JP6508461B2 - Crankshaft manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a crankshaft.

Crankshafts are required to be improved in fatigue strength and wear resistance. Generally, high frequency hardening is applied to the sliding surface of the crank journal and sliding surface of the crank pin, and the shafts of the crank journal and crank pin are Roll processing (fillet roll processing) is performed on fillets at the direction end (each independently).
Recently, in order to further improve the strength and wear resistance of the crankshaft, etc., the crank journal, the crank pin, the crank journal and the fillet on the axial end of the crank pin are subjected to induction hardening, A method has been proposed in which each fillet portion is subjected to roll processing (fillet roll processing) after the surface hardness of the above is increased (see Patent Document 1).

JP, 2000-337345, A

However, in the method of performing induction hardening on the fillet portion as in Patent Document 1, it is difficult to apply the roll processing itself because the fillet portion must be rolled after the induction hardening is finished. That is, since the surface hardness of the fillet portion is increased by induction hardening, it is difficult to directly roll-process the hardened surface.
Therefore, when rolling the fillet portion, for example, low temperature tempering of the entire crankshaft as in Patent Document 1 or the like, it is required to provide a process that allows rolling to be performed before rolling. It was difficult to manufacture.

  Therefore, an object of the present invention is to provide a method of manufacturing a crankshaft by which induction hardening can be applied to a crank journal portion, a crank pin portion, and a fillet portion by a simple method and without impairing processability.

According to an aspect of the present invention, a process of applying predetermined rolling to the axial end of the crank journal and the fillet at the axial end of the clamp pin, and a sliding surface of the crank journal after completing the rolling Including the steps of including the fillets at the axial ends of the crank journal portion and the clamp pin portion for induction hardening , the rolling process is a fillet roll process for pressing the fillet roll against the fillet area; In the fillet roll processing, deformation is given in advance so as to offset the amount of deformation of the crankshaft due to induction hardening .

According to the present invention, induction hardening in the crank journal portion, the clamp pin portion and the fillet portion of the crankshaft is carried out by a simple method by using a method in which the fillet portion is subjected to rolling before the induction hardening process. The induction hardening can be performed on the sliding surface of the crank journal portion including the fillet portion and the crank pin portion without impairing the processability. Moreover, since the fillet roll processing imparts a deformation that offsets the amount of deformation of the crankshaft brought about by induction hardening in advance, the deformation of the crankshaft is offset when the induction hardening process is finished, that is, the deformation of the crankshaft is eliminated. High precision crankshaft can be obtained quickly.

The front view of the crankshaft of one embodiment of the present invention. The front view explaining the time of giving fillet roll processing (roll processing) to the fillet part of the crank journal part of a crankshaft. The side view which shows the outline of the processing apparatus which gives the same fillet roll process. The front view explaining the time of giving the same fillet roll process. The side view which shows the outline of the processing apparatus which gives the same fillet roll process. The figure explaining the phase control performed by fillet roll processing of the crank pin part. The front view which shows when the induction hardening is given to a crankshaft with the control apparatus which carries out phase control. The figure explaining the modification of the same crankshaft. Sectional drawing which shows the hardening hardening layer in a crankshaft part, a crank pin part, and a fillet part when the induction hardening is complete | finished.

Hereinafter, the present invention will be described based on an embodiment shown in FIG. 1 to FIG.
FIG. 1 shows the appearance of the crankshaft 1. The crankshaft 1 is, for example, a crankshaft of a four-cylinder engine for a gasoline vehicle. For example, from the left side, the crankshaft 1 has a first journal 3a (hereinafter referred to simply as the journal 3a), a first pin 5a (hereinafter referred to simply as the pin 5a), and a second journal 3b (hereinafter referred to simply as the journal 3b), the second pin 5b (hereinafter referred to simply as the pin 5b), the third journal 3c (hereinafter referred to simply as the journal 3c), the third pin 5c (hereinafter referred to simply as the pin 5c), 4 The fourth journal unit 3d (hereinafter referred to simply as the journal unit 3d), the fourth pin unit 5d (hereinafter referred to simply as the pin unit 5d) and the fifth journal unit 3e (hereinafter referred to simply as the journal unit 3e). The journals 3a to 3e (corresponding to the crank journal of the present application) and the pins 5a to 5d (corresponding to the crank pin of the present application) are joined by the arm 2, respectively. 3e are arranged on the same axis, and the sliding surfaces 4 of the journals 3a to 3e are linearly arranged. In addition, pin portions 5b and 5c are arranged on the same line at positions away from the axis of the journal portions 3a to 3e by a predetermined distance. Furthermore, the pin portions 5a and 5d are aligned on the same line on the opposite side (180 °) to the pin portions 5b and 5c sandwiching the journal axis, and the pin portion 5b is disposed at a predetermined position around the journal axis. , 5c and the sliding surfaces 6 (peripheral surfaces) of the pin portions 5a, 5d. The fillet 7 is formed between the side of the arm 2 and the axial end of the journals 3a to 3e, and the fillet 9 is formed between the side of the arm 2 and the axial ends of the pins 5a to 5d. .

  The crankshaft 1 has the sliding surfaces 4 of the journals 3a to 3e, the sliding surfaces 6 of the pins 5a to 5d, and the journals 3a to 3e in order to improve wear resistance, bending (torsion) fatigue strength, and the like. Although the induction hardening is applied to the fillet portion 9 and the fillet portion 9 of the pin portions 5a to 5d, when induction hardening is performed first, the surface hardening action brought about by hardening causes rolling at the fillet portions 7 and 9 at this time, ie, Fillet rolling such as forming the fillets 7 and 9 into a rounded shape (groove) and cold rolling the fillet rounded shape is difficult.

  Therefore, in the present embodiment, fillet rolling in the fillet portions 7 and 9 of the journal portions 3a to 3e and the pin portions 5a to 5d, which are roll processing, before the induction hardening is performed so that the fillet roll processing can be easily performed. After that, the method of induction hardening is applied to the sliding surfaces 4 of the journals 3a to 3e and the sliding surfaces 9 of the pins 5a to 5d including the fillets 7 and 9.

To explain this method, first, fillet rolling processing (roll processing) is applied to the fillet portions 7 and 9 of the crankshaft 1 as shown in FIGS.
That is, in the fillet roll processing, first, as shown in FIGS. 2 and 3, for example, both ends 1a and 1b of the crankshaft 1 are rotatably supported by the support center tool 15, and a fillet dedicated to each journal portion 3a to 3e The roll processing machine 17 is assembled. For example, as shown in FIG. 3, the fillet roll processing machine 17 supports the one side sandwiching the journals 3 a to 3 e by a pair of support rolls 19, and on the other side, an inclined fillet so as to protrude toward the fillet 7. The roll 21 is arranged. Then, a fillet load is applied to each fillet roll 21 as shown by the arrow a in FIGS. 2 and 3, and the tip of the fillet roll 21 is pressed against the grooved fillet portion formed in the fillet portion 7, while the arrow b of FIG. By rotating the crankshaft 1 about the axes of the journals 3a to 3e as described above, the surface roughness of the entire circumference of each fillet 7 is increased.

  Subsequently, fillet roll processing is performed on the fillet portions 9 of the pin portions 5a to 5d. In this case, as shown in FIGS. 4 and 5, for example, both ends 1a and 1b of the crankshaft 1 are rotatably supported by the support center tool 25 and the fillet roll processing machine 27 is assembled to the respective pin portions 5a to 5d. For example, as shown in FIG. 5, the fillet roll processing machine 27 arranges a pair of support rolls 29 on one side across the pin portions 5 a to 5 d and inclines so as to protrude toward the fillet portion 7 on the other side. The fillet roll 31 is disposed to sandwich the pin portions 5a to 5d. Then, a fillet load is applied to each fillet roll 31 as shown by an arrow c in FIGS. 4 and 5, and while pressing the fillet roll 31 against the grooved fillet portion formed in the fillet portion 9, a crank as shown by an arrow d. The surface roughness of the surface of each fillet portion 9 is increased by rotating the shaft 1 about the axes of the journal portions 3a to 3e.

In fillet rolling, simply applying fillet load can not produce the crankshaft 1 quickly.
Therefore, a device is also applied to fillet roll processing. The same device is used to prepare for the amount of deformation of the crankshaft 1 that occurs when induction hardening is performed using this fillet roll processing. Specifically, fillet rolling is intended to impart a deformation that offsets the quenching deformation.

  To explain this point, the induction hardening device 41 of the crankshaft 1 rotatably supports, for example, both end portions 1a and 1b of the crankshaft 1 by the support center tool 35 as shown in FIG. 3e, the high frequency coil 39 is disposed on the outer peripheral surface of each of the pin portions 5a to 5d, and while applying a high frequency to each high frequency coil 39, the crankshaft 1 is an axial center of the journal portions 3a to 3e as shown by an arrow e. The sliding surfaces 4 of the journals 3a to 3e, the sliding surfaces 6 of the pins 5a to 5d, and the fillets of the fillets 7 of the journals 3a to 3e, and the fillets of the pins 5a to 5d. The surface of the fillet radius portion of the portion 9 is heated to form a hardened layer on the surface portion of each portion. At this time, the crankshaft 1 is deformed by heat. In many cases, the thickness dimension of the arm portion 2 joined to the pin portions 5a to 5d tends to be extremely different between the top side and the bottom side, so that deformation easily occurs around the pin portions 5a to 5d. In many cases, the arm portions 2 on both sides of the pin portions 5a to 5d expand to both sides, and the bottom sides of the pin portions 5a to 5d are deformed outward as shown by the arrow g in FIGS. In particular, the deformation of the bottom portions of the pin portions 5a to 5d at the time of quenching directly leads to the bending of the crankshaft 1. However, if the coil output does not bend enough, the quenching depth may be insufficient.

  Therefore, for example, as shown in FIG. 7, the induction hardening apparatus 41 uses a control unit 43 that controls energy input to the high frequency coil 39 and a bending amount detection sensor 45 that detects the bending amount of the arm unit 2. A phase control system is used to control the quenching energy so that the deformation amount of 1 is minimized at a predetermined hardening depth, and the deformation amount of the crankshaft 1 is suppressed as much as possible.

  The data of the amount of deformation (the amount of hardening deformation of the crankshaft 1) in the arm 2 when the induction hardening is performed on the crankshaft 1 is obtained in advance, and the induction hardening deformation is offset from the data of the amount of deformation of the arm 2 Then, the offset data for generating the deforming force is obtained, and the deforming data is applied to the arm portion 2 in advance in the case of fillet roll processing performed before induction hardening based on the offset data so as to offset the induction hardening deformation amount in advance.

  That is, the fillet roll processing machines 17 and 27 use a phase control type in which the fillet load applied to the outer peripheral portions of the journal portions 3a to 3e and the outer peripheral portions of the pin portions 5a to 5d can be varied. Therefore, the fillet roll processing controls the pressing force (fillet load) of each fillet roll 21 or 31 based on the offset data that offsets the induction hardening deformation amount.

  Specifically, since a large amount of hardening deformation occurs around the pin portions 5a to 5d as described above, the fillet load applied to the fillet portion 9 of at least the pin portions 5a to 5d is controlled. In particular, since the hardening deformation of the pins 5a to 5d tends to cause deformation in a specific direction as described above, in the fillet rolling, the deformation described above (arrow f in FIG. 4) (arrow A deformation in the opposite direction to g) is applied to the arm portion 2. That is, the bottom side of the pin portions 5a to 5d is deformed so as to be displaced inward. Therefore, in fillet rolling, a high load is applied to the top sides of the pin portions 5a to 5d, and a low load is applied to the bottom sides of the pin portions 5a to 5d, as shown in FIG. The outer side is deformed, and the bottom sides of the pin portions 5a to 5d are deformed inward.

  Specifically, in fillet rolling of the journals 3a to 3e, the fillet roll 21 is pressed against the entire periphery of the fillet 7 with only fillet load (for example, 5 kg N) for increasing the surface roughness, for example. In fillet rolling of the journals 3a to 3e, for example, as shown in FIG. 6, the fillets merely increase the surface roughness on the bottom half semicircle B (about 150 degrees as a guide) of the pins 5a to 5d. Fillet with load β (for example 5kg N; low load) added to the top side half circumference A (about 180 degrees as a guide) of the pin parts 5a to 5d larger than the above fillet load based on the offset data (amount of deformation) Load α (for example, 10 kg N; high load) is applied. That is, in the pin portions 5a to 5d, the fillet load α applied to the top side half circumference portion A is made larger than the fillet load β applied to the bottom side half circumference portion B. When the fillet load α applied to the half circumference portion A of the fillet portion 7 increases, the bottom sides of the pin portions 5a to 5d are deformed so as to be directed inward as shown in FIG. 6 (a). The amount of deformation of the arm portion 2 at this time is the amount of deformation that offsets the deformation generated in advance by induction hardening.

  Crankshaft 1 is thus subjected to the fillet roll processing at fillet portion 7.9 (roll processing step), the above-described induction hardening device 41, sliding surface 4 of journal portions 3a to 3e, pin portion The sliding surfaces 6 of 5a to 5d include the fillet 7 of the journals 3a to 3e and the fillet 9 of the pins 5a to 5d, and are induction hardened (induction hardening process). As a result, deformation of the arm portions 2 on both sides of the pin portions 5a to 5d due to fillet rolling is eliminated, and by offsetting the deformation, the crankshaft 1 having no deformation, that is, reduced deformation is obtained.

  As described above, unlike the rolling process after induction hardening, the journal section including the fillets 7 and 9 without impairing the processability by the simple method of performing roll processing first and then induction hardening. Induction hardening is applied to the sliding surfaces 4 and 6 of the pins 3a to 3e and the pins 5a to 5d. That is, the induction hardening can be easily performed on the crankshaft 1 so that the crankshaft 1 can be manufactured rapidly.

  In particular, since the induction hardening is applied to the sliding surfaces 4 and 6 of the journals 3a to 3e and the pins 5a to 5d including the fillets 7 and 9 processed by fillet rolling, it is indicated by the symbol γ in FIG. As in the case of a hardened layer, even the fillets 7 and 9 can be easily hardened at a predetermined hardening depth. For this reason, the fillets 7 and 9 can be further improved in strength, wear resistance, fatigue resistance, etc. by the synergistic effect of the surface hardening action by induction hardening and the surface roughness improvement action by fillet roll processing. it can.

  In addition, at the time when the induction hardening process is completed, the fillet roll processing using phase control is performed by giving deformation that offsets the amount of deformation of the crankshaft 1 (arm portion 2) brought about by induction hardening in advance. Since the deformation of (1) cancels out, that is, the deformation of the crankshaft 1 is eliminated, it is possible to obtain a high precision crankshaft 1 promptly. This is particularly effective for the pin portions 5a to 5d where quenching deformation is easily induced.

  Moreover, fillet rolling is easy since fillet load α applied to at least the top half of the pin portions 5a to 5d is larger than fillet load β applied to the bottom half half B based on the amount of hardening deformation. Can be given a deformation that offsets the amount of deformation. Of course, depending on the crankshaft 1, the fillet load applied to the journals 3a to 3e may be changed in the same manner as the pin portions 5a to 5d.

Further, not only fillet rolling, but also induction hardening using phase control to control the quenching energy so as to minimize the amount of deformation of the crankshaft 1 while securing a predetermined hardening depth, the deformation of the crankshaft 1 Since the amount of deformation that cancels out the amount can be minimized, the time until the crankshaft 1 is manufactured can be shortened.
Each configuration, combination, and the like in the embodiment described above is an example, and addition, omission, substitution, and other modifications of the configuration can be made without departing from the spirit of the present invention. Nor. Further, it is needless to say that the present invention is not limited by one embodiment, and is limited only by the claims.

1 Crankshaft 3a to 3e Journal section (crank journal section)
4 Slide surface 5a to 5d of the journal section Pin section (crank pin section)
6 Pin sliding surface 7, 9 Fillet A A semicircular part on the top side of the pin part B

Claims (3)

Applying predetermined rolling to the axial end of the crank journal portion and the fillet on the axial end of the clamp pin portion;
A step of induction hardening the sliding surface of the crank journal and the sliding surface of the clamp pin including the fillets of the axial ends of the crank journal and the clamp pin after finishing the rolling process Equipped with and
The roll processing is fillet roll processing for pressing the fillet roll against the fillet portion,
The method of manufacturing a crankshaft according to claim 1, wherein the fillet roll processing is deformed in advance so as to offset the amount of deformation of the crankshaft due to the induction hardening . The fillet roll process for offsetting the amount of deformation of the crankshaft is to make the fillet load applied to at least the top half of the crankpin portion greater than the fillet load applied to the bottom half of the crank pin based on the amount of deformation. A method of manufacturing a crankshaft according to claim 1 , characterized in that: 3. The crankshaft according to claim 1 , wherein the induction hardening is controlled so that the amount of deformation of the crankshaft is minimized when the amount of deformation of the crankshaft is a predetermined amount of quenching depth. Method.

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