apparatus for a crankshaft which can be carried out at a low cost.

In order to achieve the above-described object, the present invention provides a method for induction tempering a crankshaft, which is obtained by induction-hardening a pin portion which is a main component of a crankshaft and a fillet R portion of a journal portion, The crankshaft pin portion and the journal portion adjacent to the pin portion are tempered and heated by the high frequency induction heating coil body, and the crankshaft is moved in the axial direction thereof to be connected to the next pin portion and the adjacent pin portion. The journal part is tempered and heated sequentially.

Further, the present invention is a high-frequency induction heating apparatus for induction-tempering a crankshaft obtained by induction-hardening a pin portion which is a main component of the crankshaft and a fillet R portion of a journal portion . A heating coil portion surrounding a pin portion and a journal portion adjacent to the pin portion, and the crankshaft is moved in the axial direction at a pitch corresponding to the one pin portion and the adjacent journal portion with respect to the heating coil portion. There is also a high-frequency induction heating apparatus for high-frequency tempering that has a moving mechanism portion for the purpose .

The heating coil portion is a heating coil portion surrounding a plurality of sets of the pin portion and the adjacent journal portion, and the moving mechanism portion corresponds to the plurality of sets of the pin portion and the adjacent journal portion. It may be provided as a moving mechanism for moving in the axial direction at a pitch.

Further, the heating coil portion, it is preferable to consist of a substantially circular cylindrical solenoid type winding a conductive wire helically.

Further, it is more preferable that the heating coil portion has a magnetic material disposed on the inner surface close to the pin portion of the crankshaft.

In the method of the present invention, the pin portion of the crankshaft and the journal portion adjacent to the pin portion are tempered and heated by the high frequency induction heating coil body, and the crankshaft is moved in the axial direction thereof to move to the next pin portion and the pin portion. Since the adjacent journal portions are tempered and heated sequentially, particularly, a large crankshaft can be easily tempered. In addition, despite the fact that a large crankshaft can be tempered, the high-frequency induction heating coil body has the advantage of being relatively small in size and easy to handle.

Further, the apparatus of the present invention, one of the pin portion and the heating coil portion surrounding the journal portion continuous adjacent to the pin portion, wherein one of the pin portion and the adjacent journal portions of the crankshaft relative to the heating coil portion And a moving mechanism for moving in the axial direction at a pitch corresponding to the above, and can be conveniently applied to a large crankshaft, in particular, and implemented at low cost. Can do.

Further, the heating coil portion, in embodiments consisting of those of substantially circular cylindrical shape solenoid type winding a wire helically, requires only lightweight, yet can be easily and inexpensively manufactured.

Further, in the aspect in which the heating coil portion has a magnetic material disposed on the inner surface close to the pin portion of the crankshaft, the presence of the magnetic material can effectively prevent overheating of the pin portion more than necessary. And high quality tempering.

  Hereinafter, an embodiment of an induction tempering method for a crankshaft of the present invention and an induction heating coil body 10 used for the induction tempering method will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to FIG.5 and FIG.6, and the overlapping description is abbreviate | omitted.

  FIG. 1 shows a state when the crankshaft 1 is subjected to high-frequency induction heating for high-frequency tempering using the high-frequency induction heating coil body 10. The high-frequency induction heating coil body 10 includes a heating coil portion 10a of a substantially circular solenoid type formed by winding a conducting wire 11 a plurality of times in a spiral shape, and has an inner diameter φ, FIG. As shown in FIG. 2, the dimensions are such that the crankshaft 1 can be surrounded (covered) with a slight gap between the cross-sectional shape of the crankshaft 1. Further, as shown in FIG. 1, the length L of the heating coil portion 10a of the high frequency induction heating coil body 10 in the direction orthogonal to the winding direction (circumferential direction) (advancing direction of the pitch of the conducting wire 11) is, for example, It is set to a dimension that can exactly surround one journal portion 2 and one pin portion 4 adjacent thereto. Note that the length L is not limited to this, and may be set longer or shorter than the above dimension as necessary.

  Further, both ends of the conducting wire 11 of the above-described high frequency induction heating coil body 10 are connected to a high frequency power source 12 as shown in FIG. On the other hand, the conducting wire 11 is made of a pipe material having a coolant circulation hollow portion as shown in FIG. 4 and is configured so that coolant is supplied into the hollow portion from a coolant supply mechanism (not shown). And in this embodiment, it is comprised so that the movement mechanism part 13 may be connected with the crankshaft 1 so that the crankshaft 1 can move to the axial direction (direction shown by arrow A in FIG. 1).

  Thus, the high-frequency induction heating coil body 10 includes the heating coil portion 10a in which the conductive wire 11 is spirally wound as described above, but the high-frequency induction heating coil body 10 is a crankshaft 1 for a series engine. 2 and FIG. 4, the positions corresponding to the pin portions 4 that are in the interior and that are 180 degrees out of phase with each other (180 degrees apart from each other) are used. And a magnetic material (magnetic flux concentrating material) 14 such as a dust core or a silicon steel plate. In this case, the magnetic material 14 is not necessarily required, but stable tempering is achieved by preventing a temperature rise (for example, 350 ° C. or more) of the pin portion 4 close to the inner surface of the heating coil portion 10a of the high-frequency induction heating coil body 10. In order to form a layer, it is desirable that a magnetic material 14 be attached. FIG. 2 shows the arrangement of the magnetic material 14 in the case of the crankshaft 1 for an inline engine shown in FIG. In the case of the crankshaft 1 for an in-line engine, as shown in FIG. 5, since the adjacent pin portions 4 are arranged at positions shifted from each other by 180 degrees, the magnetic material 14 is also 180 degrees as shown in FIG. Arranged at two shifted symmetrical positions. FIG. 3 shows the arrangement of the magnetic material 14 in the case of the crankshaft 1 for a V-type engine. In this case, the magnetic material 14 is arranged at three positions at intervals of 120 degrees. Of course, in the case of a crankshaft for a multi-cylinder engine, the magnetic material 14 is disposed at a corresponding position in each pin portion 4 corresponding to the number of cylinders.

  Next, an example of a method (procedure) for induction-tempering the crankshaft 1 using the high-frequency induction heating coil body 10 having the above-described structure will be described.

  First, the crankshaft 1 is turned sideways and its axis (coincided with the axis of the journal portion 2) is arranged in the horizontal direction. As shown in FIGS. 1 and 4, a part of the high frequency induction heating coil body 10, that is, the same. In the drawing, the journal portion 2 and the pin portion 4 at the rightmost end are slightly spaced from the lead wire 11 of the high frequency induction heating coil body 10 in the hollow portion of the substantially circular solenoid type heating coil portion 10a of the high frequency induction heating coil body 10. Set in a state of penetrating through the center. Thereby, as described above, the journal part 2 and the pin part 4 at the rightmost end are arranged at a position (covered position) surrounded by the heating coil part 10a of the high frequency induction heating coil body 10, and under this state High frequency power is supplied from the high frequency power source 12 to the high frequency induction heating coil body 10. At this time, the tempering layer (see FIG. 6) is applied to the journal portion 2 and the pin portion 4, and the fillet R portion 8 and the fillet portion 9 by appropriately adjusting the electric energy and the heating time. Tempering layer in a region corresponding to the hardened and hardened layer S).

  Next, the moving mechanism portion 13 shown in FIG. 1 is operated to move the crankshaft 1 in the direction of arrow A in FIG. 1 by one pitch (the rightmost journal portion that has entered the hollow portion of the heating coil portion 10a of the high frequency induction heating coil body 10). 1 and FIG. 4, the next journal portion 2 and the pin portion 4 adjacent to the left side in FIG. 1 and FIG. 4 enter the hollow portion of the heating coil portion 10 a of the high-frequency induction heating coil body 10) And induction tempering as described above. Thereafter, the same operation is repeated sequentially, and the crankshaft 1 is intermittently moved (pitch movement) to the position corresponding to the leftmost journal portion 2 and pin portion 4 of the heating coil portion 10a of the high frequency induction heating coil body 10. ), The entire crankshaft 1 is tempered and heated.

  It is also possible to perform tempering heating while moving the crankshaft 1 by continuous feed (continuous feed) instead of intermittent feed (pitch feed) as described above. Further, in the large crankshaft 1, harmful overheating of the pin top portion P (see FIGS. 2, 3, and 6) can be prevented by techniques such as two-stage heating and three-stage heating. It is effective to raise the whole to a predetermined tempering temperature.

  By the above procedure, the crankshaft 1 having a high-quality tempered layer in the region of the hardened hardened layer S quenched with the fillet R shown in FIG. 6 is obtained. According to the present embodiment, as apparent from the above description, one pin portion 4 and one journal portion 2 connected to the pin portion 4 are surrounded by the substantially circular solenoid type high frequency induction heating coil body 10 and cranked. Since the shaft 1 is intermittently or continuously moved horizontally to perform the induction tempering process, particularly in the case of a large-sized crankshaft 1, it can be conveniently handled with good handling and is inexpensive. Tempering heating (tempering treatment) can be performed.

  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, when the crankshaft 1 is moved intermittently by the movement mechanism unit 13, in the above-described embodiment, one journal unit 2 and one pin unit 4 that are adjacent to each other are combined into one set and the heating coil unit. Although it arrange | positions within 10a and it was made to move intermittently, you may make it perform tempering heating by making it move intermittently by making the combination of another number into one set.

It is a front view which shows the state which has tempered the crankshaft with the high frequency induction heating coil body used for the induction tempering method which concerns on one Embodiment of this invention. FIG. 2 shows a high-frequency induction heating coil body for tempering and heating a crankshaft for an in-line engine, and is an enlarged sectional view taken along line BB in FIG. 1. It is sectional drawing similar to FIG. 2 which shows the high frequency induction heating coil body for tempering heating the crankshaft for V type engines. It is a schematic diagram which shows the state which performs the tempering heating of a crankshaft using the high frequency induction heating coil body which concerns on one Embodiment of this invention. It is a top view which shows the crankshaft for inline engines. It is a fragmentary sectional view which shows the hardening hardening layer formed in the journal part and the pin part by the induction tempering method of this invention.

DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Journal part 3 Counterweight part 4 Pin part 7 Cylindrical outer peripheral part 8 Fillet R part 9 Fillet part 10 High frequency induction heating coil body 10a Heating coil part 11 Conductor 12 High frequency power supply 13 Moving mechanism part 14 Magnetic material

Claims (5)

  A crankshaft induction tempering method in which a pin portion which is a main component of a crankshaft and a fillet R portion of a journal portion are induction-hardened, and is connected to the pin portion of the crankshaft and adjacent to the pin portion. The journal portion is tempered and heated by a high frequency induction heating coil body, the crankshaft is moved in the axial direction thereof, and the next pin portion and the adjacent journal portion are sequentially tempered and heated. Induction tempering method for crankshafts.   A high-frequency induction heating device for induction-tempering a crankshaft obtained by induction-hardening a pin portion which is a main component portion of a crankshaft and a fillet R portion of a journal portion, comprising one pin portion and this pin portion A heating coil portion surrounding adjacent journal portions; a moving mechanism portion for moving the crankshaft in the axial direction at a pitch corresponding to the one pin portion and the adjacent journal portion with respect to the heating coil portion; A high frequency induction heating apparatus for induction tempering of a crankshaft characterized by comprising: The heating coil portion is a heating coil portion surrounding a plurality of sets of the pin portion and the adjacent journal portion, and the moving mechanism portion corresponds to the plurality of sets of the pin portion and the adjacent journal portion. The high frequency induction heating apparatus for crankshaft induction tempering according to claim 2, wherein the induction mechanism is provided as a moving mechanism for moving in the axial direction at a pitch.   The high-frequency induction heating apparatus for crankshaft induction tempering according to claim 2 or 3, wherein the heating coil section is of a substantially cylindrical solenoid type in which a conducting wire is spirally wound.   The high frequency induction heating apparatus for crankshaft induction tempering according to claim 4, wherein the heating coil portion is provided with a magnetic material on an inner surface close to a pin portion of the crankshaft.

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