JP2017071808A - High frequency induction hardening device of crankshaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency induction hardening device of a crankshaft hardly interfering with a crankshaft with distortion in an axial direction when hardening each axial part of the crankshaft at the same time.SOLUTION: A mobile device 4 for moving respective induction heating coil bodies 2a to 2e at a state in which heating coils 6a to 6e are closely opposite to an axial direction of a crankshaft W independently is arranged on an axial parts w1 to w5 of the crankshaft W. Thereby respective induction heating coil bodies 2a to 2e can be moved depending on positions of respective axial parts w1 to w5 even when the crankshaft W extends to the axial direction during high frequency hardening.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an induction hardening apparatus that simultaneously hardens each shaft portion of a crankshaft.

  Each shaft portion (each pin portion and each journal portion) of the crankshaft is apt to wear because it is driven to rotate while being supported by the bearing. Therefore, conventionally, the surface of each pin portion and each journal portion has been improved in wear resistance by induction hardening.

  When induction heating the pin part and journal part of the crankshaft, the induction heating coil to which a high-frequency current is supplied is usually in a state where the half part of the entire circumference of the pin part and journal part is closely opposed. Rotate the crankshaft. And every time the crankshaft makes one revolution, the induction heating coils are sequentially opposed over the entire circumference of the pin portion and the journal portion, and a high frequency induction current is excited around the entire circumference of the pin portion and the journal portion. Uniform induction heating.

  The axis of the journal portion coincides with the rotation axis of the crankshaft, and when the crankshaft rotates around the rotation axis, the journal portion rotates around the axis. However, the shaft core of the pin portion is eccentric with respect to the rotation shaft of the crankshaft, and the pin portion revolves around the rotation shaft. Therefore, the induction heating coil for induction heating the pin portion also needs to move following the revolving movement of the pin portion. Therefore, an induction heating coil body having an induction heating coil, a spacer, and a fixing member has been conventionally used. The fixing members are two plate-like members, and are fixed by sandwiching the induction heating coil and the spacer from both sides. The spacer is a member that is made of ceramic, super steel, or the like, which is a material that is not affected by the induction due to the high-frequency current, and that contacts the pin portion. The spacer protrudes closer to the pin portion than the induction heating coil, and comes into contact with the pin portion. Therefore, the induction heating coil does not contact the pin portion. The amount of protrusion of the spacer with respect to the induction heating coil is such that when the spacer abuts on the pin portion, the distance from the pin portion to the induction heating coil is the distance at which the induction current is appropriately excited in the pin portion (part to be quenched). Is set to

  At the time of induction hardening, normally, each pin part or each journal part having the same phase is simultaneously induction-heated and then simultaneously cooled. In this way, by simultaneously quenching each pin part or each journal part in the same phase, the heat treatment time of the crankshaft can be shortened, and the productivity is improved. Patent Document 1 discloses an invention for simultaneously heat-treating a plurality of shaft portions of such a crankshaft.

Japanese Examined Patent Publication No. Sho 63-38565

  By the way, the greater the number of locations where heat treatment is performed simultaneously, the greater the distortion of the entire crankshaft at the time of temperature rise. That is, each pin part or each journal part expand | swells, and as shown in FIG. 6, a crankshaft is mainly extended in a longitudinal direction (axial direction shown by the arrow in FIG. 6). Therefore, if the position of the induction heating coil is fixed, each pin portion or each journal portion is displaced in the axial direction of the crankshaft with respect to the induction heating coil. As a result, the expanded crankshaft comes into contact with the induction heating coil body whose position does not change and further presses excessively. For this reason, the life of the fixing member and the spacer may be shortened. Specifically, there is a risk that a connecting portion that connects each pin portion or each journal portion contacts the induction heating coil body and damages a crankshaft or induction heating coil body that is a workpiece.

  On the other hand, there is no conventional crankshaft high-frequency induction heating apparatus provided with a configuration for protecting the crankshaft and induction heating coil body generated by the axial extension of the crankshaft when the temperature is raised. The invention disclosed in Patent Document 1 described above is intended to reduce the distortion of the crankshaft after the heat treatment, and does not reduce the distortion (elongation of the crankshaft) during temperature rise.

  Therefore, an object of the present invention is to provide a high-frequency quenching device for a crankshaft that is less susceptible to the distortion of the expanded crankshaft when quenching the crankshaft.

  The invention according to claim 1 for solving the above-described problem is a high-frequency quenching device for a crankshaft that simultaneously quenches a plurality of shaft portions of a crankshaft supported at both ends so as to be expandable and contractable in the axial direction. The induction heating coil includes a plurality of induction heating coil bodies each including an induction heating coil and a fixing member to which the induction heating coil is fixed. The induction heating coil includes a conductor to which a high-frequency current is supplied, and the shaft portion is inducted. The plurality of induction heating coil bodies in the state where the heating coils are closely opposed to each other have moving means for individually moving in the axial direction of the crankshaft according to the expansion and contraction of the crankshaft during induction heating and cooling. This is an induction hardening device for crankshafts.

In the quenching heating process, the amount of displacement of each shaft portion is different when the temperature of the crankshaft is raised at the same time and the crankshaft expands in the axial direction. That is, for example, when one end of the crankshaft is fixed and the other end is supported so as to be displaceable, the amount of displacement of the shaft portion closer to the fixed end is smaller, and the shaft portion closer to the other end is smaller. The amount of displacement increases. Therefore, even when the induction heating coil bodies are moved uniformly in the axial direction of the crankshaft when the clan shaft expands and extends, the induction heating coil bodies do not move appropriately to the shaft portions. That is, each induction heating coil body does not properly face each shaft portion.
Even in the quenching cooling process, the amount of displacement of each shaft when the crankshaft contracts is different, so even if each induction heating coil body is moved uniformly in the axial direction of the crankshaft, On the other hand, the induction heating coil bodies do not face each other properly.

However, according to the first aspect of the present invention, the plurality of induction heating coil bodies with the induction heating coil closely opposed to the shaft portion are individually moved in the axial direction of the crankshaft in accordance with the expansion and contraction of the crankshaft. Since it has a moving means, each induction heating coil body can be moved so that the induction heating coil of each induction heating coil body may appropriately face the corresponding shaft portion.
That is, in the induction hardening heating process and the cooling process, even if the crankshaft expands and contracts in the axial direction, the induction heating coils of each induction heating coil body are appropriately opposed to the respective shaft portions. The coil body moves. Therefore, it can prevent or suppress that a crankshaft contacts or is pressed with respect to each induction heating coil body.

  The invention according to claim 2 has storage means for storing a correlation between the time from the start of induction heating of the shaft portion to the end of induction heating and the extension of the crankshaft in the axial direction. 2. The induction hardening apparatus for a crankshaft according to claim 1, wherein the moving means moves the individual induction heating coil bodies on the basis of the above.

The crankshaft to be heated by induction increases in the axial direction as the temperature of each shaft portion increases. That is, there is a correlation between the temperature rise of each shaft portion and the amount of axial extension of the crankshaft. In addition, the temperature of each shaft portion increases as the time for induction heating increases. Therefore, there is a correlation between the induction heating time and the axial extension of the crankshaft.
The invention according to claim 2 utilizes the correlation between the induction heating time and the expansion and contraction of the crankshaft in the axial direction.
In invention of Claim 2, it can prevent or suppress that a crankshaft and each induction heating coil body collide. Further, it is not necessary to detect the actual extension of the crankshaft, and no detection means is required.
According to the second aspect of the present invention, it is not necessary to perform difficult temperature detection of each shaft portion to be heated.

  Similarly, the amount of contraction in the axial direction of the crankshaft increases as the temperature of each shaft portion decreases in the cooling step. That is, there is also a correlation between the temperature drop of each shaft and the amount of contraction in the axial direction of the crankshaft. Therefore, the correlation between the time from the start of cooling of the shaft portion to the end of cooling and the shrinkage in the axial direction of the crankshaft is stored in the storage means, and the moving means performs individual induction heating based on the storage in the storage means. The coil body can also be moved.

  According to a third aspect of the present invention, there is provided detection means for detecting expansion and contraction in the axial direction of the crankshaft, and the moving means individually moves the individual induction heating coil bodies according to the detection result of the detection means. The induction hardening apparatus for a crankshaft according to claim 1, wherein:

  In the invention according to claim 3, the axial extension of the crankshaft can be detected by the detecting means. Further, since the moving means individually moves each induction heating coil body according to the detection result of the detecting means, each induction heating coil body can be individually moved so as to follow each shaft portion of the crankshaft. it can. Therefore, each induction heating coil body can prevent or suppress contact or contact with the crankshaft.

  The invention according to claim 4 has a detecting means for detecting the expansion and contraction of the crankshaft in the axial direction, obtains the relationship between the amount of expansion and contraction during the quenching of the plurality of crankshafts and the elapsed time, and calculates the average value thereof. The control means for calculating and further setting a predetermined width around the average value, the control means, when performing the quenching of the crankshaft other than the plurality of crankshafts, the expansion and contraction amount of the crankshaft, It is determined whether or not the predetermined width is within a predetermined range, and when the control means determines that the amount of expansion and contraction of the crankshaft is not within the predetermined width, an alarm device that issues an alarm is provided. It is the induction hardening apparatus of the crankshaft of Claim 1 or Claim 2 characterized by the above-mentioned.

In the invention according to claim 4, the axial extension of the crankshaft can be detected by the detecting means.
Further, if the expansion / contraction amount of the crankshaft is not within the predetermined range set by the control means, the alarm device issues an alarm, so that the operator can recognize the abnormality. By performing appropriate maintenance, the crankshaft to be hardened next to the crankshaft can be hardened well.

  The induction hardening device for a crankshaft according to the present invention includes an induction heating coil body that hardens each shaft portion according to the amount of strain of the crankshaft when the shaft portions of the crankshaft are simultaneously induction hardened. It can be moved in the axial direction, and the crankshaft as the workpiece and each induction heating coil body can be well protected.

1 is a front view of a crankshaft induction hardening apparatus and a crankshaft according to an embodiment of the present invention. It is a perspective view in the state where an induction heating coil body is arranged in one shaft part of a crankshaft. FIG. 1 is a front view showing a state in which a plurality of shaft portions of a crankshaft are induction-heated and extend in the axial direction in FIG. 1, and each induction heating coil body moves corresponding to the extension of the crankshaft. It is a flowchart at the time of making each induction heating coil body follow each axial part of the crankshaft extended by thermal expansion. It is a flowchart at the time of making each shaft part track each induction heating coil body, when induction heating is completed and each shaft part of a crankshaft is cooled. It is a front view of the crankshaft and induction heating coil body of the state heated by induction heating with the conventional induction hardening apparatus. It is a systematic diagram which shows the relationship between the control apparatus provided in the induction hardening apparatus of the crankshaft which concerns on embodiment of this invention, and a moving apparatus. It is a graph which shows the relationship between time passage at the time of induction heating of a crankshaft, and extension of a crankshaft.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The crankshaft W to be hardened has a plurality of journal portions, a plurality of pin portions, and a connection portion 11. Hereinafter, the journal part is referred to as a shaft part (w1 to w5). In the present embodiment, a description will be given of a case where the respective journal portions (shaft portions w1 to w5) are quenched.

  As shown in FIG. 1, one end side (drive side) of the crankshaft W is gripped by a chuck 60 and the other end side (tail side) is supported by a center pin 61. The chuck 60 is connected to a driving device (not shown). That is, both ends of the crankshaft W are supported rotatably. Further, the center pin 61 that supports the other end side of the crankshaft W can be moved in accordance with the expansion and contraction of the crankshaft W in the axial direction (longitudinal direction). That is, the center pin 61 has a moving mechanism (not shown) that moves in the axial direction of the crankshaft W.

  The center pin 61 is provided with a displacement sensor 5 (proximity sensor). The displacement sensor 5 has a fixed part 5a and a movable part 5b. The fixed portion 5a is fixed to a stationary member (not shown) fixed to the floor surface or the like. The movable part 5 b is attached to the center pin 61. The fixed portion 5a and the movable portion 5b are arranged in the axial direction of the crankshaft W. When the movable portion 5b moves, the distance between the movable portion 5b and the fixed portion 5a varies, and it can be detected that the center pin 61 has moved. The displacement sensor 5 can also detect the movement distance (movement amount) of the center pin 61. That is, the displacement sensor 5 has a function of detecting the amount of movement (deviation) from the reference position with the position of the center pin 61 of the crankshaft W at normal temperature as the reference position.

  As shown in FIG. 1, the induction hardening apparatus 1 that hardens the shaft portions w1 to w5 includes an induction heating coil body 2, a transformer 3, and a moving device 4 (moving means). Moreover, the induction hardening apparatus 1 has the control apparatus 15 (FIG. 7).

As shown in FIG. 2, the induction heating coil body 2 includes a heating coil 6, side plates 7 and 8, cooling jackets 9 and 10, and the like.
The heating coil 6 is composed of a tubular member made of a good conductor such as copper or copper alloy. The heating coil 6 is formed in a so-called semi-open shape. That is, the heating coil 6 can approach and separate in the radial direction with respect to the induction heating object (the shaft portion w1 or the like). The heating coil 6 can pass a high-frequency current supplied from a high-frequency power source (not shown). In addition, a cooling liquid can be circulated and supplied inside the heating coil 6 formed of a pipe member.
Side plates 7 and 8 are arranged on both sides of the heating coil 6. That is, the side plates 7 and 8 sandwich the heating coil 6 and constitute the casing of the induction heating coil body 2.
The cooling jackets 9 and 10 are disposed below the heating coil 6 and are fixed to the side plates 7 and 8. The cooling jackets 9 and 10 have a large number of injection holes through which cooling water can be injected. The cooling jackets 9 and 10 can supply and supply cooling water to the shaft portions w1 to w5.

  The transformer 3 (transformer) is disposed between a high-frequency power source (not shown) and the heating coil 6. Although not shown, the primary side of the transformer 3 is connected to a high frequency power source, and a part of the secondary side is close to the heating coil 6 side. The transformer 3 and the induction heating coil body 2 each have a connection terminal, and are fixed integrally with the connection terminals connected to each other.

  The moving device 4 includes a fixed portion 4a (ball screw), a movable portion 4b (nut), and a servo motor (not shown). The fixed part 4a is fixed to a non-moving member (not shown) and its position does not vary, but is rotated by a servo motor. The movable portion 4b is engaged with the fixed portion 4a, and is movable with respect to the fixed portion 4a when the fixed portion 4a is rotationally driven. The movable portion 4b can perform a fine operation with respect to the fixed portion 4a, and can reciprocate along the axial direction (longitudinal direction) of the crankshaft W.

  The control device 15 has an arithmetic processing unit 16 (CPU) and has a function for controlling the operation of the moving device 4.

  Next, the operation of the moving device 4 at the time of quenching the shaft parts w1 to w5 of the crankshaft W will be described.

An induction heating coil body 2 is disposed close to the shaft portions w1 to w5 of the crankshaft W. FIG. 2 shows a state in which the induction heating coil body 2 is disposed only on one shaft portion in order to easily grasp the proximity state. The distances between the heating coils 6a to 6e and the shafts w1 to w5 are set so as to be within a predetermined range by spacers (not shown) fixed to the side plates 7 and 8.
Moreover, when the crankshaft W is rotationally driven by a drive device (not shown), preparation for quenching (induction heating process and cooling process) is completed.

Then, a high frequency current is supplied from a high frequency power source (not shown) to the heating coils 6a to 6e, and quenching (induction heating process) of the crankshaft W is started. When the temperature of the shaft portions w1 to w5 of the crankshaft W increases, the crankshaft W expands in the axial direction and the center pin 61 moves.
Therefore, the movable portion 5b approaches the fixed portion 5a of the displacement sensor 5, and the displacement sensor 5 detects the extension of the crankshaft W, detects the extension amount, and sends a detection signal to the control device 15. Send.

In the control device 15, the following operation is performed.
When the displacement sensor 5 detects that the crankshaft W has been extended, the control device 15 immediately drives each moving device 4. At that time, the arithmetic processing unit 16 of the control device 15 has the largest amount of movement of the induction heating coil body 2a that is in close proximity to the shaft portion w1 closest to the center pin 61, and the shaft portion w5 closest to the chuck 60. The amount of movement of each moving device 4 is calculated so that the amount of movement of the induction heating coil body 2e that faces and approaches each other is minimized.

Specifically, when the displacement sensor 5 detects the extension of the crankshaft W and the extension amount is E, each moving device 4 moves each induction heating coil body as follows.
The moving device 4 provided in the first induction heating coil body 2a that is in close proximity to the shaft portion w1 moves the first induction heating coil body 2a by 5E / 5 (5E / 5E, that is, E).
The moving device 4 provided in the second induction heating coil body 2b that is close to and opposed to the shaft part w2 moves the second induction heating coil body 2b by 4E / 5 (4 / 5E).
The moving device 4 provided in the third induction heating coil body 2c that is close to and opposed to the shaft portion w3 moves the third induction heating coil body 2c by 3E / 5 (3 / 5E).
The moving device 4 provided in the fourth induction heating coil body 2d that is in close proximity to the shaft portion w4 moves the fourth induction heating coil body 2d by 2E / 5 (2 / 5E).
The moving device 4 provided in the fifth induction heating coil body 2e that is in close proximity to the shaft portion w5 moves the fifth induction heating coil body 2e by E / 5 (E of 5 minutes).

  That is, the portion of the crankshaft W gripped by the chuck 60 is fixed in the position in the direction in which the rotating shaft extends, and each of the shaft portions w1 to w5 is heated to expand and expand. Therefore, the closer to the portion gripped by the chuck 60 in the crankshaft W, the smaller the amount of displacement from the chuck 60, and the larger the amount of displacement accumulated in the shaft portion away from the portion gripped by the chuck 60, The amount of movement of the first induction heating coil body 2a that faces and opposes the shaft portion w1 is maximized, and the amount of movement of the fifth induction heating coil body 2e that faces and opposes the shaft portion w5 is minimized.

  In quenching, when the induction heating process is completed, the cooling process is promptly performed. In the cooling process, cooling water is jetted and supplied from the cooling jackets 9 and 10 to the respective shaft portions w1 to w5. Each of the shaft portions w1 to w5 is cooled by the cooling water, and the temperature quickly decreases to the Ms point (martensitic transformation point).

  At that time, the crankshaft W contracts, and the positions of the shaft portions w1 to w5 change. The displacement sensor 5 detects the contraction of the crankshaft W and transmits a detection signal to the control device. The control device that has received the detection signal from the displacement sensor 5 drives each moving device 4 to move the induction heating coil bodies 2a to 2e facing the shaft portions w1 to w5.

Specifically, when the displacement sensor 5 detects the contraction of the crankshaft W and the contraction amount is F, each moving device 4 moves each induction heating coil body as follows.
The moving device 4 provided in the first induction heating coil body 2a that is close to and opposed to the shaft portion w1 moves the first induction heating coil body 2a by 5F / 5 (5F, that is, F).
The moving device 4 provided in the second induction heating coil body 2b that is close to and opposed to the shaft portion w2 moves the second induction heating coil body 2b by 4F / 5 (4 / 5F).
The moving device 4 provided in the third induction heating coil body 2c that is close to and opposed to the shaft portion w3 moves the third induction heating coil body 2c by 3F / 5 (3 / 5F).
The moving device 4 provided in the fourth induction heating coil body 2d that is in close proximity to the shaft portion w4 moves the fourth induction heating coil body 2d by 2F / 5 (2 / 5F).
The moving device 4 provided in the fifth induction heating coil body 2e that is in close proximity to the shaft portion w5 moves the fifth induction heating coil body 2e by F / 5 (F of 5 minutes).

  That is, the portion of the crankshaft W gripped by the chuck 60 is fixed in a position in the direction in which the rotating shaft contracts, and the shaft portions w1 to w5 contract each other after being cooled. Therefore, the closer to the portion gripped by the chuck 60 in the crankshaft W, the smaller the amount of displacement from the chuck 60, and the larger the amount of displacement accumulated in the shaft portion away from the portion gripped by the chuck 60, The amount of movement of the first induction heating coil body 2a that faces and opposes the shaft portion w1 is maximized, and the amount of movement of the fifth induction heating coil body 2e that faces and opposes the shaft portion w5 is minimized.

  As described above, in the induction heating process and the cooling process of the crankshaft W, the respective induction heating coil bodies 2a to 2e (each heating coil 6a to 6e) move so as to follow the respective shaft portions w1 to w5. The apparatus 4 moves each induction heating coil body 2a-2e (each heating coil 6a-6e). Thereby, each induction heating coil body 2a-2e and the crankshaft W can avoid the situation where it is pressed strongly and is damaged.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the induction hardening apparatus 1 having the same configuration as that of the first embodiment is used, but the displacement sensor 5 is not used. The control device 15 includes a storage unit 17 (memory) in addition to the arithmetic processing unit 16.
That is, a test for measuring the elongation of the crankshaft W from the induction heating of the crankshaft W until the quenching temperature is reached is performed in advance, and the temperature rise (elapsed time) of the crankshaft W and the crank The correlation of the extension of the shaft W is stored in the storage unit 17.
And according to the temperature rise (elapsed time) of the crankshaft W, each moving apparatus 4 is operated, and each induction heating coil body 2a thru | or 2e is moved.

  In other words, the correlation between the elapsed time from the start of induction heating and the elongation of the crankshaft W is stored in the storage unit 17 of the control device 15. Further, a program for operating each moving device 4 is executed by the arithmetic processing unit 16 of the control device 15 based on the stored contents of the storage unit 17.

  As a result, each induction heating coil body 2a to 2e is moved in the axial direction of the crankshaft W by each moving device 4 in accordance with the start timing of induction heating. That is, each induction heating coil body 2a to 2e moves according to a preset program, and induction heats each shaft portion w1 to w5 while maintaining an appropriate facing position with respect to each shaft portion w1 to w5.

  Even when the shafts w1 to w5 that have reached the quenching temperature are cooled, the induction heating coil bodies 2a to 2e are moved according to a preset program, and are appropriately opposed to the shafts w1 to w5. While maintaining the above, the cooling liquid is jetted and supplied from the cooling jackets 9 and 10 to cool the shaft portions w1 to w5.

Next, a third embodiment of the present invention will be described.
In the third embodiment, the same induction hardening apparatus 1 as in the first embodiment is used, and the control device 15 has a storage unit 17. The storage unit 17 is a memory to which data can be added or rewritten, and can store a displacement amount (detected value) detected by the displacement sensor 5.
The control device 15 is provided with an alarm device 18. The alarm device 18 operates according to a command from the control device 15.

In the third embodiment, the induction hardening apparatus 1 initially performs the length measurement mode and continues to perform the monitoring mode. The control device 15 controls the implementation of the length measurement mode and the monitoring mode.
The length measurement mode is a mode in which data relating to the elongation of the first plurality (for example, 3 to 5) of crankshafts W is acquired as a sample and the tendency of elongation is examined.
The monitoring mode is a mode performed after the length measurement mode is performed, and is a mode for comparing the elongation data acquired in the length measurement mode with the actual elongation of the crankshaft W other than the sample. .

  First, in the length measurement mode, the control device 15 stores the tendency of extension of the crankshaft W detected by the displacement sensor 5 in the storage unit 17. Specifically, the extension of the entire crankshaft W from the start to the end of induction heating of the heating coils 6 a to 6 e is detected by the displacement sensor 5, and the relationship between the passage of time and the extension is stored in the storage unit 17. For a plurality of (for example, 3 to 5) crankshafts W, the relationship between the passage of time and the elongation is stored in the storage unit 17.

  Then, the arithmetic processing unit 16 calculates an average value of a plurality of elongations stored in the storage unit 17. Furthermore, the arithmetic processing unit 16 sets a predetermined width (for example, 0.1 mm to 10 mm) around the calculated average value.

FIG. 8 is a graph showing the relationship between the passage of time and the elongation of the crankshaft W during induction heating of the crankshaft W, and the average value calculated by the arithmetic processing unit 16 is shown by a solid line.
As shown in FIG. 8, an upper limit value and a lower limit value indicated by a broken line are set around a graph of an average value indicated by a solid line. The predetermined width is a difference between an upper limit value and a lower limit value indicated by a broken line in FIG.

  Next, in the monitoring mode, it is monitored whether or not the elongation of the crankshaft W currently undergoing induction heating is within the upper limit value and lower limit value of the elongation set in the length measurement mode.

  Specifically, when induction heating of the crankshaft W is performed, each moving device 4 is operated according to the procedure described in the first embodiment or the second embodiment, and the control device 15 includes the heating coils 6a to 6a. It is monitored whether 6e is following the movement of each axial part w1-w5. That is, the control device 15 monitors whether or not the extension of the crankshaft W is within the upper limit value and the lower limit value (predetermined width range) set in the length measurement mode.

  As shown by the alternate long and short dash line in FIG. 8, if the extension of the crankshaft W is between the upper limit value and the lower limit value, the heating coils 6a to 6e follow the movements of the shaft portions w1 to w5. Can be considered.

  If the extension of the crankshaft W does not fall between the upper limit value and the lower limit value, the heating coils 6a to 6e do not follow the movements of the shaft portions w1 to w5. The device 15 activates the alarm device 18 (FIG. 7) to issue an alarm. Thereby, an operator can recognize abnormality.

  Furthermore, it is analyzed whether the current abnormality is a problem of only this piece or whether there is a problem in the setting of the upper limit value and the lower limit value set in the length measurement mode. If there is a problem with the setting of the upper limit value and the lower limit value, the upper limit value and the lower limit value are corrected. For example, the average value is calculated by combining the elongation of the piece with the elongation of the sample. Alternatively, the predetermined width between the upper limit value and the lower limit value is increased (for example, 0.1 mm to 10 mm).

  By doing in this way, it can prevent that the crankshaft W and induction heating coil bodies 2a-2e hardened after this by the said induction hardening apparatus 1 are damaged.

  Also in the quenching cooling step, it is preferable to calculate an average value and set an upper limit value and a lower limit value as in the induction heating step.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, the same quenching apparatus 1 as in the third embodiment is used.

In the fourth embodiment, the arithmetic processing unit 16 of the control device 15 compares the detection result by the displacement sensor 5 with a predetermined length stored in advance in the storage unit 17 to determine whether or not to operate the moving device 4. To do.
That is, the storage unit 17 stores first to fifth predetermined lengths obtained in advance by experiments. The first to fifth predetermined lengths are lengths to be compared with the amount of extension of the entire crankshaft W detected by the displacement sensor 5. The arithmetic processing unit 16 has a function of comparing the first to fifth predetermined lengths with the amount of elongation detected by the displacement sensor 5 and determining which is greater. The control device 15 can control the operation of each moving device 4. That is, the operation of each moving device 4 is governed by the control device 15, and each moving device 4 is operated by a command from the control device 15 to move each induction heating coil body 2 a to 2 e of the quenching device 1. it can.

  As shown in FIG. 1, induction heating coil bodies 2 a to 2 e are arranged on the respective shaft portions w1 to w5 of the crankshaft W. The width dimensions of the induction heating coil bodies 2a to 2e are slightly shorter than the lengths of the shaft portions w1 to w5 that are close to each other. Therefore, the induction heating coil bodies 2a to 2e can be easily brought close to and opposed to the shaft portions w1 to w5 without colliding with the connection portion 11.

  Next, the operation of the moving device 4 at the time of quenching the shaft parts w1 to w5 of the crankshaft W will be described.

An induction heating coil body 2 is disposed close to the shaft portions w1 to w5 of the crankshaft W. FIG. 2 shows a state in which the induction heating coil body 2 is disposed only on one shaft portion in order to easily grasp the proximity state. The distances between the heating coils 6a to 6e and the shafts w1 to w5 are set so as to be within a predetermined range by spacers (not shown) fixed to the side plates 7 and 8.
Further, when the crankshaft W is rotationally driven by a driving device (not shown), preparation for quenching is completed.

Hereinafter, it demonstrates along the flowchart of FIG.
Before starting the induction heating, the displacement sensor 5 is operated (step 1).

  Then, a high frequency power source (not shown) is turned on, and a high frequency current is applied to the heating coils 6a to 6e (step 2). A high frequency induction current is excited in each of the shaft portions w1 to w5 adjacent to the heating coils 6a to 6e, and each of the shaft portions w1 to w5 is heated by induction heating. Each of the shaft portions w1 to w5 is heated to expand and expand in the axial direction (longitudinal direction) of the crankshaft W.

In step 3, the extension amount of the entire crankshaft W detected by the displacement sensor 5 is compared with the first predetermined length stored in the storage unit 17 of the control device 15.
If the extension amount of the entire crankshaft W does not exceed the first predetermined length, step 3 is repeated. When the amount of elongation exceeds a preset first predetermined length, the first induction heating coil body 2a closest to the center pin 61 side (tail side) is moved by the first predetermined length (step 4). That is, the first induction heating coil body 2a is moved toward the center pin 61 so as to follow the movement and elongation of the shaft portion w1. The first predetermined length is, for example, 0.2 to 0.3 mm.

In step 5, the amount of extension of the entire crankshaft W detected by the displacement sensor 5 is compared with the second predetermined length stored in the storage unit 17 of the control device 15. The second predetermined length is twice as long as the first predetermined length.
If the extension amount of the entire crankshaft W does not exceed the second predetermined length, step 5 is repeated. When the amount of elongation exceeds a preset second predetermined length, the first induction heating coil body 2a and the second induction heating coil body 2b adjacent to the first induction heating coil body 2a are moved by the first predetermined length. Move (step 6). That is, the induction heating coil bodies 2a and 2b are moved to the center pin 61 side so as to follow the movement and elongation of the shaft portions w1 and w2. The first predetermined length is, for example, 0.2 to 0.3 mm.

In step 7, the extension amount of the entire crankshaft W detected by the displacement sensor 5 is compared with the third predetermined length stored in the storage unit 17 of the control device 15. The third predetermined length is three times the first predetermined length.
If the extension amount of the entire crankshaft W does not exceed the third predetermined length, step 7 is repeated. When the amount of elongation exceeds a preset third predetermined length, the first to third induction heating coil bodies 2a to 2c are moved by the first predetermined length, respectively (step 8). That is, the induction heating coil bodies 2a to 2c are moved to the center pin 61 side so as to follow the movement and elongation of the shaft portions w1 to w3. The first predetermined length is, for example, 0.2 to 0.3 mm.

In step 9, the extension amount of the entire crankshaft W detected by the displacement sensor 5 is compared with the fourth predetermined length stored in the storage unit 17 of the control device 15. The fourth predetermined length is four times as long as the first predetermined length.
If the extension amount of the entire crankshaft W does not exceed the fourth predetermined length, step 9 is repeated. When the amount of elongation exceeds a preset fourth predetermined length, each of the first to fourth induction heating coil bodies 2a to 2d is moved by the first predetermined length (step 10). That is, the induction heating coil bodies 2a to 2d are moved to the center pin 61 side so as to follow the movement and elongation of the shaft portions w1 to w4. The first predetermined length is, for example, 0.2 to 0.3 mm.

In step 11, the extension amount of the entire crankshaft W detected by the displacement sensor 5 is compared with the fifth predetermined length stored in the storage unit 17 of the control device 15. The fifth predetermined length is five times as long as the first predetermined length.
If the extension amount of the entire crankshaft W does not exceed the fifth predetermined length, step 11 is repeated. If the amount of elongation exceeds a preset fifth predetermined length, the first to fifth induction heating coil bodies 2a to 2e are moved by the first predetermined length, respectively (step 12). That is, the induction heating coil bodies 2a to 2e are moved to the center pin 61 side so as to follow the movement and elongation of the shaft portions w1 to w5. The first predetermined length is, for example, 0.2 to 0.3 mm.

  The execution timings of steps 3, 5, 7, 9, and 11 shown in FIG. 4 correspond to the temperatures of the shaft portions w1 to w5, and as the shaft portions w1 to w5 are heated, steps 3, 5, 7, 9, and 11 are performed in order. And in the stage which performs step 12, each axial part w1 thru | or w5 has exceeded the quenching temperature. When the induction heating process is completed, a high frequency power source (not shown) is turned off, and energization of the high frequency current to each of the heating coils 6a to 6e is stopped.

  As described above, the fifth induction heating coil body 2e on the chuck 60 side (fixed side) does not move until reaching step 12, and the first induction heating coil body 2a on the center pin 61 side (movable side) In steps 4, 6, 8, 10, and 12, each has moved by a first predetermined length. That is, the shaft portion w1 on the center pin 61 side has the largest displacement amount, and the shaft portion w5 on the chuck 60 side has the smallest displacement amount. Therefore, a difference is also provided in the amount of movement of each induction heating coil body 2a to 2e.

  When each induction heating coil body 2a to 2e is moved by each moving device 4 along the flowchart shown in FIG. 4, each induction heating coil body 2a to 2e does not collide with the connecting portion 11 of the crankshaft W. A state in which the shaft portions w1 to w5 are in close proximity to each other can be maintained. That is, each shaft part w1 thru | or w5 can be induction-heated favorably.

  Next, the case where each axial part w1-w5 is cooled is demonstrated along the flowchart shown in FIG.

  In step 31, injection of cooling water from the cooling jackets 9 and 10 is started. The displacement sensor 5 uses the position of the center pin 61 when the induction heating is finished as a reference position. That is, the position of the center pin 61 when this induction heating is completed is stored in the storage unit 17 of the control device 15.

  In step 32, it is determined whether or not the amount of contraction of the crankshaft W exceeds the first predetermined length. If the amount of shrinkage does not exceed the first predetermined length, step 32 is repeated. If the amount of shrinkage exceeds the first predetermined length, the routine proceeds to step 33. In step 33, the first induction heating coil body 2a is moved toward the chuck 60 by the moving device 4 by a first predetermined length.

  In step 34, it is determined whether or not the amount of contraction of the crankshaft W exceeds the second predetermined length. If the amount of shrinkage does not exceed the second predetermined length, step 34 is repeated. If the amount of shrinkage exceeds the second predetermined length, the routine proceeds to step 35. In step 35, the first and second induction heating coil bodies 2a, 2b are moved to the chuck 60 side by the first predetermined length by the respective moving devices 4.

  In step 36, it is determined whether or not the amount of contraction of the crankshaft W exceeds a third predetermined length. If the amount of shrinkage does not exceed the third predetermined length, step 36 is repeated. If the amount of shrinkage exceeds the third predetermined length, the routine proceeds to step 37. In step 37, the first to third induction heating coil bodies 2a to 2c are moved to the chuck 60 side by the first predetermined length by the respective moving devices 4.

  In step 38, it is determined whether or not the amount of contraction of the crankshaft W exceeds a fourth predetermined length. If the amount of shrinkage does not exceed the fourth predetermined length, step 38 is repeated. If the amount of shrinkage exceeds the fourth predetermined length, the routine proceeds to step 39. In step 39, the first to fourth induction heating coil bodies 2a to 2d are moved to the chuck 60 side by the first predetermined length by the respective moving devices 4.

  In step 40, it is determined whether or not the amount of contraction of the crankshaft W exceeds the fifth predetermined length. If the amount of shrinkage does not exceed the fifth predetermined length, step 40 is repeated. If the amount of shrinkage exceeds the fifth predetermined length, the routine proceeds to step 41. In step 41, the first to fifth induction heating coil bodies 2a to 2e are moved to the chuck 60 side by the first predetermined length by the respective moving devices 4.

  The execution timings of steps 33, 35, 37, 39, and 41 shown in FIG. 5 correspond to the temperatures of the shaft portions w1 to w5, and as the temperatures of the shaft portions w1 to w5 decrease, steps 33 and 35 are performed. , 37, 39, 41 are performed in order. And in the stage which implements step 41, the temperature of each axial part w1-w5 has fallen below Ms point. When the cooling process is finished, the cooling jackets 9 and 10 are stopped.

  As described above, the fifth induction heating coil body 2e on the chuck 60 side (fixed side) does not move until reaching step 41, and the first induction heating coil body 2a on the center pin 61 side (movable side) In steps 33, 35, 37, 39, and 41, the first predetermined length is moved. That is, the shaft portion w1 on the center pin 61 side has the largest displacement amount, and the shaft portion w5 on the chuck 60 side has the smallest displacement amount. Therefore, a difference is also provided in the amount of movement of each induction heating coil body 2a to 2e.

  When each induction heating coil body 2a to 2e is moved by each moving device 4 along the flowchart shown in FIG. 5, each induction heating coil body 2a to 2e does not collide with the connecting portion 11 of the crankshaft W. A state in which the shaft portions w1 to w5 are in close proximity to each other can be maintained. That is, the cooling water sprayed from the cooling jackets 9 and 10 can satisfactorily reach the respective shaft portions w1 to w5 and cool the respective shaft portions w1 to w5.

  In the above, the behavior of the induction heating coil bodies 2a to 2e is shown according to the extension or contraction of the crankshaft W. However, the induction heating coil bodies 2a to 2e may be moved as follows. That is, each induction heating coil body 2a to 2e is always moved to the center pin 61 side during induction heating. In this case, the moving amount of the first induction heating coil body 2a is five times the moving speed of the fifth induction heating coil body 2e. Similarly, the second, third, and fourth induction heating coil bodies. The moving speeds of 2b, 2c and 2d are 4 times, 3 times and 2 times the moving speed of the fifth induction heating coil body 2e, respectively. Therefore, each moving device 4 moves the first to fifth induction heating coil bodies 2a to 2e at different speeds.

  In the above description, the journal portion has been described as an example of the shaft portion of the crankshaft W. However, the present invention can be implemented in the same manner as the journal portion even when the pin portion is quenched.

  In any of the above embodiments, one end of the crankshaft W is gripped by the chuck 60 and fixed so as not to move in the axial direction, and the other end is supported by the center pin 61 so as to be movable in the axial direction. However, both ends of the crankshaft W may be supported so as to be movable in the axial direction. In this case, the movement direction of the induction heating coil bodies 2a to 2e disposed to face the shaft portions w1 to w5 according to the movement of the shaft portions w1 to w5 in the axial direction due to the expansion and contraction of the crankshaft W, and Set the amount of movement as appropriate.

1 quenching devices 2a to 2e induction heating coil body 4 moving device (moving means, servo motor)
4a Fixed part (ball screw)
5 Displacement sensor (detection means)
6a-6e Heating coil (induction heating coil)
7, 8 Side plate (fixing member)
15 Control device 17 Storage part (storage means)
18 Alarm device W Crankshaft w1-w5 Shaft

Claims (4)

A crankshaft induction hardening device for simultaneously hardening a plurality of shaft portions of a crankshaft supported at both ends so as to be extendable and contractible in the axial direction,
A plurality of induction heating coil bodies including an induction heating coil and a fixing member to which the induction heating coil is fixed;
The induction heating coil is composed of a conductor to which a high frequency current is supplied,
The plurality of induction heating coil bodies having the induction heating coil close to and opposite to the shaft portion are individually moved in the axial direction of the crankshaft according to the expansion and contraction of the crankshaft during induction heating and cooling. An induction hardening apparatus for crankshafts, characterized in that.   Storage means for storing the correlation between the time from the start of induction heating of the shaft portion to the end of induction heating and the expansion of the crankshaft in the axial direction. The induction hardening apparatus for a crankshaft according to claim 1, wherein the heating coil body is moved.   2. The apparatus according to claim 1, further comprising a detection unit configured to detect expansion and contraction of the crankshaft in an axial direction, wherein the moving unit individually moves each induction heating coil body according to a detection result of the detection unit. Crankshaft induction hardening equipment. Having detection means for detecting axial expansion and contraction of the crankshaft;
Having control means,
The control means acquires the relationship between the amount of expansion and contraction detected by the detection means and the elapsed time;
A function of calculating the average value of the relationship between the amount of expansion and contraction during the quenching of the acquired plurality of crankshafts and the elapsed time;
A function of setting a predetermined width around the average value;
When performing quenching of crankshafts other than the plurality of crankshafts, the crankshaft has a function of determining whether the amount of expansion and contraction of the crankshaft is within the predetermined width range,
Have an alarm device,
3. The warning device according to claim 1, wherein the warning device issues a warning on the condition that the amount of expansion / contraction of the crankshaft is determined not to fall within a predetermined width by the control means. The induction hardening apparatus for crankshafts described in 1.

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