JP3013453B2 - Laser hardening equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser quenching apparatus for irradiating a workpiece with a laser beam, moving the irradiation position of the laser beam to the workpiece, and quenching the workpiece.

[0002]

2. Description of the Related Art Conventionally, as an apparatus of this type, for example, as shown in Japanese Patent Application Laid-Open No. 64-39318, a shaft (workpiece) is placed in a straight line in opposition to a fixed laser beam gun. It is known that a laser beam is emitted from the laser beam gun, and the shaft body is moved in the axial direction while rotating, whereby a hardened hardened layer is continuously formed on the shaft body.

[0003]

However, in the above-mentioned prior art, since the amount of movement in the axial direction with respect to one rotation of the shaft body is set to be smaller than the irradiation width of the laser beam, the overlapping of the laser beams is prevented. On the other hand, the amount of heat is accumulated in the shaft body.

[0004] For this reason, at the start side of laser quenching, since no heat is accumulated in the shaft, the quenched hardened layer becomes shallow,
At the end of laser quenching, the heat is accumulated in the shaft body and the temperature is high, so that the hardened hardened layer becomes deep. Also, if the energy of the laser beam is set high to deepen the quench hardened layer on the start side of laser quenching, the temperature will be too high on the end side and the laser beam will be irradiated there, so the surface of the shaft body will May melt.

[0005] Therefore, it is difficult to make the depth of the quenched hardened layer constant, and the quenching distortion tends to be non-uniform due to the uneven depth of the hardened layer, and deformation tends to occur. For this reason, there is a problem that it is difficult to perform post-processing, and the amount of wear varies depending on the position during use, resulting in malfunction. This occurs not only in the case described above, but also in the case of a workpiece having a high heat storage property, for example, when a thin plate is used and its surface is hardened by a laser scanning method.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a laser hardening apparatus capable of keeping the hardening depth of a hardened hardened layer constant even for a workpiece having a high heat storage property. To provide.

[0007]

In order to achieve this object, the present invention irradiates a workpiece with a laser beam, moves the irradiation position of the laser beam to the workpiece, and hardens the workpiece. The laser quenching apparatus includes a cooling gas supply source that generates a cooling gas, and a blowing nozzle that blows the cooling gas from the cooling gas supply source toward the movement direction with respect to the irradiation position of the laser beam. .

[0008]

According to the present invention having the above-described structure, the cooling gas generated by the cooling gas supply source is blown by the blowing nozzle toward the laser beam irradiation position in the movement direction. As a result, the amount of heat applied to the workpiece by laser beam irradiation and conducted to the irradiation position in the forward direction with respect to the irradiation position is reduced by the cooling gas, and the temperature of that portion is lowered. Becomes constant.

[0009]

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

FIG. 1 is a configuration diagram showing the entire configuration. Here, a description will be given of a case where the workpiece is a thin shaft having a high heat storage property (heat is easily stored) and the entire periphery of the workpiece 1 is quenched with a laser beam.

The work table 16 is slidably provided along a linear guide 50 fixed to the apparatus frame F, and has a ball screw support 22 protruding from a lower surface thereof. A screw shaft 24 is screwed into a screw portion of the ball screw support 22, and the screw shaft 24 is fixed to an output shaft of a table feed pulse motor 23 fixed to a support 25 protruding from the apparatus frame F. ing. Therefore, the work table 16 is slid along the linear guide 50 by rotating the table feed pulse motor 23. The amount of movement at that time is performed by controlling the amount of rotation of the pulse motor 23.

On the other hand, a support table 30 is fixed on the upper surface of the work table 16, and the chuck 12 is rotatably supported on one side of the support table 30. A rolling center 13 is fixed to the work table 16 so as to be able to approach and separate from the chuck 12. The workpiece (shaft) 1 has one end fixed to the chuck 12 and the other end connected to the rolling center 13. Pressed by center pin. The rotating shaft of the chuck 12 protrudes from the other side of the support table 30, and a helical gear 41
Has been fixed. A chuck rotation pulse motor 40 is fixed to the work table 16, and a helical gear 42 meshing with the helical gear 41 is fixed to an output shaft thereof. Therefore, the chuck rotation pulse motor 40
The workpiece 1 is rotated by rotating.

The chuck 12 is mounted on the apparatus frame F.
Beam projection nozzle 3 facing workpiece 1 fixed to
1 is fixed, and the lens 15 is accommodated in the beam projection nozzle 31. The laser beam 3 is emitted from the oscillator 2, passes through a correction lens (not shown), is reflected at a right angle by the bend mirror 4, enters the lens 15, and forms a spot of a predetermined diameter on the workpiece 1.

In the present embodiment, the workpiece 1 is moved to the left in the drawing while being rotated.
Will move to the right. Therefore, the area 18 to be heated by the preheating is formed on the right side of the quenching part 17.

The cooling gas blowing nozzle 6 is fixed to the beam projection nozzle 31, and the nozzle 6 is directed to the preheating area 18. This cooling gas is produced by a compressor (cooling gas supply source) 19 and supplied to the nozzle 6 via a cooling gas flow control device 20 and a gas pipe 21. The cooling gas flow control device 20 includes a driven gear 202 fixed to a flow control shaft of a well-known flow control valve 201.
The drive gear 203 meshing with the
By rotating at 4, the flow control shaft is rotated to control the flow rate of the cooling gas flowing through the gas pipe 21. Here, air is used as the cooling gas.

The laser hardening apparatus is controlled by a controller 70. The control device 70, as shown in FIG.
The main component is a computer including a CPU 72, a ROM 74, a RAM 76, a bus 78, and the like. Bus 7
8, an input interface 80 is connected, and a start switch 82 and a well-known infrared radiation thermometer 84 are connected to the input interface 80. The infrared radiation thermometer 84 is of a type in which the effective detection area in the detected part is determined based on the built-in detection lens and the distance from the lens to the detected part. It is set to 5 mm. The infrared radiation thermometer 84 is of a type that detects infrared radiation emitted according to the temperature of the effective detection area and changes the detection current.

An output interface 100 is connected to the bus 78, and the table feed pulse motor 23 and the chuck rotation pulse motor 40 are connected to the output interface 100 via motor drive circuits 104, 106 and 108 and an oscillator drive circuit 110. , The flow control pulse motor 204 and the oscillator 2 are connected.

Also, as shown in FIG.
The detection temperature of the effective detection area of the infrared radiation thermometer 84 is divided into predetermined temperature ranges, and the rotation amount data of the flow control pulse motor 204 for each temperature range (cooling gas flow rate for cooling the preheating area) Is provided together with the working area. Further, the control program of FIG. 4 is stored in the ROM 74.

Next, the operation of this embodiment will be described.

First, the CPU 72 waits for the start switch 82 to be turned on (step S1), and when turned on, starts the oscillation of the laser oscillator 2 (step S2). Therefore, the laser beam is reflected at right angles by the bend mirror 4, enters the lens 15, and irradiates the workpiece 1.

After the oscillation of the laser oscillator 2 starts, C
The PU 72 rotates the chuck rotation pulse motor 40 and the table feed pulse motor 23 (steps S3 and S4). Thereafter, the CPU 72 reads the detected current value of the infrared radiation thermometer 84 and detects the temperature of the preheating unit (step S5). CPU 72
The temperature range to which the detected temperature belongs is determined based on the data table of M76, the rotation amount data of the flow control pulse motor 204 corresponding to the determined detected temperature range is read, and the drive of the pulse motor 204 is controlled ( Step S6).

Thereafter, the CPU 72 determines whether or not the quenching process has been completed (step S7). If NO, the process returns to the step S3. If YES, the laser oscillator stops oscillation and ends. (Step S8). That is, while the quenching process is not completed, the workpiece 1 is rotated and sent in the axial direction while rotating, and the quenching process proceeds over the entire circumference. However, the process of steps S5 and S6 always corresponds to the temperature of the preheating section. Then, an appropriate flow rate of the cooling gas is blown to cool the preheating portion and maintain the predetermined temperature, so that the hardening depth of the hardened hardened layer can be made constant.

In the above-described embodiment, when the processing conditions are a laser beam diameter (spot diameter) of 6 mm, a laser output of 800 w, and a peripheral speed of the workpiece of 2 m / min, the temperature of the preheating portion becomes about 200 ° C. Cooling gas flow rate 150L
When it was set to / min, it was cooled to 50 ° C.

The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the temperature of the preheating unit is kept constant by controlling the flow rate of the cooling gas. However, the temperature of the preheating unit can be kept constant by controlling the temperature of the cooling gas. .

[0025]

As is apparent from the above description, the present invention irradiates a workpiece with a laser beam, moves the irradiation position of the laser beam to the workpiece, and hardens the workpiece. Since the quenching apparatus includes a cooling gas supply source that generates a cooling gas, and a blowing nozzle that blows the cooling gas from the cooling gas supply source to the irradiation direction of the laser beam in the moving direction. Even if the workpiece has high heat storage, the hardening depth of the hardened hardened layer can be made constant. Accordingly, there is an advantage that the quenching strain generated in the workpiece can be made uniform, the deformation hardly occurs, and the post-processing is easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a laser hardening apparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram showing the electrical configuration.

FIG. 3 is an explanatory diagram showing a data table stored in a RAM 76;

FIG. 4 is a flowchart showing a control program.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Workpiece 2 Laser oscillator 6 Cooling gas blowing nozzle 17 Quenching part 18 Preheating area 20 Cooling gas flow control device 72 CPU 84 Infrared radiation thermometer 204 Flow control pulse motor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C21D 1/09 C21D 1/18 C21D 1/34

Claims (1)

(57) [Claims] 1. A laser quenching apparatus for irradiating a workpiece with a laser beam, moving an irradiation position of the laser beam on the workpiece, and quenching the workpiece.
A laser, comprising: a cooling gas supply source that generates a cooling gas; and a blowing nozzle that blows the cooling gas from the cooling gas supply source toward the forward side in the moving direction with respect to the irradiation position of the laser beam. Hardening equipment.