JP7496109B2 - High frequency induction heating equipment for shaft-shaped workpieces - Google Patents

Description

The present invention relates to a high-frequency induction heating device for axial workpieces that has multiple heating coil bodies with integrated disk-type transformers. In particular, the present invention relates to a high-frequency induction heating device that is suitable for high-frequency induction heating of crankshafts.

The crankshaft has a journal portion whose center coincides with the center of rotation of the crankshaft, and a pin portion whose center does not coincide with the center of rotation of the crankshaft.

When induction hardening the journal portion of such a crankshaft and the pin portion adjacent to this journal portion, a heating coil body for the journal portion, which has a semi-open heating coil that faces closely to the journal portion, and a heating coil body for the pin portion, which has a semi-open heating coil that faces closely to the pin portion, have been used in the past.

Because the center of the journal portion coincides with the center of rotation of the crankshaft, when the crankshaft rotates, the journal portion rotates on the spot without changing its position. The journal portion heating coil body stops on the spot without changing its position. As the journal portion rotates (spins) relative to the heating coil of the journal portion heating coil body that is stopped, the entire circumference of the journal portion comes into close contact with the heating coil of the journal portion heating coil body through which high-frequency current is passed, and high-frequency induced current is excited around the entire circumference, causing the entire circumference to be heated uniformly to the hardening temperature.

However, because the center of the pin does not coincide with the center of rotation of the crankshaft, when the crankshaft rotates, the pin rotates (revolves) in a circular orbit around the center of rotation of the crankshaft. The pin rotates once on its own axis for each revolution around the center of rotation of the crankshaft.

The heating coil body for the pin portion moves following the revolution of the pin portion, approaching the pin portion from the same direction. Therefore, the semi-open structure heating coil of the heating coil body for the pin portion and the rotating pin portion rotate relatively. Then, while the pin portion rotates once around the rotation center of the crankshaft, the entire circumference of the pin portion sequentially approaches and faces the heating coil of the heating coil body for the pin portion through which high-frequency current is passed, and a high-frequency induced current is excited around the entire circumference of the pin portion, causing the temperature of the entire circumference of the pin portion to rise uniformly to the hardening temperature.

In addition, the heating coil of the first heating coil body and/or the heating coil body for the pin part is located close to the boundary between the journal part and the pin part, and high-frequency induced current is excited in the same way as in the journal part and the pin part, raising the temperature to the hardening temperature.

When the journal and pin parts reach their hardening temperature, the high-frequency current is turned off and cooling liquid is sprayed from the cooling jacket to rapidly cool the journal and pin parts from their hardening temperature to a specified temperature, completing the induction hardening process.

To successfully harden the journal and pin parts, it is necessary to ensure that the heating coils do not shift in the axial direction of the crankshaft relative to the journal and pin parts, respectively. Between the journal and pin parts, arms extending in a direction perpendicular to the axial direction of the crankshaft are provided, and by arranging the heating coil body between the opposing arms, the heating coil body is restrained by both arms and is prevented from moving axially beyond the range of the pin and journal parts to be heat treated.

However, only the journal portion (end journal portion) located at the very end of the crankshaft has an arm portion on only one side, so the heating coil body that high-frequency induction heats the end journal portion can move freely to the side where there is no arm portion, and the axial position cannot be fixed.

Patent document 1 discloses a configuration in which a pressing member is provided to press the heating coil body, which high-frequency induction heats the end journal portion, toward the arm portion, preventing the heating coil body from moving in the axial direction.

The induction hardening device disclosed in Patent Document 1 prevents the heating coil from shifting out of position relative to the crankshaft by pressing a heating coil (coil body) that induction hardens the journal portion at the very end of the crankshaft, which is adjacent to the arm portion only on one axial side of the crankshaft, toward the arm portion from the outside of the end of the crankshaft.

Japanese Patent No. 3723316

Incidentally, engines today are becoming smaller, and crankshafts are also becoming smaller.
That is, in order to shorten the axial length of the crankshaft, a crankshaft W in which the arm portion is omitted has been developed, as shown in Fig. 9. The crankshaft W shown in Fig. 9 is not provided with the arm portion.

When induction hardening the journal portion J (end journal portion) at the end of the crankshaft W shown in Figure 9 and the pin portion P adjacent to this journal portion J at the same time, it is not possible to fix the two coil bodies in the appropriate positions by pressing either the coil body for induction hardening the journal portion J or the coil body for induction hardening the pin portion P with a pressing device such as the conventional induction hardening device disclosed in Patent Document 1.

The present invention aims to provide a high-frequency induction heating device for axial workpieces that can simultaneously high-frequency induction heat at least two adjacent parts of the axial workpiece that are to be heated by high-frequency induction, and that can position a heating coil appropriately close to and facing each of the parts to be heated by high-frequency induction.

A first aspect for solving the above problem is a high-frequency induction heating device for an axial workpiece, which has a plurality of disk-type transformers integrated with a heating coil body having a heating coil through which a high-frequency current is passed, and the disk-type transformers are arranged in a line in the axial direction of the axial workpiece in close proximity to each other, and the disk surface of each disk-type transformer is perpendicular to the axial direction of the axial workpiece, and the disk-type transformers are spaced apart at a predetermined interval, and the device has a position holding means for allowing relative movement of each disk-type transformer in a direction perpendicular to the axial workpiece ,
The position holding means has a fixed portion, a clamped portion having a fixed side member and a moving side member , and a pressing portion, the fixed portion is disposed on the outside of the outermost disk-type transformer in the arrangement direction of all the disk-type transformers lined up in a row, the pressing portion is disposed on the outside of the outermost disk-type transformer on the opposite side to the fixed portion, the clamped portion is disposed between adjacent disk-type transformers, the pressing portion has a function of pressing the disk-type transformer at one end or the heating coil body integrated with the disk-type transformer toward the fixed portion, and the fixed portion has a function of pressing the disk-type transformer at the other end or the heating coil body integrated with the disk-type transformer toward the fixed portion. the clamped portion has a function of abutting against a heating coil body integrated with the disk-type transformer and preventing movement of the disk-type transformer at the other end in the arrangement direction of the disk-type transformers, the clamped portion is fixed to one of the adjacent disk-type transformers and has a plurality of spherical rolling bodies that can rotate freely, and abuts against the other adjacent disk-type transformer to maintain a predetermined distance between these disk-type transformers and fix them in place, and each of the rolling bodies abuts against the other adjacent disk-type transformer, and the moving side member revolves in accordance with the movement of the disk-type transformer .

In this aspect, the position holding means has a fixed part, a clamped part having a fixed side member and a moving side member , and a pressing part, the fixed part is arranged outside the outermost disk type transformer in the arrangement direction of all the disk type transformers lined up in a row, the pressing parts are arranged outside the outermost disk type transformers on both sides opposite to the fixed parts, and the clamped parts are arranged between adjacent disk type transformers. That is, there are at least some disk type transformers that are clamped between the fixed part and the clamped part, and some that are clamped between the clamped part and the pressing part.
In addition, the pressing portion has the function of pressing the disk-type transformer at one end or the heating coil body integrated with the disk-type transformer toward the fixed portion, and the fixed portion abuts the disk-type transformer at the other end or the heating coil body integrated with the disk-type transformer, and has the function of preventing movement of the disk-type transformer at the other end in the arrangement direction of the disk-type transformers.
The clamped portion is fixed to one of the adjacent disk-type transformers and abuts against the other adjacent disk-type transformer to maintain a predetermined distance between these disk-type transformers and fix them in place, while each of the rolling elements abuts against the other adjacent disk-type transformer, and the moving member revolves in accordance with the movement of the disk-type transformer.
That is, when the pressing portion presses the disk-type transformer or the heating coil body integrated with the disk-type transformer, the pressing force is transmitted from the disk-type transformer to another adjacent disk-type transformer via the clamped portion. That is, the moving member is moved in an orbital motion while being kept pressed against the fixed member. The clamped member can transmit the pressing force from the disk-type transformer to another adjacent disk-type transformer while following the movement of the heating coil body.

It is preferable that the pressing portion follows the movement of the disk-type transformer pressed by the pressing portion, or the heating coil body integrated with the disk-type transformer, in a direction perpendicular to the shaft-shaped workpiece .

According to this configuration, the pressing portion follows the movement of the disk-type transformer pressed by the pressing portion, or the heating coil body integrated with the disk-type transformer, in a direction perpendicular to the axial workpiece , so that the disk-type transformer pressed by the pressing portion, or the heating coil body integrated with the disk-type transformer, can move smoothly in a direction perpendicular to the axial workpiece .

The axial workpiece is a crankshaft having a journal portion and a pin portion, and the surface of the connection portion between the journal portion and the pin portion does not protrude in a direction perpendicular to the axial workpiece; the fixed portion abuts against a disk-type transformer arranged on the journal portion of the crankshaft, or a heating coil body integral with the disk-type transformer; and when the pressing portion presses a disk-type transformer arranged on a pin portion adjacent to the journal portion, or a heating coil body integral with the disk-type transformer, the pressing member maintains a state in which the moving side member constituting the clamped member is pressed against a fixed side member constituting the clamped member, and is moved by the clamped member in a direction perpendicular to the axial workpiece in accordance with the movement of the disk-type transformer or the heating coil body integral with the disk-type transformer in the direction perpendicular to the axial workpiece.

It is preferable that the pressing portion has a coil spring that bends to resist the pressing force when pressing down on the disk-type transformer or the heating coil body integrated with the disk-type transformer, and that the coil spring in the pressing portion follows the movement of the disk-type transformer or the heating coil body integrated with the disk-type transformer in a direction perpendicular to the axial workpiece .

According to this configuration, when the pressing portion presses the disk-type transformer or the heating coil body integrated with the disk-type transformer, the pressing portion has a coil spring that bends to resist the force, and the coil spring in the pressing portion follows the movement of the disk-type transformer or the heating coil body integrated with the disk-type transformer in a direction perpendicular to the axial workpiece, so that the coil constitutes a following mechanism, and the following mechanism can be realized with a simple configuration. In other words, if the contact portion between the disk-type transformer or the heating coil integrated with the disk-type transformer and the pressing portion is fixed by, for example, frictional force, when the disk-type transformer or the heating coil body integrated with the disk-type transformer moves in a circular orbit, the bending direction of the bending coil spring in the pressing portion changes to follow the movement of the circular orbit.

According to the present invention, the heating coil can be positioned appropriately close to and facing each of the parts of the axial workpiece that are to be subjected to high-frequency induction heating, thereby enabling each part to be heat-treated to be effectively subjected to high-frequency induction heating.

1 is a schematic system diagram of a high-frequency induction heating device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which two heating coil bodies integrated with a disk-type transformer are disposed adjacent to a workpiece in the high-frequency induction heating device according to the present embodiment. FIG. 3 is a perspective view showing a state in which the two heating coil assemblies are separated from the workpiece in FIG. 2 and the fixing member is removed from the workpiece. 4 is a perspective view of the two heating coil assemblies in which the workpiece, the fixing member, and the disk-type transformer shown in FIG. 3 are integrated, as viewed from different angular positions. 5A to 5B are side views showing the state in which two heating coil bodies integrated with the disk-type transformers of Figures 2 to 4 are in close proximity to the journal portion and pin portion of the crankshaft, which is the workpiece, where (a) shows the state in which one heating coil body is in close proximity to the pin portion at the top dead center position, and (b) shows the state in which one heating coil body is in close proximity to the pin portion at the bottom dead center position. FIG. 4 is a side view showing a state in which the workpiece and the two heating coil bodies are separated from each other. 1A is a side view of the position holding mechanism, and FIG. FIG. 8 is an exploded perspective view of the position holding mechanism as viewed from an angle position different from that of FIG. 7( b ). FIG. 2 is a perspective view of a workpiece to be high-frequency induction heated in the present embodiment. 10A to 10D are front views showing imaginary positional relationships between a fixed member and a movable member of a clamped member when a workpiece is rotated. FIG. 3 is a perspective view showing a state in which two heating coil bodies integrated with a disk-type transformer are disposed adjacent to a workpiece in a high-frequency induction heating device according to another embodiment different from that shown in FIG. 2 . FIG. 12 is a perspective view of the position retention mechanism of FIG. 11 .

The following description will be given with reference to the drawings.
As shown in FIG. 1, a high-frequency induction heating device 1 for a shaft-shaped workpiece W has a high-frequency oscillator 2, a disk-type transformer 3 (3a, 3b), and a heating coil 4 (4a, 4b).

The high-frequency induction heating device 1 is connected to a commercial power source 20 .
The high-frequency oscillator 2 converts the power supplied from a commercial power source 20 into a high-frequency signal and outputs it to the disk-type transformer 3 (3a, 3b). The disk-type transformer 3 (3a, 3b) has a primary side (primary winding) connected to the high-frequency oscillator 2 and a secondary side (secondary winding) connected to the heating coil 4 (4a, 4b).

As shown in FIG. 2, in this embodiment, the high-frequency induction heating device 1 has two disk-type transformers 3a and 3b. That is, the disk-type transformers 3a and 3b are connected in parallel to the high-frequency oscillator 2 in FIG. 1, and heating coils 4a and 4b are connected to the disk-type transformers 3a and 3b, respectively.

Although the disk-type transformers 3a and 3b differ slightly in size, they have the same basic structure, so the following will describe the disk-type transformer 3a and will omit a duplicated description of the disk-type transformer 3b.

As shown in FIG. 2, the outer shape of the disk-type transformer 3a is a thin box shape.
The disk-type transformer 3a has a housing 12a made of a material that is rigid and not easily affected by electromagnetic induction. That is, a primary winding and a secondary winding are provided inside the housing 12a, and the housing 12a forms the outer shape (contour) of the disk-type transformer 3a.
Connection terminals 9a and 9b (FIGS. 1 and 2) are provided on the lower portion of the housing 12a. As shown in FIG. 1, the connection terminals 9a and 9b are terminals provided on both ends of the secondary winding.

An engagement part 10 is provided on the upper part of the housing 12a. The engagement part 10 is attached to a support member 11 that is suspended and supported by a hanging member 22 (chain) on a fixed structure (not shown). That is, the engagement part 10 is connected to the support member 11 by a connecting shaft 14. The connecting shaft 14 penetrates the support member 11 and the engagement part 10. The connecting shaft 14 also extends parallel to the axial direction of the crankshaft W when the disk-type transformer 3a is placed on the workpiece W (crankshaft) described below. There is no clearance between the engagement part 10 and the support member 11 in the direction in which the connecting shaft 14 extends. That is, the engagement part 10 (disk-type transformer 3a) is supported so as to be able to only swing relative to the support member 11 (fixed structure) via the connecting shaft 14.

In addition, a protruding member 16 that is integrated with a fixed structure (not shown) is provided above the disk-type transformer 3a. The protruding member 16 has rigidity and is a member whose position is fixed regardless of the operation of the disk-type transformer 3a.

Next, the heating coils 4a and 4b will be described.
The heating coils 4a, 4b are slightly different in size but have the same basic structure, so the following description will focus on the heating coil 4a and will omit a duplicated description of the heating coil 4b.

The heating coil 4a is composed of a tube member made of a good conductor such as copper or a copper alloy. A cooling liquid can be circulated and supplied inside the heating coil 4a. As shown in FIG. 1, the heating coil 4a has a pair of lead portions 13a, 13b and a closely facing portion 13c. The ends of the lead portions 13a, 13b are provided with connection terminals 8a, 8b (FIGS. 1 and 2), respectively. The connection terminals 8a, 8b are electrically connected to the connection terminals 9a, 9b of the disk-type transformer 3a, respectively. The closely facing portion 13c is a portion that closely faces the workpiece W (crankshaft). The closely facing portion 13c has a semi-open structure with an arc shape with a central angle of approximately 180 degrees.

The heating coil 4a is placed between side plates 5a, 5b (Fig. 2) made of a material that is rigid and not easily affected by electromagnetic induction. The side plates 5a, 5b are arranged parallel to each other with a specified distance between them. Both side plates 5a, 5b have arc-shaped cutouts along the closely facing portion 13c of the heating coil 4a, and spacers 15a to 15c (Fig. 1) are placed in multiple locations (three locations on each of the side plates 5a, 5b) of the arc-shaped cutouts. Each of the spacers 15a to 15c protrudes radially inward from the closely facing portion 13c of the heating coil 4a.

In addition, a cooling jacket 6 (FIG. 2) that sprays cooling liquid is provided below the heating coil 4a. The cooling jacket 6 has the function of spraying cooling liquid (quenching water) supplied from a cooling liquid supply source (not shown) toward the heated part of the workpiece W.

The side plates 5a and 5b, the multiple spacers 15a to 15c fixed to the side plates 5a and 5b, the heating coil 4, and the cooling jacket 6 are integrated together to form the heating coil body 7a (7b).

The aforementioned connection terminals 8a, 8b at both ends of the heating coil 4a (lead portions 13a, 13b) are provided on the upper part of the heating coil body 7a. The heating coil body 7a is connected to the connection terminals 9a, 9b of the disk-type transformer 3a via the connection terminals 8a, 8b. When the connection terminals 8a, 8b on the heating coil 4a side and the connection terminals 9a, 9b on the disk-type transformer 3a side are connected, the disk-type transformer 3a (secondary side) and the heating coil 4a are in a state in which electricity can flow.

The disk-type transformer 3a and the heating coil body 7a are electrically connected, and the housing 12a of the disk-type transformer 3a and the housing (side plates 5a, 5b) of the heating coil body 7a are integrated.

The support member 11 has other configurations for balancing the suspended disk-type transformer 3a, but as they are not directly related to the main part of the present invention, their description will be omitted.

The workpiece W to be induction heated by the high-frequency induction heating device 1 is a crankshaft (shaft-shaped workpiece) having pin portions PA and PB and journal portions JA and JB, as shown in FIG. 9. The journal portions JA and JB are arranged on both sides of the workpiece W in the longitudinal direction. The pin portion PA is adjacent to and continuous with the journal portion JA, and the pin portion PB is adjacent to and continuous with the journal portion JB. An eccentric portion H is provided between the pin portions PA and PB. In other words, the workpiece W has a structure in which, from one end, the journal portion JA, pin portion PA, eccentric portion H, pin portion PB, and journal portion JB are continuous.

The surface of the connection between the journal portion JA and the pin portion PA does not protrude radially outward from the workpiece W, and the journal portion JA and the pin portion PA are smoothly continuous. The centers of the journal portions JA and JB coincide with the center of rotation of the workpiece W. In addition, the centers of the pin portions PA and PB are offset from the center of rotation of the workpiece W, and the phase of the pin portions PA and PB is shifted by 180 degrees.

Furthermore, before heat treatment, the workpiece W has an excess portion EA on the end side of the journal portion JA. The excess portion EA forms a tapered surface that becomes larger in diameter as it moves from the end toward the journal portion JA. The excess portion EA is also a portion that will be cut off once heat treatment of the workpiece W is complete. Similarly, an excess portion EB is provided on the end side of the journal portion JB. The excess portion EB has a cylindrical shape. The excess portion EB is also cut off once heat treatment of the workpiece W is complete.

Next, the position holding mechanism 21 (position holding means), which is a main part of the present invention, will be described with reference to Figures 7 and 8. The position holding mechanism 21 has the function of holding the heating coil bodies 7a, 7b at a specific position on the workpiece W. As shown in Figures 7(a), 7(b) and 8, the position holding mechanism 21 has a fixing member 23 (fixing portion), a clamped member 24 (clamped portion), and a pressing member 25 (pressing portion). The fixing member 23 and the pressing member 25 are arranged on both sides of the arrangement direction of the disk-type transformers 3a, 3b (all disk-type transformers), and the clamped member 24 is arranged between the adjacent disk-type transformers 3a, 3b.

The fixed member 23 (fixed portion) is a member that is fitted onto the outside of a rotation support member (center pin) that rotatably supports the workpiece W. The fixed member 23 has a rigid cylindrical member 26 and an annular abutment member 27. In particular, the abutment member 27 is made of a material with excellent abrasion resistance. The abutment member 27 is integrated with the cylindrical member 26 by screwing or the like so that it is concentric with the cylindrical member 26.

The inner diameter of the cylindrical member 26 is larger than the workpiece W (excess length EA) and is large enough to be fixed to a rotation support member. The inner diameter of the abutment member 27 is also larger than the excess length EA and journal portion JA of the workpiece W.

When the fixed member 23 is attached to the rotation support member, the abutment member 27 is positioned concentrically with the journal portion JA without contacting the workpiece W. Furthermore, the end face of the abutment member 27 is positioned on or near a vertical plane that includes the boundary K between the excess portion EA of the workpiece W and the journal portion JA.

The pressing member 25 (pressing portion) has a main body portion 28 and an abutment mechanism portion 29. The pressing member 25 has the function of pressing the disk-type transformer 3a or the heating coil body 7a integrated with the disk-type transformer 3a against the fixed member 23.

The main body portion 28 has rigidity and constitutes the framework of the pressing member 25. The main body portion 28 has an attachment portion 28a, an extension portion 28b, a reinforcing portion 28c, and a tip portion 28d.
The mounting portion 28a is a flat plate-shaped portion that is fixed to the protruding member 16 by a fixing means such as a screw.
The extension portion 28b is a portion that is continuous with the attachment portion 28a and extends parallel (or approximately parallel) to the attachment portion 28a.
The reinforcing portion 28c extends along the longitudinal direction of the extending portion 28b and is integrated with the extending portion 28b to reinforce the extending portion 28b.
The tip portion 28d is a portion provided on the free end side of the extension portion 28b, and is a portion to which the abutment mechanism portion 29 is attached.

Abutment mechanism 29 is fixed to tip 28d. Abutment mechanism 29 has support portion 29a and pressing portion 29b.

The support portion 29a is constructed by bending a long, thin plate-like member, with one end fixed to the tip portion 28d and an attachment hole 29c provided near the other end, which is the free end.

The pressing portion 29b has a roller 30a, a holding portion 30b, and an attachment portion 30c.
The roller 30a is a rigid spherical member. The holding portion 30b can hold the roller 30a, and a part of the roller 30a is exposed from the holding portion 30b. When an external force acts on the roller 30a, the roller 30a can freely rotate in response to the external force while being held by the holding portion 30b.

The mounting portion 30c is a shaft-shaped portion, and one end is fixed to the side of the holding portion 30b opposite to the portion where the roller 30a is exposed. In other words, the mounting portion 30c and the holding portion 30b are integral. The mounting portion 30c is attached to the mounting hole 29c of the support portion 29a. It is preferable that the mounting portion 30c is a male thread and the mounting hole 29c is a female thread.

That is, the pressing portion 29b can finely adjust the position of the pressing portion 29b (roller 30a) relative to the tip portion 28d. The mounting position of the roller 30a relative to the holding portion 30b can be adjusted so that the roller 30a just abuts against the surface of the housing 12a of the disk-type transformer 3a (described below) that is hung from the support member 11 (hanging member 22). Because the main body portion 28 has rigidity, the position of the roller 30a relative to the protruding member 16 (fixed structure) is fixed.

The clamped member 24 (clamped portion) has a fixed side member 31 and a movable side member 32.

The fixed member 31 is a disk-shaped member made of a wear-resistant material, with one surface forming the mounting surface 31a and the other surface forming the abutment surface 31b. The fixed member 31 is fixed to the housing 12 of the disk-type transformer 3b (described below) by a fixing means such as a screw. In this case, the mounting surface 31a is in close contact with the housing 12, and the abutment surface 31b is the exposed surface. The abutment surface 31b forms a flat surface with a small coefficient of friction. Note that the fixed member 31 can be omitted, and the clamped member 24 can be composed of only the moving member 32 (described below).

The moving member 32 has a base 32a and pressing portions 33a to 33c.
The pressing parts 33a to 33c have the same mechanism as the pressing part 29b of the pressing member 25 described above, and have holding parts 34a to 34c and spherical rollers 35a to 35c (rolling bodies). That is, the pressing parts 33a to 33c have a structure in which the rollers 35a to 35c are held in a state in which a part of the rollers 35a to 35c is exposed relative to the holding parts 34a to 34c that function as housings. The rollers 35a to 35c are held so as to be freely rotatable relative to the holding parts 34a to 34c, respectively. The mounting parts 36a to 36c protrude from the parts of the holding parts 34a to 34c opposite the parts where the rollers 35a to 35c are exposed.

The base 32a is a member on which multiple pressing parts 33a to 33c can be installed at equal angular intervals, and in this embodiment, has a circular ring shape. The base 32a has mounting holes 37a to 37c at equal angular intervals. The mounting parts 36a to 36c of the pressing parts 33a to 33c are attached to the respective mounting holes 37a to 37c, and the pressing parts 33a to 33c are fixed to the base 32a. It is preferable that the mounting parts 36a to 36c are male threaded, and the mounting holes 37a to 37c of the base 32a are female threaded.

As shown in Figures 10(a) to 10(d), the outer diameter of the base 32a is smaller than the outer diameter of the fixed member 31. In other words, the base 32a can revolve without departing from the fixed member 31, with the center 39 of the base 32a tracing a circular orbit of a predetermined size around the center 38 of the fixed member 31. When the base 32a moves tracing a circular orbit, the rollers 35a to 35c of the pressing parts 33a to 33c each move within the range of the fixed member 31. In other words, the rollers 35a to 35c are constantly in contact with the fixed member 31 during the orbital movement of the base 32a.

Next, the layout of the position holding mechanism 21 will be described.
9, the excess part EB of the workpiece W is held by a chuck (not shown) that is rotatably driven, and the excess part EA is supported by a center pin (support member) (not shown). In other words, the workpiece W is supported rotatably.

The fixing member 23 shown in FIG. 6 is attached so as to fit onto the center pin that rotatably supports the workpiece W. This fixing member 23 is arranged around the excess portion EA of the workpiece W, and the end face of the fixing member 23 is arranged within a vertical plane that includes the boundary K between the excess portion EA and the journal portion JA.

As shown in Figures 3 and 6, the fixed side member 31 of the clamped member 24 is wear-resistant and is fixed to a portion of the housing 12b of the disk-type transformer 3b that faces the disk-type transformer 3a. In other words, the fixed side member 31 is integrated with the disk-type transformer 3b. As shown in Figures 4 and 6, the movable side member 32 (base 32a) corresponding to the fixed side member 31 is fixed to a portion of the housing 12a of the disk-type transformer 3a that faces the disk-type transformer 3b.

The pressing member 25 is disposed on the surface of the housing 12a of the disk-type transformer 3a opposite to the disk-type transformer 3b (the right side as viewed in FIG. 6). The pressing member 25 is attached to the support member 11 that is integral with the hanging member 22 that hangs the disk-type transformer 3a. The pressing portion 29b (roller 30a) of the pressing member 25 abuts against the housing 12a of the disk-type transformer 3a.

A pressing member 25 is provided on one side (the right side as viewed in FIG. 6) of the disk-type transformer 3a, and a movable member 32 of the clamped member 24 is attached to the other side (the left side as viewed in FIG. 6). In addition, a fixed member 31 of the clamped member 24 is attached to one side (the right side as viewed in FIG. 6) of the disk-type transformer 3b.

Furthermore, there is no member attached to the other side (left side as viewed in FIG. 6) of the disk-type transformer 3b, but when the disk-type transformer 3b (heating coil body 7b) is placed on the journal part JA, the fixing member 23 is placed on the side of the heating coil body 7b opposite the side on which the fixed side member 31 is placed. Then, the annular abutment member 27 of the fixing member 23 abuts against the heating coil body 7b (side plate 5b).

Furthermore, when the disk-type transformer 3a is placed on the pin portion PA of the workpiece W, the fixed-side member 31 fixed to the disk-type transformer 3b faces the movable-side member 32 fixed to the disk-type transformer 3a, and the pressing portions 33a to 33c (rollers 35a to 35c) of the movable-side member 32 come into contact with the fixed-side member 31.

Next, we will explain the positional relationship between the workpiece W, the disk-type transformers 3a and 3b (heating coil bodies 7a and 7b), and the position holding mechanism 21 when the workpiece W is high-frequency induction heated by the high-frequency induction heating device 1 (Figure 1).

As shown in FIG. 5(a), the heating coil bodies 7a and 7b with the disk-type transformers 3a and 3b integrated therewith and the fixing member 23 are placed on the workpiece W shown in FIG. 6.

As shown in FIG. 5(a), the disk-type transformer 3b has the heating coil 4b positioned close to the journal portion JA (FIG. 6) so that the side plate 5b of the heating coil body 7b abuts against the annular abutment member 27 of the fixing member 23. In other words, the hanging member 22 is driven so that the disk-type transformer 3b and the heating coil body 7b are in that position.

As a result, the spacer 15a shown in FIG. 1 comes into contact with the workpiece W (journal portion JA), and the height positions of the heating coil body 7b and the disk-type transformer 3b relative to the journal portion JA are set. In other words, the disk-type transformer 3b and the heating coil body 7b are placed on the journal portion JA and are horizontally balanced on the journal portion JA.

The distance between the left and right spacers 15b, 15c shown in FIG. 1 is slightly larger than the diameter of the workpiece W. The distance between the spacers 15b, 15c of the heating coil body 7b is slightly larger than the diameter of the journal portion JA.

The side plate 5b of the heating coil body 7b abuts against the annular abutment member 27 of the fixing member 23, and the horizontal positions (axial direction of the workpiece W) of the heating coil body 7b and the disk-type transformer 3b are fixed. At this time, the heating coil 4b of the heating coil body 7b is closely opposed to an area spanning approximately half the circumference of the journal portion JA.

The heating coil 4a of the heating coil body 7a, which is integrated with the disk-type transformer 3a, is brought close to the pin portion PA of the workpiece W. In other words, the hanging member 22 is driven so that the disk-type transformer 3a and the heating coil body 7a are in that position.

As a result, the spacer 15a shown in FIG. 1 comes into contact with the workpiece W (pin portion PA), and the heightwise positions of the heating coil body 7a and the disk-type transformer 3a relative to the pin portion PA are set. In other words, the disk-type transformer 3a and the heating coil body 7a are placed on the pin portion PA, and are horizontally balanced on the pin portion PA. At this time, the heating coil 4a closely faces an area spanning approximately half the circumference of the pin portion PA. The distance between the left and right spacers 15b, 15c shown in FIG. 1 is slightly larger than the diameter of the workpiece W. The distance between the spacers 15b, 15c of the heating coil body 7a is slightly larger than the diameter of the pin portion PA.

As shown in FIG. 5(a), when the pin portion PA of the workpiece W is at the top dead center position, the heating coil body 7a (disk type transformer 3a) is in the raised position. Also, as shown in FIG. 5(b), when the pin portion PA of the workpiece W is at the bottom dead center position, the heating coil body 7a (disk type transformer 3a) is in the lowered position.

As shown in FIGS. 5(a) and 5(b), a space D is formed between the disk-type transformers 3a and 3b, but the heating coil bodies 7a and 7b are close to each other.
That is, since the journal portion JA and the pin portion PA of the workpiece W are adjacent to each other, the heating coil body 7a (heating coil 4a) and the heating coil body 7b (heating coil 4b) need to be close to each other in the axial direction of the workpiece W.

On the other hand, the disk-type transformers 3a and 3b integrated with the heating coil bodies 7a and 7b do not need to be close to each other, and in this embodiment, a space D (FIG. 5(a)) is provided between the disk-type transformers 3a and 3b. The clamped member 24 is placed in this space D.

When the heating coil 4a is brought close to and facing the pin portion PA, as shown in Figures 5(a) and 5(b), the moving side member 32 of the clamped member 24 fixed to the housing 12a of the disk-type transformer 3a faces and comes into contact with the fixed side member 31 fixed to the housing 12b of the disk-type transformer 3b.

A pressing member 25 is provided on the side of the housing 12a of the disk-type transformer 3a opposite to the side on which the moving member 32 is provided. The contact mechanism 29 (roller 30a) of the pressing member 25 contacts the housing 12a of the disk-type transformer 3a.

When the pressing member 25 (contact mechanism 29) presses against the disk-type transformer 3a, the pressing force is transmitted to the fixed member 31 fixed to the disk-type transformer 3b via the rollers 35a to 35c (Figure 4) of the movable member 32 of the clamped member 24.

That is, the disk-type transformer 3a and the heating coil body 7a are suspended by the hanging member 22 so that the moving side member 32 of the clamped member 24 on the disk-type transformer 3a side abuts against the fixed side member 31 of the clamped member 24 on the disk-type transformer 3b side. That is, the rollers 35a to 35c of the moving side member 32 abut against the fixed side member 31 of the clamped member 24, thereby maintaining a predetermined distance between the disk-type transformers 3a and 3b.

In addition, the pressing member 25 fixed to the protruding member 16 presses the disk-type transformer 3a, preventing the disk-type transformer 3a from moving in a direction away from the fixed member 23. This fixes the horizontal positions of the disk-type transformer 3a and the heating coil body 7a.

Next, we will explain the operation of the position holding mechanism 21 when high-frequency induction heating the workpiece W.

When high-frequency power is supplied to the heating coils 4a and 4b from the high-frequency power supply side of the high-frequency induction heating device 1, a high-frequency current flows through the heating coils 4a and 4b, and the journal portion JA and pin portion PA that are close to the heating coils 4a and 4b are high-frequency induction heated.

During this process, the workpiece W is rotated, and with each rotation of the workpiece W, the entire circumference of the journal portion JA and the pin portion PA are sequentially opposed to the heating coils 4a and 4b, and are uniformly heated by high-frequency induction until the temperature rises to the hardening temperature.

While the journal portion JA rotates (spins), the heating coil 4b (heating coil body 7b) arranged on the journal portion JA stops in place and moves closer to the entire circumference of the journal portion JA in sequence. On the other hand, when the workpiece W rotates, the pin portion PA rotates (revolves) in a circular orbit around the center of rotation of the workpiece W.

Figure 5 (b) shows the state where the pin portion PA is at the bottom dead center position. When the pin portion PA reaches the bottom dead center position, the heating coil body 7a and the disk-type transformer 3a integrated with the heating coil body 7a also move down.

As a result, the heating coil bodies 7a and 7b move relative to each other. That is, the heating coil body 7a and the disk-type transformer 3a rotate in the same manner as the orbital movement of the pin portion PA. At that time, the fixed side member 31 and the moving side member 32 (rollers 35a to 35c) of the clamped member 24 move relative to each other, and the rollers 35a to 35c rotate by receiving an external force from the fixed side member 31. That is, the rollers 35a to 35c roll on the fixed side member 31 while being pressed against the fixed side member 31.

As a result, the heating coil body 7a can smoothly follow the revolution of the pin portion PA. In other words, the heating coil body 7a can follow the revolution of the pin portion PA while the axial position of the workpiece W is maintained at the position of the pin portion PA by the position holding mechanism 21. Therefore, the pin portion PA is efficiently heated by high-frequency wave induction heating by the heating coil 4a through which high-frequency current is passed.

In addition, because the disk-type transformer 3b (fixed member 31) is pressed against the disk-type transformer 3a (movable member 32), the heating coil body 7b is constantly pressed against the fixed member 23 (contact member 27), and the position of the heating coil body 7b in the axial direction of the workpiece W is maintained at the position of the journal portion JA. Therefore, the journal portion JA is effectively high-frequency induction heated by the heating coil 4b through which high-frequency current is passed.

The operation of the position holding mechanism 21 at this time will be further explained with reference to Figures 10(a) to 10(d).

Figures 10(a) to 10(d) are front views showing the positional relationship between the fixed side member 31 and the movable side member 32 of the position holding mechanism 21 when the heating coil body 7b integrated with the disk-type transformer 3b is placed on the journal part JA of the work W, and the heating coil body 7a integrated with the disk-type transformer 3a is placed on the pin part PA. That is, Figures 10(a) to 10(d) omit the depiction of the disk-type transformer 3a and show the positional relationship between the fixed side member 31 and the movable side member 32.

FIG. 10A shows the position of the movable member 32 relative to the fixed member 31 when the pin portion PA is at the top dead center position (the highest position).
FIG. 10B shows the position of the movable member 32 relative to the fixed member 31 when rotated 90 degrees from the rotation angle position of FIG. 10A.
Figure 10 (c) shows the position of the movable side member 32 relative to the fixed side member 31 when rotated 180 degrees from the rotation angle position of Figure 10 (a) and the pin portion PA is at the bottom dead center position (the lowest height position).
FIG. 10D shows the position of the movable member 32 relative to the fixed member 31 when rotated 270 degrees from the rotation angle position of FIG. 10A.

The center of the journal part JA coincides with the center of rotation of the workpiece W, so the height position of the journal part JA does not change even if the workpiece W rotates. In other words, the positions of the heating coil body 7b and the disk-type transformer 3b, which are adjacent to and face the journal part JA, do not change.

On the other hand, since the center of the pin portion PA is located away from the center of rotation of the workpiece W, when the workpiece W rotates, the pin portion PA revolves (moves in a circular orbit) around the center of rotation of the workpiece W. Therefore, the heating coil body 7a and the disk-type transformer 3a, which are adjacent to and face the pin portion PA, move following the pin portion PA.

As a result, while the workpiece W rotates once, the movable member 32 fixed to the disk-type transformer 3a, which moves along a circular path, moves relative to the fixed member 31 fixed to the stationary disk-type transformer 3b, as shown in Figures 10(a) to 10(d).

As shown in Figures 10(a) to 10(d), while the workpiece W rotates once, the pressing parts 33a to 33c of the moving member 32 move within the range of the abutment surface 31b of the fixed member 31, following the movement of the disk-type transformer 3a. Therefore, the moving member 32 can move smoothly relative to the fixed member 31. In other words, the moving member 32 (heating coil body 7a) can be moved orbitally while keeping the moving member 32 pressed against the fixed member 31. In other words, the clamped member 24 constitutes a following mechanism that moves the pressing parts 33a to 33c (rollers 35a to 35c) following the movement of the heating coil body 7a, which is integral with the disk-type transformer 3a, along a circular orbit.

As a result, the heating coil body 7b (side plate 5b) abuts against the fixed member 23, the position of the heating coil body 7b in the axial direction of the workpiece W is fixed, and the entire circumferential surface of the journal portion JA is uniformly high-frequency induction heated by the heating coil 4b through which high-frequency current is passed. In addition, the fixed side member 31 and the moving side member 32 of the clamped member 24 abut against each other, so that the axial position of the workpiece W of the disk-type transformer 3a is fixed, and the entire circumferential surface of the pin portion PA is uniformly high-frequency induction heated by the heating coil 4a through which high-frequency current is passed.

After high-frequency induction heating of the journal portion JA and the pin portion PA (after both portions have reached their hardening temperature), the high-frequency current flow through the heating coils 4a and 4b is stopped, and then cooling liquid is sprayed from the cooling jackets 6 (Figure 2) attached to the individual heating coil bodies 7a and 7b onto the journal portion JA and the pin portion PA to rapidly cool both portions, completing the induction hardening process.

In this way, with the high-frequency induction heating device 1 according to this embodiment, even if the axially shaped workpiece W (crankshaft) does not have a portion (the arm portion of a conventional crankshaft) that supports the heating coil bodies 7a, 7b in the axial direction, the heating coils 4a, 4b can be held at the positions of the adjacent journal portion JA and pin portion PA. This allows the workpiece W to be well-high-frequency induction heated (high-frequency hardened).

In this embodiment, the fixed side member 31 of the clamped member 24 is fixed to the disk-type transformer 3b, but the fixed side member 31 can be omitted. In other words, if the surface of the housing 12b of the disk-type transformer 3b is smooth and the housing 12b is wear-resistant, the position holding mechanism 21 can be composed of only the moving side member 32 without the fixed side member 31, and the rollers 35a to 35c of the moving side member 32 can be in direct contact with the housing 12b.

In this case, by providing a spacer between the base 32a of the moving member 32 and the housing 12a (disk type transformer 3a), the distance between the two disk type transformers 3a, 3b can be set to a predetermined distance (a distance at which the heating coil 4a faces the pin portion PA in an appropriate proximity). In addition, by providing washers (not shown) on the mounting portions 36a to 36c (FIG. 8) of the pressing portions 33a to 33c, the protruding positions of the rollers 35a to 35c can be adjusted.

In addition, in this embodiment, the pressing member 25 (pressing portion) presses against the housing 12 of the disk-type transformer 3a, but the pressing member 25 may also press against the heating coil body 7a (side plate 5a).

Furthermore, in this embodiment, the fixing member 23 (fixing portion) is described as contacting the side plate 5b of the heating coil body 7b that is integral with the disk-type transformer 3b, but instead, the fixing member 23 may be contacted with the housing 12b of the disk-type transformer 3b.

Next, a modified example of the position holding mechanism 21 will be described with reference to FIGS.
The position holding mechanism 41 shown in FIGS. 11 and 12 has a pressing member 45, and a fixed member 23 and a clamped member 24 similar to those of the position holding mechanism 21 shown in FIG.

That is, the position holding mechanism 41 and the position holding mechanism 21 differ from each other in the pressing member 45 only, and the other configurations are the same. Therefore, we will omit redundant explanations here and will only explain the configuration of the pressing member 45.

The pressing member 45 (pressing portion) has a main body portion 48 and a contact mechanism portion 49 .
The main body portion 48 has rigidity and constitutes the framework of the pressing member 45. The main body portion 48 has an attachment portion 48a, an extension portion 48b, a reinforcing portion 48c, and a tip portion 48d.
The mounting portion 48a is a flat plate-like portion that is fixed to a fixed structure (not shown) by a fixing means such as a screw.
The extension portion 48b is a portion that is continuous with the attachment portion 48a and extends parallel (or approximately parallel) to the attachment portion 48a.
The reinforcing portion 48c extends along the longitudinal direction of the extending portion 48b and is integrated with the extending portion 48b to reinforce the extending portion 48b.
The tip portion 48d is a portion provided on the free end side of the extension portion 48b, and is a portion to which the abutment mechanism portion 49 is attached.

The contact mechanism 49 is fixed to the tip 48d. The contact mechanism 49 has a support portion 49a and a pressing portion 49b.

The support portion 49a is formed by bending a long, thin plate-like member, with one end fixed to the tip portion 48d and the pressing portion 49b attached to the other end, which is the free end.

The pressing portion 49b has a roller 50a and a holding portion 50b.
The roller 50a is a rigid spherical member. The holding portion 50b can hold the roller 50a, and a part of the roller 50a is exposed from the holding portion 50b. When an external force acts on the roller 50a, the roller 50a can freely rotate in response to the external force while being held by the holding portion 50b.

The pressing member 25 is attached to the protruding member 16, and the extension portion 28b extends in the vertical direction, whereas the pressing member 45 has the extension portion 48b extending in the horizontal direction and is attached to a fixed structure (not shown) on the side.

The rollers 50a of the pressing member 45 press the housing 12a of the disk-type transformer 3a, and the movable member 32 fixed to the disk-type transformer 3a presses the fixed member 31 fixed to the disk-type transformer 3b. In addition, the side plate 5b of the heating coil body 7b integral with the disk-type transformer 3b abuts against the fixed member 23. Therefore, the position of the disk-type transformers 3a, 3b (heating coil bodies 7a, 7b) in the axial direction of the workpiece W is fixed, and the heating coil bodies 7a, 7b (heating coils 4a, 4b) are closely opposed to the pin portion PA and journal portion JA, respectively. In other words, the positions of the heating coils 4a, 4b do not shift in the axial direction of the workpiece W. Therefore, the journal portion JA and pin portion PA of the workpiece W are well high-frequency induction heated (high-frequency hardened).

In each of the above-described embodiments, two disk-type transformers 3a, 3b integrated with heating coil bodies 7a, 7b have been described, but when there are three or more locations on an axial workpiece that are to be simultaneously high-frequency induction heated, a disk-type transformer integrated with a heating coil body is disposed at each of the three or more locations to be heat-treated. That is, three or more disk-type transformers integrated with heating coil bodies are disposed in a row, a fixing member (fixing portion) and a pressing member (pressing portion) are disposed on both sides of the row of disk-type transformers, and a clamped member (clamped portion) is disposed between each of the adjacent disk-type transformers.

When configured in this manner, the heating coils of each heating coil body integrated into the disk-type transformer are positioned opposite each of the heat treatment target portions of the axial workpiece, and do not shift in position in the axial direction of the axial workpiece. In addition, each disk-type transformer can move smoothly relative to each other in a direction perpendicular to the axial direction of the axial workpiece (the direction in which each disk-type transformer is lined up).

In the above embodiment, the pressing member 25 (position holding mechanism 21) and the pressing member 45 (position holding mechanism 41) as the pressing part move in synchronization with the movement of the disk-type transformer 3a along a circular orbit.

In addition to the above, the pressing portion of the present invention may be a coil spring with one end fixed to a fixed structure, which presses against the housing 12a of the disk-type transformer 3a. In this case, when the disk-type transformer 3a moves in a circular orbit, the coil spring presses against the disk-type transformer 3a (housing 12a) while deforming at its intermediate (middle) portion. Also, a flexible rod may be used instead of the coil spring.

1 High frequency induction heating device 3a, 3b Disk type transformer 4a, 4b Heating coil 7a, 7b Heating coil body 21 Position holding mechanism (position holding means)
23: fixed portion 24: clamped portion 25: pressing portions 35a to 35c: rollers (rolling elements)

Claims (4)

A high-frequency induction heating device for an axial workpiece, comprising a plurality of disk-type transformers integrated with a heating coil body having a heating coil through which a high-frequency current is passed, the disk surface of each of the disk-type transformers being approximately perpendicular to the axial direction of the axial workpiece, and the disk-type transformers being arranged in a line in the axial direction of the axial workpiece close to each other,
A position holding means is provided for holding the disk-type transformers at a predetermined interval and allowing the disk-type transformers to move relative to each other in a direction perpendicular to the shaft-shaped workpiece ;
The position holding means has a fixed portion, a clamped portion having a fixed member and a movable member , and a pressing portion,
A fixing portion is disposed on the outer side of the outermost disk-type transformer in the arrangement direction of all the disk-type transformers arranged in a row, and a pressing portion is disposed on the outer side of the outermost disk-type transformer on the opposite side to the fixing portion,
The sandwiched portion is disposed between adjacent disk-type transformers,
the pressing portion has a function of pressing the disk-type transformer at one end or the heating coil body integrated with the disk-type transformer toward the fixed portion,
the fixing portion abuts against the disk-type transformer at the other end or a heating coil body integral with the disk-type transformer, and has a function of preventing the disk-type transformer at the other end from moving in the arrangement direction of the disk-type transformers,
The clamped portion is fixed to one of the adjacent disk-type transformers, has a plurality of spherical rolling elements capable of freely rotating, and abuts against the other adjacent disk-type transformer to maintain a predetermined distance between the disk-type transformers and fix them in place, and each of the rolling elements abuts against the other adjacent disk-type transformer,
A high-frequency induction heating device for an axial workpiece, characterized in that the moving member revolves in accordance with the movement of the disk-type transformer . The high-frequency induction heating device for an axial workpiece as described in claim 1, characterized in that the pressing portion follows the movement of the disk-type transformer pressed by the pressing portion, or the heating coil body integrated with the disk-type transformer, in a direction perpendicular to the axial workpiece . the shaft-shaped workpiece is a crankshaft having a journal portion and a pin portion, and a surface of a connection portion between the journal portion and the pin portion does not protrude in a direction perpendicular to the shaft-shaped workpiece;
the fixed portion is in contact with a disk-type transformer disposed on the journal portion of the crankshaft or a heating coil body integral with the disk-type transformer,
The high -frequency induction heating device for axial workpieces as described in claim 1 or 2, characterized in that when the pressing portion presses a disk-shaped transformer arranged on a pin portion adjacent to the journal portion, or a heating coil body integrated with the disk-shaped transformer, the pressing member is moved by the clamped member in a direction perpendicular to the axial workpiece, following the movement of the disk-shaped transformer or the heating coil body integrated with the disk-shaped transformer, while maintaining the moving side member constituting the clamped member pressed against the fixed side member constituting the clamped member. The high-frequency induction heating device for axial workpieces as described in claim 3, characterized in that the pressing portion has a coil spring that bends to resist the pressing force when pressing down on the disk-type transformer or the heating coil body integrated with the disk-type transformer, and the coil spring in the pressing portion follows the movement of the disk-type transformer or the heating coil body integrated with the disk-type transformer in a direction perpendicular to the axial workpiece.

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