JPS61201731A - Heater for tooth shape surface - Google Patents

Abstract

PURPOSE:To heat uniformly a tooth shape surface having an intricately curved surface by splitting and reflecting laser light to different directions by the reflector of a polygon mirror, condensing the reflected light by plural reflectors and constituting each reflection surface of a plane mirror part and a concave quadratic surface mirror part. CONSTITUTION:This heater makes the heating treatment of the tooth shape surface of a rotating gear 80 by splitting and reflecting the incident laser light 1 generated from a laser light generator 60 to the different directions by the 1st reflector 10 consisting of the polygon mirror, reflecting the split and reflected laser light 2, 3, 4, by the 2nd, 3rd and 4th reflectors 20, 30, 40 respectively and making incident the reflected laser light 2', 3', 4' to the tooth shape surface from the different directions so as to intersect with each other. The plane mirror part and the concave quadratic surface mirror part are provided to each reflection mirror surface of the above-mentioned reflectors 10-40. The irradiation of the rectangular pseudo multi-mode beams from the plural directions is thus made possible and the uniform and efficient heating is made possible by bringing the incident direction of the beams in proximity to the respective normals of the side face 80a, base 80b and tip 80c of the tooth profile of the gear 80.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention is useful for heating the tooth profile surface of a product (component) having a tooth profile such as a gear or a rack/binion to harden the surface. The present invention relates to a heating device for a tooth profile surface to be used.

(Prior art) Hitherto, known methods for heating the surface of products (components) include methods using high frequency waves and methods using flames, and recently methods using plasma and lasers have come into use. ing. Among these, there is one disclosed in Japanese Patent Application Laid-Open No. 54-116799, which uses a laser, and this is shown in Fig. 13.
The heating device shown in FIG. 3 divides an incident laser beam 101' emitted from a laser oscillator (not shown) and has an optical axis included in a reference plane (paper surface) into two parts by a first reflector 100 and reflects them in different directions. , respectively, the incident laser beam 10
1 components 101a and 101b of divided reflected light 10 facing each other
2a and 102b are reflected by the cylindrical mirrors 110 and 120, and the reflected laser beams 103a and 103b corresponding to the divided reflected beams 102a and 102b are reflected by the cylindrical mirror 1.
By overlapping each other at the focal points of the laser beams 10 and 120, a linear beam having a power density distribution in a direction perpendicular to the optical axis of the incident laser beam 101 is formed within the reference plane. Here, the first reflector 100 includes the optical axis of the incident laser beam 101 and is symmetrical with respect to a plane perpendicular to the reference plane (hereinafter referred to as a plane of symmetry), and the normal line thereof is the reference plane. Two plane mirrors included in the surface 1
05, 106. Further, the cylindrical mirrors 110 and 120 have reflecting surfaces 111 and 121 of the same shape, are symmetrical to the reference plane, and have their cylindrical axes included in the reference plane, and are mutually symmetrical to the symmetrical plane. They are arranged symmetrically.

(Problems to be solved by the invention) However, in such a conventional heating device,
When the incident laser beam 101 is a so-called circular multimode beam having a power density distribution as shown in FIG. 14 (cross section A-A in FIG. 13), the resulting linear beam (cross section B-B in FIG. ) has a power density distribution that is high in the center as shown in FIG. Therefore, when such a linear beam is used to harden a steel surface (the beam feeding direction is the y direction in FIG. 15(b)), the cross-sectional pattern of the hardened layer is deep in the center and shallow at both ends. There is a problem that it becomes uniform, and especially when the surface has a complicated curved shape such as a tooth profile surface, the angle of incidence of the linear beam on the tooth surface varies greatly, so the position of the tooth surface changes. Therefore, there was a problem in that the depth of the hardened layer was largely non-uniform.

This invention was made in view of these conventional problems, and it is possible to uniformly heat the surface of an object to be heated even when the object has a complex curved shape, such as the surface of a gear. The object of the present invention is to provide a heating device for a tooth profile surface.

[Structure of the Invention] (Means for Solving the Problems) A tooth profile surface heating device according to the present invention includes a laser beam generator, a first reflector that divides and reflects the laser beam emitted from the laser beam generator, and a plurality of second and subsequent reflectors that each reflect the plurality of divided laser beams that have been divided and reflected by the first reflector and irradiate the divided laser beams toward the side and bottom surfaces of the tooth. The first reflector is a polyhedron consisting of a plurality of continuous mirror surfaces, and each of the mirror surfaces has a flat mirror portion and a concave quadratic curved mirror portion, and the second and subsequent reflectors corresponds to each mirror surface of the first reflector, and has a mirror surface consisting of only a plane mirror section or a plane mirror section and a concave quadratic curved mirror section, which is a more preferred embodiment. In the above, each plane mirror portion of the first reflector is parallel to one reference straight line perpendicular to the optical axis of the incident laser beam, and the concave quadratic curved mirror portion of the first reflector is parallel to the one reference straight line perpendicular to the optical axis of the incident laser beam. It is smoothly connected to the plane mirror part in the direction of a straight line serving as a reference, and the concave quadratic curved mirror part of the second and subsequent reflectors is smoothly connected to one side or both sides of the plane mirror part, and the second
A plane that is perpendicular to the plane mirror portion of the subsequent reflector and includes the normal to the concave quadratic curved mirror portion is perpendicular to the reference straight line, and the concave quadratic plane of each mirror surface of the first reflector The curved mirror portion and the concave quadratic curved mirror portion of the second and subsequent reflectors corresponding to the mirror surface have a confocal relationship or a relationship close to that, and furthermore, the light reflected by the second and subsequent reflectors. It is characterized in that the laser beams are arranged so as to intersect with each other near the focal point of the concave quadratic mirror portion of each mirror surface of the first reflector.

(Example) Hereinafter, five embodiments of the present invention will be described based on the drawings.

FIG. 4 to FIG. 1O are diagrams showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes a circular multi-mode incident laser beam with a beam diameter DL emitted from a laser beam generator 60, and the power density distribution in the cross section CC is the same as that shown in FIG. Further, 10 is a first reflector, 20
, 30 and 40 are the second and subsequent reflectors, that is, 20 is the second reflector, 30 is the third reflector, and 40 is the fourth reflector.

The first reflector 10 has three consecutive mirror surfaces 11, 12, and 13 as shown in FIG.
12 and 13 are plane mirror portions 11a, as shown in FIGS. 2(b), 2(c), and 2(d), respectively.

12a, 13a and concave quadratic curved surfaces on both sides thereof, that is, in this case, a concave cylindrical mirror portion 11b.

It consists of 11c, 12b, 12c, 13b, and 13c.

Among these, the plane mirror portion 11a.

12a and 13a are parallel to one reference straight line (hereinafter referred to as [reference line]) perpendicular to the optical axis of the incident laser beam 1, and the concave cylindrical mirror portions 11b, llc, 1
2b, 12c, 13b.

13c has the same radius of curvature (here, the radius of curvature is R1°), and the plane mirror portions 11a and 12 are arranged in the direction of the reference line (hereinafter referred to as [S direction]).
a, smoothly connected to 13a. Further, in the first reflector 10, the orthogonal projection of the mirror surface portion (including the mirror surfaces 11, 12, 13) onto a plane perpendicular to the optical axis of the incident laser beam 1 is It is designed to completely encompass the beam cross section (circle with beam diameter DL),
The widths of the plane mirror parts 11a, 12a, and 13a in the S direction are equal to each other (this width is referred to as SSO), and the relationship Sto<Db holds. Therefore, the components 1a, lb of the incident laser beam 1.

The ICs are mirror surfaces 11 and 12 of the first reflector 10, respectively.
．． 13, and the optical path length R□ from each mirror surface 11°12.13. The divided reflected laser beams 2, 3, . . . have a power density distribution in the S direction as shown in FIG.
It becomes 4.

Next, the second reflector 20, as shown in FIG.
It consists of a plane mirror part 20a and a concave quadratic curved surface smoothly connected to one side of the plane mirror part 2Qa, that is, in this case, a concave cylindrical mirror part 20b, which is perpendicular to the plane mirror part 20a and has a normal line to the concave cylindrical mirror part 20b. Including surface (hereinafter [mirror surface])
) is perpendicular to the reference line. Further, the second reflector 20 is designed so that the split laser beam 2 can be completely reflected by the plane mirror portion 20a and the concave cylindrical mirror portion 20b, and the radius of curvature of the concave cylindrical mirror portion 20b is set to R20. Then, the optical path length from the mirror surface 11 of the first reflector 10 to the second reflector 20 is (R1o-R2°)
/2. Therefore, the components 2a and 2b of the split reflected laser beam 2 are reflected by the plane mirror part 20a and the concave cylindrical mirror part 20b of the second reflector 20, respectively, and the optical path length R2°/2 is reflected from the plane mirror part 20a. That is, the mirror surface 11 of the first reflector 10
At a position of optical path length R1o/2, the incident laser beam 1 enters from a direction forming an angle of 02 with the optical axis of the incident laser beam 1, and S The reflected laser beam 2' has a power density distribution in a direction perpendicular to the direction (tzS direction) as shown in FIG.

Here, 02 and T2 are the normal line of the plane mirror portion 11a of the mirror surface 11 of the first reflector 10 and the second reflector 2.
The angle between the normal line of the plane mirror section 20a of 0 and the optical axis of the incident laser beam 1 is θll+θ2o, and the width of incidence of the component 2a of the split reflected laser beam 2 on the plane mirror section 20a of the second reflector 20 is (That is, the width in the direction perpendicular to the S direction in the plane mirror portion 20a) is T2°, then θ2=2(θ2°−011) T2 =−T2, cos(θ2O−2011).

Next, the third reflector 30, as shown in FIG.
It consists of a plane mirror section 30a and concave quadratic curved surfaces smoothly connected to both sides of the plane mirror section 30a, that is, concave cylindrical mirror sections 30b and 30c in this case, and the mirror-shaped surfaces are perpendicular to the reference line. Further, the third reflector 30 includes the plane mirror portion 3
Qa and the concave cylindrical mirror parts 30b and 30c are designed to completely reflect the split laser beam 3, and the radius of curvature of the concave cylindrical mirror parts 30b and 3Qc is set to R2O.
Then, the optical path length from the mirror surface 12 of the first reflector 10 to the third reflector 30 is (Rr O-R30) /2
It is arranged so that. Therefore, the split reflected laser beam 3 is.

The components 3a, 3b, 3c are the plane mirror portion 30a and the concave cylindrical mirror portions 30b, 3 of the third reflector 30, respectively.
0c, and the optical path length R35 is reflected from this plane mirror portion 30a.
/ 2, that is, at a position with an optical path length R1°/2 from the mirror surface 12 of the first reflector 10, the laser beam enters from a direction forming an angle of θ3 with the optical axis of the incident laser beam 1, and a plane perpendicular to this direction of incidence. (E-E cross section in Figure 1), the reflected laser beam 3' has a power density distribution in the direction perpendicular to the S direction (tsS direction) as shown in Figure 8.Here, θ3 and T3 is the angle between the normal line of the plane mirror part 12a of the mirror surface 12 of the first reflector 10 and the normal line of the plane mirror part 30m of the third reflector 30 and the optical axis of the incident laser beam 1, respectively. Let the angle be 2.03o, and the width of the plane mirror portion 30a of the third reflector 30 in the direction perpendicular to the S direction be Tso.

θ3 = 2 (03G-012) T3 = -Tso cos (θ3 o -20
12).

Next, as shown in FIG. 5, the fourth reflector 40 is composed of a plane mirror part 40a and a concave quadratic curved surface smoothly connected to one side of the plane mirror part 40a, that is, in this case, a concave cylindrical mirror part 40b. , the mirror surface is perpendicular to the reference line.

Further, the fourth reflector 40 is designed to completely reflect the split laser beam 4 with the flat mirror section 40a and the concave cylindrical mirror section 40b.
If the radius of curvature of 0b is R4°, then the first reflector 1
The optical path length from the mirror surface 13 at 0 to the fourth reflector 40 is (R
1o-Rao)/2. Therefore, the components 4a and 4b of the split reflected laser beam 4 are reflected by the plane mirror section 40a and the concave cylindrical mirror section 40b of the fourth reflector 40, respectively, and the optical path length R40/2, that is, the At a position at an optical path length RIO/2 from the mirror surface 13 of the first reflector 10.

The power density is incident from a direction forming an angle of 04 with the optical axis of the incident laser beam 1, and in a direction perpendicular to the S direction (t4 direction) on a plane (15th] F-F cross section perpendicular to this direction of incidence. The reflected laser beam 4' has a distribution as shown in FIG. Here, θ4 and T4 are the first reflector 1
The angles formed by the normal line of the plane mirror part 13a of the mirror surface 13 of o and the normal line of the plane mirror part 40a of the fourth reflector 40 with the optical axis of the incident laser beam '1-' are θ13+040, respectively.
The incidence of the component 4a of the split reflected laser beam 4 on the plane mirror section 40a of the fourth reflector 40 +111 (in the direction perpendicular to the S direction in the plane mirror section 40a) is T2O.
Then, θ=2(θ4°−θ!3) T4=−T46 coS(θ4o−2013).

Furthermore, the second. Third. Fourth reflector 2o, 30.4
The reflected laser beams 2', 3', and 4' due to
．． They intersect each other near a position where the optical path length from 13 is R, ◇/2, and the side surface 80a and bottom surface 80b of the tooth surface of a workpiece, for example, a gear 80, are located near this position. Perform laser treatment.

Therefore, when performing hardening heat treatment on the tooth surface of the gear 8o using a heating device having such a configuration, for example, the first
As shown in the figure and FIG. 10, the gear 80 is rotated in the direction of the arrow around the point θ (center axis of the gear 8o), and the reflected laser beams 2', 3', and 4' are irradiated. .

In this case, FIG. 10(a) shows that the laser beam 2' is reflected at the tip of the tooth,
This shows the state where 3' and 4' are irradiated,
Figure 1θ (b) shows the reflected lasers 2', 3', 4 at the root of the tooth.
' indicates the state where it is irradiated. This 1st θ
As can be seen from the figure, the incident direction of at least one of the rectangular pseudo multimode beams incident from three directions is made to match the normal direction at each position of the tooth surface, that is, the side surface 80a and the bottom surface 80b, which are the parts to be processed. A uniform hardened layer can be obtained because the hardened layer can be brought close to the surface. In this case, as a method for preventing overheating of the tooth tip 80c, for example, by not applying a laser absorbing material to the tooth tip 80c and leaving the tooth tip 80c in a state where the reflectance of laser light is high, It is also possible to reduce excessive temperature rise at the tooth tip portion 80c to achieve more uniform heating. Another method is to provide a shutter on the optical path of the 5-split reflected laser beam 3.4 or the reflected laser beams 3' and 4', and to direct the reflected laser beam 3 to the tooth tip 80c.
Overheating may be prevented by turning off the irradiation of ' and 4'.

Although the case of hardening has been described here, it is clear that the present invention can also be applied to treatments that melt the surface.

Figure 11 and! Figure s12 is a diagram showing another embodiment of the present invention.

In the figure, 1 is a circular multi-mode incident laser beam with a beam diameter DL emitted from a laser beam generator 6o, 10 is a first reflector, and 2o.

3G, 40.50 is the second and subsequent reflectors, that is.

20 is the second reflector, 30 is the third reflector, 4° is the fourth reflector
50 is a fifth reflector.

The first reflector 10 has four continuous mirror surfaces 11, 12, 13.14 as shown in FIG. It consists of a concave quadratic curved surface smoothly connected to both sides of the mirror, that is, a concave cylindrical mirror portion in this case, and its details can be the same as those of the previous embodiment.

Further, the second reflector 20. Third reflector 30, fourth
reflector 40. and the fifth reflector 50 both consist of a flat mirror part and a concave quadratic curved surface smoothly connected to both sides of the flat mirror part, that is, in this case, a concave cylindrical mirror part, the details of which are as in the above embodiment. can be made the same as

Therefore, when heating and hardening the tooth surface of the gear 80 using a heating device having such a configuration, for example, the first
Laser beams 2", 3", 4', 5 as shown at 21m
'Irradiate. At this time, the incident direction of at least one beam among the rectangular pseudo multimode beams incident from four directions.

Since it is possible to align or approach the normal direction at each position of the tooth surface, particularly the side surface 80a and the bottom surface 80b, a uniform hardened layer can be obtained. In this case, it is also possible to partially change the coating of the laser absorbing material on the tooth surface or provide a shutter that blocks the laser beam as appropriate to make the heating even more uniform. .

In each of the above-mentioned embodiments, the concave quadratic curved mirror portion of each mirror surface is a cylindrical mirror, but these quadratic curved mirror portions extend the parabola parallel to the direction perpendicular to the plane containing the parabola. Even with a curved surface obtained as a locus during movement, it is clear that exactly the same result can be obtained if each concave quadratic curved mirror section is in a confocal relationship as described above.

Furthermore, even if the concave quadratic mirror parts do not have a confocal relationship as mentioned above, it is clear that almost the same results can be obtained if they have a close relationship. It is.

[Effects of the Invention] As described above, the tooth profile surface heating device according to the present invention includes a laser beam generator, a first reflector that divides and reflects the laser beam emitted from the laser beam generator, and a first reflector that divides and reflects the laser beam emitted from the laser beam generator, and A plurality of laser beams each reflecting a plurality of divided laser beams that have been divided and reflected by a first reflector, and irradiating the divided laser beams toward the tooth-shaped surface. s2 and subsequent reflectors, the first reflector is a polyhedron consisting of a plurality of continuous mirror surfaces, and each of the mirror surfaces accommodates a plane mirror portion and a concave quadratic curved mirror portion, The second and subsequent reflectors correspond to each mirror surface of the first reflector, and have a mirror surface consisting of only a plane mirror portion or a plane mirror portion and a concave quadratic curved mirror portion. , like the tooth surface of a gear.

Even when the part to be processed has a complicated curved shape, it is possible to irradiate the rectangular pseudo multimode beam from multiple directions, and the direction of incidence of at least one of the rectangular pseudo multimode beams can be adjusted. Since it is possible to match or approach the normal direction at each position of the processed part, as a result,
For example, a very good effect can be obtained in that a fairly uniform hardened layer can be formed in a treatment such as hardening.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the main part configuration of a tooth profile surface heating device according to an embodiment of the present invention, FIG. 2(a) is a front view of the first reflector shown in FIG. 1, and FIG. (b), (c), and (d) are explanatory diagrams of the shape taken along lines GG, H-H, and I-I in Figure 2 (L), respectively, and Figures 3, 4, and 5 are diagrams showing the shapes, respectively. An explanatory diagram showing the shapes of the second reflector, third reflector, and fourth reflector shown in FIG. 1, and FIGS. 6, 7, 8, and 9 are the first reflection Explanatory diagram showing the power density distribution in the S direction + t2 direction + j3 direction + L4 direction at the focal position of the laser beam reflected by the body, the second reflector, the third reflector, and the fourth reflector, Figure 1O (a) (b) is an explanatory view showing the state of irradiation of laser light to the top and bottom portions of a gear, respectively; FIG. 11 is a perspective view of a first reflector according to another embodiment of the present invention; FIG. 12 is an explanatory diagram showing a situation in which the tooth surface of a gear is heated using the reflector shown in FIG. 11 and the second and subsequent reflectors, and FIG. 13 is an explanatory diagram showing the main part configuration of a conventional heating device using laser light. FIG. 14 is an explanatory diagram showing the power density distribution of a circular multi-mode incident laser beam, and FIG. 15 is an explanatory diagram showing the power density distribution at the irradiation position [cross section BB in FIG. 13]. 1...Incoming laser light, la, lb, lc, ld-...Components of the incident laser light, 2
．． 3, 4.5...Divided reflected laser beam, 2', 3', 4
', 5'...Reflected laser beam, 10...First reflector, 20...Second reflector, 30...Third reflector, 40...Fourth reflector . 50... Fifth reflector, 60... Laser light generator, 11.12, 13.14... Mirror surface of first reflector, 11a, 12a, 13a, 20a, 30a. 40a...Plane mirror portion, 11b, 12b, 13b, 20b, 30b. 40b, llc, 12c, 13c, 30c - concave quadratic curved mirror section. Patent Applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Yutaka Oshio Figure 2 r, a> (b) Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 figure

Claims (1)

[Claims] (1) A laser beam generator, a first reflector that divides and reflects the laser beam emitted from the laser beam generator, and each reflects a plurality of divided laser beams that are divided and reflected by the first reflector. , and a plurality of second and subsequent reflectors that irradiate the divided laser beams toward the side and bottom surfaces of the teeth, and the first reflector is a polyhedral mirror consisting of a plurality of continuous mirror surfaces, and the Each mirror surface has a plane mirror section and a concave quadratic curved mirror section, and the second and subsequent reflectors respectively correspond to each mirror surface of the first reflector, and only the plane mirror section or the plane mirror section is provided. 1. A heating device for a tooth profile surface, characterized in that the device has a mirror surface consisting of a concave quadratic mirror section and a concave quadratic mirror section.