Screw fixing structure, in-vehicle device, screw fixing method

Abstract

This invention provides a technology that efficiently suppresses the generation of metallic foreign matter when fixing screws to a metal plate. [Solution] The metal chassis 300 has a first surface 310, a second surface 312 facing the opposite side of the first surface 310, and a first through-hole 330 that penetrates between the first surface 310 and the second surface 312. The rear resin cover 500 has a third surface 510 facing the second surface 312, a cylindrical projection 520 that protrudes from the third surface 510 and is inserted into the first through-hole 330, a fourth surface 512 facing the opposite side of the third surface 510, and a second through-hole 530 that penetrates between the tip 522 of the cylindrical projection 520 and the fourth surface 512. The screw 600 has a shaft portion 610 that is inserted into the second through-hole 530, and a head portion 612 that is connected to the shaft portion 610 and is positioned on the fourth surface 512 without being inserted into the second through-hole 530.

Description

Technical Field

[0001] The present disclosure relates to a screw fixing structure, an in-vehicle device, and a screw fixing method.

Background Art

[0002] In electronic devices, screws are generally used for fixing between components. Metal foreign matters such as burrs or chips are generated by inserting or tightening screws into a metal plate. When burrs or chips fall inside the device, failures or malfunctions such as short-circuiting of the circuit may occur. In order to suppress failures or malfunctions caused by metal foreign matters, for example, the screw hole is made bag-shaped so that metal foreign matters do not come out of the screw hole (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When adopting a bag-shaped screw hole, the number of die processes or the number of components of the metal plate increases. Therefore, the manufacturing cost or the assembly process increases due to the increase in the processing process.

[0005] The present disclosure has been made in view of such a situation, and an object thereof is to provide a technique for efficiently suppressing the generation of metal foreign matters when fixing a screw to a metal plate.

Means for Solving the Problems

[0006] To solve the above problems, a screw fixing structure in one aspect of the present disclosure comprises a metal plate having a first surface, a second surface facing the opposite side of the first surface, and a first through hole penetrating between the first and second surfaces; a resin member having a third surface facing the second surface, a cylindrical projection protruding from the third surface and inserted into the first through hole, a fourth surface facing the opposite side of the third surface, and a second through hole penetrating between the tip of the cylindrical projection and the fourth surface; and a screw having a shaft portion inserted into the second through hole and a head portion connected to the shaft portion and positioned on the fourth surface without being inserted into the second through hole.

[0007] Another aspect of the present disclosure is a screw fastening method. This method is a screw fastening method for fastening a metal plate and a resin member with a screw, wherein the metal plate has a first surface, a second surface facing the opposite side of the first surface, and a first through hole passing between the first surface and the second surface. The resin member has a third surface, a cylindrical projection protruding from the third surface, a fourth surface facing the opposite side of the third surface, and a second through hole passing between the tip of the cylindrical projection and the fourth surface. The screw has a shaft and a head connected to the shaft. The method comprises the steps of: placing the second surface of the metal plate and the third surface of the resin member opposite each other and overlapping the metal plate and the resin member while passing the cylindrical projection of the resin member through the first through hole of the metal plate; inserting the shaft of the screw into the second through hole from the side of the fourth surface of the resin member; and positioning the head of the screw on the fourth surface without inserting it into the second through hole. [Effects of the Invention]

[0008] According to this disclosure, the generation of metallic foreign matter can be efficiently suppressed when fixing screws to a metal plate. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the structure of the interior of a vehicle according to the embodiment. [Figure 2] Figures 2(a) and 2(b) show the structure of the in-vehicle unit shown in Figure 1. [Figure 3] Figure 2(b) is a cross-sectional view showing the structure of the in-vehicle unit. [Figure 4]Figures 4(a)-(c) are partial cross-sectional views showing the structure of the in-vehicle unit shown in Figure 2(b). [Figure 5] This diagram shows the screw fastening structure shown in Figure 4(c). [Figure 6] Figures 6(a)-(c) are partial cross-sectional views showing the structure of the in-vehicle device of Modified Example 1. [Figure 7] This diagram shows the screw fixing structure of modified example 2. [Figure 8] Figures 8(a)-(c) are partial cross-sectional views showing the structure of the in-vehicle device of Modification Example 3. [Figure 9] Figures 9(a) and 9(b) show the structure of the rear resin cover shown in Figure 8(a). [Figure 10] Figures 10(a)-(j) show the structure of the metal chassis and rear resin cover of Modification 4. [Modes for carrying out the invention]

[0010] Before specifically describing the embodiments of this disclosure, an overview of the embodiments will be given. These embodiments relate to in-vehicle devices mounted in vehicles. They may also be electronic devices other than in-vehicle devices. In in-vehicle devices, a metal plate (e.g., a metal chassis) and a resin member (e.g., a rear resin cover) are fixed together with screws. In such screw-fixing structures, it is necessary to suppress the generation of metallic foreign matter. In these embodiments, a cylindrical projection is provided on the flat resin cover for insertion into a through-hole in the metal plate (hereinafter referred to as the "first through-hole"). When the cylindrical projection is inserted into the first through-hole and a screw is inserted into the through-hole of the cylindrical projection (hereinafter referred to as the "second through-hole"), the annular projection expands due to screw tightening, and the cylindrical projection is incorporated into the end face of the first through-hole, thereby fixing the metal plate and the resin member together with the screw. Since the screw does not directly contact the metal plate, the generation of metallic foreign matter is suppressed. In the following description, "parallel" and "orthogonal" include not only perfectly parallel and orthogonal, but also cases where they deviate from parallel and orthogonal within an error range.

[0011] Figure 1 shows the structure of the interior of the vehicle 10. A windshield 52 is positioned in front of the dashboard 50, which is located at the front of the interior. The steering wheel 54 is positioned on the right side of the dashboard 50, but the steering wheel 54 may be positioned on the left side of the dashboard 50. A center console 56 extending vertically is positioned in the center of the dashboard 50, and an in-vehicle device 100 is fitted into the center console 56. Alternatively, only the lower part of the in-vehicle device 100 may be fitted into the center console, and the entire design of the in-vehicle device 100 may be exposed to the outside. The in-vehicle device 100 is included in electronic equipment such as a navigation system. The in-vehicle device 100 may be capable of displaying map images, etc. The in-vehicle device 100 may be a meter display positioned in front of the steering wheel.

[0012] Figures 2(a)-(b) show the structure of the in-vehicle unit 100. As shown in Figures 2(a)-(b), a Cartesian coordinate system including the x, y, and z axes is defined. The x and y axes are orthogonal to each other. The z axis is perpendicular to the x and y axes and extends in the vertical direction of the in-vehicle unit 100. The positive direction of the x, y, and z axes is defined by the direction of the arrows in Figures 2(a)-(b), and the negative direction is defined in the direction opposite to the arrows. Here, the positive direction of the x axis may also be called "forward" or "front side", the negative direction of the x axis may be called "rear" or "rear side", the positive direction of the y axis may be called "right" or "right side", the negative direction of the y axis may be called "left" or "left side", the positive direction of the z axis may be called "up" or "upper side", and the negative direction of the z axis may be called "down" or "down side". Therefore, it can be said that the x axis extends in the front-to-back direction, the y axis extends in the left-to-right direction, and the z axis extends in the up-to-down direction.

[0013] Figure 2(a) is a front perspective view showing the external appearance of the in-vehicle unit 100, and Figure 2(b) is a rear perspective view showing the external appearance of the in-vehicle unit 100. A plate-shaped glass lens 110 extending in the yz plane is arranged on the front surface of the in-vehicle unit 100. The glass lens 110 is a light-transmitting member and is made of glass. Resin may be used instead of glass for the glass lens 110, and the glass lens 110 may also be called a transparent member.

[0014] On the rear side of the in-vehicle device 100, a box-shaped rear resin cover 500 with an open front side is arranged. The rear resin cover 500 is a resin member made of resin. A glass lens 110 is attached to the front-side opening of the rear resin cover 500. A plurality of screws 600 are arranged on the rear-side surface of the rear resin cover 500, and the screws 600 fix the metal chassis (not shown) inside the rear resin cover 500 and the rear resin cover 500.

[0015] FIG. 3 is a cross-sectional view showing the structure of the in-vehicle device 100 along the line A-A' in FIG. 2(b). A display panel (not shown) is arranged on the rear side of the glass lens 110. An example of the display panel is a liquid crystal panel. The display panel emits display light toward the glass lens 110. The rear side of the display panel is covered by a metal chassis 300. The metal chassis 300 is an example of a metal plate.

[0016] The rear side of the metal chassis 300 is covered by the rear resin cover 500. Also, a substrate 400 is arranged between the metal chassis 300 and the rear resin cover 500. A plurality of electronic components are arranged on the substrate 400. The metal chassis 300, the substrate 400, and the rear resin cover 500 are fixed by screws 600. When burrs or chipping metal foreign matters are generated from the metal chassis 300 when fixing these with the screws 600, if the metal foreign matters fall onto the substrate 400, there is a risk of short-circuiting the electronic components on the substrate 400.

[0017] Hereinafter, a screw fixing structure for suppressing the generation of metal foreign matters from the metal chassis 300 will be described. FIGS. 4(a)-(c) are partial cross-sectional views showing the structure of the in-vehicle device 100. These show the procedure of fixing the metal chassis 300, the substrate 400, and the rear resin cover 500 with screws 600 in the order of FIGS. 4(a), FIG. 4(b), and FIG. 4(c), and FIG. 4(c) corresponds to the screw fixing structure region R in FIG. 3.

[0018] In FIG. 4(a), the metal chassis 300 includes a first surface 310 facing the front side and a second surface 312 facing the opposite of the first surface 310. Further, a first through hole 330 penetrating between the first surface 310 and the second surface 312 is provided. The hole diameter of the first through hole 330 is made slightly larger than the outer diameter of a cylindrical protrusion 520 described later.

[0019] The rear resin cover 500 includes a third surface 510 facing the front side, a cylindrical protrusion 520 protruding forward from the third surface 510, and a fourth surface 512 facing the opposite of the third surface 510. Here, the third surface 510 faces the second surface 312. Further, a second through hole 530 penetrating between the front end 522 of the cylindrical protrusion 520 and the fourth surface 512 is provided. The hole diameter of the second through hole 530 is made smaller than the outer diameter of a shaft portion 610 of a screw 600 described later.

[0020] A substrate 400 is disposed between the second surface 312 of the metal chassis 300 and the third surface 510 of the rear resin cover 500. A third through hole 430 penetrating in the front-rear direction is provided in the substrate 400. The screw 600 includes a shaft portion 610 and a head portion 612 connected to the shaft portion 610.

[0021] In FIG. 4(b), the metal chassis 300, the substrate 400, and the rear resin cover 500 are arranged in order from the front side. The cylindrical protrusion 520 of the rear resin cover 500 is inserted continuously from the rear side into the third through hole 430 of the substrate 400 and the first through hole 330 of the metal chassis 300. Thereby, the metal chassis 300, the substrate 400, and the rear resin cover 500 are overlapped.

[0022] In Figure 4(c), the shaft portion 610 of the screw 600 is inserted into the second through-hole 530 of the rear resin cover 500 from the rear side while being tightened. As mentioned above, since the diameter of the second through-hole 530 is smaller than the outer diameter of the shaft portion 610 of the screw 600, the cylindrical projection 520 bulges out. As a result, the cylindrical projection 520 bites into the first through-hole 330 of the metal chassis 300 and is fixed in place. Consequently, the shaft portion 610 is inserted into the second through-hole 530, and the head portion 612 is not inserted into the second through-hole 530 but is positioned on the fourth surface 512. In addition, the pressing force of the screwdriver (not shown) when tightening the screw 600 causes the substrate 400 to be sandwiched between the metal chassis 300 and the rear resin cover 500 and held without any gaps. In this way, since the screw 600 does not directly contact the metal chassis 300, no metallic foreign matter (burrs or chips) is generated when inserting or tightening the screw 600. Figure 5 shows the screw fixing structure. This corresponds to the state shown in Figure 4(c) viewed from the front.

[0023] (Variation 1) Figures 6(a)-(c) are partial cross-sectional views showing the structure of the in-vehicle device 100. Figure 6(a) shows a state similar to that of Figure 4(b). The diameter of the second through-hole 530 at the tip 522 of the cylindrical projection 520 is shown as the first hole diameter L1, and the diameter of the second through-hole 530 in the portion of the cylindrical projection 520 closer to the third surface 510 than the tip 522 is shown as the second hole diameter L2. Here, the first hole diameter L1 is smaller than the second hole diameter L2. In other words, the second through-hole 530 has a roughly conical shape that becomes narrower as it approaches the tip 522.

[0024] Figure 6(b) shows a state similar to that of Figure 4(c), and Figure 6(c) is an enlarged view of Figure 6(b). When the shaft portion 610 is tightened, the cylindrical projection 520 expands, generating a thrust that pulls the rear resin cover 500 into the end face of the first through hole 330 of the metal chassis 300, improving the adhesion between the metal chassis 300, the substrate 400, and the rear resin cover 500.

[0025] (Modification 2) Figure 7 shows the screw fixing structure. This shows the state when the metal chassis 300, the substrate 400, and the rear resin cover 500 are fixed with screws 600, as viewed from the front. Here, in order to prevent cracks from occurring in the cylindrical projection 520 when tightened by the shaft portion 610, the cylindrical projection 520 is provided with a slit 524 extending from the tip 522 toward the third surface 510.

[0026] (Variation 3) Figures 8(a)-8(c) are partial cross-sectional views showing the structure of the in-vehicle unit 100. Figure 8(a) shows the same state as in Figure 4(a). The rear resin cover 500 is provided with an opening 540 that penetrates between the third surface 510 and the fourth surface 512. The edge of the opening 540 and the portion of the cylindrical projection 520 on the fourth surface 512 side are connected by a plurality of bridges 542. In other words, the cylindrical projection 520 consists only of the tip portion that engages with the metal chassis 300, and is connected to the metal chassis 300 by a plurality of bridges 542. Figure 8(b) shows the same state as in Figure 4(b).

[0027] Figure 8(c) shows a state similar to that in Figure 4(c). The shaft portion 610 of the screw 600 is inserted into the second through-hole 530 of the rear resin cover 500 from the rear side while being tightened. As described above, since the diameter of the second through-hole 530 is smaller than the outer diameter of the third surface 510, the cylindrical projection 520 bulges out. As a result, the cylindrical projection 520 bites into the first through-hole 330 of the metal chassis 300 and is fixed in place. Subsequently, the head portion 612 comes into contact with the fourth surface 512 of the rear resin cover 500. The thrust of the screw 600 causes the bridge 542 to bend, so that the metal chassis 300, the substrate 400, and the rear resin cover 500 are tightly fixed together.

[0028] Figures 9(a) and 9(b) show the structure of the rear resin cover 500. Figure 9(a) shows the cylindrical projection 520 viewed from the rear, and Figure 9(b) shows the cylindrical projection 520 viewed from the front. Four bridges 542 are shown here, but the number of bridges 542 is not limited to "4".

[0029] (Modification 4) In the modified example 3, the cylindrical projection 520 is connected to the rear resin cover 500 by a thin bridge 542, so it may be subjected to rotational deformation due to the torque when tightening the screw 600. In the modified example, a rotation stopper is provided to prevent this. Figures 10(a)-(j) show the structure of the metal chassis 300 and the rear resin cover 500. Figure 10(a) shows the first through hole 330 as viewed from the front. The first through hole 330 has a rectangular shape. Therefore, the first through hole 330 has four corners, and each corner is a first rotation stopper 350.

[0030] Figure 10(b) shows the state in which the cylindrical projection 520 is inserted into the first through hole 330 of Figure 10(a). The cylindrical projection 520 has a rectangular cross-section to match the shape of the first through hole 330. Therefore, the cylindrical projection 520 has four corners, each of which is a second anti-rotation portion 550. The first anti-rotation portion 350 is a component that suppresses the rotation of the cylindrical projection 520 within the third surface 510, and the second anti-rotation portion 550 is a component that is combined with the first anti-rotation portion 350. By combining the second anti-rotation portion 550 and the first through hole 330, rotational deformation of the cylindrical projection 520 is suppressed.

[0031] Figures 10(c)-(d) show the same conditions as Figures 10(a)-(b), respectively. The first through-hole 330 is hexagonal in shape, with each corner being a first anti-rotation portion 350. The cylindrical projection 520 has a hexagonal cross-section to match the shape of the first through-hole 330. Therefore, the cylindrical projection 520 has six corners, each being a second anti-rotation portion 550.

[0032] Figures 10(e)-(f) show the same conditions as Figures 10(a)-(b), respectively. The first through-hole 330 is circular in shape with a D-cut, and the straight portion is the first anti-rotation portion 350. The cylindrical projection 520 has a circular cross-section with a D-cut to match the shape of the first through-hole 330. Therefore, the straight portion of the cylindrical projection 520 is the second anti-rotation portion 550.

[0033] Figures 10(g)-(h) show the same conditions as Figures 10(a)-(b). The first through-hole 330 is circular in shape with a protrusion, which is the first anti-rotation portion 350. The cylindrical projection 520 has a circular cross-section with a protrusion that matches the shape of the first through-hole 330. Therefore, the protrusion of the cylindrical projection 520 is the second anti-rotation portion 550.

[0034] Figures 10(i)-(j) show the same conditions as Figures 10(a)-(b), respectively. The first through-hole 330 is circular in shape with a recess, which is the first anti-rotation portion 350. The cylindrical projection 520 has a circular cross-section with a recess that matches the shape of the first through-hole 330. Therefore, the recess of the cylindrical projection 520 is the second anti-rotation portion 550.

[0035] Due to dimensional differences between the components, a misalignment occurs between the first anti-rotation part 350 and the second anti-rotation part 55. When the metal chassis 300 is assembled into the rear resin cover 500 while this misalignment exists, the bridge 542 deforms, absorbing the misalignment.

[0036] In this embodiment, the cylindrical projection 520 of the rear resin cover 500 is inserted into the first through hole 330 of the metal chassis 300, and the screw 600 is inserted into the second through hole 530 of the cylindrical projection 520. Since the screw 600 does not directly contact the metal chassis 300, the generation of metallic foreign matter during insertion or tightening of the screw 600 can be efficiently suppressed. Furthermore, since the substrate 400 is placed between the metal chassis 300 and the rear resin cover 500, the substrate 400 can also be fixed by inserting the screw 600 into the second through hole 530.

[0037] Furthermore, by making the first hole diameter L1 of the second through hole 530 at the tip 522 of the cylindrical projection 520 smaller than the L2 of the second through hole 530 in the portion closer to the third surface 510 than the tip 522, the cylindrical projection 520 can be made to bulge further by inserting the screw 600. Also, because the cylindrical projection 520 bulges further by inserting the screw 600, the adhesion between the metal chassis 300, the substrate 400, and the rear resin cover 500 can be improved.

[0038] Furthermore, since the cylindrical projection 520 has a slit 524, the occurrence of cracks can be suppressed. Also, since the cylindrical projection 520 is connected to the rear resin cover 500 by a bridge 542, the bridge 542 can be bent by the thrust of the screw 600. In addition, since the bridge 542 is bent by the thrust of the screw 600, the metal chassis 300, the substrate 400 and the rear resin cover 500 can be fixed in close contact. Furthermore, since the first through hole 330 is provided with a first anti-rotation part 350 and the second through hole 530 is provided with a second anti-rotation part 550, the rotational deformation of the bridge 542 due to the torque when tightening the screw 600 can be suppressed.

[0039] An overview of one aspect of this disclosure is as follows: (Item 1) A metal plate having a first surface, a second surface facing the opposite side of the first surface, and a first through-hole penetrating between the first surface and the second surface, A resin member having a third surface facing the second surface, a cylindrical projection protruding from the third surface and inserted into the first through hole, a fourth surface facing the opposite side of the third surface, and a second through hole passing between the tip of the cylindrical projection and the fourth surface, A screw having a shaft portion inserted into the second through hole, and a head portion connected to the shaft portion and positioned on the fourth surface without being inserted into the second through hole, A screw-fixing structure equipped with this feature.

[0040] (Item 2) The system further comprises a substrate disposed between the second surface of the metal plate and the third surface of the resin member, The substrate has a third through hole, The cylindrical projection is inserted continuously into the third through hole and the first through hole, as described in item 1.

[0041] (Item 3) The screw fixing structure described in item 1, wherein the diameter of the second through hole at the tip of the cylindrical projection is defined as the first hole diameter, and the diameter of the second through hole in the portion of the cylindrical projection on the third surface side from the tip is defined as the second hole diameter, wherein the first hole diameter is smaller than the second hole diameter.

[0042] (Item 4) The screw fixing structure according to item 1, wherein the cylindrical projection further has a slit extending from its tip in the direction of the third surface.

[0043] (Item 5) The aforementioned resin member is An opening that penetrates between the third surface and the fourth surface, The screw fixing structure according to item 1, further comprising a plurality of bridges connecting the edge of the opening and the cylindrical projection.

[0044] (Item 6) The first through-hole further has a first anti-rotation portion for suppressing the rotation of the cylindrical projection within the third surface, The screw fixing structure according to item 5, wherein the cylindrical projection has a second anti-rotation portion that is combined with the first anti-rotation portion.

[0045] (Item 7) The screw fastening structure is provided as described in any one of items 1 to 6, The aforementioned metal plate is a metal chassis, The aforementioned resin component is a rear resin cover for an in-vehicle device.

[0046] (Item 8) A screw fastening method for fixing a metal plate and a resin component with screws, The metal plate has a first surface, a second surface facing the opposite side of the first surface, and a first through hole that penetrates between the first surface and the second surface. The resin member has a third surface, a cylindrical projection protruding from the third surface, a fourth surface facing the opposite direction from the third surface, and a second through-hole that penetrates between the tip of the cylindrical projection and the fourth surface. The screw has a shaft and a head connected to the shaft. The steps include: placing the second surface of the metal plate and the third surface of the resin member opposite each other, and overlapping the metal plate and the resin member while passing the cylindrical projection of the resin member through the first through-hole of the metal plate; The steps include inserting the shaft portion of the screw into the second through hole from the fourth surface side of the resin member, The steps include: positioning the head of the screw on the fourth surface without inserting it into the second through hole; A screw fastening method that includes the following features.

[0047] The present disclosure has been described above based on examples. These examples are illustrative, and it will be understood by those skilled in the art that various modifications are possible for each component or combination of processing steps, and that such modifications are also within the scope of the present disclosure. [Explanation of Symbols]

[0048] 10 Vehicle, 50 Dashboard, 52 Windshield, 54 Steering wheel, 56 Center console, 100 In-vehicle unit, 110 Glass lens, 300 Metal chassis, 310 First surface, 312 Second surface, 330 First through hole, 350 First anti-rotation part, 400 Substrate, 430 Third through hole, 500 Rear resin cover, 510 Third surface, 512 Fourth surface, 520 Cylindrical projection, 522 Tip, 524 Slit, 530 Second through hole, 540 Opening, 542 Bridge, 550 Second anti-rotation part, 600 Screw, 610 Shaft part, 612 Head.

Claims

1. A metal plate having a first surface, a second surface facing the opposite side of the first surface, and a first through-hole penetrating between the first surface and the second surface, A resin member having a third surface facing the second surface, a cylindrical projection protruding from the third surface and inserted into the first through hole, a fourth surface facing the opposite direction from the third surface, and a second through hole passing between the tip of the cylindrical projection and the fourth surface, A screw having a shaft portion inserted into the second through hole, and a head portion connected to the shaft portion and positioned on the fourth surface without being inserted into the second through hole, A screw-fixing structure equipped with this feature.

2. The system further comprises a substrate disposed between the second surface of the metal plate and the third surface of the resin member, The substrate has a third through hole, The screw fixing structure according to claim 1, wherein the cylindrical projection is inserted continuously into the third through hole and the first through hole.

3. The screw fixing structure according to claim 1, wherein the diameter of the second through hole at the tip of the cylindrical projection is defined as the first hole diameter, and the diameter of the second through hole in the portion of the cylindrical projection on the third surface side from the tip is defined as the second hole diameter, and the first hole diameter is smaller than the second hole diameter.

4. The screw fixing structure according to claim 1, wherein the cylindrical projection further has a slit extending from its tip in the direction of the third surface.

5. The aforementioned resin member is An opening that penetrates between the third surface and the fourth surface, The screw fixing structure according to claim 1, further comprising a plurality of bridges connecting the edge of the opening and the cylindrical projection.

6. The first through-hole further has a first anti-rotation portion for suppressing the rotation of the cylindrical projection within the third surface, The screw fixing structure according to claim 5, wherein the cylindrical projection has a second anti-rotation portion that is combined with the first anti-rotation portion.

7. The screw fixing structure is provided according to any one of claims 1 to 6, The aforementioned metal plate is a metal chassis, The aforementioned resin component is a rear resin cover for an in-vehicle device.

8. A screw fastening method for fixing a metal plate and a resin component with screws, The metal plate has a first surface, a second surface facing the opposite side of the first surface, and a first through-hole that penetrates between the first surface and the second surface. The resin member has a third surface, a cylindrical projection protruding from the third surface, a fourth surface facing the opposite direction from the third surface, and a second through-hole that penetrates between the tip of the cylindrical projection and the fourth surface. The screw has a shaft and a head connected to the shaft. The steps include: placing the second surface of the metal plate and the third surface of the resin member opposite each other, and overlapping the metal plate and the resin member while passing the cylindrical projection of the resin member through the first through-hole of the metal plate; The steps include inserting the shaft portion of the screw into the second through hole from the fourth surface side of the resin member, The steps include: positioning the head of the screw on the fourth surface without inserting it into the second through hole; A screw fastening method that includes the following features.

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