Laser welding method, cover, and resin molded product

Abstract

To suppress occurrence of a defective joint spot when joining an outer periphery of a resin cover to a resin housing by laser welding.SOLUTION: There is provided a laser welding method for joining a resin cover to a resin housing by laser welding, comprising: a pressing step of pressing the cover from a front side by a flat pressing surface of a movable jig in a state where an outer periphery of the cover is positioned with respect to a laser joining surface of a housing; and a laser welding step in which a laser beam is irradiated from the front side of the cover to an outer periphery of the cover to laser weld the outer periphery of the cover to the laser joining surface of the housing, wherein in the pressing step, a pressing surface of the movable jig presses a plurality of protrusions provided on the surface of the outer periphery of the cover.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a laser welding method, a cover, and a resin molded product. [Background technology]

[0002] The following Patent Document 1 discloses a technique for joining a resin casing and a metal material by applying laser light from a laser light application means while the metal material is pressed against the resin casing by a movable mold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5941563 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with conventional laser welding methods, warping can occur in the plastic casing, which can prevent the pressing surface of the movable jig from uniformly pressing the metal material against the laser joining surface of the plastic casing, resulting in the risk of poor joining. [Means for solving the problem]

[0005] A laser welding method according to one embodiment is a laser welding method for joining a resin cover to a resin housing by laser welding, and includes a pressurizing process in which, with the outer periphery of the cover positioned relative to the laser joining surface of the housing, the cover is pressed from the front side by a planar pressing surface of a movable jig, and a laser welding process in which the outer periphery of the cover is laser welded to the laser joining surface of the housing by irradiating laser light from the front side of the cover to the outer periphery of the cover. In the pressurizing process, pressure is applied to multiple protrusions provided on the surface of the outer periphery of the cover by the pressing surface of the movable jig. Effect of the Invention

[0006] According to the laser welding method of one embodiment, it is possible to suppress the occurrence of poor joining locations when joining the outer periphery of a resin cover to a resin housing by laser welding. [Brief description of the drawings]

[0007] [Figure 1] 1 is a plan view of a resin molded product according to one embodiment; [Diagram 2] 1 is a side view of a resin molded product according to one embodiment; [Diagram 3] A flowchart showing an example of a procedure for a method for producing a resin molded product according to an embodiment. [Figure 4] FIG. 1 is a diagram illustrating a case setting step in a manufacturing method for a resin molded product according to an embodiment; [Diagram 5] FIG. 1 is a diagram illustrating a cover placement step in a method for manufacturing a resin molded product according to an embodiment; [Figure 6] FIG. 1 is a diagram showing a pressurizing step in a method for producing a resin molded product according to an embodiment of the present invention; [Figure 7] FIG. 1 is a diagram showing a laser welding step in a method for producing a resin molded product according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings.

[0009] An embodiment will be described below with reference to the drawings. For convenience, in the following description, the X-axis direction in the drawing is the front-rear direction, the Y-axis direction in the drawing is the left-right direction, and the Z-axis direction in the drawing is the up-down direction. However, the positive X-axis direction is the forward direction, the positive Y-axis direction is the rightward direction, and the positive Z-axis direction is the upward direction. These indicate the relative positional relationship within the device, and do not limit the installation direction or operation direction of the device. Anything that has the same relative positional relationship within the device, even if the installation direction or operation direction is different, is included in the scope of the present invention.

[0010] (Configuration of resin molded product 100) Fig. 1 is a plan view of a resin molded product 100 according to one embodiment. Fig. 2 is a side view of the resin molded product 100 according to one embodiment.

[0011] The resin molded product 100 shown in Fig. 1 and Fig. 2 is mounted on a vehicle such as an automobile and used as a display device, etc. In the example shown in Fig. 1 and Fig. 2, the resin molded product 100 has a rectangular parallelepiped shape with the left-right direction (Y-axis direction) as the longitudinal direction. As shown in Fig. 1 and Fig. 2, the resin molded product 100 includes a housing 110 and a cover 120.

[0012] The housing 110 is a box-shaped member made of resin and having a hollow structure. In the example shown in Fig. 1 and Fig. 2, the housing 110 has a rectangular parallelepiped outer shape with the left-right direction (Y-axis direction) as the longitudinal direction. However, the housing 110 is not limited to a rectangular parallelepiped shape and may have other outer shapes. For example, the housing 110 may have any shape as long as it has an outer shape such that when a line is drawn around the periphery, the start point and the end point are connected to close the periphery.

[0013] Furthermore, the housing 110 has an upper opening 112 on the top surface thereof that is rectangular in plan view from above (positive direction of the Z axis). However, the upper opening 112 is not limited to a rectangular shape and may have other shapes.

[0014] Furthermore, the housing 110 has a rectangular cylindrical outer circumferential wall portion 111 extending in the up-down direction (Z-axis direction). The upper end surface of the outer circumferential wall portion 111 has a rectangular frame shape when viewed from above (Z-axis positive direction) and serves as a flat laser bonding surface 111A surrounding the upper opening 112. The laser bonding surface 111A is a portion on which the outer circumferential portion 121 of the cover 120 is placed and to which the outer circumferential portion 121 of the cover 120 is laser welded.

[0015] The cover 120 is a flat plate-shaped member made of resin. The cover 120 is disposed on the upper surface of the housing 110 (that is, the laser-bonded surface 111A of the outer peripheral wall portion 111) to close the upper opening 112 of the housing 110.

[0016] Cover 120 has the same shape as outer peripheral wall 111 of housing 110 in plan view from above (positive Z-axis direction). That is, in this embodiment, outer peripheral wall 111 has a rectangular shape with its longitudinal direction in the left-right direction (Y-axis direction) in plan view from above (positive Z-axis direction), and correspondingly, cover 120 also has a rectangular shape (an example of a "longitudinal shape") with its longitudinal direction in the left-right direction (Y-axis direction).

[0017] The cover 120 is placed on the laser bonding surface 111A of the outer peripheral wall portion 111 and is laser welded to the outer peripheral wall portion 111. Specifically, the rectangular frame-shaped outer peripheral portion 121 of the cover 120 is placed on the laser bonding surface 111A of the outer peripheral wall portion 111 over the entire circumference. Then, the cover 120 is laser welded to the laser bonding surface 111A of the outer peripheral wall portion 111 by irradiating the entire circumference of the outer peripheral portion 121 with laser light L from the front surface 120A side (Z-axis positive side). In this way, the cover 120 is bonded to the housing 110. However, when the cover 120 does not require airtightness and is simply intended for bonding, the laser light L may not be irradiated to a part of the outer peripheral portion 121.

[0018] In this embodiment, the cover 120 is made of a transparent resin material. As a result, when a display device such as an LCD is provided inside the housing 110 of the resin molded product 100, the contents displayed by the display device can be seen by a user from the front surface 120A side of the cover 120 (the positive side of the Z axis) through the cover 120.

[0019] As shown in FIGS. 1 and 2, the cover 120 has a plurality of protrusions 122 on the outer periphery 121 of the surface 120A.

[0020] Specifically, cover 120 has a plurality of protrusions 122 arranged in the left-right direction (Y-axis direction) protruding upward (positive Z-axis direction) from surface 120A on each of a straight portion on the front side (positive X-axis side) of outer circumferential portion 121 and a straight portion on the rear side (negative X-axis side) of outer circumferential portion 121.

[0021] The heights of the plurality of protrusions 122 are individually set according to the width of the gap between the outer periphery 121 of the cover 120 and the laser bonding surface 111A of the housing 110 due to warping occurring in the housing 110.

[0022] In this embodiment, due to warping occurring in the housing 110, a gap occurs between the outer periphery 121 of the cover 120 and the laser bonding surface 111A of the housing 110 along the longitudinal direction of the outer periphery 121 of the cover 120. For this reason, in this embodiment, the multiple protrusions 122 are arranged along the longitudinal direction of the outer periphery 121 of the cover 120.

[0023] In particular, in this embodiment, due to warping occurring in housing 110, the gap width is largest at central portion 121A in the longitudinal direction (Y-axis direction) of outer circumferential portion 121 of cover 120. For this reason, in this embodiment, the heights of the multiple protrusions 122 are individually set so that the heights gradually increase toward central portion 121A in the longitudinal direction (Y-axis direction) of outer circumferential portion 121 of cover 120, as shown in FIG.

[0024] It is sufficient that the plurality of protrusions 122 are arranged along the gap. Therefore, for example, if the gap is generated in a direction other than the longitudinal direction of the outer circumferential portion 121 of the cover 120, the plurality of protrusions 122 may be arranged along the direction other than the longitudinal direction.

[0025] Furthermore, the heights of the multiple protrusions 122 may be set individually so that the heights gradually increase toward the position where the gap width is the largest. Therefore, for example, in the gap, when the gap width is largest at a portion other than the center in the direction along the gap, the heights of the multiple protrusions 122 may be set individually so that the heights gradually increase toward the portion other than the center.

[0026] Furthermore, in this embodiment, each of the multiple protrusions 122 has a semicircular shape that is convex upward (positive Z-axis direction) when viewed in a plane from the front-to-back direction (X-axis direction), and has a rectangular shape with its longitudinal direction being the front-to-back direction (X-axis direction) when viewed in a plane from above (positive Z-axis direction).

[0027] (Procedure for manufacturing resin molded product 100) Fig. 3 is a flow chart showing an example of the steps of a method for producing a resin molded product 100 according to one embodiment. Hereinafter, the steps of the method for producing the resin molded product 100 shown in Fig. 3 will be described with reference to Figs.

[0028] First, as shown in Fig. 4, the housing 110 is set on the fixing jig 11 (step S301: housing setting process). Fig. 4 is a diagram showing the state of the housing setting process in the manufacturing method of the resin molded product 100 according to one embodiment. Here, as shown in Fig. 4, the laser bonding surface 111A of the housing 110 is warped in a concave shape curved downward (Z-axis negative direction).

[0029] Next, as shown in Fig. 5, the cover 120 is placed on the laser bonding surface 111A of the housing 110 so that the outer periphery 121 of the cover 120 overlaps with the laser bonding surface 111A of the housing 110 (i.e., so that the outer periphery 121 of the cover 120 is positioned on the laser bonding surface 111A of the housing 110) (step S302: cover placing step). Fig. 5 is a diagram showing the cover placing step in the manufacturing method for the resin molded product 100 according to one embodiment. At this time, as shown in Fig. 5, a gap D is generated between the outer periphery 121 of the cover 120 and the laser bonding surface 111A of the housing 110 due to warping of the laser bonding surface 111A.

[0030] Next, as shown in Fig. 6, the cover 120 is pressed from the front surface 120A side by the flat pressing surface 12A of the movable jig 12 (step S303: pressing step). Fig. 6 is a diagram showing the pressing step in the manufacturing method of the resin molded product 100 according to the embodiment. At this time, as shown in Fig. 6, the cover 120 is curved concavely downward along the laser bonding surface 111A by the pressing surface 12A of the movable jig 12 pressing the multiple protrusions 122 and pressing them against the laser bonding surface 111A. As a result, the gap D is eliminated, and the outer periphery 121 of the cover 120 is in close contact with the laser bonding surface 111A over the entire circumference.

[0031] The warping of the laser bonding surface 111A occurs in the same manner for each of the multiple housings 110 formed by injection molding using a metal mold. For this reason, the warping of the laser bonding surface 111A can be measured in advance using a housing 110 formed experimentally as a sample.

[0032] Furthermore, the specifications (number, positions, height, etc.) of the multiple protrusions 122 provided on the cover 120 can be determined in advance by simulation or the like based on the measurement results of the warpage of the laser bonding surface 111A.

[0033] Then, the cover 120 is formed by injection molding using a mold according to the specifications of the plurality of protrusions 122 that have been determined in advance, whereby the plurality of protrusions 122 can be formed integrally with the cover 120.

[0034] In this way, by providing multiple protrusions 122 of suitable specifications on cover 120 in accordance with the warping of laser bonding surface 111A, when cover 120 is pressed from the front surface 120A side by the planar pressing surface 12A of movable jig 12, outer periphery 121 of cover 120 can be tightly adhered to laser bonding surface 111A around the entire circumference.

[0035] 7, laser light L is applied from the front surface 120A side of the cover 120 to the entire circumference of the outer periphery 121 of the cover 120, thereby laser welding the outer periphery 121 of the cover 120 to the entire circumference of the laser joining surface 111A of the housing 110 (step S304: laser welding process). Fig. 7 is a diagram showing the laser welding process in the manufacturing method of the resin molded product 100 according to one embodiment.

[0036] Specifically, in step S304, the laser light L irradiated to the outer periphery 121 of the cover 120 passes through the outer periphery 121 and is irradiated to the laser bonding surface 111A of the housing 110. As a result, the laser bonding surface 111A of the housing 110 absorbs the laser light L over the entire circumference, generating heat and melting. As a result, the outer periphery 121 of the cover 120 is laser welded to the laser bonding surface 111A of the housing 110 over the entire circumference. As a result, the cover 120 is bonded to the housing 110, and the resin molded product 100 is completed.

[0037] At this time, since the outer periphery 121 of the cover 120 is in close contact with the laser bonding surface 111A over its entire circumference, the outer periphery 121 of the cover 120 can be reliably laser welded to the entire circumference of the laser bonding surface 111A.

[0038] Since the surface 120A of the cover 120 is covered by the movable jig 12, the movable jig 12 has a passing portion 12B, at least in the portion overlapping with the outer circumferential portion 121 of the cover 120, which has an opening shape or is transparent to the laser light L, allowing the laser light L irradiated from above the movable jig 12 to pass through or be transmitted therethrough, thereby enabling the laser light L to be irradiated onto the outer circumferential portion 121 of the cover 120.

[0039] As described above, the laser welding method of one embodiment is a laser welding method for joining a resin cover 120 to a resin housing 110 by laser welding, and includes a pressurizing process in which, with the outer periphery 121 of the cover 120 positioned relative to the laser joining surface 111A of the housing 110, the cover 120 is pressed from the surface 120A side by the planar pressing surface 12A of the movable jig 12, and a laser welding process in which the outer periphery 121 of the cover 120 is laser welded to the laser joining surface 111A of the housing 110 by irradiating laser light L to the outer periphery 121 of the cover 120 from the surface 120A side of the cover 120, and in the pressurizing process, pressure is applied to multiple protrusions 122 provided on the surface 120A of the outer periphery 121 of the cover 120 by the pressing surface 12A of the movable jig 12.

[0040] As a result, in the laser welding method of one embodiment, by applying pressure to multiple protrusions 122, the outer periphery 121 of cover 120 can be tightly adhered to the warped laser bonding surface 111A, thereby ensuring that the outer periphery 121 of cover 120 can be laser welded to the laser bonding surface 111A.

[0041] Therefore, according to the laser welding method of the one embodiment, it is possible to suppress the occurrence of defective joints when joining outer periphery 121 of resin cover 120 to resin housing 110 by laser welding.

[0042] Furthermore, according to the laser welding method of one embodiment, a plurality of protrusions 122 are provided on surface 120A of cover 120 so that cover 120 is deformed in accordance with the warping of laser bonding surface 111A. This eliminates the need to redesign the mold for housing 110 to correct the warping of housing 110, and makes it possible to suppress the occurrence of poor bonding areas in laser welding at a relatively low cost.

[0043] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0044] For example, the cover 120 is not limited to being entirely transparent, but may be any cover as long as at least the outer periphery 121 has transparency to the laser light L.

[0045] Also, for example, the multiple protrusions 122 may be arranged along the gap so that the arrangement intervals become gradually narrower toward the portion where the gap width is the largest in the gap. For example, when the gap occurs along the longitudinal direction (Y-axis direction) of the outer circumferential portion 121 of the cover 120 and the gap width is the largest in the central portion 121A in the longitudinal direction (Y-axis direction) of the outer circumferential portion 121 of the cover 120, the multiple protrusions 122 may be arranged along the longitudinal direction (Y-axis direction) of the outer circumferential portion 121 of the cover 120 so that the arrangement intervals become gradually narrower toward the central portion 121A in the longitudinal direction (Y-axis direction) of the outer circumferential portion 121 of the cover 120. [Explanation of symbols]

[0046] 11 Fixture 12 Movable jig 12A Pressing surface 12B Passage section 100 Resin molded products 110 Cabinet 111 Outer wall 111A Laser bonding surface 112 Upper opening 120 Cover 120A surface 121 Outer periphery 121A Central part 122 Protrusion D Gap L Laser light

Claims

1. A laser welding method for joining a resin cover to a resin housing by laser welding, comprising the steps of: a pressing step of pressing the cover from a front surface side by a flat pressing surface of a movable jig in a state where an outer periphery of the cover is positioned with respect to the laser joining surface of the housing; a laser welding process of laser-welding the outer periphery of the cover to the laser joining surface of the housing by irradiating a laser beam to the outer periphery of the cover from a front surface side of the cover; Including, In the pressurizing step, A pressing surface of the movable jig presses a plurality of protrusions provided on a surface of the outer circumferential portion of the cover. A laser welding method comprising:

2. The plurality of protrusions include The height is set individually according to the width of the gap between the outer periphery of the cover and the laser bonding surface of the housing due to warping occurring in the housing.

2. The laser welding method according to claim 1.

3. The plurality of protrusions include The plurality of protrusions are disposed along the gap, and the height of each of the plurality of protrusions is set so that the height gradually increases toward a position where the gap width is largest in a direction along the gap.

3. The laser welding method according to claim 2.

4. The plurality of protrusions include The electrodes are arranged along the gap such that the spacing between the electrodes becomes gradually narrower toward the position where the gap width is largest in the direction along the gap.

3. The laser welding method according to claim 2.

5. The cover is At least the outer periphery is transparent to the laser light.

2. The laser welding method according to claim 1.

6. A resin cover is joined to a resin housing by laser welding in a state where the cover is pressed from a front side by a flat pressing surface of a movable jig, a peripheral portion that is laser welded to the laser joining surface of the housing by irradiating a laser beam from the front surface side of the cover; The outer peripheral surface has a plurality of protrusions. A cover characterized by:

7. The plurality of protrusions include The height is set individually according to the width of the gap between the outer periphery of the cover and the laser bonding surface of the housing due to warping occurring in the housing.

7. The cover according to claim 6.

8. The plurality of protrusions include The plurality of protrusions are disposed along the gap, and the height of each of the plurality of protrusions is set so that the height gradually increases toward a position where the gap width is largest in a direction along the gap.

8. The cover according to claim 7.

9. The plurality of protrusions include The electrodes are arranged along the gap such that the spacing between the electrodes becomes gradually narrower toward the position where the gap width is largest in the direction along the gap.

8. The cover according to claim 7.

10. The cover is At least the outer periphery is transparent to the laser light.

7. The cover according to claim 6.

11. A cover according to any one of claims 6 to 10; the housing to which the cover is joined by laser welding; A resin molded product comprising:

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