JP2000313916A - High frequency induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency induction heating apparatus which can execute uniform and good hardening and tempering to a gear, etc. SOLUTION: In the high frequency induction heating apparatus for executing the induction heating while shifting an inductor 2 disposed near a tooth of the gear 1 in the tooth trace direction, a laser beam irradiating device 4 is used and the inductor 2 and the upper surface of the tooth are irradiated with the beam and this reflected beam is detected with an image pickup unit 5. Based on this detected value, a shifting device 3 is controlled so as to keep the interval between the tooth of the gear 1 and the inductor 2 shifted in the tooth trace direction always to a fixed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating apparatus used for quenching or tempering a surface layer of a material such as a gear used in a construction machine.

[0002]

2. Description of the Related Art Conventionally, when induction hardening of a gear tooth is performed, a high-frequency inductor is manufactured according to the shape of the tooth, and the inductor is heated while being moved in the direction of the tooth line (the width direction of the gear). In addition, a method of performing quenching by cooling is generally used. When a high-frequency current is caused to flow through an inductor disposed near a tooth, an induced eddy current is concentrated in the material surface layer of the tooth, and the material surface layer is quenched by the Joule heat of the current. Therefore, the gap between the inductor and the tooth is a very important factor, and the size of this gap changes the energy transfer efficiency to the object to be heated and changes the heating temperature.

[0003] Usually, a contact detection jig is provided in conjunction with the inductor while keeping the relative position constant, and the inductor is brought close to the tooth until the jig contacts the tooth. Is retracted until the distance between the two reaches a predetermined value to position the inductor. Once the inductor is positioned, induction hardening is performed while moving the inductor in the direction of the teeth.

[0004]

However, as described above, in the method of performing quenching while moving the inductor in the tooth streak direction, the inductor is accurately positioned using a contact detection jig before the start of quenching. In addition, the distance between the inductor and the teeth during the movement in the tooth streak direction may change.
In the above-mentioned conventional method, the positional relationship between the moving inductor and the target object cannot be grasped, and the heating temperature changes due to a change in the interval, which may cause uneven quenching.

[0005] Further, since the contact detection jig is brought into contact with an object, the contact detection jig may be deformed at that time.
In such a case, a gap occurs between the measured position of the inductor and the actual position, and the reliability of position detection is impaired.

An object of the present invention is to provide a high-frequency heating apparatus capable of uniformly and favorably quenching and tempering gears and the like.

[0007]

An embodiment of the present invention will be described with reference to FIGS. 1 and 4. FIG. (1) The invention according to claim 1 is applied to a high-frequency heating device that performs high-frequency heating while moving an inductor 2 disposed in the vicinity of a heating target 1 along the surface of the target 2, 2
Measuring devices 4 and 5 for measuring the position of the object, and a correcting device 3 for always maintaining a constant distance between the target 1 and the inductor 2 moving along the surface thereof based on the measurement values of the measuring devices 4 and 5. , 1
The above object is achieved by providing 0. (2) The invention of claim 2 is applied to a high-frequency heating device that performs high-frequency heating while moving the inductor 2 disposed in the vicinity of the teeth of the gear 1 in the direction of the teeth of the teeth. Along with irradiating light linearly so as to span both teeth,
Measuring devices 4 and 5 for detecting the position of the inductor 2 with respect to the tooth by detecting the reflected light from the inductor 2 and the tooth, and based on the measured values of the measuring devices 4 and 5, the tooth and its tooth streak direction Correction device 3 that always keeps the distance between moving inductor 2 and constant constant
10 to achieve the above object.

In the meantime, in the section of the means for solving the above-mentioned problems which explains the constitution of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand, but the present invention However, the present invention is not limited to the embodiment.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a view showing an embodiment of a high-frequency heating device according to the present invention, and is a perspective view showing a schematic configuration of the high-frequency heating device. The gear 1 to be quenched is, for example, a turning gear used for a construction machine such as a hydraulic shovel provided with an upper turning body on a lower traveling body, and has a tooth formed inside an annular body. Gears. FIG. 1 shows only a part of the gear 1. 2
Is an inductor used for induction hardening. To describe an example of the gear 1, the outer diameter is 1200 (mm), the tooth width is 95 (mm), the number of teeth is 90, and the height of the teeth is 50 (mm). The thickness of the inductor 2 used in the gear 1 in the z direction is 10 to 20 (m
m).

Reference numeral 3 denotes a moving device for positioning the inductor 2 with respect to the teeth of the gear 1 and moving the inductor 2 along the direction of the tooth line during quenching. The moving device 3 includes a uniaxial stage 301 and xy mounted on the uniaxial stage 301.
The stage includes a stage 302, a z stage 303 mounted on the xy stage 302, and a mounting section 304 to which the inductor 2 is mounted. The uniaxial stage 301 is the inductor 2
The xy stage 302 is used for fine positioning after the coarse positioning, and the z stage 303 is used for fine positioning in the z direction and movement of the inductor 2 in the tooth streak direction at the time of quenching.

The mounting portion 304 to which the inductor 2 is fixed includes
The laser beam irradiation device 4 and the imaging device 5 which are position measuring devices are fixed. Therefore, the inductor 2, the laser beam irradiation device 4, and the imaging device 5 move integrally in each of the x, y, and z directions. The laser light irradiation device 4 irradiates a pair of linear lights along the x direction and the y direction onto the upper surfaces of the inductor 2 and the gear 1, and generates light having a wavelength outside the infrared region. The imaging device 4 detects laser light reflected on the top surfaces of the inductor 2 and the gear 1, and for example, a CCD camera or the like is used.

In the case of induction hardening, since the portion to be observed by the imaging device 5 is a heated portion and infrared rays are radiated from the gear 1, the light outside the infrared region is used as the laser beam as described above. Further, the present invention can be similarly applied to induction tempering. In this case, since the gear 1 does not become hot and does not glow as in the case of quenching, it can be observed with visible light.

FIGS. 2A and 2B are views showing the inductor 2, the laser beam irradiating device 4 and the image pickup device 5 fixed to the mounting portion 304. FIG. 2A is a side view, and FIG. It is a figure showing a laser beam. The imaging device 5 is installed so that its optical axis is perpendicular to the upper surface of the inductor 2.
On the other hand, the laser light irradiation device 4 is installed such that linear light L2 (described later) applied to the upper surface of the inductor 2 makes a predetermined angle θ with respect to the optical axis of the imaging device 5. This angle θ
Is set in consideration of the mounting space of the laser beam irradiation device 4, ease of position measurement, and the like. L1 in FIG. 2B is y
L2 indicates linear light in the x direction, and L2 indicates linear light in the x direction, and crosses each other on the optical axis of the imaging device 5. The laser beam irradiation device 4 may scan the spot light in the x and y directions instead of the linear light.

Returning to FIG. 1, reference numeral 6 denotes a positioning jig for coarse positioning, which includes a pair of contacts 6a used for coarsely positioning the inductor 2. The positioning jig 6 is fixed to the uniaxial stage 301,
1 driven in the y-axis direction. FIG. 3 is a view showing the relationship between the positioning jig 6 and the gear 1 when coarse positioning is performed, and the uniaxial stage 301 (FIG. 1) is driven to drive the contact 6a.
Is positioned so that the tip of the gear contacts the tooth groove portion of the gear 1. When the contact 6a comes into contact with the gear 1, the positioning jig 6
, A signal is transmitted to the control device 10 (not shown) (see FIG. 4 described later), and the movement of the uniaxial stage 301 is stopped.

After coarsely positioning the inductor 2 in this way,
Further, the xy stage 302 and the z stage 303 are driven to perform fine positioning. Reference numeral 7 denotes a pinion gear that meshes with the gear 1. The pinion gear 7 is rotated by a motor (not shown) to rotate the gear 1. That is, if the quenching for one tooth space of the gear 1 is completed,
Once the inductor 2 and the positioning jig 6 have been released from the tooth space (for example, after having been released in the z direction), the gear 1 is rotated using the pinion gear 7 and the inductor 2 is inserted into the next adjacent tooth space. And quenching the part.

FIG. 4 is a block diagram showing the configuration of the high-frequency heating device. Reference numerals 305 to 307 denote motors for driving the stages 301 to 303 of the moving device 3, which are controlled by the control device 10 of the high-frequency heating device. Reference numerals 308 and 309 denote position sensors for detecting the positions of the xy stage 302 in the x and y directions, respectively, and reference numeral 310 denotes a position sensor for detecting the position of the z stage 303 in the z direction. The position data detected by the position sensors 308 to 310 are sent to the control device 10 and xy based on those position data.
Position control of the stage 302 and the z stage 303 is performed. Reference numeral 12 denotes a motor for rotating the pinion gear 7;
Reference numeral 3 denotes a rotation angle sensor such as a rotary encoder that detects the number of rotations of the pinion gear 7. The control device 10 calculates the rotation angle of the gear 1 based on the rotation angle detected by the rotation angle sensor 13 and drives the motor 12 to rotate the gear 1 by one pitch. 11 is a power supply of the inductor 2, 14 is a monitor for outputting an image of the imaging device 5, and 15 is an input device for inputting an instruction from an operator to the high-frequency heating device, and starts and stops the device and various data. Can be entered.

[Regarding Fine Positioning and Position Correction During Hardening] Next, fine positioning of the inductor 2 with respect to the gear 1 and position correction of the inductor 2 during hardening will be described. First, referring to FIG.
The positioning in the direction will be described. In FIG. 5, (a)
Is a plan view of the gear 1 and the inductor 2, and FIG.
FIG. 5 is a diagram showing an image captured by the above. When performing y-positioning, as shown in FIG. 5A, linear light L1 along the y-axis direction is irradiated onto the gear 1 and the inductor 2. L11 shown in FIG. 5B is an image of the linear light L1 described above, and points a1 and a2 are points corresponding to points A1 and A2 in FIG. 5A. Point a1, on the obtained image
From the y-coordinates y1 and y2 of a2, the y-coordinate Y of points A1 and A2
1, Y2 is calculated, and the gap interval (Y1-Y2) between the inductor 2 and the tooth bottom surface of the gear 1 is calculated. Then, the xy stage 30 is adjusted so that the gap interval (Y1-Y2) becomes a predetermined value.
2 is moved in the y direction and stopped. In this manner, minute positioning of the inductor 2 in the y direction is performed. In addition,
The calculation for obtaining the coordinates of the points A1 and A2 from the coordinates of the points a1 and a2 on the image is performed by the control device 10 in FIG.

On the other hand, when positioning in the x and z directions is performed, as shown in FIG.
2 is irradiated onto the inductor 2 and the gear 1 from an oblique direction.
FIGS. 6B and 6C show images obtained at this time, and FIG. 6B shows a case where the z positions of the top surfaces of the inductor 2 and the gear 1 match, and FIG. () Shows a case where the upper surface of the inductor 2 is shifted from the upper surface of the gear 1 in the positive direction of the z-axis. In FIG. 6, L21, L22, a3
Ａa6 are images of the linear light L2 and points A3 to A6.
Hereinafter, x-positioning will be described by taking the case of FIG. 6C as an example. However, in the case of FIG. 6B, x-positioning is performed in the same manner. Note that the image L2 with respect to the image L21 in FIG.
The deviation of 2 will be described later.

As shown in FIG. 6A, the inductor 2 is located at a position deviated in the positive x direction with respect to the gear 1, and the gap on the left side in the figure is smaller than that on the right side in the figure. Therefore, if the x-coordinates of the points A3 to A6 calculated from the x-coordinates x3 to x6 of the points a3 to a6 in the image are X3 to X6, the relationship represented by the following equation (1) is established.

X3-X4 <X5-X6 (1) Therefore, the left and right gap intervals (X3-X4) and (X5-X4)
The xy stage 302 is driven in the negative x-axis direction so that X6) becomes equal, and stops when they become equal.

In this manner, when the fine positioning of the inductor 2 in the x direction is performed, when the inductor 2 is displaced in the negative direction of the z-axis with respect to the gear 1, FIGS.
The image changes to an image as shown in (b), and points a3 and a4
The interval between them becomes equal to the interval between points a5 and a6.

Next, positioning in the z direction will be described. In this case, the positioning is performed so that the z position on the upper surface of the inductor 2 and the z position on the upper surface of the gear 1 are equal. FIG.
(A) is a figure explaining the case where the inductor 2 is displaced with respect to the gear 1 in the positive direction of the z-axis. The upper surface of the inductor 2 is displaced from the upper surface of the gear 1 by a distance z. Since the linear light L2 emitted from the laser light irradiation device 4 is inclined by the angle θ with respect to the optical axis of the imaging device 5, the point A4 is shifted in the negative y-axis direction with respect to the point A3. The size of this shift Y
d is obtained by the following equation (2).

## EQU2 ## Yd = z · tan θ (2)

In FIG. 7B, images L21 and L21
Numeral 22 is shifted in the y direction by an interval yd corresponding to Yd in equation (2). Therefore, by moving the z stage 303 so that the displacement yd becomes yd = 0, the inductor 2
Of the z position is finely positioned. In this case, Yd may be calculated from yd, and the moving distance z may be calculated backward from Equation (2) using the obtained Yd. FIG. 7C shows an image after the z positioning is performed, and FIG.
Similar images are obtained when x positioning is performed from the state shown in FIG. As described above, x direction, y direction, z
By performing the positioning in the direction, the minute positioning before quenching is completed.

Further, the inductor 2 is moved to the z stage 303 by z
In the case where quenching is performed while moving in the direction, the position of the inductor 2 can be similarly corrected. In this case, the correction is performed in the x direction and the y direction. In the y direction, the difference (y1-y) between the y-coordinates of points a1 and a2 shown in FIG.
y2) is monitored, and if the difference (y1-y2) deviates from the value corresponding to the predetermined interval (constant value), the xy stage 302 is driven so as to cancel the deviation. On the other hand, in the x direction, the xy stage 302 is driven such that the x-direction interval between points a3 and a4 and the x-direction interval between points a5 and a6 shown in FIG.

By the way, when the inductor 2 is inclined with respect to the y-axis when the inductor 2 is fixed to the mounting portion 304, or when the rotation angle of the gear 1 is not accurate, FIG. As described above, the inductor 2 is inclined with respect to the tooth space of the gear 1. Such inconvenience can be solved by using the laser beam irradiation device 4 and the imaging device 5.

For example, when the inductor 2 is inclined with respect to the y-axis, an image L22 of the linear light L2 on the inductor 2 is as shown in FIG. FIG. 8B also shows the inductor 2 for easy understanding. Point O indicates the center of the screen, and is a position corresponding to the optical axis of the imaging device 5. When the inductor 2 is correctly fixed, the image L of the linear light L2
22 is symmetric with respect to the center O, but becomes asymmetric as shown in FIG. 8B when the inductor 2 is inclined with respect to the y-axis. Therefore, the operator may fix the inductor 2 again so that the distance between the center O and the point a4 is equal to the distance between the center O and the point a5.

On the other hand, when the gear 1 is not correctly positioned, the image L22 of the laser beam on the gear 1 is shown in FIG.
The result is as shown in FIG. FIG. 8C also shows the gear 1 for easy understanding. Also in this case, if the gear 1 is rotated so that the distance between the center O and the point a3 of the screen is equal to the distance between the center O and the point a6, the gear 1 is positioned at a correct position.

[Explanation of Quenching Procedure] Next, a quenching procedure using the high-frequency heating device of the present embodiment will be described with reference to a flowchart shown in FIG. First, step S1
After the coarse positioning has been performed in step 2, the process proceeds to step S2 to perform fine positioning. Next, induction hardening is started in step S3, and the inductor 2 is moved along the tooth line by the z stage 303. Step S4 is a step of performing position correction, and as described above, x of the inductor 2
And position correction in the y direction.

Step S5 is a step for judging, from the z position of the inductor 2 detected by the position sensor 309, whether or not quenching has been completed for the entire tooth width of one tooth space portion. If it is determined, the process proceeds to step S6 to stop quenching, and if it is determined that the process is not completed, the process returns to step S4. Step S4 is repeatedly executed at predetermined time intervals until the quenching is completed for the entire tooth width. Step S7 is a step of determining whether or not quenching of all the teeth of the gear 1 has been completed. When it is determined that the quenching has been completed, a series of processes is completed, and when it is determined that it has not been completed, the process proceeds to step S8. After the inductor 2 and the positioning jig 6 are released by the above, the gear 1 is set at a predetermined angle [= 360
[Degree / (number of teeth)]] and returns to step S1. That is, when the number of teeth of the gear 1 is N, the processes of steps S1 to S6 are performed N times.

In the embodiment described above, the pinion gear 7
The control device 10 also controls the rotation of the gear 1 using the gears, so that the quenching of all the teeth of the gear 1 is automatically performed as a series of operations. The operation from positioning to quenching may be performed automatically by the control device 10, and the rotation of the gear 1 may be performed manually.
That is, the program of steps S1 to S6 in the flowchart of FIG. 9 is input to the control device 10 to automatically perform the work of this part, and the work of steps S7 and S8 is performed by the operator. At this time, the single-axis stage 301 for coarse positioning may be driven manually. In this case, the positioning jig 6 does not need to emit a signal to the control device 10 at the time of contact.

As described above, in the present embodiment,
Since induction hardening is performed while correcting the position of the inductor 2 so that the distance between the teeth of the gear 1 and the inductor 2 is constant, uniform and good hardening can be performed. In addition, since the positioning of the inductor 2 and the position measurement at the time of position correction are performed in a non-contact manner, there is no inconvenience due to the contact with the gear 1, and highly reliable measurement can be always performed. Further, in the present embodiment, quenching of the teeth of the gear 1 has been described as an example, but the present invention is not limited to the gear, but can be applied to high-frequency heating of other objects to be heated.

In the correspondence between the embodiment described above and the elements of the claims, the gear 1 is an object, the laser beam irradiation device 4 and the imaging device 5 are measuring devices, and the moving device 3
The control device 10 constitutes a correction device.

[0032]

As described above, according to the present invention,
Since high-frequency heating is performed while correcting the position of the inductor so that the distance between the object or gear teeth and the inductor is constant,
Uniform and good heating can be performed. In particular, claim 2
Since the measurement of the position of the inductor with respect to the tooth is performed in a non-contact manner, interference between the measuring device and the gears can be avoided, and a decrease in the reliability of the measuring device due to interference or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a high-frequency heating device according to the present invention.

2A and 2B are diagrams showing an inductor 2, a laser beam irradiation device 4, and an imaging device 5, wherein FIG. 2A is a side view, and FIG.
FIG. 3 is a view showing a laser beam applied to the laser beam.

FIG. 3 shows a positioning jig 6 and a gear 1 when coarse positioning is performed.
FIG.

FIG. 4 is a block diagram illustrating a configuration of a high-frequency heating device.

5A and 5B are diagrams for explaining positioning in the y direction, and FIG.
FIG. 3 is a plan view of the gear 1 and the inductor 2, and FIG.

6A and 6B are diagrams for explaining positioning in the x direction, and FIG.
Is a plan view of the gear 1 and the inductor 2, (b) and (c).
FIG.

FIGS. 7A and 7B are views for explaining positioning in the z direction, and FIG.
FIG. 3B is a side view of the inductor 2 and the gear 1 irradiated with the linear light L2, and FIGS.

FIGS. 8A and 8B are diagrams illustrating a case where the gear 1 and the inductor 2 are relatively inclined. FIG. 8A is a plan view of the gear 1 and the inductor 2, and FIG. Image if
(C) is an image when the gear 1 is tilted.

FIG. 9 is a flowchart for explaining the procedure of induction hardening.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 gear 2 inductor 3 moving device 4 laser beam irradiation device 5 imaging device 6 positioning jig 7 pinion gear 10 control device 11 power supply

Claims (2)

[Claims] 1. A high-frequency heating device that performs high-frequency heating while moving an inductor disposed near a heating target along a surface of the target, and a measuring device that measures a position of the inductor. A high-frequency heating device comprising: a correction device that always keeps a constant distance between the object and the inductor that moves along the surface thereof based on a measurement value of the measurement device. 2. An inductor disposed near a gear tooth,
In a high-frequency heating device that performs high-frequency heating while moving in the tooth streak direction of the tooth, while irradiating light linearly so as to extend over both the inductor and the tooth, reflection from the inductor and the tooth A measuring device that detects light and measures the position of the inductor with respect to the tooth; and, based on a measurement value of the measuring device, always keeps a distance between the tooth and the inductor that moves in the direction of the tooth line. A high-frequency heating device comprising: a correction device for maintaining the value at a value.