Welding head

Abstract

To provide a welding head which contributes to improvement of effect of suppressing adhesion of dust to a protective glass.SOLUTION: A welding head (1) according to one aspect of the present disclosure includes an optical unit, a protective glass (2) for preventing dust from entering the inside of the optical unit, and a nozzle (5) that ejects gas in a first axial direction orthogonal to laser light. The nozzle (5) has: a curved portion (5f) that is smoothly curved in an S-shape from an introduction side toward an ejection side of the gas in a flow path of the gas disposed inside the nozzle (5) when viewed from a second axial direction orthogonal to the laser light and the first axial direction; a widened portion (5g) that is smoothly widened in the second axial direction from the curved portion (5f) toward the ejection port (5e) of the gas in the flow path of the gas; and a fin (5c) for throttling a flow amount at a portion immediately before the ejection port (5e) of the gas in the flow path of the gas.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a welding head of a laser welding apparatus.

Background Art

[0002] A welding head of a general laser welding apparatus includes a protective glass for preventing the intrusion of dust such as spatter and fume into an optical unit for guiding laser light to a welding object. At this time, when dust adheres to the protective glass, the output of the laser light decreases, and welding defects occur.

[0003] Therefore, for example, the welding head of Patent Document 1 passes a gas jet (gas) in a direction orthogonal to the laser light between the protective glass and the welding object to suppress the adhesion of dust to the protective glass.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The applicant of the present application has found the following problems. The welding head of Patent Document 1 passes a gas in a direction orthogonal to the laser light between the protective glass and the welding object to suppress the adhesion of dust to the protective glass, but an improvement in the effect of suppressing the adhesion of dust to the protective glass is desired.

[0006] The present disclosure has been made in view of such problems, and realizes a welding head that contributes to an improvement in the effect of suppressing the adhesion of dust to the protective glass.

Means for Solving the Problems

[0007] A welding head according to an aspect of the present disclosure is a welding head of a laser welding apparatus, and An optical unit for guiding a laser beam to an object to be welded, A protective glass disposed on the side of the optical unit in the emission direction of the laser beam to prevent dust from entering the interior of the optical unit, A nozzle disposed between the protective glass and the object to be welded, for ejecting a gas in a first axial direction orthogonal to the laser beam, Comprising, The nozzle, A curved portion that smoothly curves in an S shape from the introduction side to the ejection side of the gas in the gas flow path disposed inside the nozzle when viewed from a second axial direction orthogonal to the laser beam and the first axial direction, An expanding portion that smoothly expands in the second axial direction from the curved portion to the gas ejection port in the gas flow path, Fins for restricting the flow rate at a portion immediately before the gas ejection port in the gas flow path, Having.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to contribute to an improvement in the effect of suppressing the adhesion of dust to the protective glass.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying out the Invention

[0010] Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate. Here, in the following explanation, for clarity of explanation, a three-dimensional (XYZ) coordinate system is used for the explanation.

[0011] <Embodiment 1> FIG. 1(a) is a perspective view schematically showing the welding head of the present embodiment, and FIG. 1(b) is a cross-sectional view at the position of the IB-IB cross section of FIG. 1(a). The welding head 1 of the present embodiment includes, for example, an optical unit (not shown), a protective glass 2, a purge unit 3, and a cross jet unit 4 as shown in FIGS. 1(a) and 1(b).

[0012] The optical unit includes, for example, lenses, mirrors, etc. so that the laser light incident from the optical fiber can be emitted toward the Z-axis side and irradiated onto the welding object. As shown in FIGS. 1(a) and 1(b), the protective glass 2 is fixed to the end portion on the Z-axis side of the optical unit in order to prevent the intrusion of dust such as spatter and fume into the optical unit.

[0013] The purge unit 3 is arranged, for example, as shown in FIGS. 1(a) and 1(b), so as to surround the laser light emitted from the optical unit on the Z-axis side with respect to the protective glass 2, and is configured to eject gas toward the radially inner side of the purge unit 3 in order to suppress the adhesion of dust to the protective glass 2.

[0014] Note that since the configuration of the purge unit 3 is not an essential part of the present disclosure, a detailed description thereof will be omitted. Here, in FIG. 1(a), the gas flow path of the purge unit 3 and the like are shown by solid lines.

[0015] FIG. 2(a) is a perspective view showing the cross jet unit of the welding head of the present embodiment, and FIG. 2(b) is a perspective view showing the flow path of the nozzle in the welding head of the present embodiment. The cross jet unit 4 is configured to eject gas, for example, toward the +X axis side in order to suppress the adhesion of dust to the protective glass 2.

[0016] As shown in FIGS. 1(b) and 2(a), the cross jet unit 4 includes a nozzle 5 and a flow-through portion 6. The nozzle 5 is, for example, substantially right-angled triangular when viewed in the Y-axis direction and extends in the Y-axis direction. The nozzle 5 has an inclined surface 5a that inclines toward the -Z axis side as it goes toward the +X axis side. Inside the nozzle 5, as shown in FIGS. 1(b) and 2(b), a flow path 5b that penetrates the nozzle 5 in the X-axis direction and fins 5c are formed.

[0017] As shown in FIGS. 1(b) and 2(b), the flow path 5b includes an inlet 5d, an outlet 5e, a curved portion 5f, a widened portion 5g, and a throttle portion 5h. Here, in FIG. 1(a), the flow path 5b and the like are shown by solid lines.

[0018] As shown in FIGS. 1(b) and 2(b), the inlet 5d is disposed at the X-axis - side end of the flow path 5b and is formed at the X-axis - side end of the nozzle 5. The inlet 5d is, for example, substantially circular, and a supply pipe 7 for supplying gas is connected thereto.

[0019] As shown in FIGS. 1(b) and 2(b), the outlet 5e is disposed at the X-axis + side end of the flow path 5b and is formed at the X-axis + side end of the nozzle 5. The outlet 5e is substantially rectangular and extends in the Y-axis direction.

[0020] The bent portion 5f is curved in a substantially S shape from the inlet 5d toward the outlet 5e as viewed from the + side of the Y axis, for example, as shown in FIGS. 1(b) and 2(b). That is, the bent portion 5f smoothly connects the inlet 5d and the outlet 5e.

[0021] The bent portion 5f includes, for example, as shown in FIGS. 1(b) and 2(b), a first portion 5i, a second portion 5j, a third portion 5k, a fourth portion 5l, and a fifth portion 5m. The first portion 5i extends from the inlet 5d toward the + side of the X axis.

[0022] The second portion 5j is curved, for example, as shown in FIGS. 1(b) and 2(b), so as not to protrude from the end on the + side of the X axis of the first portion 5i toward the - side of the Z axis. The third portion 5k extends from the end on the - side of the Z axis of the second portion 5j toward the - side of the Z axis.

[0023] The fourth portion 5l is curved, for example, as shown in FIGS. 1(b) and 2(b), so as not to protrude from the end on the - side of the Z axis of the third portion 5k toward the + side of the X axis. The fifth portion 5m extends from the end on the + side of the X axis of the fourth portion 5l toward the + side of the X axis and reaches the outlet 5e.

[0024] The widening portion 5g is disposed, for example, as shown in FIG. 2(b), between the bent portion 5f and the outlet 5e, and the width dimension of the widening portion 5g in the Y-axis direction smoothly widens from the bent portion 5f toward the outlet 5e.

[0025] Specifically, the widening portion 5g is disposed, for example, as shown in FIG. 2(b), from the vicinity of the end on the - side of the Z axis of the second portion 5j of the bent portion 5f to the vicinity of the end on the + side of the X axis of the fourth portion 5l. At this time, the fifth portion 5m of the bent portion 5f is continuous with the widening portion 5g so as to maintain the width dimension in the Y-axis direction at the end on the + side of the X axis of the widening portion 5g.

[0026] The throttle portion 5h is disposed, for example, as shown in FIG. 1(b), in the curved portion 5f, and restricts the gas flow rate in the curved portion 5f toward the side of the jet outlet 5e as viewed from the Y-axis direction. Specifically, the throttle portion 5h is disposed from the vicinity of the Z-axis - side end of the second portion 5j of the curved portion 5f to the vicinity of the X-axis + side end of the fourth portion 5l.

[0027] As shown in FIG. 1(b), for example, the throttle portion 5h smoothly curves such that the height in the Z-axis direction of the curved portion 5f decreases toward the side of the jet outlet 5e as viewed from the Y-axis direction. As a result, as shown in FIG. 2(b), the YZ cross-sectional shape of the curved portion 5f smoothly transitions from a substantially circular shape to a substantially rectangular shape that is long in the Y-axis direction and flat toward the side of the jet outlet 5e.

[0028] The fins 5c are disposed, for example, as shown in FIG. 2(b), immediately before the jet outlet 5e of the flow path 5b, and restrict the gas flow rate in the portion immediately before the jet outlet 5e of the flow path 5b. Specifically, the fins 5c are disposed in the fifth portion 5m of the curved portion 5f and are spaced apart in the Y-axis direction.

[0029] As shown in FIG. 2(b), for example, the fins 5c are columnar bodies having a substantially deformed rhomboid shape that is long in the X-axis direction as viewed from the Z-axis direction, and the angle of the X-axis - side corner is wider than the angle of the X-axis + side corner. However, the fins 5c may have a shape that can increase the gas pressure in the portion of the flow path 5b on the side of the inlet 5d with respect to the fins 5c and has little resistance when the gas passes between the fins 5c.

[0030] As shown in FIG. 1(b), the flow-through portion 6 guides the gas ejected from the nozzle 5 toward the X-axis + side. The flow-through portion 6 includes a main body portion 6a, a first drawing-in portion 6b, and a second drawing-in portion 6c, as shown in FIG. 2(a). The main body portion 6a has a so-called scoop shape, and the Z-axis + side and the X-axis - side are open.

[0031] Specifically, as shown in Fig. 2(a), the main body portion 6a includes a bottom portion 6d, a first side wall portion 6e, a second side wall portion 6f, and a third side wall portion 6g. As shown in Fig. 1(b), the bottom portion 6d is substantially rectangular when viewed from the Z-axis direction and is arranged substantially parallel to the XY plane.

[0032] As shown in Fig. 1(b), a passage portion 6h through which the laser light passes is formed in the bottom portion 6d. The passage portion 6h can be formed, for example, in a substantially circular shape when viewed from the Z-axis direction, but any shape that allows the laser light to pass through is acceptable.

[0033] At this time, the width dimension in the Y-axis direction of the passage portion 6h of the flow-through portion 6 is narrower than the width dimension in the Y-axis direction of the nozzle opening 5e of the flow path 5b of the nozzle 5. Generally, when viewed from the Z-axis direction, the center in the Y-axis direction of the nozzle opening 5e in the flow path 5b of the nozzle 5 passes through, and the center in the Y-axis direction of the passage portion 6h in the flow-through portion 6 is preferably arranged on an axis extending in the X-axis direction.

[0034] For example, as shown in Fig. 2(a), the first side wall portion 6e is substantially trapezoidal when viewed from the Y-axis direction, and the side on the +X-axis side of the first side wall portion 6e curves toward the +X-axis side as it goes toward the +Z-axis side. The first side wall portion 6e rises from the end portion on the +Y-axis side of the bottom portion 6d. An intake portion 6i for taking in gas into the inside of the flow-through portion 6 is formed at substantially the center of the side on the +Z-axis side of the first side wall portion 6e.

[0035] As shown in Fig. 2(a), the second side wall portion 6f has substantially the same shape as the first side wall portion 6e when viewed from the Y-axis direction and rises from the end portion on the -Y-axis side of the bottom portion 6d. An intake portion 6j for taking in gas into the inside of the flow-through portion 6 is formed at substantially the center of the side on the +Z-axis side of the second side wall portion 6f.

[0036] For example, as shown in Fig. 2(a), the intake portion 6i of the first side wall portion 6e and the intake portion 6j of the second side wall portion 6f can be formed in a substantially triangular shape with the +Z-axis side open when viewed from the Y-axis direction, but any shape that can take in gas into the inside of the main body portion 6a is acceptable.

[0037] As shown in FIGS. 1(b) and 2(a), the third side wall portion 6g has a curved shape that curves toward the +X axis as it goes toward the +Z axis, extends from the +X axis end of the bottom portion 6d toward the +X axis, and connects the +X axis side of the first side wall portion 6e and the +X axis side of the second side wall portion 6f.

[0038] The first intake portion 6b guides gas into the main body portion 6a from the +Y axis side. As shown in FIG. 2(a), the first intake portion 6b is a hollow substantially right-angled triangular prism with the +Z axis side and the -Y axis side open. Specifically, the first intake portion 6b includes a first side wall portion 6k, a second side wall portion 6l, and a third side wall portion 6m.

[0039] As shown in FIG. 2(a) for example, the first side wall portion 6k has a substantially right trapezoidal shape when viewed from the Y-axis direction, and the +X axis side of the first side wall portion 6k is inclined toward the -X axis as it goes toward the +Z axis. And the first side wall portion 6k is inclined toward the +Y axis as it goes toward the +Z axis when viewed from the X-axis direction.

[0040] As shown in FIG. 2(a) for example, the second side wall portion 6l has a substantially right triangular shape when viewed from the Y-axis direction, and is formed by bending toward the -Y axis around the +X axis side of the first side wall portion 6k. At this time, the second side wall portion 6l is inclined toward the -X axis and the +Y axis as it goes toward the +Z axis, and the -Y axis side of the second side wall portion 6l is arranged substantially parallel to the Z axis.

[0041] As shown in FIG. 2(a) for example, the third side wall portion 6m has a substantially right triangular shape when viewed from the Y-axis direction, and is formed by bending from the -X axis side of the first side wall portion 6k toward the -Y axis. At this time, the third side wall portion 6m is arranged substantially parallel to the YZ plane, and the -Y axis side of the third side wall portion 6m is arranged substantially parallel to the Z axis.

[0042] As shown in Fig. 2(a), such a first drawing-in part 6b is fixed to the first side wall part 6e so as to surround the drawing-in part 6i of the first side wall part 6e in the main body part 6a from the +Y axis side.

[0043] As shown in Fig. 2(a), since the second drawing-in part 6c has a line-symmetric configuration with an axis passing through the center in the Y-axis direction in the flow-through part 6 and extending in the X-axis direction as the axis of symmetry when viewed from the Z-axis direction, a detailed description is omitted, but it includes a first side wall part 6n, a second side wall part 6o, and a third side wall part 6p.

[0044] As shown in Fig. 2(a), a nozzle 5 is disposed between the X-axis - side portion of the first side wall part 6e of the main body part 6a in the flow-through part 6 and the X-axis - side portion of the second side wall part 6f. And the +Y axis side end of the nozzle 5 is fixed to the X-axis - side portion of the first side wall part 6e of the main body part 6a in the flow-through part 6, and the -Y axis side end of the nozzle 5 is fixed to the X-axis - side portion of the second side wall part 6f of the main body part 6a in the flow-through part 6.

[0045] That is, the X-axis - side portion of the first side wall part 6e of the main body part 6a and the X-axis - side portion of the second side wall part 6f in the flow-through part 6 function as fixing parts to which the nozzle 5 is fixed. At this time, as shown in Fig. 1(b), the nozzle 5 is disposed on the X-axis - side with respect to the passing part 6h of the main body part 6a of the flow-through part 6.

[0046] And, for example, as shown in Figs. 1(b) and 2(a), the +Z axis side end of the nozzle 5 and the +Z axis side end of the main body part 6a of the flow-through part 6 are disposed at substantially the same position in the Z-axis direction, and a gap is formed between the -Z axis side end of the nozzle 5 and the bottom 6d of the main body part 6a of the flow-through part 6.

[0047] As shown in Fig. 1(b), such a cross jet unit 4 is fixed to the purge unit 3 by fixing the +Z axis side ends of the first side wall part 6e and the second side wall part 6f of the main body part 6a in the flow-through part 6 to the -Z axis side end of the purge unit 3.

[0048] At this time, when viewed from the Z-axis direction, the cross jet unit 4 is fixed to the purge unit 3 such that the center of the passing portion 6h of the main body portion 6a of the flow-through portion 6 is disposed on the optical path of the laser beam. Further, when viewed from the Z-axis direction, the opening portion on the Z-axis + side with respect to the third side wall portion 6g of the main body portion 6a in the flow-through portion 6, the opening portion on the Z-axis + side of the first drawing-in portion 6b, and the opening portion on the Z-axis + side of the second drawing-in portion 6c are arranged so as to protrude from the purge unit 3.

[0049] Next, the state when the welding head 1 of the present embodiment welds a welding object will be described. When welding the welding object with the welding head 1, for example, while the welding head 1 moves to the Y-axis - side, a laser beam is emitted from the optical unit and irradiated onto the welding object to weld the welding object.

[0050] At this time, dust enters the inside of the main body portion 6a of the flow-through portion 6 from the passing portion 6h, the intake portion 6i of the first side wall portion 6e, the intake portion 6j of the second side wall portion 6f, and the gap between the Z-axis - side end of the nozzle 5 and the bottom portion 6d of the main body portion 6a of the flow-through portion 6. However, the purge unit 3 ejects gas toward the radially inner side of the purge unit 3, and the cross jet unit 4 ejects gas toward the X-axis + side, thereby suppressing the adhesion of dust to the protective glass 2.

[0051] Here, in the cross jet unit 4 of the present embodiment, the opening portion on the Z-axis + side with respect to the third side wall portion 6g of the main body portion 6a in the flow-through portion 6 can function as a discharge portion for discharging dust to the outside of the welding head 1.

[0052] Then, the cross jet unit 4 of the present embodiment can take in outside air from the intake portion 6i of the first side wall portion 6e, the intake portion 6j of the second side wall portion 6f, and the gap between the Z-axis - side end of the nozzle 5 and the bottom portion 6d of the main body portion 6a of the flow-through portion 6, and can satisfactorily discharge the dust that has entered the inside of the main body portion 6a of the flow-through portion 6.

[0053] Next, a comparison will be made between the airflow analysis result of the cross jet unit 4 using the flow path 5b of the nozzle 5 of the present embodiment for the welding head 1 and the airflow analysis result of the cross jet unit using the flow path of the nozzle of the comparative shape for the welding head. Fig. 3(a) is a perspective view showing the flow path of the nozzle of the comparative shape, and Figs. 3(b) to 3(d) are diagrams showing the cross-sectional positions such as the welding head.

[0054] Fig. 4 is a diagram showing the airflow analysis result of the cross jet unit when the flow path of the nozzle of the present embodiment is used for the welding head at each cross-sectional position and the airflow analysis result of the cross jet unit when the nozzle of the comparative shape is used for the welding head.

[0055] Here, as shown in Fig. 3(a), the flow path 100 of the nozzle of the comparative shape is bent so that the bent portion 100c connecting the inlet 100a and the outlet 100b stands at an angle, and the widening portion 100d has a shape that widens rapidly in the Y-axis direction from the middle of the bent portion 100c.

[0056] And, as shown in Fig. 3(c), the height in the Z-axis direction of the outlet 100b of the flow path 100 of the nozzle of the comparative shape is 0.5 mm, whereas, as shown in Fig. 3(d), the height in the Z-axis direction of the outlet 5e of the flow path 5b of the nozzle 5 of the present embodiment is 1.5 mm.

[0057] This is because the flow path 100 of the nozzle of the comparative shape does not include the fins 5c of the nozzle 5 of the present embodiment, and in order to increase the pressure of the gas near the outlet 100b of the flow path 100, the height in the Z-axis direction of the outlet 100b is narrowed compared to the height in the Z-axis direction of the outlet 5e of the flow path 5b of the nozzle 5 of the present embodiment.

[0058] When gas is supplied to the flow path 5b of the nozzle 5 of this embodiment and the flow path 100 of the nozzle of the comparative shape at a pressure of 167 kPa, at the position of the A-A cross section of the welding head, as shown on the left side of FIG. 4, the flow rate of the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of this embodiment is 987 L / min, while the flow rate of the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape is 450 L / min.

[0059] And, as shown on the left side of FIG. 4, it can be understood that the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of this embodiment reaches the + side of the X axis compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape.

[0060] At the position of the B-B cross section of the welding head, as shown in the center of FIG. 4, the thickness of the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of this embodiment in the Z-axis direction is 4.6 mm, while the thickness of the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape in the Z-axis direction is 3.6 mm.

[0061] As described above, since the nozzle 5 of this embodiment includes the fins 5c, even if the height in the Z-axis direction is not reduced like the ejection port 100b of the flow path 100 of the nozzle of the comparative shape, the pressure of the gas at the portion on the inlet 5d side with respect to the fins 5c in the flow path 5b can be increased.

[0062] Therefore, the ejection port 5e of the flow path 5b of the nozzle 5 of this embodiment can have a higher height in the Z-axis direction compared to the ejection port 100b of the flow path 100 of the nozzle of the comparative shape, and the flow rate of the gas can be increased.

[0063] At the position of the C-C cross section of the welding head, as shown on the right side of FIG. 4, it can be understood that a region with a high flow velocity where the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of this embodiment is distributed over a wider range compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape.

[0064] In particular, the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of the present embodiment is distributed so as to cover the passage portion 6h disposed on the +Z axis side with respect to the welding portion of the object to be welded in the main body portion 6a of the flow-through portion 6, where there is a high-velocity area with a higher flow velocity compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape.

[0065] And, as shown on the right side of FIG. 4, it can be understood that the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of the present embodiment reaches the +X axis side compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape.

[0066] In this way, the curved portion 5f of the flow path 5b of the nozzle 5 of the present embodiment smoothly connects the inlet 5d and the ejection port 5e compared to the bent portion 100c of the flow path 100 of the nozzle of the comparative shape. Therefore, the resistance at the curved portion 5f is small, and the decrease in the flow velocity of the gas is suppressed.

[0067] Therefore, the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of the present embodiment has a wider high-velocity area with a higher flow velocity compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape, and the gas can reach the +X axis side. Moreover, due to the synergistic effect with the fins 5c, the gas can reach the +X axis side.

[0068] Further, the widened portion 5g of the flow path 5b of the nozzle 5 of the present embodiment widens smoothly in the Y-axis direction compared to the widened portion 100d of the flow path 100 of the nozzle of the comparative shape. Therefore, the gas ejected from the ejection port 5e of the flow path 5b of the nozzle 5 of the present embodiment can equalize the velocity distribution of the gas in the Y-axis direction compared to the gas ejected from the ejection port 100b of the flow path 100 of the nozzle of the comparative shape.

[0069] Thereby, the welding head 1 of the present embodiment can distribute a high-velocity area where the flow velocity of the gas is high when the gas is ejected over a wide range, for example, compared to the gas ejected from the flow path 100 of the nozzle of the comparative shape, and moreover, a large amount of gas can reach the +X axis side.

[0070] Therefore, the welding head 1 of the present embodiment can improve the effect of suppressing the adhesion of dust to the protective glass 2, for example, as compared with the case where the flow path 100 of a nozzle having a comparative shape is used for the welding head.

[0071] The width dimension in the Y-axis direction of the ejection port 5e of the flow path 5b of the nozzle 5 of the present embodiment is wider than the width dimension in the Y-axis direction of the passing portion 6h of the circulation portion 6. Generally, when viewed from the Z-axis direction, the center in the Y-axis direction of the ejection port 5e in the flow path 5b of the nozzle 5 passes through and is arranged on the axis extending in the X-axis direction, and the center in the Y-axis direction of the passing portion 6h in the circulation portion 6 is arranged. Therefore, the dust entering from the passing portion 6h of the circulation portion 6 can be discharged well from the circulation portion 6.

[0072] The widened portion 5g of the flow path 5b of the nozzle 5 of the present embodiment widens smoothly in the Y-axis direction as compared with the widened portion 100d of the flow path 100 of a nozzle having a comparative shape. Therefore, the velocity distribution of the gas in the Y-axis direction can be made uniform, and the remaining of dust inside the main body portion 6a of the circulation portion 6 can be suppressed.

[0073] <Embodiment 2> FIG. 5 is a perspective view showing the cross jet unit of the welding head of the present embodiment. As described above, when the welding head is moved to the Y-axis - side to weld the welding object, a large amount of dust enters the inside of the main body portion 6a of the circulation portion 6 from the intake portion 6i of the first side wall portion 6e arranged on the Y-axis + side, which is the side opposite to the moving direction of the welding head in the circulation portion 6.

[0074] Therefore, the circulation portion 61 of the present embodiment omits the intake portion 6i of the first side wall portion 6e and also omits the first drawing-in portion 6b. That is, the first side wall portion 6e of the circulation portion 61 functions as a blocking portion that blocks the intrusion of outside air into the circulation portion 61. Thereby, the intrusion of dust into the inside of the main body portion 6a of the circulation portion 6 when welding the welding object can be reduced.

[0075] The present disclosure is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist thereof. For example, although the welding heads of the above-described Embodiments 1 and 2 are provided with the purge unit 3, it may be omitted. The configurations of the nozzles 5 and the flow-through portions 6 of the cross jet unit 4 of the above-described Embodiments 1 and 2 are merely illustrative, and can be appropriately changed. For example, the flow-through portion 6 may be omitted, and the nozzle 5 may be fixed to the purge unit 3.

Explanation of Reference Numerals

[0076] 1 Welding head 2 Protective glass 3 Purge unit 4 Cross jet unit 5 Nozzle, 5b Flow path, 5c Fin, 5d Inlet, 5e Outlet, 5f Curved portion, 5g Widening portion, 5h Throttle portion 6 Flow-through portion, 6a Main body portion, 6b First drawing-in portion, 6c Second drawing-in portion, 6h Passage portion, 6i Intake portion, 6j Intake portion 61 Flow-through portion

Claims

1. A welding head of a laser welding apparatus, comprising: an optical unit for guiding laser light to a welding object; a protective glass disposed on the side of the optical unit in the emission direction of the laser light to prevent dust from entering the interior of the optical unit; a nozzle disposed between the protective glass and the welding object, and ejecting gas in a first axial direction orthogonal to the laser light; wherein the nozzle has: a curved portion that smoothly curves in an S shape from the introduction side to the ejection side of the gas in the gas flow path disposed inside the nozzle when viewed from a second axial direction orthogonal to the laser light and the first axial direction; a widening portion that smoothly widens in the second axial direction from the curved portion toward the gas ejection port in the gas flow path; and fins for restricting the flow rate at a portion immediately before the gas ejection port in the gas flow path. A welding head having the above features.

2. When the moving direction of the welding head is parallel to the second axial direction and the direction orthogonal to the moving direction of the welding head is parallel to the first axial direction, the nozzle is fixed, and a flow passage portion for guiding the gas ejected from the nozzle in the first axial direction is provided, wherein the flow passage portion has: a passage portion through which the laser light passes; a fixing portion disposed on one side with the passage portion in between in the first axial direction, and fixing the nozzle; a discharge portion disposed on the other side with the passage portion in between in the first axial direction, and discharging the gas; an intake portion disposed on the side of the moving direction of the welding head with the passage portion in between in the second axial direction, and taking in outside air into the flow passage portion; and a blocking portion disposed on the side opposite to the side of the moving direction of the welding head with the passage portion in between in the second axial direction, and blocking the intrusion of outside air into the flow passage portion. The welding head according to Claim 1 having the above features.

3. The width dimension in the second axial direction of the gas ejection port of the nozzle is wider than the width dimension in the second axial direction of the passage portion of the flow passage portion, and when viewed in the emission direction of the laser light, the center in the second axial direction of the passage portion of the flow passage portion is disposed on an axis passing through the center in the second axial direction of the gas ejection port of the nozzle and extending in the first axial direction. The welding head according to Claim 2 having the above features.

4. The welding head according to any one of claims 1 to 3, further comprising a throttle portion for restricting the flow rate of the gas at the curved portion in the gas flow path toward the side of the gas ejection port as viewed from the second axial direction.

Images