JP7586016B2 - Quenching device and quenching method - Google Patents

Description

This disclosure relates to laser-based hardening technology.

Lasers can concentrate energy in a very small area, so in recent years, they have been used for welding and hardening. For the latter, for example, as shown in Reference 1, it has been proposed to use a laser to harden the surface of a shaft.

Patent No. 2666288

However, the method shown in Patent Document 1 has the problem that the laser is sequentially irradiated along the outer periphery of the irradiated object to be hardened, which takes a long time for hardening. Furthermore, in Patent Document 1, the laser irradiation range is overlapped along the axial direction so that the energy density of the irradiated laser is uniform along the axial direction of the shaft body, which is the irradiated object. As a result, a part that has reached the hardening temperature after being irradiated once is heated again after the irradiation time for one circumference of the circumference, which is called tempering, and it may not be possible to obtain the hardness that was intended to be achieved by hardening. If the relative rotation speed of the irradiated object is increased using a high-power laser beam in an attempt to shorten the time required for one circumference, it is possible that melting will occur on the surface of the irradiated object, causing spattering.

The present disclosure can be realized in the following forms or application examples. One embodiment of the present disclosure is a hardening device. The hardening device includes a laser emitting unit arranged at a position where a laser beam irradiation position on a surface of an object to be hardened forms a continuous path along an outer periphery of the object to be hardened, an irradiation position moving unit that moves the laser beam irradiation position over a hardening range of the object to be hardened in a direction intersecting the path, and an electric current supply unit that supplies electric current to the laser emitting unit at least when the laser beam irradiation position on the object to be hardened is within the hardening range.
Another embodiment of the present disclosure is a hardening method using laser light, in which a laser emitting unit is disposed so that a laser light irradiation position on a surface of an object to be hardened forms a continuous path along an outer periphery of the object to be hardened, the laser light irradiation position is moved across a hardening range of the object to be hardened in a direction intersecting the path, and at least when the laser light irradiation position on the object to be hardened is within the hardening range, current is applied to the laser emitting unit to emit a laser light from the laser emitting unit, and the hardening is performed by heating the irradiation position of the object to a hardening temperature or higher.
According to such a hardening device and hardening method, the hardening range of the object is irradiated with the laser light at positions that form a continuous path around the outer periphery of the object, so that hardening can be performed at once along a continuous path along the outer periphery of the object, and the time required for hardening can be shortened. Also, since the vicinity of a position that has been irradiated with the laser light once is not irradiated again after a predetermined time, the position that has been hardened once is not tempered again, and there is no concern that the hardness of the object will decrease due to tempering.

FIG. 1 is a schematic diagram showing the overall configuration of a hardening device using a surface emitting laser. FIG. FIG. 2 is an explanatory diagram showing an example of an irradiation area on a workpiece and an arrangement of a surface-emitting laser. FIG. 6 is an explanatory diagram showing the range of hardening using the laser unit by a cross section taken along the line VI-VI in FIG. 2 . 4 is a flowchart showing a hardening process control routine. FIG. 4 is an enlarged explanatory diagram showing the arrangement of surface emitting lasers. FIG. 13 is an explanatory diagram showing a state in which an overlap is provided in the laser irradiation range. FIG. 6 is a schematic configuration diagram of a quenching device according to a second embodiment.

A. First embodiment:
(A1) Hardware configuration:
FIG. 1 is a schematic diagram showing the overall configuration of a hardening device 10 using a surface-emitting laser. As shown in the figure, the hardening device 10 includes a laser emitting unit 20 that irradiates a workpiece WK, which is a shaft body, with a laser beam to perform hardening, a moving unit 30 that moves the laser emitting unit 20 in the axial direction of the workpiece WK, a conveying device 50 that conveys the workpiece WK to the laser emitting unit 20, and a control unit 40 that controls the entire device. The laser emitting unit 20 has an annular shape and has a space therein through which the workpiece WK passes. The detailed configuration of the laser emitting unit 20 will be described later. In this embodiment, a shaft body made of chrome steel SCr435H or chrome molybdenum steel SCM435H, which have excellent hardening characteristics, is used as the workpiece WK. Other types of carbon steel may be used as long as the steel is hardened. Furthermore, the shaft is not limited to a cylindrical shaft, but may be a cylindrical shaft having a hollow portion therein, a prismatic shaft, a shaft having a polygonal, elliptical or oval cross section, or even a shaft other than a shaft. Therefore, the workpiece WK does not necessarily have an axis of rotation, but for convenience of explanation, the direction in which the laser emission unit 20 moves by the moving unit 30 may be called the "axial direction", and the direction along the ring in the laser emission unit 20 may be called the "circumferential direction".

The laser emission unit 20 is supported by a support portion 31 that protrudes from the moving portion 30. The moving portion 30 moves this support portion 31 along the axial direction of the workpiece WK (up and down in the figure) by an actuator such as a motor (not shown). In FIG. 1, the position of the laser emission unit 20 indicated by the dashed line is the origin position when moving the laser emission unit 20. In the absence of a signal Sm from the control portion 40, the moving portion 30 keeps the laser emission unit 20 waiting at the origin position OP.

The control unit 40 is a computer having a known CPU and memory, and operates according to a program stored in the memory. The control unit 40 reads signals from external sensors and outputs signals to actuators and the like to control the operation of the entire hardening apparatus 10. The control unit 40 outputs a signal Sm to instruct the moving unit 30 to move, as well as a signal Se to instruct the laser emitting unit 20 to energize and a signal Sb to instruct the conveying operation of the conveying device 50. The signal Se is output to the laser emitting unit 20 via the moving unit 30, and turns on and off the output of the laser light in the laser emitting unit 20. The signal Sb instructs the operation of an actuator such as a motor (not shown) that drives the conveyor 55 that conveys the workpiece WK in the conveying device 50. The conveying device 50 is provided with rollers 51, 52, etc. that send the conveyor 55 in one direction, and when the actuator operates in response to the signal Sb, the rollers 51, 52 rotate to convey the workpiece WK in the direction of the arrow FW shown in the figure. The conveyor 55 is provided with a fixing jig (not shown), and the workpiece WK is positioned using this jig. The transport position of the workpiece WK is detected by a sensor 57. Instead of the transport device 50, a robot arm or the like may be used to transport and position the workpiece WK to the desired position.

The configuration of the laser emission unit 20 will be described with reference to Fig. 2 to Fig. 4. As shown in Fig. 2, which is a plan view, the laser emission unit 20 includes a plurality of surface-emitting lasers 21 and a case 22 that holds the plurality of surface-emitting lasers 21 in an annular shape. The surface-emitting lasers 21 are fixed to the case 22 by using a base portion 25. The base portion 25 not only fixes the surface-emitting lasers 21, but also houses a drive circuit (not shown) and also functions as a heat sink for the surface-emitting lasers 21. In the first embodiment, a total of 36 surface-emitting lasers 21 are used. The number of surface-emitting lasers 21 is arbitrary, and may be determined as the number required to form a path in which the irradiated light from the surface-emitting lasers 21 continuously surrounds the outer periphery of the workpiece WK, depending on the diameter of the workpiece WK and the width of the light emitted by the surface-emitting lasers 21. When using a surface-emitting laser 21 having a light-emitting surface with a width LL and a height HH, the number N of the surface-emitting lasers 21 can be roughly determined by the following equation (1) using the diameter 2R of the workpiece WK and the width LL of the light-emitting surface.
N≧2R・π/LL…(1)
In this embodiment, the workpiece WK to be hardened is a shaft having a diameter 2R of 148 mm, and the width LL of the surface emitting laser 21 is about 13 mm.

Since laser light has a high degree of linearity and the laser light from the surface-emitting laser 21 hardly spreads, the above formula (1) holds true regardless of the distance (hereinafter referred to as the gap) GP from the light-emitting surface of the surface-emitting laser 21 to the surface of the workpiece WK. In this embodiment, the gap GP is set to about several millimeters. In the following description, when it is necessary to distinguish between individual surface-emitting lasers 21, the suffixes A, B, etc. will be added, such as surface-emitting lasers 21A, 21B.

The surface-emitting lasers 21 are of the continuous emission type, the wavelength of the laser light is in the near-infrared region (e.g., 900 to 1100 nm), and each surface-emitting laser has an output of about 100 W. In this embodiment, 36 surface-emitting lasers 21 are used, so the total output of the laser emission unit 20 is 3.6 kW. Heat generated by the operation of the surface-emitting lasers 21 is conducted from the base 25 to the case 22 and dissipated from heat dissipation fins (not shown) provided on the case 22. Of course, a heat dissipation device using an air-cooling fan or a refrigerant or heat pipe may be incorporated into the case 22.

Figure 3 is an explanatory diagram showing the relationship between the surface-emitting lasers 21 and the irradiation positions on the workpiece WK, using the surface-emitting lasers 21A to 21D as an example, among the multiple surface-emitting lasers 21 arranged to surround the workpiece WK. In the embodiment, 36 surface-emitting lasers 21 are used, but for convenience of illustration, FIG. 3 shows four of them, the surface-emitting lasers 21A to 21D. As shown in the figure, the laser light emitted from the surface-emitting lasers 21A to 21D travels straight without spreading and reaches the outer surface of the shaft, which is the workpiece WK. The irradiation range of one surface-emitting laser 21 is approximately equal to the size of the light-emitting surface of the surface-emitting laser 21, and has a width LL in the circumferential direction of the workpiece WK and a height HH in the axial direction of the workpiece WK. The irradiation areas iA to iD on the workpiece WK of the laser light emitted from each adjacent surface-emitting laser 21A to 21D are adjacent to each other and form an irradiation range IRR that is a continuous path.

As can be seen from the figure, even if the irradiation areas iA-iD on the workpiece WK are adjacent to each other, the light-emitting surfaces of the surface-emitting lasers 21A-21D, which are arranged at a gap GP from the surface of the workpiece WK, can be positioned slightly away from the adjacent light-emitting surfaces. Therefore, the base portion 25 that supports the surface-emitting laser 21 can be made larger in the circumferential direction than the surface-emitting laser 21, making it easier to manufacture the laser emission unit 20. In addition, the spacing between the surface-emitting lasers 21 can be made wider, which is also advantageous in terms of cooling.

Figure 4 is a schematic diagram illustrating the quenching process, taken along the line VI-VI in Figure 2. In the figure, the workpiece WK is not hatched to indicate a cross-sectional view. The single-hatched area TQA indicates the entire area of the workpiece WK that is to be quenched. The area PQA indicates the area that has been quenched by the movement of the laser emission unit 20. In this example, the laser emission unit 20 waits at the origin position OP, and when the workpiece WK is placed in a position where it can be quenched, the annular laser emission unit 20 moves toward the workpiece WK by the movement unit 30. When the laser emission unit 20 reaches the irradiation start position ST, current is applied to the surface-emitting laser 21 of the laser emission unit 20, and irradiation of the laser light begins.

By irradiating the laser light, the surface temperature of the workpiece WK reaches the 1200 to 1400 ° C required for hardening in a short time. Therefore, if the laser emitting unit 20 is moved by the moving unit 30 while continuing to emit laser light from the surface emitting laser 21, the hardening area PQA on the workpiece WK expands in the moving direction as it moves. Hardening is performed for a predetermined hardening length QL, and when the laser emitting unit 20 reaches the hardening end position EP, the power supply to the surface emitting laser 21 is stopped and hardening is completed. After that, the laser emitting unit 20 is returned to the origin position OP by the moving unit 30, and the workpiece WK is transported to the next process by the conveying device 50. In this embodiment, the moving speed of the laser emitting unit 20 by the moving unit 30 is about several mm / second, and the hardening length is about several tens of mm to more than 100 mm. Naturally, the moving speed should be set so that the energy of the laser light irradiated per unit time on the surface of the workpiece WK can raise the surface temperature of the workpiece WK to the hardening temperature. In other words, if a surface-emitting laser 21 with high emission energy is used, the moving speed can be increased. In addition, if the movable range of the moving part 30 is widened, it is easy to further widen the hardening length QL.

(A2) Quenching treatment:
Next, the hardening process by the control unit 40 will be briefly described. In this embodiment, the hardening of the workpiece WK is controlled by the control unit 40. The hardening process control routine executed by the control unit 40 is shown in FIG. 5. This control routine is started in conjunction with the hardening process of the workpiece WK. When the hardening process is started, first, a signal Sb is output to the conveying device 50, and the workpiece WK is conveyed (step S100). The workpiece WK is conveyed by the conveying device 50.

Then, it is determined whether the workpiece WK has reached the position where the hardening process is performed, that is, the position directly below the laser emission unit 20 (step S105). This determination is made by reading the signal Ss from the sensor 57 that detects the position of the workpiece WK. If the workpiece WK has not reached the hardening position, transportation by the transport device 50 continues (step S100), and if it is determined that the workpiece WK has reached the hardening position (step S105: "YES"), transportation by the transport device 50 is temporarily stopped (step S110).

Next, a signal Sm is sent to the moving unit 30 to move the laser emitting unit 20 from the origin position OP along the axial direction of the workpiece WK at a predetermined speed (step S120). As a result, the laser emitting unit 20 approaches the workpiece WK, and further processes the workpiece WK in the axial direction when the workpiece WK is located inside the ring shape. The control unit 40 determines whether the laser emitting unit 20 has entered the hardening range by controlling the amount of movement of the moving unit 30 (step S125). If the moving unit 30 uses a stepping motor as a moving actuator, the control unit 40 can know the moving distance of the laser emitting unit 20 from the number of steps output to the moving unit 30. Therefore, the movement of the laser emission unit 20 continues (step S120) until the laser emission unit 20 reaches the predetermined hardening start position ST (step S125: "NO"), and when the laser emission unit 20 enters the hardening range (step S125: "YES"), a signal Se is output and electricity is applied to the 36 surface-emitting lasers 21 provided in the laser emission unit 20 (step S130).

As a result, the surface-emitting laser 21 emits laser light toward the workpiece WK, and the surface of the workpiece WK irradiated with the laser light is heated and heated, and hardened. Since the movement of the laser emitting unit 20 continues while the surface-emitting laser 21 is irradiating the laser light, the control unit 40 judges whether the laser emitting unit 20 is outside the predetermined hardening range (step S135), and continues to energize the surface-emitting laser 21 until it is outside the hardening range (step S130). If the laser emitting unit 20 exceeds the hardening end position EP and is outside the hardening range (step S135: "YES"), the output of the signal Se is stopped and the power supply to the surface-emitting laser 21 is terminated (step S140). As a result, the workpiece WK is heated and heated by the energy of the laser light from the hardening start position ST to the hardening end position EP, hardening is performed, and a hardened area TQA is formed on the surface of the workpiece WK.

Then, the control unit 40 stops outputting the signal Sm and causes the moving unit 30 to return the laser emission unit 20 to the origin position OP (step S150). The control unit 40 then determines whether the hardening process of all the planned workpieces WK has been completed (step S155), and if the hardening process of the preset number of workpieces WK has been completed (step S155: "NO"), the control unit 40 returns to step S100 and repeats the above-mentioned steps S100 to S155) for a new workpiece WK. If the hardening process of all the planned workpieces WK has been completed (step S155: "YES"), the control unit 40 exits to "END" and ends this control routine.

According to the hardening device 10 of the first embodiment described above, in the hardening range TQA of the workpiece WK, which is the object to be hardened, the laser light is irradiated to the irradiation range IRR including the position that is a continuous path around the outer periphery of the workpiece WK, so that hardening can be performed in one go along a continuous path along the outer periphery of the workpiece WK, and the time required for hardening can be shortened. In addition, since the vicinity of a position that has been irradiated once with the laser light is not irradiated again after a predetermined time, tempering does not occur in which a position that has been hardened once is heated again, and the hardness of the workpiece WK is not reduced by tempering.

In addition, in this embodiment, since multiple surface-emitting lasers 21 are used in the laser emission unit 20, it is easy to form a continuous path. Moreover, when focusing on a point on the path around the outer periphery of the workpiece WK, the point continues to be irradiated for a predetermined time until the irradiation surface of the laser light, which has a two-dimensional spread, passes by, so that the energy per unit area given to the workpiece WK can be increased and the time until the hardening temperature is reached can be shortened.

In addition, in this embodiment, the surface-emitting laser 21 is provided at a position directly facing the surface of the workpiece WK, so that the illumination position can be easily adjusted, and the loss due to scattering of the laser light can be reduced. Since a gap of a predetermined length GP is provided between the workpiece WK and the surface-emitting laser 21, the installation of the surface-emitting laser 21 is also easy. This point will be explained using FIG. 6. As shown in the figure, the laser light emitted from the surface-emitting laser 21 travels almost straight, so at a position separated from the workpiece WK by a gap of a predetermined length GP, the total length of the path surrounding the workpiece WK increases. Therefore, it is possible to provide a predetermined interval between the adjacent surface-emitting lasers 21A and 21B, making it easy to arrange the surface-emitting laser 21. Even if the surface-emitting laser 21 is provided on the base portions 25A and 25B with a width LF wider than the width LL of its light-emitting surface, the surface-emitting lasers 21 can be arranged.

As shown in the figure, when the radius of the workpiece WK is R and N surface-emitting lasers 21 surround the workpiece WK to provide a continuous irradiation range on its outer surface, the width LL of one surface-emitting laser 21 is equal to the length of the chord of an arc having a central angle of 360°/N, and therefore the width LL can be calculated by the following equation (2).
LL=2R・sin(360/2N)=2R・sin(180/N)…(2)
On the other hand, the length LF of the chord at a position separated from the surface of the workpiece WK by a gap of a predetermined length GP, that is, at the position where the surface emitting laser 21 is actually disposed, is calculated by the following equation (3).
LF=2(R+GP)・sin(180/N)...(3)

Therefore, the difference ΔL between the two is
ΔL=LF-LL=2GP・sin(180/N)
Therefore, there is no need to make the width LF of the base portion 25 completely coincident with the width LL of the light-emitting surface of the surface-emitting laser 21, and the degree of freedom in design and manufacturing is increased. In actual manufacturing, if the width LF of the base portion 25 is made to be the same as the width LL of the light-emitting surface of the surface-emitting laser 21, this is preferable because it provides a margin for alignment using the base portion 25.

Furthermore, because of the existence of this difference ΔL, it is easy to slightly overlap the irradiation ranges of the laser light from the surface-emitting laser 21 on the surface of the workpiece WK, for example as shown in FIG. 7. In this example, the width Lf of the base portion 25 is made smaller than the width LF calculated by the above-mentioned formula (3), and the adjacent surface-emitting lasers 21a, 21b are arranged closer together than in FIG. 6. In this way, an overlapping region OL can be formed in which the laser light from the two adjacent surface-emitting lasers 21A, 21B overlaps. Therefore, even if there is a slight misalignment in the positioning of the base portions 25a, 25b on which the surface-emitting lasers 21a, 21b are mounted, it is possible to prevent the occurrence of an area on the surface of the workpiece WK where the laser light does not hit.

B. Second embodiment:
8 is a schematic cross-sectional view of the hardening apparatus 100 according to the second embodiment, excluding the workpiece WK. The hardening apparatus 100 includes a laser emission unit 200, a moving unit 300, and a conveying unit 500. Although not shown, the hardening apparatus 100 also includes a control unit that controls these units.

The laser emission unit 200 has a plurality of surface-emitting lasers 221 arranged in a ring shape. The annular mirror 230 that pairs with the laser emission unit 200 has approximately the same shape as the laser emission unit 200 and is arranged coaxially with the laser emission unit 200. The annular mirror 230 is supported by the moving unit 300 via a support unit 331. As in the first embodiment, the moving unit 300 moves the support unit 331 to move the annular mirror 230 along the axial direction of the workpiece WK.

The laser light emitted from the multiple surface-emitting lasers 221 formed in an annular shape is directed in the axial direction, not toward the inside of the annular ring, unlike in the first embodiment. The laser light from the surface-emitting lasers 221 is emitted toward the annular mirror 230 located vertically below the laser emission unit 200, and is reflected at a right angle by the surface reflecting mirror 235 provided on the annular mirror 230 to irradiate the surface of the workpiece WK. The surface reflecting mirror 235 is formed inside the annular mirror 230 in a shape that has an isosceles triangle in cross section. The surface reflecting mirror 235 may be formed by evaporating a metal film on the surface of the annular mirror 230, or may be formed by polishing the surface of the surface reflecting mirror 235 to give it a mirror finish. Since the surface reflecting mirror 235 has an annular shape following the shape of the annular mirror 230, the laser light from the surface-emitting lasers 221 of the laser emission unit 200 is reflected by the surface reflecting mirror 235 and irradiates the irradiation range IRR on the surface of the workpiece WK.

As a result, the irradiation range IRR is heated by the energy of the laser light, and the hardening temperature is reached and hardening is performed, similar to the first embodiment. Of course, as explained in FIG. 5 of the first embodiment, the workpiece WK is transported to the hardening position by the transport device 500 and stopped there, and then the annular mirror 230 moves from the origin position OP in the axial direction of the workpiece WK. When the workpiece WK enters the hardening range, electricity is applied to the surface-emitting laser 221 of the laser emission unit 200, also similar to the first embodiment.

The hardening device 100 of the second embodiment described above has the same effect as the first embodiment, and has the advantage that it is not necessary to move the laser emitting unit 200 equipped with multiple surface-emitting lasers 221, and the device configuration can be simplified. In the hardening device 100 of the second embodiment, the annular mirror 230 moved by the moving unit 300 is merely a reflector of the laser light, and does not require electrical wiring to the surface-emitting laser 221. Therefore, the weight can be reduced, and the configuration of the moving unit 300 can be simplified. In the second embodiment, the distance from the surface-emitting laser 221 that emits the laser light to the surface of the workpiece WK to be hardened is longer than in the first embodiment, but the laser light has high linearity, so the workpiece WK can be heated without significant energy loss.

The annular mirror 230 functions as a simple plane mirror when reflecting the laser light from the surface-emitting laser 221 in the axial AX direction of the workpiece WK, but since it is a curved concave mirror in the circumferential direction, the laser light from the surface-emitting laser 221 converges slightly in the circumferential direction. Therefore, the size and spacing of the light-emitting surface of the surface-emitting laser 221 can be determined taking into account the convergence by the surface reflector 235 so that the laser light from the multiple surface-emitting lasers 221 constituting the laser emission unit 200 forms a continuous irradiation range IRR on the outer periphery of the workpiece WK. Of course, if the surface reflector 235 is formed by connecting together the same number of plane mirrors as the number N of the surface-emitting lasers 221, there is no need to consider the convergence of the laser light in the circumferential direction.

In the second embodiment, a surface reflector 235 is used to change the direction of the laser light, but a prism or the like may also be used. Alternatively, the direction of the laser light may be changed by a low-loss optical fiber or light guide path.

In the first and second embodiments described above, the laser emission unit 20, the laser emission unit 200, and the annular mirror 230 are all in a closed annular shape, but they do not necessarily have to be in a closed annular shape. If the range to be hardened in the circumferential direction of the workpiece WK is not the entire circumference, they may be in an arc shape according to the hardening range. Furthermore, if the workpiece WK is other than a circular shape such as a rectangular column, they may be in a shape similar to the non-circular cross-sectional shape of the workpiece WK. As long as the irradiation position of the laser light on the surface of the hardening object is a continuous path along the outer periphery of the hardening object, the shape of the laser emission unit 20, etc. is not important.

In the first and second embodiments, hardening is performed by moving a single irradiation range IRR on the workpiece WK, but for example, two sets of laser emission units 20 of the first embodiment may be provided, and laser light irradiation may be started from the axial center of the hardening range TQA of the workpiece WK as the starting position ST, and the two sets of laser emission units 20 may be moved away from each other to perform hardening in each irradiation range IRR up to both ends of the hardening range TQA. Even in this case, the area that has already been hardened will not be heated again, and the time required for hardening can be reduced by approximately half.

C. Other embodiments:
(1) The hardening device of the present disclosure can be implemented in other forms. One of the other embodiments of the hardening device is a hardening device including a laser emitting unit arranged at a position where the irradiation position of the laser light on the surface of the hardening object forms a continuous path along the outer periphery of the hardening object, an irradiation position moving unit that moves the irradiation position of the laser light in a direction intersecting the path over the hardening range of the hardening object, and an electric current supply unit that supplies electric current to the laser emitting unit at least when the irradiation position of the laser light on the hardening object is in the hardening range. In this hardening device, the laser light is irradiated at a position that forms a continuous path along the outer periphery of the hardening object in the hardening range of the hardening object, so that hardening can be performed at once along the continuous path along the outer periphery of the hardening object, and the time required for hardening can be shortened. Furthermore, since there is no need to re-irradiate the vicinity of a position that has already been irradiated with laser light after a specified period of time, there is no need to re-heat a position that has already been hardened, thereby eliminating the risk of tempering causing a decrease in the hardness of the object to be hardened due to tempering.

The laser light irradiation position only needs to be located at a position that forms a continuous path along the outer circumference of the hardening object, and does not necessarily need to be closed in a ring. If there is a part of the hardening object that does not need to be hardened, the path can be determined so that the laser light is not irradiated to the part corresponding to that part. The movement direction of the laser light irradiation position only needs to be a direction that intersects with this path, and the two do not necessarily need to be perpendicular to each other. For example, if the hardening object has a cylindrical shape and is bent in the middle of the length direction, the movement direction of the laser light irradiation position relative to the path may change before and after the bent part. In addition, the hardening object is not limited to a cylindrical shape such as a shaft, and may be any shape, such as a rectangular column or a flange. The laser emission unit may be provided at a position that surrounds the hardening object, or at a position different from the position that surrounds the hardening object.

(2) In such a configuration, the laser emission unit may include a plurality of surface-emitting lasers. In this way, the irradiation position of the laser light can be easily made to be a continuous path along the outer periphery of the hardening object. In addition, since the emitted laser light of a surface-emitting laser has a two-dimensional area, the irradiation position on the surface of the hardening object also has a predetermined width in the direction intersecting the path. Therefore, when the irradiation position is moved, if a point on the outer periphery of the hardening object is focused on, it will continue to be irradiated for a predetermined time until the irradiated surface of the laser light passes by, so that the energy per unit area given to the hardening object can be increased and the time to reach the hardening temperature can be shortened. Of course, as long as the irradiation position of the laser light on the surface of the hardening object can be made to be a continuous path along the outer periphery of the hardening object, the laser emission unit can be configured by using lasers other than surface-emitting lasers, such as semiconductor lasers or gas lasers that emit a laser beam of a predetermined diameter, and by arranging multiple lasers in a row.

(3) In such a configuration, the multiple surface-emitting lasers may be arranged at positions facing the surface of the hardening object with a gap of a predetermined length between them. In this way, the distance between the laser emitting unit and the hardening object can be made close, and the illumination position can be accurately positioned. In addition, the relationship between the surface-emitting laser and the illumination position can be easily understood, and for example, when an object that has actually been hardened is inspected and a defect in the hardening is found, the surface-emitting laser corresponding to the location where the defect occurred can be easily identified. Since the laser light emitted from the surface-emitting laser travels almost straight, even if a gap of a predetermined length is placed from the surface-emitting laser to the surface of the hardening object, the energy per unit area of the laser light that reaches the hardening object is hardly reduced. Conversely, at a position separated by a gap of a predetermined length from the hardening object, the total length of the path surrounding the hardening object increases. This makes it easy to arrange a surface-emitting laser with a predetermined light-emitting area. Even if the surface-emitting laser is provided on a base with a width wider than the width of its light emission, the surface-emitting laser can be arranged.

(4) In such a configuration, the irradiation position moving unit may move at least one of the object to be hardened and the laser emission unit in the direction. In this way, hardening can be performed over a predetermined range of the object to be hardened. The movement may involve moving either the object to be hardened or the laser emission unit alone, or both may be moved in opposing directions.

(5) In such a configuration, the multiple surface-emitting lasers may be arranged at equal intervals along the outer periphery. This makes it easier to manufacture the laser emission unit, and the energy imparted by the laser light can be made uniform simply by making the gap between the hardening object and the laser emission unit constant along the outer periphery of the hardening object.

(6) In this configuration, the object to be hardened may be a shaft member having a circular outer periphery, and the multiple surface-emitting lasers may be arranged concentrically with the shaft member. This makes it easier to manufacture and adjust the laser emission unit.

(7) In this configuration, the irradiation range of the laser light irradiated from each of the multiple surface-emitting lasers onto the surface of the hardening object may have an overlapping area in the direction along the path. In this way, even if there is a misalignment of the multiple surface-emitting lasers, it is possible to prevent the occurrence of areas that are not irradiated by the laser light.

(8) In such a configuration, the irradiation position moving unit may move the irradiation position over a range wider than the hardening range, and the current supply unit may supply current to the laser emission unit from when the irradiation position of the laser emission unit enters the hardening range until when it leaves the hardening range as the position moves. In this way, the temperature increased by the laser light at the end of the hardening range can be continuously increased, and temperature variation at the end of the hardening range can be prevented.

(9) In addition, the method can be implemented as a hardening method using laser light. In this hardening method, a laser emitting unit is arranged so that the irradiation position of the laser light on the surface of the hardening object is a continuous path along the outer periphery of the hardening object, and the irradiation position of the laser light is moved across the hardening range of the hardening object in a direction intersecting the path. At least when the irradiation position of the laser light on the hardening object is within the hardening range, current is applied to the laser emitting unit to emit laser light from the laser emitting unit, and the irradiation position of the hardening object is heated to the hardening temperature or higher, thereby performing hardening. This hardening method can achieve the same effects as the hardening device described above.

(10) In each of the above embodiments, a part of the configuration realized by hardware may be replaced by software. At least a part of the configuration realized by software may be realized by a discrete circuit configuration. In addition, when a part or all of the functions of the present disclosure are realized by software, the software (computer program) may be provided in a form stored in a computer-readable recording medium. The term "computer-readable recording medium" is not limited to portable recording media such as floppy disks and CD-ROMs, but also includes internal storage devices within a computer such as various RAMs and ROMs, and external storage devices fixed to a computer such as hard disks. In other words, the term "computer-readable recording medium" has a broad meaning including any recording medium to which data packets can be fixed, not temporarily.

The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in each form described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

10...hardening device, 20...laser emitting unit, 21, 21A, 21B, 21a, 21b...surface emitting laser, 22...case, 25, 25A, 25B, 25a, 25b...base unit, 30...moving unit, 31...supporting unit, 40...control unit, 50...conveying device, 51, 52...rollers, 55...conveyor, 57...sensor, 100...hardening device, 200...laser emitting unit, 221...surface emitting laser, 230...annular mirror, 235...surface reflecting mirror, 300...moving unit, 331...supporting unit, 500...conveying device

Claims (8)

a laser emitting unit arranged at a position where a laser beam is irradiated onto a surface of an object to be hardened so as to form a continuous path along an outer periphery of the object to be hardened;
an irradiation position moving unit that moves an irradiation position of the laser light in a direction intersecting the path over a hardening range of the object to be hardened;
an energizing unit that energizes the laser emitting unit at least when the irradiation position of the laser light on the object to be hardened is within the hardening range;
Equipped with
The hardening device , wherein the laser emission unit includes a plurality of surface emitting lasers . 2. The hardening device according to claim 1 , wherein the plurality of surface emitting lasers are arranged at positions facing the surface of the object to be hardened with a gap of a predetermined length therebetween. The hardening device according to claim 2 , wherein the irradiation position moving unit moves at least one of the object to be hardened and the laser emission unit in the direction. 4. The hardening device according to claim 2, wherein the plurality of surface emitting lasers are arranged at equal intervals along the outer periphery. 5. The hardening device according to claim 1 , wherein the object to be hardened is a shaft member having a circular outer periphery, and the plurality of surface emitting lasers are arranged concentrically with the shaft member. 6. The hardening device according to claim 1 , wherein irradiation ranges of the laser light irradiated onto the surface of the object to be hardened from each of the plurality of surface emitting lasers have an overlapping region in a direction along the path. the irradiation position moving unit moves the irradiation position over a range wider than a hardening range,
the current supply unit supplies current to the laser emission unit during a period from when an irradiation position of the laser emission unit enters the hardening range to when the irradiation position leaves the hardening range as the laser emission unit moves;
The quenching device according to any one of claims 1 to 6 . A hardening method using laser light, comprising the steps of:
a laser emitting unit including a plurality of surface emitting lasers is arranged so that the irradiation positions of the laser light from the laser emitting unit on the surface of the object to be hardened form a continuous path along the outer periphery of the object to be hardened ;
moving an irradiation position of the laser light in a direction intersecting the path over a hardening range of the object to be hardened;
At least when the irradiation position of the laser light on the object to be hardened is within the hardening range, energizing the laser light emitting unit to emit a laser light from the laser light emitting unit;
the irradiated position of the object to be quenched is heated to a quenching temperature or higher to perform quenching.

Images