JP5204505B2 - Induction heat treatment equipment - Google Patents

Description

  The present invention relates to a high-frequency heat treatment apparatus for quenching a workpiece in which heat treatment portions exist at a plurality of coaxial positions such as a camshaft cam used in a multi-cylinder engine.

When a heat treatment part with a distorted outer shape such as a camshaft cam is heat-treated (quenched) with a conventional high-frequency heating device equipped with an annular heating coil, the heating amount in the part closest to the heating coil is heated in other parts. More than the amount, the difference in quenching depth will occur. If quenching of the entire periphery of the heat treatment part is not performed uniformly, it causes cracking. A high frequency heating apparatus capable of avoiding this is disclosed in Patent Document 1. That is, the high-frequency heating device disclosed in Patent Document 1 can perform heat treatment so that the entire periphery of the heat treatment portion of the workpiece is uniformly heated.
JP 2001-131638 A

  By the way, in the high frequency heating device disclosed in Patent Document 1, the annular heating coil is configured in a so-called daruma shape having a small diameter portion and a large diameter portion. Then, when the work rotates and the part that protrudes most outward in the radial direction of the heat treatment part is opposed to the small diameter part of the heating coil, the heating amount of the heating coil is reduced, and the protruded part is conversely changed to the large diameter part. When facing each other, the heating amount of the heating coil is increased, so that the heat treatment around the entire heat treatment portion is made uniform.

  However, the configuration disclosed in Patent Document 1 is effective when there is only one heat treatment part (cam), but heats a workpiece provided with a plurality of heat treatment parts with different installation angles around the axis. Takes a lot of time. That is, in the high-frequency heating device disclosed in Patent Document 1, if a plurality of heat treatment parts having different installation angles around the axis are not heat-treated one by one in order, the entire quenching depth of all heat treatment parts is uniform. Can not be. Therefore, in the high-frequency heating device disclosed in Patent Document 1, it takes a considerable time to complete the heat treatment of the plurality of heat treatment portions of the workpiece.

  In addition, in order to simultaneously heat-treat a plurality of heat treatment units with the high-frequency heating device disclosed in Patent Document 1, the same number of high-frequency power sources (inverters) as the heat treatment units are required. A control mechanism is required to control individually. This complicates the apparatus configuration and increases the cost.

  Instead of adopting the high-frequency heating device disclosed in Patent Document 1 as described above, as a method for uniformizing the quenching depth around the entire heat treatment portion (cam) of the workpiece with a simple configuration, for example, It is conceivable that the annular heating coils respectively arranged around the plurality of heat treatment parts of the workpiece are individually reciprocated in one direction according to the rotation angle position of the heat treatment part. However, even if the high-frequency heating apparatus can be simply configured with this, the quenching depth of the heat treatment part of the workpiece is not uniform.

  Accordingly, the present invention provides a high frequency capable of simultaneously heat-treating each strain-shaped workpiece heat treatment section of a workpiece in which a plurality of identical strain-shaped workpiece heat treatment sections on the same axis are installed at different angles simultaneously with a simple configuration. An object is to provide a heat treatment apparatus.

  The invention of claim 1 for solving the above-mentioned problem is a high-frequency heat treatment apparatus for heat-treating a work in which a plurality of strain-shaped work heat treatment portions are coaxially arranged at different angles in the axial direction. And a heating member disposed around each strained workpiece heat treatment section, and a control means for controlling the heating amount of the heating member, and when the shaft rotates, from each strain workpiece heat treatment section to the heating member In the high-frequency heat treatment apparatus, the heating member is configured so that the shortest distance is uniformly changed.

In the invention of claim 1, the heating member is configured such that the shortest distance from each strained workpiece heat treatment portion to the heating member is uniformly changed when the shaft rotates. Thereby, the shortest distance from each distorted work heat treatment part to a heating member can be synchronized.
Therefore, the high-frequency heating apparatus embodying the invention of claim 1 can simultaneously heat treat each strain-shaped workpiece heat treatment part simultaneously. Since the entire periphery of each strain workpiece heat treatment portion can be simultaneously heat treated, the heat treatment can be completed in a short time.
The invention of claim 1 can be carried out even if the installation angles of the respective strain-shaped workpiece heat treatment portions with respect to the shaft are shifted by an arbitrary angle, but the installation angles of the respective strain-shaped workpiece heat treatment portions are shifted by a predetermined angle. This can be suitably implemented when

  According to the invention of claim 2, in the invention of the high-frequency heat treatment apparatus of claim 1, the control means increases the heating amount as the shortest distance from each strained workpiece heat treatment section to the heating member becomes longer.

In the invention of claim 2, since the control means increases the heating amount as the shortest distance from each strained workpiece heat treatment section to the heating member becomes longer, the heat treatment on the entire periphery of each strain workpiece heat treatment section is uniform. Can be
That is, in the second aspect of the invention, the control means adjusts the output of the high frequency power source. Since the output adjustment is performed so that the heating amount is increased as the shortest distance from each strain-shaped workpiece heat treatment section to the heating member is increased, the heat treatment on the entire periphery of each strain-shaped workpiece heat treatment section can be made uniform.
The shortest distance from the strained workpiece heat treatment part to the heating member is the shortest when the top part of the strained workpiece heat treatment part is closest to the heating member, and the base part of the strained workpiece heat treatment part is closest to the heating member. In this case, the strain-shaped workpiece heat treatment part and the heating member are arranged so as to be the longest.

  According to a third aspect of the present invention, in the high frequency heat treatment apparatus according to the first or second aspect of the present invention, the heating member is formed in an annular shape and is individually arranged on the outer periphery of each strained workpiece heat treatment portion.

  In the invention of claim 3, since the heating member is provided for each strained workpiece heat treatment part, each strained workpiece heat treatment part can be heat treated simultaneously. Further, the position can be finely adjusted for each heating member.

  A fourth aspect of the present invention is the high frequency heat treatment apparatus according to any one of the first to third aspects, wherein one high frequency power source is provided.

According to the fourth aspect of the present invention, each strained workpiece heat treatment portion of the workpiece is simultaneously heat treated with one high frequency power source. That is, since the shortest distance from each strained workpiece heat treatment section to the heating member can be synchronized, the entire periphery of each strained workpiece heat treatment section can be uniformly heat treated at the same time by adjusting the output of one high frequency power source.
Therefore, when the invention of claim 4 is carried out, the configuration of the high-frequency heat treatment apparatus can be simplified. In addition, the high-frequency heat treatment apparatus can be configured at low cost.

  The high-frequency heat treatment apparatus of the present invention uniformly heats the entire periphery of each strain-shaped workpiece heat treatment section of a workpiece in which a plurality of strain-shaped workpiece heat treatment sections having the same shape on the same axis are installed at different angles simultaneously in a short time. be able to.

FIG. 1 is an overall schematic diagram of the high-frequency heat treatment apparatus of the present invention, and FIGS. 2A to 2D are front views showing the positional relationship between each heating coil and a workpiece, respectively. (B) is the top view and side view of each heating coil and workpiece | work (camshaft) of a high frequency heat processing apparatus, respectively. FIG. 4 is a front view of each heating coil of the high-frequency heat treatment apparatus in which the workpiece is disposed.
First, the outline of the high-frequency heat treatment apparatus 1 will be described with reference to FIG. 1, and then the heating coils 2a to 2d which are characteristic structures of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the high frequency heat treatment apparatus 1 includes an inverter 6 (high frequency oscillator), a control device 15, a drive device 16, output transformers 7a to 7d, conductors 8 to 11, and the like.

  The inverter 6 is connected to the three-phase AC power source 5 and converts an AC voltage of 400 volts AC and a frequency of 50 Hz or 60 Hz into a high frequency current and supplies the high frequency current to the output transformers 7a to 7d. The control device 15 detects the rotational angle position of a drive device 16 that rotationally drives a camshaft 14 (workpiece) described later, and controls the output of the inverter 6 to the output transformers 7a to 7d.

  The output transformers 7a to 7d are connected in parallel to the inverter 6, and receive high-frequency current from the inverter 6 to generate high-frequency induced current in the conductors 8 to 11. Inside the conductors 8 to 11, a coolant passage 12 (FIG. 3) through which coolant is passed is provided. In addition, annular heating coils 2a to 2d are formed by the conductors 8 to 11, respectively.

As shown in FIGS. 2A to 2D, each of the heating coils 2a to 2d is an annular coil and has the same size and shape. However, as shown in FIG. The centers 4a to 4d are not coincident. When the heating coils 4a to 4d are individually viewed as shown in FIGS. 3A and 3B, the center 4a of the heating coil 2a and the center 4b of the heating coil 2b are shifted by a distance L1 in the horizontal direction and the vertical direction, respectively. ing. That is, the heating coil 2a is located obliquely above and to the right of the heating coil 2b as viewed in FIG.
The center 4a of the heating coil 2a and the center 4c of the heating coil 2c coincide in the horizontal direction, but are shifted by a distance (L1 + L1) in the vertical direction, and the center 4a of the heating coil 2a is on the upper side. .
The center 4b of the heating coil 2b and the center 4c of the heating coil 2c are shifted by a distance L1 in the horizontal direction and further shifted by a distance L1 in the vertical direction. Therefore, the heating coil 2b is located obliquely above and to the left of the heating coil 2c as seen in FIG.
The center 4d of the heating coil 2d is shifted from the center 4a of the heating coil 2a in the horizontal direction by a distance L1 to the opposite side of the center 4b of the heating coil 2b, and more vertically than the center 4a of the heating coil 2a. It is shifted downward by a distance L1.

As a result, the heating coils 2a to 2d are displaced vertically and horizontally as shown in FIG.
In addition, the heating coil 2a arrange | positioned around each distortion | strained workpiece | work heat processing part that the shape and magnitude | size which each distortion | strained workpiece | work heat treatment part (cam 13a-13d mentioned later) assumes of the workpiece | work which is heat-processed is the same. Since ˜2d has the same size, the centers 4a to 4d of the heating coils 2a to 2d are deviated from the axis 3a of the rotating shaft 3 either vertically or horizontally by a distance L1.
As described above, the plurality of cams 13a to 13d (strained workpiece heat treatment portions) are simultaneously heat treated by the high-frequency heat treatment apparatus 1 described above.

Next, the workpiece | work heat-processed with the high frequency heat processing apparatus 1 is demonstrated.
The workpiece is a camshaft 14 having four cams 13a to 13d. The cam shaft 14 is configured such that the cams 13 a to 13 d are fixed to the rotating shaft 3 by changing the direction by 90 degrees at predetermined intervals in the axial direction. That is, the mounting angles of the cams 13a to 13d with respect to the rotating shaft 3 are different by 90 degrees.
Here, the number of cams fixed to the rotating shaft 3 and the installation angle are arbitrarily set according to the purpose of use of the workpiece. For example, if the number of cams is 3, the interval between the installation angles of the cams can be 120 degrees, but the installation angles of the cams are not necessarily equal.

Heating coils 2a to 2d are arranged around the cams 13a to 13d, respectively. That is, the camshaft 14 penetrates the inside of each heating coil 2a-2d, and both ends are rotatably supported by a support mechanism (not shown). The camshaft 14 (rotating shaft 3) can be driven to rotate by a driving device 16 (FIG. 1).
As shown in FIG. 2A, the axis 3a (rotation center) of the rotation shaft 3 of the camshaft 14 does not coincide with the centers 4a to 4d of the heating coils 2a to 2d as described above. That is, the axis 3a of the rotating shaft 3 and the centers 4a to 4d of the heating coils 2a to 2d are separated from each other by a distance L1 toward the protruding portion of the cam. In other words, each of the heating coils 2a to 2d is disposed on the protruding portion side of the cam such that the centers 4a to 4d are separated from the axis 3a by a distance L1.

  Since the cams 13a to 13d are integrally fixed to the same rotary shaft 3, when the rotary shaft 3 rotates, the cams 13a to 13d also rotate together. This will be described mainly with reference to FIGS. 2 (a) to 2 (d).

  When a high frequency current is supplied from the inverter 6 to the output transformers 7a to 7d, a high frequency induction current is generated in the conductors 8 to 11. A high-frequency induction current flows simultaneously through the conductors 8 to 11 (each heating coil 2a to 2d), a high-frequency induction current is also generated on each cam 13a to 13d, and each cam 13a to 13d is heated simultaneously. Here, since the cooling fluid passage 12 is provided in the conductors 8 to 11 and the cooling fluid flows in the cooling fluid passage 12, the heating temperature rise of the conductors 8 to 11 is suppressed, but each cam 13a to 13a. 13d heats up according to the magnitude of the generated high frequency induction current.

In the state shown in FIG. 2A, the shortest distance from the cam 13a to the inner wall of the heating coil 2a, the shortest distance from the cam 13b to the inner wall of the heating coil 2b, and the shortest distance from the cam 13c to the inner wall of the heating coil 2c. , And the shortest distance from the cam 13d to the inner wall of the heating coil 2d is the distance X1.
FIG. 2B shows a state where the rotating shaft 3 of the camshaft 14 is rotated 90 degrees from the state shown in FIG. In this case, the shortest distance from each cam to the inner wall of the heating coil is X2.
FIG. 2C shows a state in which the rotating shaft 3 of the camshaft 14 is rotated 90 degrees from the state shown in FIG. In this case, the shortest distance from each cam to the inner wall of the heating coil is X3.
FIG. 2D shows a state in which the rotating shaft 3 of the camshaft 14 is rotated 90 degrees from the state shown in FIG. In this case, the shortest distance from each cam to the inner wall of the heating coil is X4.

  That is, when the rotating shaft 3 of the camshaft 14 rotates and the cams 13a to 13d rotate integrally, the shortest distance from each cam to the inside of each heating coil changes uniformly. This shortest distance becomes the shortest shortest distance X3 when the top portion T (FIG. 2) of each cam 13a to 13d is closest to the heating coils 2a to 2d, and the base portion E (FIG. 2) of each cam 13a to 13d. Each of the cams 13a to 13d and the heating coils 2a to 2d are arranged so as to have the longest shortest distance X1 when approaching the heating coils 2a to 2d. Then, the control device 15 shown in FIG. 1 detects the rotational angle position of the camshaft 14 that is rotationally driven by the drive device 16, indirectly detects the shortest distances X1 to X4, and adjusts the output of the inverter 6. Do. That is, when the output adjustment (power reduction) of the inverter 6 is performed in accordance with the rotational angle position of the rotating shaft 3 of the camshaft 14, the heat treatment (quenching process) is performed uniformly around the entire cams 13a to 13d. Will be able to.

  Therefore, the high frequency heat treatment apparatus 1 can simultaneously quench the cams 13a to 13d with a single inverter 6, and can uniformly quench the entire periphery of the cams 13a to 13d. .

  A method of power reduction of the inverter 6 will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the aforementioned shortest distances X1 to X4 (FIG. 2) and the output (power) adjusted by the inverter 6. In FIG. As shown in FIG. 5, the shortest distance at time t1 is X1, the shortest distance at time t2 is X2, the shortest distance at time t3 is X3, and the shortest distance at time t4 is X4. As for the shortest distance, X1 is the longest and X3 is the shortest. X2 and X4 are equal, and the length of both is between X1 and X3.

  On the other hand, the inverter 6 performs power reduction so that the power (heating amount) increases as the shortest distance increases, and conversely, the power (heating amount) decreases as the shortest distance decreases. Therefore, the power supplied from the inverter 6 is the maximum W1 at time t1, and the power at time t3 is the minimum W3.

  The power switching (switching from W1 to W3 and from W3 to W1) is performed at time tB and time tC. The time tB is a time slightly before the time t2 at which the shortest distance becomes X2, and the amount of time before the time t2 is determined in advance by experiments in consideration of the shape of the workpiece. The time tC is a time slightly after the time t4 when the shortest distance becomes X4. The time tC is set to the time after the time t4 by taking into account the shape of the workpiece and conducting an experiment in advance. I ask for it. As described above, the peripheral surface of the work (distorted work heat treatment parts 13a to 13d) can be heated substantially uniformly only by switching the electric power when the shortest distance becomes X2 or X4.

  When the power is switched from W1 to W2 at time tA and further from W2 to W3 at time tB, the peripheral surfaces of the cams (distorted workpiece heat treatment units) 13a to 13d can be heated more uniformly. Become. Here, the time tA is preferably an intermediate time between the time t1 and the time tB. Further, the power W2 is a power intermediate between the power W1 and the power W3 (that is, W3 <W2 <W1).

  That is, if the electric power is not suddenly switched from W1 to W3 but gradually changed in conjunction with the passage of time from W1 to W2 to W3, the cams (distorted workpiece heat treatment parts) 13a to 13d The surface can be heated (quenched) more uniformly. Similarly, after time tC, this time, the power W3 is switched stepwise from power W3 to power W1 in conjunction with the passage of time (for example, the power is switched from W3 to W2 at time tC, and further switched to W1 at time tD). ) And heating (quenching) of the peripheral surfaces of the cams (distorted workpiece heat treatment portions) 13a to 13d can be made more uniform.

  When the electric power is switched from W1 to W3 or from W3 to W1, the heating of the peripheral surfaces of the cams (distorted workpiece heat treatment units) 13a to 13d can be made more uniform as the electric power is switched in a plurality of stages. However, when the power is switched from W1 to W3 or from W3 to W1 in two or three stages, the heating of the peripheral surfaces of the cams (distorted workpiece heat treatment units) 13a to 13d can be preferably made uniform. In addition, it is possible to configure the high-frequency heat treatment apparatus 1 having both advantages without complicating the switching of electric power.

In the above-described example, the case where the shape and size of each cam 13a to 13d (strained workpiece heat treatment portion) is the same is shown. However, the size or shape of one of the cams is different from the other cams. Then, the deviation (distance L1) of the center position of the heating coil that heat-treats the cam or the size and shape of the heating coil differs from the heating coil that heat-treats the other cam.
That is, the center position of the heating coil is shifted, or the shape and size of the heating coil are changed so that the shortest distance from each cam to the inner wall of the heating coil is the same for each rotation angle position of the rotating shaft 3 of the camshaft 14. Thus, the heat treatment around the entire circumference of each cam can be made uniform.

1 is an overall schematic diagram of a high-frequency heat treatment apparatus of the present invention. (A)-(d) is a front view which shows the positional relationship of each heating coil and a workpiece | work, respectively. (A), (b) is each the top view and side view of each heating coil and workpiece | work (camshaft) of a high frequency heat processing apparatus. It is a front view of a heating coil. It is a graph which shows the relationship between the shortest distance from a heating coil to a cam, and the output (electric power) adjusted by an inverter.

Explanation of symbols

1 High-frequency heat treatment apparatus 2a to 2d Heating coil (heating member)
3 Rotating shaft 3a Axes 4a-4d Center of heating coil 6 Inverter (high frequency power supply)
7 Output transformers 8 to 11 Conductors 13a to 13d Cam (strained workpiece heat treatment section)
14 Camshaft 15 Control device

Claims (4)

A high-frequency heat treatment apparatus for heat-treating a work in which a plurality of strain-shaped work heat treatment portions on the same axis are spaced apart from each other in the axial direction at different angles,
A heating member arranged around each strain-shaped workpiece heat treatment section, and a control means for controlling the heating amount of the heating member;
The high frequency heat treatment apparatus, wherein the heating member is configured such that the shortest distance from each strained workpiece heat treatment portion to the heating member changes uniformly when the shaft rotates.   2. The high frequency heat treatment apparatus according to claim 1, wherein the control means increases the heating amount as the shortest distance from each strained workpiece heat treatment section to the heating member increases.   The high frequency heat treatment apparatus according to claim 1 or 2, wherein the heating members are annular and are individually arranged on the outer periphery of each strained workpiece heat treatment portion.   The high frequency heat treatment apparatus according to any one of claims 1 to 3, further comprising a single high frequency power supply.

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