JP3524037B2 - Induction tempering method and apparatus for crankshaft - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for collectively induction hardening an induction hardened journal portion, a pin portion, etc. of a crankshaft.

[0002]

2. Description of the Related Art FIG. 4 shows the structure of a 4-cylinder medium-sized crankshaft 1 which is an example of a crankshaft. The 4-cylinder medium-sized crankshaft 1 includes five journal portions 1J to 5J arranged along the same axis line (rotational axis line of the crankshaft 1) X, and these journal portion 1
Eight counter weights CW1 to CW8 provided integrally with J to 5J, and counter weights CW1 and CW2, CW3 and CW, which are arranged adjacent to each other and facing each other.
4, CW5 and CW6, CW7 and CW8, and four pin portions 1P which are respectively installed at positions offset from the axis of the journal portions 1J to 5J.
4P, the shaft portions S1 and S2 integrally formed coaxially with the journal portion 1J on the one end side, and the journal portion 5J on the other end side.
And a flange portion F integrally formed coaxially therewith.

Of the above-mentioned pin portions 1P to 4P, the pin portions 1P and 2P which are adjacent to each other in the direction of the rotation axis X are arranged at positions shifted by 180 ° from each other and are also adjacent to each other in the direction of the rotation axis X. Pins 3P and 4P
Are arranged at positions 180 ° out of phase with each other, the pin portions 1P and 4P at the left and right ends are arranged at the same phase with each other, and the pin portions 2P and 3P adjacent to each other in the rotation axis X direction are The phases are arranged at the same position as each other. In addition, as shown in FIG. 4, the flanges F at both ends of the crankshaft 1 and the axes of the shaft portions S1 and S2 are aligned with the extension of the rotation axis X of the journal portions 1J to 5J. It is configured to be rotationally driven about a linear rotation axis X. In FIG. 4, Y is a linear axis line of the pin portions 1P and 4P arranged in the in-phase position, and Z is a linear axis line of the pin portions 2P, 3P arranged in the same-phase position.

In such a crankshaft 1, usually, the cylindrical outer peripheral surfaces of the journal portions 1J to 5J are subjected to quenching treatment, and the pin portions 1P to 1P to
Quenching treatment is also applied to 4P. There are roughly two ways of quenching the pin portions 1P to 4P, namely, flat quenching and fillet R quenching.
There is a way. Here, the following briefly describes two methods of quenching the pin portions 1P to 4P.

First, each of the pin portions 1P to 4P has a columnar portion A having a cylindrical outer peripheral surface α, an R portion (corner or corner portion) B following the columnar portion A, and a subsequent R portion B. And a fillet portion C formed so as to extend at right angles to the axis X of the crankshaft 1 (see FIG. 5). Thus, the quenching method of quenching only the cylindrical outer peripheral surface α of the cylindrical portion A of the pin portions 1P to 4P is referred to as flat quenching, and the cylindrical outer peripheral surface α, the bay-shaped surface β of the R portion B and The method of quenching for quenching all the continuous surface portions (the portions indicated by a large number of points in FIG. 5) including the side surfaces γ of the fillet portion C is called fillet R quenching.

FIG. 5 shows an example of a quench hardening layer pattern when fillet R quenching is performed (in FIG. 5, only the quench hardening layer pattern of the pin portion 1P and the journal portions 1J, 5J is shown. ), In this case, the journal section 5
J, 5J cylindrical outer peripheral portion δ and pin portions 1P to 4P cylindrical outer peripheral portion α, as well as a right angle direction continuous from the cylindrical outer peripheral portion α through the curved surface β of the R portion B of the corner. The quench-hardened layer 6 is formed in a region continuous to the side surface γ of the fillet portion C. On the other hand, the journal part 1 at both left and right ends
For J and 5J, as shown in FIG. 5, the cylindrical outer peripheral portion δ of the cylindrical portion D and the side surface ε of the fillet portion C adjacent to the journal portions 1J and 5J are hardened by quenching the fillet R. The layer pattern 7 is generally formed (however, the other journal portions 2J to 4J are not subjected to quenching treatment). When forming different hardening hardening layer patterns 6 and 7 by induction hardening as shown in FIG. 5, each is heated to a required hardening temperature by using a dedicated high-frequency induction heating coil and then rapidly cooled. As a result, desired quench hardened layer patterns 6 and 7 are formed.

The crankshaft 1 thus hardened is usually tempered for the purpose of improving toughness and removing internal strain. By the way, conventionally, when tempering the crankshaft 1,
An electric furnace is generally used as a heating means.

[0008]

However, in the conventional tempering method in which the crankshaft 1 after quenching is heated to a required temperature by an electric furnace and then cooled, uniform and stable tempering quality can be obtained. However, since a comparatively long heating time is required, the compressive residual stress obtained by induction hardening is reduced during the heating, and the fatigue strength is greatly lowered. Moreover, the heating by the electric furnace is indirect heating, and since the crankshaft which is the body to be tempered is heated by the radiant heat from the heating element or the heat conduction from the atmosphere, it takes time to raise the temperature, There is a problem that the processing efficiency of tempering is poor. Incidentally, depending on the size and mass of the crankshaft to be tempered, generally, a heating time of about 0.5 to 1.5 hours is required, and 1 to heat soaking and maintaining the temperature are required. It takes 1.5 hours and the total tempering time is 1.5 to 3
Since it takes a long time, this is a serious obstacle to the incorporation of the induction tempering device into the crankshaft quenching processing line.

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

However, in the conventional induction tempering method as described above, fillet R-quenched journal portions 1J and 5 are used.
Since the flat heating coil heats only the cylindrical peripheral surface α of the column portion A of J and the pin portions 1P to 4P, the R portion B and the fillet portion C following the column portion A are separated from the column portion A. Heating is performed only by heat conduction.
Therefore, a relatively large temperature difference may occur between the heating temperature of the cylindrical portion A and the heating temperatures of the R portion B and the fillet portion C, and a relatively large temperature variation may occur in these respective portions. If such temperature difference and temperature variation remarkably occur, the tempering quality deteriorates, and there is a problem that a product (defective product) out of the specification is likely to occur.

Further, in order to carry out the conventional induction tempering method, the high frequency induction heating coil for heating the journal portion and the high frequency induction heating coil for heating the pin portion are used.
It is necessary to prepare different types of heating coils, and there is a problem that the equipment price becomes expensive. Also, journal section 1
It is necessary to perform the tempering treatment of J, 5J and the pin portions 1P to 4P in separate tempering treatment steps (two steps) using separate high frequency induction heating coils. There is also a problem that it takes time and labor and the processing efficiency is poor.

[0012] In short, in the conventional tempering method using an electric furnace, the time required for the tempering treatment is long, which is a great obstacle in incorporating the equipment into the tempering treatment processing line, and in the tempering method using the conventional high frequency induction heating. However, the fact is that the tempering quality and equipment price are difficult.

The present invention has been made in view of the above circumstances, and all the hardened parts such as the journal part and the pin part of the crankshaft are collectively (in one step) by the high frequency induction heating coil. ) By tempering, it is possible to obtain uniform and stable tempering quality while maintaining the retention of compressive residual stress, which is one of the advantages of induction hardening, and the equipment cost is low. An object of the present invention is to provide an induction tempering method for a crankshaft and an induction tempering apparatus for the same.

[0014]

In order to achieve the above-mentioned object, in the present invention, after the journal portion and the pin portion constituting the main portion of the crankshaft are hardened by fillet R,
Fillet R A method for tempering a quenched and hardened portion, comprising: (A) forming a coiled wire around the entire crankshaft including not only the hardened portion but also the non-quenched portion It is arranged at a position completely surrounded by a circular solenoid type high frequency induction heating coil, and in response to energization of the high frequency induction heating coil, the entire crankshaft is subjected to high frequency induction heating all at once. The quenching portion of the crankshaft is subjected to high frequency induction heating, and at the same time, the counterweight portion of the crankshaft, which is easy to be subjected to high frequency induction heating and has a large heat capacity, is also subjected to high frequency induction heating to conduct the heat to the R portion of the quenching portion. A heating step of heating the R portion, which is hard to be heated, together with the other quenching portions by high frequency induction heating up to a required tempering temperature, ) After the heating step, a soaking step for allowing the entire crankshaft to cool by heat conduction in the crankshaft for uniform heating, and (C) a polishing process following the tempering step is performed at room temperature. In order to achieve this, a cooling process of injecting a cooling liquid onto the crankshaft to cool the crankshaft is sequentially carried out, and a method of induction tempering a crankshaft is characterized. Further, in the present invention, after the steps described in (A) to (C), (D) an air blow step of removing the cooling liquid adhering to the crankshaft from the crankshaft in the cooling step is further performed. I am trying. Further, in the present invention, the heating step, the soaking step, the cooling step, and the air blowing step are sequentially and continuously performed while intermittently horizontally moving the crankshaft. Further, according to the present invention, there is provided a device for tempering a journal portion or a pin portion of a crankshaft which has been hardened with fillet R, including: (a) the crankshaft including not only the quenched portion but also the non-quenched portion. Is placed at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil formed by spirally winding a conductive wire, and in accordance with energization of the high frequency induction heating coil, The entire crankshaft is subjected to high frequency induction heating to heat the quenched portion of the crankshaft at the same time, and at the same time, the counterweight part of the crankshaft, which is easy to be subjected to high frequency induction heating and has a large heat capacity, is also subjected to high frequency induction heating. By conducting the heat to the R part of the hardened part, the R part, which is hard to be heated, together with the other hardened parts A heating station for high-frequency induction heating to a required tempering temperature, and (b) soaking the high-frequency induction-heated crankshaft so as to uniformly cool it by heat conduction of the crankshaft itself. A station and (c) a cooling station for cooling the crankshaft by injecting a cooling liquid onto the crankshaft in order to carry out the polishing process subsequent to the tempering step at room temperature. Further, in the present invention, in addition to the stations (a) to (c), (d) an air blow station for removing the cooling liquid attached to the surface of the crankshaft from the surface of the crankshaft in the cooling step, I am trying to prepare more. Further, in the present invention, in order to continuously perform the respective processing steps in the heating station, the soaking station, the cooling station and the air blow station while intermittently horizontally moving the crankshaft, (a) the crankshaft (B) a horizontal movement mechanism that horizontally moves the crankshaft under the condition that the crankshaft is supported by the support mechanism, and (c) the horizontal movement mechanism. The entire crankshaft, including not only the hardened portion but also the non-hardened portion, is completely surrounded by the entire crankshaft moved to the desired tempering temperature. A substantially circular solenoid tie formed by spirally winding a wire for high-frequency induction heating up to A heating mechanism having a high-frequency induction heating coil, a heat treatment section of the journal portion or a pin portion of the crankshaft which is high-frequency induction heating at; (d) heating mechanism, allowed to cool by thermal conduction of the crankshaft A soaking mechanism for achieving soaking; (e) an injection cooling mechanism for cooling the soaked heat treatment portion of the crankshaft transferred from the soaking mechanism to room temperature with an injection cooling liquid, (F) A tempering system including an air blow mechanism that applies air blow to the crankshaft transferred from the injection cooling mechanism is provided. Further, in the present invention, the crankshaft support mechanism disposed in the heating station includes: (a) the crankshaft being surrounded by a high-frequency induction heating coil in the heating station, and A pair of supporters made of a ceramic-based heat-resistant material that are in contact with both ends of the crankshaft in the axial direction when the support is arranged coaxially with the heating coil, and (b) the pair of supporters. And a pair of non-magnetic metal crankshaft supporting shafts, each of which is attached to the tip portion and is arranged so as to extend along the extension direction of the axis of the high-frequency induction heating coil. There is. Further, in the present invention, the horizontal movement mechanism of the crankshaft includes: (a) a supporter arranged at a predetermined interval corresponding to an arrangement interval of the soaking station, the cooling station, and the air blow station; And a crankshaft transport mechanism for sequentially transporting the crankshaft to the heating station, the soaking station, the cooling station, and the air blow station by moving the crankshaft in the up-down direction and the front-rear direction. ing. Further, in the present invention, the heating mechanism arranged in the heating station is composed of a high-frequency induction heating coil in which a conductive wire is spirally wound, and a coil portion corresponding to a flange portion on one end side of the crankshaft is wound. The wires are wound so that the line intervals are relatively close. Further, in the present invention, when the heating is stopped, the high-frequency induction heating coil is arranged in a standby position which is retracted in advance, and the high-frequency induction heating is started by supporting the crankshaft with a pair of supporting members made of the ceramic heat-resistant material. Prior to the above, a heating coil horizontal moving mechanism for advancing the high frequency induction heating coil from the standby position to a predetermined heating position and retracting it to the standby position after completion of the high frequency induction heating is provided. Further, in the present invention, the injection cooling mechanism disposed in the cooling station is (a) disposed with a predetermined distance from the crankshaft supported by the supporter, and the entire length and width of the crankshaft are provided. (B) a cooling water introducing pipe and a water supply pump connected to the injection cooling ring, the injection cooling ring having a rectangular shape corresponding to the above, and provided with a large number of cooling liquid injection holes on the surface facing the crankshaft. ) A moving mechanism that lowers the injection cooling ring to a position that is a predetermined distance from the crankshaft at the start of cooling and raises it to a predetermined standby position after the cooling is finished,
Are prepared for each. Further, in the present invention,
The air blow mechanism provided in the air blow station includes: (a) a plurality of air nozzles arranged at a predetermined distance from the crankshaft supported by the supporting device, the air nozzles corresponding to the size and shape of the crankshaft; (B) an air introducing pipe connected to the air nozzle, and (c) lowering the air nozzle to a position at a predetermined distance from the crankshaft at the start of air blowing, and moving to a predetermined standby position after the end of the air blowing. A moving mechanism and (d) a swinging device for swinging the air nozzle back and forth and left and right when air is blown are respectively provided. Further, in the present invention, one of the pair of supports made of the ceramic heat-resistant material is disposed adjacent to a support which supports a flange portion on one end side of the crankshaft. In addition, an induction assisting member that is made of a magnetic material that locally enhances the magnetic flux density and that functions to control the heating temperature of the flange-side portion of the crankshaft is provided at the flange-side end of the high-frequency induction heating coil. It is arranged near the part.
Further, in the present invention, the guide assisting member is a disc-shaped adjusting member made of a magnetic material and provided with a water passage therein.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. 1 to 4, the same parts as those in FIG. 5 are designated by the same reference numerals, and overlapping description will be omitted.

FIG. 1 shows an induction tempering apparatus 1 for carrying out a crankshaft induction tempering method according to an embodiment of the present invention.
0 of the crankshaft 1 of the crankshaft 1 and the pin 1P of which the fillet R has been hardened by the induction hardening device 11 as shown in FIG.
4P is for performing tempering treatment using one high-frequency induction heating coil 12.

The heat treatment mechanism 13 shown in FIG. 1 comprises the journal portions 1J and 5J of the crankshaft 1 and the pins 1P to 4P.
Induction hardening apparatus 11 for quenching fillet R, and a tempering apparatus 10 for collectively tempering the journal portions 1J and 5J and the pin portions 1P to 4P that have been fillet R quenched in this induction hardening apparatus 11. It consists of and. Then, when the crankshaft 1 is loaded from the charging port at the left end of the induction hardening device 11, the transport device 14 intermittently goes through each station in the hardening device 11 and the tempering device 10 thereafter. It is automatically discharged to the outlet OUT on the right end while being horizontally moved to. However, the transfer device 14 in the quenching device 11 is not shown.

The tempering device 10 described above is a heating station for high-frequency induction heating (heating heating) up to the required tempering temperature by the high-frequency induction heating coil 12 for the entire crankshaft 1 which is the object to be tempered (work). 21, and heat equalization stations 22 and 23 for cooling the entire crankshaft 1 (high-frequency induction heated) by heat conduction of the crankshaft 1 itself (quenched portion and hardened portion) to equalize the temperature.
In order to perform the polishing process following the tempering process at room temperature, the crankshaft 1 is sprayed with a cooling liquid.
A cooling station 24 that cools the air and an air blow station 25 that removes the cooling liquid that has adhered in the cooling process from the crankshaft 1 are respectively provided. It is configured to be automatically conveyed intermittently via 21 to 25 sequentially.

The heating station 21 is provided with equipment such as a furnace body 30 having a high-frequency induction heating coil 12 for heating the crankshaft 1 therein. As shown in FIGS. 1 and 2, the furnace body 30 is attached to a lower portion of the power source matching section 33. The high frequency induction heating coil 12 of FIG. 3 used in this embodiment is
A substantially circular solenoid-type coil including a single-layer multi-winding in which conductive wires are spirally wound so that winding intervals of a coil portion corresponding to a flange portion F of the crankshaft 1 are relatively close to each other. Both terminals 34a, 34b of the high-frequency induction heating coil 12 are connected to terminals (not shown) arranged below the power supply matching section 33 which supplies a high-frequency current (power supply). In addition, when the crankshaft 1 is conveyed to the heating station 21, the power supply matching unit 33 causes the cylinder 3 to move.
5 and is moved along the guide rail 36, so that the furnace body 30 is horizontally moved from the standby position M shown by the broken line in FIG. 2 to the heating position N shown by the solid line. Is configured. After heating,
It is returned to the standby position M again.

Further, the heat equalizing stations 22 and 23 are provided with only crankshaft supports 63 and 64, respectively, and the cooling station 24 turns the entire heated crankshaft 1 into a cooling liquid such as water. It is equipped with equipment such as an injection cooling ring 41 for cooling by cooling (Fig. 1
reference).

The air blow station 25 also includes
Equipment such as an air nozzle 42 for removing particles (water droplets or the like) of the cooling liquid adhering to the crankshaft 1 after cooling is provided (see FIG. 1).

As shown in FIG. 1, the mechanism (conveying device 14) for conveying and supporting the crankshaft 1 is laid so as to extend from the left end of the induction tempering device 10 on the crankshaft insertion side to the right end on the discharge side. It has a series of moving beams 50 and a fixed beam 60 fixedly arranged between the moving beam 50 and the induction hardening apparatus 11. .
Both of these beams 50 and 60 are respectively composed of a pair of beam members laid parallel to each other along the crankshaft conveying direction.
On the inside and the fixed beam 60 on the outside. Further, a pair of supports are attached to both beams 50 and 60 at positions facing each other of a pair of beam members at intervals corresponding to the adjacent intervals of the stations 21 to 25 along the crankshaft transport direction. There is.
That is, the moving beam 5 that carries the crankshaft 1
0, 6 pairs of supporters 51 to 56, which are V-shaped blocks, are fixedly arranged between the crankshaft input side and the discharge side, and on the fixed beam 60 on which the crankshaft 1 is mounted and supported, Similarly, 7 pairs of supports 61 composed of V-shaped blocks are provided between the crankshaft input side and the discharge side.
~ 67 are fixedly arranged.

The supports 51 to 56 on the moving beam 50 and the supports 61 to 67 (except 62) on the fixed beam 60 are made of metal. In addition, the supporting device 62 arranged in the heating station 21 is made of a ceramic heat resistant material. Supports 51-of the moving beam 50
Reference numeral 56 denotes the journal portion 2J of the crankshaft 1
And 4J, the support 62 of the fixed beam 60 disposed in the heating station 21 supports the flange portion F and the shaft portion S1 of the crankshaft 1, and the supporters 61, 63 to 67 of the other fixed beams 60. Is crankshaft 1
It supports the journal parts 1J and 5J.

Further, as shown in FIG. 2, a pair of ceramic supporters 62 fixedly arranged in the heating station 21 are horizontally arranged on the fixed beam 60 so as to face each other along the same axis. A pair of nonmagnetic metal shafts 68 for supporting the crankshaft,
A disc-shaped guide auxiliary member (guide adjustment member) 38 made of a magnetic material having a water passage inside is fixed to the tip of one shaft 68, and is fixed to the tip of the flange portion F.
It is provided to assist in heating the crankshaft portion on the side of. A cooling liquid is supplied from a cooling facility (not shown) to the water passage of the guide assisting member 38. The other shaft 69 has a standby position M.
The high frequency induction heating coil 12 is placed coaxially around the periphery of the coil. Thus, the pair of crankshaft supporting shafts 6
8 and 69 are coaxially arranged so as to extend along the extension direction of the axis of the high-frequency induction heating coil 12.

The above-mentioned moving beam 50 is moved up / down / moved from the low position before the operation by the transfer device 14.
It is configured to be moved along a circulation path having four cycles of retreat as one cycle. Then, the fixed beam 6
The crankshaft 1 mounted on the supporters 61 to 67 of 0 supports the supporter 51 as the moving beam 50 moves upward.
˜56 to move forward, and with the subsequent downward movement of the moving beam 50, the support 61 of the fixed beam 60.
By returning it to the upper position of ~ 67, it is conveyed step by step along the downstream side in the crankshaft conveying direction. Then, after the transfer of one step, the moving beam 50
Is moved backward and returned to the original standby position. The moving beam 50 is moved up and down, moved forward and backward, all on an arc drawn by the tips of the operating arm 71 of the lifting mechanism of the transfer device 14 and the operating arm 72 of the front-rear moving device driven by a cylinder (not shown). Is converted into a linear motion in the vertical direction and the front-back direction (see FIG. 1). The moving beam 50 shown in FIG.
Shows that the tips of the supports 51 to 56 of the moving beam 50 are substantially at the same height as the tips of the supports 61 to 67 of the fixed beam 60.

The phase of the crankshaft 1 is from the time of insertion of the crankshaft 1 to the time of discharge thereof.
The axis Y of the pin portions 1P and 4P is arranged at the uppermost position (top dead center position) with respect to the axis X of the pin portions 2P and 3P.
The axis Z of P is set to be located at the lowest position (bottom dead center).

Next, a method for tempering the crankshaft 1 using the above-described induction tempering device 10 will be described below. First, the crankshaft 1 that has been subjected to a predetermined quenching treatment by the induction hardening device 11 in the previous step is put into the charging port indicated by the arrow on the left side of the induction hardening device 10, and the journal portions 1J and 5J of the crankshaft 1 are inserted. Is mounted and supported on the support 61 of the fixed beam 60, the moving beam 50 is immediately moved up. Along with this, the journal portion 2J of the crankshaft 1 supported by the support 61 of the fixed beam 60,
4J is received by the support 51 on the moving beam 50, and the crankshaft 1 is supported by the support 51. Under this state, the moving beam 50 spans one span between the supports 61 and 62 of the fixed beam 60. It is advanced by a distance corresponding to the length and then lowered. At this time, the heating station 21
The flange portion F and the shaft portion S1 of the crankshaft 1 are mounted on the ceramic supporter 62 at the tips of the shafts 68 and 69 (see FIG. 2) fixedly arranged inside and fixed to the fixed beam 60. It is delivered to the supporter 62.

Then, the moving beam 50 is further moved down, then moved backward to complete the moving operation for one cycle, and is placed at the standby position in preparation for the next cycle. On the other hand, on the support 61 of the fixed beam 60, the next crankshaft 1 which is continuously fed from the induction hardening apparatus 11 in the previous step is placed.

When the crankshaft 1 is conveyed to the heating station 21 and placed on the supporter 62 as described above, the furnace body 30 accommodating the high frequency induction heating coil 12 is in a standby state shown by a broken line in FIG. It is horizontally moved from the position M to the heating position N shown by the solid line. At this time, the axis of the high frequency induction heating coil 12 held in the furnace body 30 is moved substantially along the axis of the horizontal shaft 69, and the crankshaft 1 supported by the supporter 62 is subjected to the high frequency induction heating. The coil 12 is disposed at a position where it passes through the opening 32 of the coil 12 relatively and is completely surrounded by the high frequency induction heating coil 12, that is, a heating position N (see FIG. 2). Then, in synchronization with this, a required high-frequency current is supplied to the high-frequency induction heating coil 12 from a high-frequency power source (not shown) through the power source matching section 33, whereby the crankshaft 1 is not only hardened but also hardened. (In particular, the counterweight part CW1
To CW8) are collectively subjected to high-frequency induction heating (heating by heating). In this case, the counterweight parts CW1 to CW8 of the crankshaft 1 are the parts having the largest heat capacity, and the outer diameter side tip corners are located on the outer diameter side of the journal parts 1J to 5J and the pins 1P to 4P. Since it is at the protruding position and is most likely to be heated due to the characteristics of high frequency induction heating, the outer diameter side corner of the counterweight part is in a so-called "overheated" state, that is, a heating state at a temperature extremely higher than the peripheral portion. Becomes Therefore, the heat of the outer diameter side tip corner portion in the "overheated" state is immediately transferred to the pin portion of the crankshaft or the R portion of the journal portion, and as a result, it has been recognized that tempering heating is difficult in the past. In addition to heating the R portion by the induction heating action of the high frequency induction heating coil, the R portion is also heated by the heat conduction action from the outer diameter side corner portion of the counterweight portion that is in the “overheated” state. Can be efficiently heated uniformly along with its peripheral portion.

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

In the soaking stations 22 and 23, the crankshaft 1 is supported by the support 63 of the fixed beam 60.
While being placed and supported on Nos. 64 and 64, they are allowed to cool to a predetermined tempering temperature and soaked. Then, after being soaked for a predetermined time, the crankshaft 1 is transported to the cooling station 24 by the transport device 14.

In the cooling station 24, when the crankshaft 1 is placed on the pair of supports 65 of the fixed beam 60, the plurality of injection cooling rings 41 are moved downward by the cylinders 43 from the upper side to the lower side. Corresponding to the entire length and width of the crankshaft 1, and cooling liquid (for example, cooling water) is directed toward the crankshaft 1 from a large number of cooling liquid injection holes (not shown) provided in these injection cooling rings 41. Is jetted. As a result, the crankshaft 1 is cooled and tempered. Then, after cooling is completed, the injection cooling ring 41 is returned to the initial standby position, and the crankshaft 1 is transported to the air blow station 25 by the transport device 14.

In the air blow station 25,
When the crankshaft 1 is placed on the support 66 of the fixed beam 60, the plurality of air nozzles 42 according to the size and shape of the crankshaft 1 are driven by the drive mechanism integrated with the injection cooling ring 41. The compressed air is ejected toward the crankshaft 1 from the air compressor (not shown) via the air introduction pipe from the air compressor (not shown). At this time, the air nozzle 42 is swung back and forth and left and right by a swing mechanism (not shown). As a result, the cooling liquid (eg, water droplets) adhering to and remaining on the surface of the crankshaft 1 at the cooling station 24 in the previous step is blown off and removed from the surface of the crankshaft 1. Then, after the air blow is completed, the air nozzle 42 is returned to the initial standby position, and the crankshaft 1 is transported by the transport device 14 onto the support 67 of the fixed beam 60 on the discharge side.

Through the series of operations described above, all the steps of the tempering process are completed, and thereafter, the subsequent steps are taken over.
Under continuous operation, a new crankshaft 1 is continuously introduced every one cycle of the operation of the moving beam 50, and the processed crankshaft 1 is continuously discharged with a cycle time of, for example, 42 seconds.

A specific example of operating conditions of the induction tempering apparatus 10 will be described below. Specific example (1) Crankshaft material Steel type: S48CL (2) High frequency induction heating coil frequency: Approx. 2 kHz Electric power: 40 kW (3) High frequency induction heating time: 28 seconds (4) Soaking time: Approximately 90 seconds soaking Temperature: Approx. 200 ° C (5) Cooling liquid temperature: 35 ° C or less Workpiece temperature: 40 ° C or less

When the crankshaft 1 is tempered using the induction tempering device 10 under the above-described conditions, when the quenching hardness is Hv800, the hardness after the tempering treatment is the hardness specification. Was Hv513-830, while the tempering hardness was Hv650-700.

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

As described above, according to the crankshaft induction tempering method and apparatus of the present invention, the tempering treatment of the journal portion and the pin portion of the crankshaft that has undergone the quenching treatment encloses the entire crankshaft. Since this is achieved by using high-frequency induction heating coils and performing high-frequency induction heating to a uniform temperature all at once (in one step), while retaining the compressive residual stress obtained by induction hardening. Excellent uniform tempering quality,
It can be obtained with inexpensive equipment having a simple structure.

That is, comparing the case of heating a crankshaft using a heating furnace as in the prior art and the case of heating a crankshaft using a high frequency induction heating coil as in the present invention, the crankshaft The ultimate heating temperature is the same as about 200 ° C., but the heating time by the electric furnace is, for example, 1.5 to 3.0 (heating 0.5 hour,
For soaking 1 to 1.5 hours, the heating time by the high frequency induction heating coil is, for example, about 2 minutes (heating 28 seconds, soaking 90).
Seconds), and there is a large time difference between these two.
In this way, since the heating time by the electric furnace is quite long,
Although the residual stress related to the fatigue strength will be significantly reduced during the heating period, according to the method and apparatus of the present invention using the high frequency induction heating coil, the heating time can be extremely short. The reduction of residual stress can be suppressed to an extremely small level, and sufficient residual stress can be maintained.

Further, in the conventional tempering method using the high-frequency induction heating coil, only the quenched crankshaft portion is locally heated, so that the crankshaft is locally distorted to cause crankshaft distortion. However, in the present invention, the entire quenched crankshaft is placed at a position surrounded by one high-frequency induction heating coil, and the entire heating by high-frequency induction (if only the quenching portion is used, Instead, the entire heating of the crankshaft can be performed uniformly with a small temperature difference, and the occurrence of distortion and bending can be suppressed. Therefore, according to the present invention, the effect of the high frequency induction heating that the reduction of the compressive residual stress can be suppressed to a small extent by the heat treatment for a short time by the high frequency induction heating, and the crankshaft of the crankshaft as in the case of using the electric furnace. It is possible to obtain the same effect as that of the electric furnace heating that uniform heating can be performed and distortion and bending can be suppressed to a small level.

In the conventional case, the whole of the crankshaft is not heated by the high frequency induction heating coil. The reason is that it is extremely difficult to uniformly heat the crankshaft because the shape of the crankshaft is complicated and the heat capacity of each part is different. Because there is. Therefore, in order to overcome such a problem, in the present invention, the winding interval of the coil portion of the high frequency induction heating coil corresponding to the flange portion on the one end side of the crankshaft is set relatively dense, or Since an induction assisting member (a magnetic material that locally enhances the magnetic flux density) that functions to control the heating temperature of the flange side of the crankshaft is arranged, one high frequency induction heating coil is used. It is possible to uniformly heat the entire crankshaft.

Therefore, according to the present invention, induction hardening is performed by collectively tempering all of the hardened parts of the crankshaft journal and pins with the induction heating coil. A practical crankshaft induction heating that can obtain uniform and stable excellent tempering quality while ensuring retention of compressive residual stress, which is one of the advantages, and at a low equipment cost. A tempering method and an induction tempering apparatus thereof can be provided.

Further, in the present invention, the cooling liquid is sprayed onto the crankshaft to cool the crankshaft to room temperature in order to carry out the polishing process following the tempering process at room temperature. There are many advantages. That is, there is a polishing step after the tempering step, but since the portion to be polished is quenched, the hardness of this portion is low, local heating due to polishing occurs violently, and in some cases polishing cracks (cracks) occur. However, as in the present invention, the tempering temperature of about 200 ° C to normal temperature (for example, 40 ° C or less)
Since the cooling is performed at a low temperature, the polishing operation can be performed easily without causing polishing cracks.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of an induction tempering apparatus for carrying out an induction tempering method for a crankshaft according to an embodiment of the present invention.

FIG. 2 is a side view of a heating station in the induction tempering apparatus described above.

3A and 3B show a high-frequency induction heating coil arranged in a heating station, FIG. 3A is a front view of the high-frequency induction heating coil, and FIG. 3B is a side view of the high-frequency induction heating coil. .

FIG. 4 is a side view of a crankshaft that is a body to be tempered.

FIG. 5 is an explanatory view showing a quench hardened layer pattern formed on a crankshaft.

[Explanation of symbols]

1 crankshaft 1P-4P pin part 1J-5J Journal Department 10 Induction tempering equipment 11 Induction hardening equipment 12 High frequency induction heating coil 13 Heat treatment mechanism 14 Conveyor 21 heating station 22, 23 Soaking station 24 cooling stations 25 air blow station 30 furnace body 38 Guidance auxiliary member 41 Cooling water injection cooling ring 42 Air nozzle 50 moving beams 51-56 Supporter 60 fixed beam 61-67 Supporter 68,69 Crankshaft support shaft CW1-CW8 counterweight F flange M standby position N heating position S1, S2 shaft X Crankshaft rotation axis Axis of Y pin 1P, 4P Axis of Z pin part 2P, 3P

Continuation of the front page (56) Reference JP-A-5-156346 (JP, A) JP-A-4-325630 (JP, A) JP-A-8-165517 (JP, A) JP-B 5-87565 (JP , B2) JP-B-64-3924 (JP, B2) JP-B-63-43443 (JP, B2) JP-B 1-14671 (JP, Y2) JP-B-63-42481 (JP, Y2) Patent 2886265 (JP JP, B2) Patent 2660408 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C21D 9/00-9/44 C21D 9/50 C21D 1/02-1/84

Claims (14)

(57) [Claims] 1. A method for tempering a hardened portion of a crankshaft, which comprises a main portion of a crankshaft, and then quenching the hardened portion of the fillet R, the method comprising: (A) only the hardened portion; Of course, the whole of the crankshaft including the non-quenched portion is placed at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil formed by spirally winding a conductive wire, and the high frequency When the induction heating coil is energized, the whole crankshaft is subjected to high frequency induction heating to heat the quenching portion of the crankshaft by high frequency induction heating, and at the same time, the crank having a large heat capacity and being easily subjected to high frequency induction heating. The counterweight part of the shaft is also heated by simultaneously conducting high frequency induction heating and conducting the heat to the R part of the quenching part. Pile The heating step of high-frequency induction heating the part R together with the other quenching parts to a required tempering temperature, and (B) after the heating step, the entire crankshaft by heat conduction in the crankshaft. In order to carry out the soaking process for cooling the steel to obtain a soaking process, and (C) the polishing process following the tempering process at room temperature, a cooling liquid is sprayed on the crankshaft to cool the crankshaft. A method of induction tempering a crankshaft, which comprises sequentially performing a cooling step and a cooling step. 2. After the steps (A) to (C), (D) an air blow step of removing the cooling liquid adhering to the crankshaft from the crankshaft in the cooling step is further performed. The high frequency induction heating device for a crankshaft according to claim 1, wherein: 3. The heating step, the soaking step, the cooling step, and the air blowing step are sequentially and continuously performed while intermittently horizontally moving the crankshaft. Item 3. The induction tempering method for a crankshaft according to Item 1 or 2. 4. A device for tempering a journal portion or a pin portion of a crankshaft that has been subjected to fillet R quenching, comprising: (a) not only the quenched portion but also the non-quenched portion of the crankshaft. The whole is placed at a position completely surrounded by a substantially circular solenoid type high frequency induction heating coil formed by spirally winding a conductive wire, and the crank is rotated according to the energization of the high frequency induction heating coil. The whole shaft is subjected to high frequency induction heating to heat the quenching portion of the crankshaft by high frequency induction heating, and at the same time, the counterweight portion of the crankshaft, which is easy to be subjected to high frequency induction heating and has a large heat capacity, is also subjected to high frequency induction heating. By conducting the heat to the R portion of the quenched portion, the R portion which is difficult to be heated is required together with the other quenched portions. A heating station for high-frequency induction heating up to the tempering temperature; and (b) a soaking station for soaking the high-frequency induction-heated crankshaft by cooling the whole by heat conduction of the crankshaft itself. And (c) a cooling station for injecting a cooling liquid into the crankshaft to cool the crankshaft, in order to perform a polishing process subsequent to the tempering process at room temperature. Induction tempering equipment. 5. In addition to the stations (a) to (c), (d) an air blow station for removing the cooling liquid adhering to the surface of the crankshaft from the surface of the crankshaft in the cooling step, The induction tempering device for a crankshaft according to claim 4, further comprising: 6. In order to continuously perform the respective processing steps in the heating station, the soaking station, the cooling station and the air blow station while intermittently horizontally moving the crankshaft, (a) the crankshaft is used. A support mechanism that supports the crankshaft in a mounted state; (b) a horizontal movement mechanism that horizontally moves the crankshaft while the crankshaft is supported by the support mechanism; and (c) the horizontal movement mechanism. Completely moving the crankshaft, that is, not only the hardened part but also the non-hardened part, to completely surround the crankshaft to the required tempering temperature. For high-frequency induction heating all at once, a substantially circular solenoid type coil consisting of spirally wound conductor wires A heating mechanism having a frequency induction heating coil; and (d) a heat treatment unit for the journal portion and the pin portion of the crankshaft, which has been subjected to high frequency induction heating by the heating mechanism, is allowed to cool by heat conduction of the crankshaft and is evened. (E) An injection cooling mechanism that cools the heat-treated part of the crankshaft that has been heat-equalized and transferred from the heat equalizing mechanism to room temperature with an injection cooling liquid; f) An induction tempering device for a crankshaft according to claim 4 or 5, further comprising: a tempering system including: an air blow mechanism that applies an air blow to the crankshaft transferred from the injection cooling mechanism. . 7. The crankshaft support mechanism disposed in the heating station includes: (a) the crankshaft being surrounded by a high frequency induction heating coil in the heating station, and the high frequency induction heating. A pair of supports made of a ceramic-based heat-resistant material that abuts on both ends of the crankshaft in the axial direction when the coils are supported coaxially, and (b) the pair of supports is A pair of non-magnetic metal crankshaft supporting shafts, each of which is attached to the tip portion and is arranged so as to extend along the extension direction of the axis of the high-frequency induction heating coil; The induction hardening device for a crankshaft according to claim 6, 8. The horizontal movement mechanism of the crankshaft comprises: (a) a supporter arranged at a predetermined interval corresponding to an arrangement interval of the soaking station, the cooling station, and the air blow station; And a crankshaft transfer mechanism for sequentially transferring the crankshaft to the heating station, the soaking station, the cooling station, and the air blow station by moving the crankshaft in the vertical direction and the front-back direction. The induction hardening device for a crankshaft according to claim 6 or 7. 9. The heating mechanism arranged in the heating station comprises a high-frequency induction heating coil in which a conductive wire is spirally wound, and a coil portion winding corresponding to a flange portion on one end side of the crankshaft. The induction tempering device for a crankshaft according to any one of claims 6 to 8, wherein the coils are wound so that the intervals are relatively close to each other. 10. When the heating is stopped, the high frequency induction heating coil is arranged in a standby position which is retracted in advance, and the high frequency induction heating is started by supporting the crankshaft with a pair of supporting members made of the ceramic heat resistant material. Prior to the above, a heating coil horizontal moving mechanism for advancing the high frequency induction heating coil from the standby position to a predetermined heating position and retracting it to the standby position after completion of the high frequency induction heating is provided. The induction hardening device for a crankshaft according to any one of 4 to 9. 11. The injection cooling mechanism arranged in the cooling station is: (a) arranged at a predetermined distance from the crankshaft supported by the supporting device, and is arranged over the entire length and width of the crankshaft. An injection cooling ring having a corresponding rectangular shape and provided with a large number of cooling liquid injection holes on a surface facing the crankshaft; (b) a cooling water introducing pipe and a water supply pump connected to the injection cooling ring; 7. A moving mechanism for lowering the injection cooling ring to a position at a predetermined distance from the crankshaft at the start of cooling and raising it to a predetermined standby position after completion of cooling, respectively. 10. The induction hardening device for a crankshaft according to any one of 10 items. 12. The air-blowing mechanism provided in the air-blowing station is (a) arranged at a predetermined distance from a crankshaft supported by the supporter, depending on the size and shape of the crankshaft. A plurality of air nozzles; (b) an air introducing pipe connected to the air nozzle; (c) lowering the air nozzle to a position at a predetermined distance with respect to the crankshaft at the start of air blowing, and performing a predetermined operation after the end of the air blowing. 12. A moving mechanism for moving to a standby position, and (d) a rocking device for rocking the air nozzle back and forth and left and right at the time of air blowing, respectively. Induction tempering device for a crankshaft according to item. 13. A support of one of a pair of supports made of the ceramics heat-resistant material, which is arranged adjacent to a support for supporting a flange portion on one end side of the crankshaft. At the same time, an induction assisting member that is made of a magnetic material that locally enhances the magnetic flux density and that functions to control the heating temperature of the flange side portion of the crankshaft is provided on the flange side end portion of the high frequency induction heating coil. The induction tempering device for a crankshaft according to any one of claims 6 to 12, wherein the induction tempering device is arranged in a vicinity of the above. 14. The induction tempering device for a crankshaft according to claim 13, wherein the guide assisting member is a disk-shaped adjusting member made of a magnetic material and provided with a water passage therein.