JPH0790358A - Laser beam quenching apparatus - Google Patents

Abstract

PURPOSE:To provide a laser beam quenching apparatus, by which uniform heating can be executed and good worked quality can be obtd. even if a driving control for relatively shifting a material to be worked to the laser beam is executed by a simple mean. CONSTITUTION:The laser beam 9 emitted from a CO2 laser beam oscillator 1 is changed to the laser beam 18 having uniformized strength distribution and rectangular shape by a kaleidoscope 3, and this direction is changed with a reflecting mirror 4 capable of changing the irradiation angle to irradiate the cam surface of a cylindrical groove cam 5 as the material to be worked. The cylindrical groove cam 5 receives prescribed driving control by a rotary table 6 and an XY table 7 and the quenching is executed under relative shifting against the laser beam 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser hardening apparatus for irradiating a workpiece with a laser beam emitted from a laser oscillator for hardening.

[0002]

2. Description of the Related Art Conventionally, in-hardening in the industrial field, in-furnace hardening such as carburizing hardening, induction hardening, and flame hardening have been widely used. However, in any case of quenching, the heat input to the material to be quenched is excessive and the distortion due to quenching is large. For this reason, in parts that require precision, such as cam members, correction of distortion due to quenching is a heavy burden.

On the other hand, in laser hardening, which has been attracting attention in recent years, it is possible to selectively irradiate only the portion to be hardened with laser light. Therefore, for example, in the cam member, it is possible to locally quench only the cam surface, and since the amount of heat input is small compared to induction hardening with the same local quenching, quenching strain is significantly reduced, and correction of strain is not possible. It is unnecessary or can be reduced.

An example of the laser hardening apparatus for the cam member using the laser light will be described with reference to FIG. The laser light 52 output from the laser oscillator 51 is reflected by the reflecting mirror 5.
The direction is changed by 3, and the light is irradiated on the cam surface of the cam 55 while being condensed by the condenser lens 54. The cam 55 is fixed to a rotary table 57 arranged on a moving table 56 and capable of multi-axis control, and can move relative to the laser light 52. The moving table 56 and the rotary table 57 are controlled by the NC control device 58 and can perform preset drive control. The cam surface of the cam 55 is locally heated to the quenching temperature by the irradiation of the laser light 52, but the relative movement of the cam 55 with respect to the laser light 52 terminates the local heating. At this time, the locally heated portion is rapidly cooled by heat conduction to the inside of the cam 55, and the quench hardened layer 59 is formed.

[0005]

However, in the conventional laser hardening apparatus described above, the intensity distribution of the laser beam 52 emitted from the laser oscillator is non-uniform, and the laser beam 52 shown in FIG.
The cross-sectional shape is circular as shown in FIG. Therefore, when the laser light 52 moves, the action time of the laser light 52 differs at a point 60 passing through the center of the laser light and a point 61 deviating from the center of the laser light. As a result, the quenching characteristics of the points 60 and 61 are different, and when the position of the point 61 is close to the end of the laser beam 52, a hardened layer cannot be obtained. As described above, in the above-described conventional laser hardening apparatus, the ratio of the region where the hardened layer cannot be obtained while the laser light acts is relatively large. For this reason, it is difficult to obtain a wide quenching width uniformly, and there is a problem that excessive heat input occurs if the quenching width has a margin in consideration of the deviation of the quenching path. Further, for example, in the case of having a curved surface like a cam member, the quenching characteristics are likely to change depending on the quenching location, such as the irradiation angle of laser light changing.

Therefore, in the above-mentioned conventional laser hardening apparatus, for example, when hardening a cam member, it is necessary that the center of the laser beam always coincides with the hardening path on the cam member. Further, it is necessary that the laser light is always applied to the cam surface within a certain angle.

Therefore, in order to move the cam member relative to the laser light, the rotary table for multi-axis control as described above is required, which is a complicated structure. For example, an apparatus as shown in FIG. 5 requires control of at least four axes of X axis, Z axis, θ axis, and ψ axis in the figure. Further, the NC data input to the NC control device for drive control of the rotary table and the like becomes complicated, and a lot of labor and time are required to create the NC data.

The present invention has been made to solve the above-mentioned problems, and even if the drive control for moving the workpiece relative to the laser beam is performed by a simple means, it is possible to uniformly heat the workpiece. It is an object of the present invention to provide a laser hardening device capable of obtaining good processing quality.

[0009]

In order to achieve this object, a laser hardening apparatus of the present invention irradiates a laser beam emitted from a laser oscillator onto a workpiece to quench the workpiece. The intensity distribution equalizing means for equalizing the intensity distribution of the laser light emitted from the laser oscillator and the laser light for which the intensity distribution is uniformized by the intensity distribution equalizing means for supporting the workpiece are processed. It is provided with a rotation drive means for rotating the work piece so that the work piece is irradiated with the light.

[0010]

In the laser hardening apparatus of the present invention having the above-mentioned structure, the work piece is quenched by irradiating the work piece with the laser beam emitted from the laser oscillator. Makes the intensity distribution of the laser light emitted from the laser oscillator uniform. The rotary drive means
The workpiece is rotated and driven so that the workpiece is supported and the workpiece is irradiated with the laser beam whose intensity distribution is uniformized by the intensity distribution uniformizing means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the outline of the laser hardening apparatus of the present invention will be described with reference to FIGS. 1 and 2. The laser hardening apparatus of the present invention comprises a CO ₂ laser oscillator 1, a fixed reflecting mirror 2 for reflecting laser light, a kaleidoscope 3 for making the intensity distribution of the laser light uniform, and a variable angle reflection for reflecting the laser light. A mirror 4 and a rotary table 6 that supports a cylindrical grooved cam 5 that is a cam member of a workpiece and that drives the cylindrical grooved cam 5 to rotate, and an XY that mounts the rotary table 6 and drives it in the X and Y directions. Table 7, and the rotary table 6 and XY
It is composed of an NC control device 8 for controlling the drive of the table 7.

The laser beam 9 output from the CO ₂ laser oscillator 1 has a wavelength of 10.6 μm (micrometer).
Is. The fixed reflecting mirror 2, the kaleidoscope 3, and the reflecting mirror 4 with a variable angle are arranged on the optical axis of the laser beam 9.

The kaleidoscope 3 is an entrance lens 1.
0, a multiple reflection mirror 11, and an imaging lens 12. The multiple reflection mirror 11 has a structure in which the inner surface of a prism formed by four flat reflection mirrors facing each other is a reflection mirror.
The intensity distribution of the laser light 9 is made uniform by multiple reflection inside the kaleidoscope 3.

The rotary table 6 is arranged on the XY table 7, both of which are connected to the NC control device 8 and perform a predetermined drive in accordance with the data previously input to the NC control device 8. On the rotary table 6, a cylindrical grooved cam 5, which is a cam member for the workpiece, is detachably supported. The cylindrical groove cam 5 has a shape as shown in FIG. 3, and is configured such that the center line of the cylindrical groove cam 5 and the rotation center of the rotary table 6 coincide with each other. The cylindrical groove cam 5 is made by cutting carbon steel, and its cam surface 14 is hardened. Further, a graphite-based laser light absorber 15 for increasing the absorptance of the laser light 9 is applied to the surface thereof.

Next, with reference to FIGS. 1 and 2, the state of quenching using the laser quenching apparatus of the present invention will be described. Laser light 9 emitted from CO ₂ laser oscillator 1
Has a circular cross-sectional shape, and the laser light intensity is stronger toward the center thereof. The laser light 9 is redirected by the fixed reflecting mirror 2 arranged on the optical axis thereof, and then enters the entrance lens 10 in the kaleidoscope 3. The laser beam 9 condensed by the incident lens 10 is input to the input end 16 of the multiple reflection mirror 11.
And is reflected by four plane reflecting mirrors and then emitted from the output end 17. At this time, the laser light 9 becomes rectangular according to the shape of the multiple reflection mirror 11, and the intensity distribution of the laser light 9 is also made uniform. The size of the laser light to be formed is determined by the incidence lens 10, the multiple reflection mirror 11, and the imaging lens 1.
2 is determined by the characteristics of each component and the distance between each component, and is adjusted in advance to a desired size.

The rectangular laser light 18 of which the intensity distribution is made uniform by the kaleidoscope 3 is redirected by the angle-variable reflecting mirror 4 arranged on its optical axis,
The cam surface 14 of the cylindrical groove cam 5 is irradiated. The angle of the reflecting mirror 4 whose angle is variable is set in advance according to the shape of the cylindrical groove cam 5 and the like, and does not require variable control during processing.

Cylindrical groove cam 5 irradiated with laser light 18
The cam surface 14 is rapidly heated to the quenching temperature. The cylindrical groove cam 5 is moved relative to the laser beam 18 by driving the rotary table 6 and the XY table 7, so that the portion irradiated with the laser beam 18 is not irradiated with the laser beam 18. Along with this, the heated portion is the cylindrical groove cam 5
It is rapidly cooled by heat conduction to the inside to form a quench-hardened layer 19. By continuing the above process, a predetermined quenching process is completed.

As shown in FIG. 4, since the laser light 18 has a rectangular shape by the kaleidoscope 3 and the intensity distribution is uniformized, when the laser light 18 moves, a point 20 passing through the center of the laser light 20. At a point 21 deviated from the center of the laser beam, the action time of the laser beam 22 becomes the same. As a result, the quenching characteristics of points 21 and 22 are almost the same,
It is possible to obtain a cured layer that is more uniform than before. Further, the ratio of the area of the hardened layer to the area irradiated with the laser beam is improved. Therefore, it is possible to perform processing with a margin for quality such as the required quenching width, and it is not necessary to match the irradiation position and angle of the laser beam with the quenching path extremely accurately as in the conventional case.

As a result of the above, for example, in the drive control when laser hardening the cylindrical groove cam 5, even if at least two axes of the X axis and the θ axis in the drawing of FIG. Can be applied. Since the number of axes to be controlled is reduced, the entire apparatus can be simplified and the NC data to be input to the NC control device for control can be easily created.

The present invention is not limited to the embodiments described in detail above, and various modifications can be made without departing from the spirit of the invention. For example, the laser light intensity distribution uniforming means can use a segment mirror in addition to the above-mentioned kaleidoscope. Further, the reflection mirror of the laser light only needs to be on the laser optical axis between the laser oscillator and the cam member, and the number and position thereof do not affect the effects of the present invention.

Further, although the present invention is particularly useful when laser hardening a workpiece such as a cam member,
It can be applied to various kinds of workpieces other than the above-mentioned embodiment.

[0023]

As is apparent from the above description, according to the laser hardening apparatus of the present invention, the intensity distribution of the laser beam is made uniform and the workpiece is irradiated, so that the required quality is obtained. The allowable range of processing conditions is widened. As a result, the work piece can be heated uniformly without complicated control of the relative movement of the work piece with respect to the laser beam as in the conventional art. It has a significant industrial effect such that quality can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a laser hardening apparatus of this embodiment.

FIG. 2 is a diagram showing details of the periphery of a processed portion of the laser hardening apparatus according to the present embodiment.

FIG. 3 is a schematic view showing an example of a workpiece.

FIG. 4 is a schematic cross-sectional view of laser light after passing through a kaleidoscope.

FIG. 5 is a diagram showing an outline of a conventional laser hardening device.

FIG. 6 is a schematic sectional view of laser light in a conventional laser hardening apparatus.

[Explanation of symbols]

1 CO ₂ laser oscillator 2 fixed reflecting mirror 3 kaleidoscope 4 variable angle reflecting mirror 5 cylindrical groove cam 6 rotary table 7 XY table 8 NC control device 9 laser light 18 laser light

Claims (1)

[Claims] 1. A laser hardening apparatus for quenching a workpiece by irradiating the workpiece with a laser beam emitted from the laser oscillator, wherein the intensity distribution of the laser light emitted from the laser oscillator is made uniform. And an intensity distribution equalizing means for supporting the workpiece, and rotating the workpiece so that the workpiece is irradiated with laser light whose intensity distribution is uniformized by the intensity distribution uniformizing means. A laser hardening device comprising a rotary drive means for driving.