Component mounting structure

Abstract

To suppress concentration of stress generated in a fastening part due to heat deformation without installing additional members, in a structure to which a plurality of members having different linear expansion coefficients is fastened with a fastener.SOLUTION: A member fitting structure includes a first member 1 and a second member 2 having a linear expansion coefficient that is smaller than that of the first member 1, where the first member and the second member are fastened to each other by a fastener. The first member 1 is formed with a concave fitting part 6 to which the fastener is fitted. The second member 2 is formed with a movable part 7 by a cut-out 5. The movable part 7 is fastened to the fitting part 6 by the fastener and is displaceable together with the fitting part 6.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a member mounting structure.

Background Art

[0002] When the ambient temperature of a structure in which a plurality of members having different coefficients of linear expansion are fastened by a fastener changes, stress concentration occurs at the fastening portion due to thermal deformation. For example, Patent Document 1 describes a technique for designing a structure such that the stress at the fastening portion is equal to or less than the allowable value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technique described in Patent Document 1 is characterized in that a regulating means for regulating the displacement in the inner direction due to the thermal deformation of the resin panel is provided. In the technique described in Patent Document 1, it is necessary to provide a regulating means. For this reason, there are problems that the number of parts increases, the cost increases, and the assembly man-hours increase. In addition, since a space for providing the regulating means is required, there is also a problem that the degree of freedom in design is reduced.

[0005] The present disclosure is for solving the above problems. An object of the present disclosure is to suppress stress concentration generated at the fastening portion due to thermal deformation without providing additional parts in a structure in which a plurality of members having different coefficients of linear expansion are fastened by a fastener.

Means for Solving the Problems

[0006] The member mounting structure according to the present disclosure is a member mounting structure that fastens a first member and a second member having a coefficient of linear expansion smaller than that of the first member with a fastener. A concave mounting portion to which a fastener is attached is formed in the first member, and a movable portion is formed in the second member by a cut. The movable portion is fastened to the mounting portion by a fastener and is displaceable together with the mounting portion. Moreover, a round hole portion is formed at the base of the movable part. Alternatively, a concave mounting portion for attaching a fastener is formed on the first member, and a movable part is formed on the second member by a cut. The movable part is fastened to the mounting portion by a fastener and is displaceable together with the mounting portion. The movable part includes a tip portion that constitutes the tip end portion of the movable part and a base portion that constitutes the base portion of the movable part. The tip portion is fixed in contact with the first member by a fastener, and the width of the base portion is smaller than the width of the tip portion. Alternatively, a concave mounting portion to which a fastener is attached is formed in the first member, and a peninsula-shaped movable portion is formed in the second member. The movable portion is fastened to the mounting portion by a fastener and is displaceable together with the mounting portion. Moreover, the movable part includes a tip portion that constitutes the tip end portion of the movable part and a base portion that constitutes the base portion of the movable part. The tip portion is fixed in contact with the first member by a fastener, and the width of the base portion is smaller than the width of the tip portion. Alternatively, the first member is flat, a fastener is attached to the flat surface of the first member, and a peninsula-shaped movable portion is formed in the second member. The movable portion is fastened to the first member by a fastener and is displaceable together with the first member. Moreover, the movable part includes a tip portion that constitutes the tip end portion of the movable part and a base portion that constitutes the base portion of the movable part. The tip portion is fixed in contact with the first member by a fastener, and the width of the base portion is smaller than the width of the tip portion.

Advantages of the Invention

[0007] According to the present disclosure, in a structure in which a plurality of members having different coefficients of linear expansion are fastened by a fastener, stress concentration generated in the fastening portion due to thermal deformation can be suppressed without providing additional parts.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the member mounting structure according to the present disclosure will be described with reference to the accompanying drawings. The same reference numerals in each figure indicate the same or corresponding parts. In the present disclosure, duplicate explanations will be appropriately simplified or omitted as necessary. Note that the present disclosure is not limited to the embodiments described below, and may include any combinations and modifications of the configurations disclosed by the following embodiments.

[0010] Embodiment 1. FIG. 1 is a perspective view showing an example of the first member 1 and the second member 2 constituting the member mounting structure according to Embodiment 1. Let the coefficient of linear expansion of the first member 1 be the first coefficient of linear expansion. Let the coefficient of linear expansion of the second member 2 be the second coefficient of linear expansion. The second coefficient of linear expansion is smaller than the first coefficient of linear expansion. The first coefficient of linear expansion is, for example, 30 to 400 (10 -6 / °C). The second coefficient of linear expansion is, for example, 1 to 30 (10 -6 / °C).

[0011] FIG. 2 is an exploded perspective view showing the relationship between the first member 1 and the second member 2 constituting the member mounting structure according to Embodiment 1. The first member 1 and the second member 2 are fastened by fasteners such as bolts 3 and nuts 4. A concave mounting portion 6 for attaching fasteners such as bolts 3 is formed on the first member 1.

[0012] Figure 3 is a sectional view taken along the line SA - SA in Figure 2. Figure 3(a) shows the normal state. Figures 3(b) and 3(c) show the states during thermal deformation.

[0013] As an example, the attachment portion 6 of the first member 1 is formed in a U - shape in the SA - SA cross - section. Among the first member 1, parts other than the attachment surface which is the bottom surface of the U - shaped attachment portion 6 are separated from the second member 2.

[0014] As described above, the first linear expansion coefficient is larger than the second linear expansion coefficient. Therefore, when the ambient temperature of the first member 1 and the second member 2 changes, the amount of thermal deformation of the first member 1 becomes larger than that of the second member 2. In the attachment portion 6 of the first member 1, since the deformation due to thermal stress is restricted, stress concentration occurs.

[0015] In the present embodiment, a notch 5 is formed in the second member 2. A movable portion 7 is formed in the second member 2 by this notch 5. The movable portion 7 can be displaced together with the attachment portion 6 of the first member 1. By this movable portion 7, stress concentration generated at the fastening portion between the first member 1 and the second member 2 can be suppressed.

[0016] Here, examples of stress concentration caused by the specific materials, dimensions, and temperature changes of the first member 1 and the second member 2 will be described. The first member 1 is, for example, a plate - shaped material made of a polycarbonate - based polymer alloy resin (PCABS). The linear expansion coefficient of PCABS is 55(10 -6 / °C). The second member 2 is, for example, a cold - rolled steel sheet (SECC). The linear expansion coefficient of SECC is 12(10 -6 / °C).

[0017] The respective outer dimensions of the first member 1 and the second member 2 are, for example, 800 mm×400 mm. The plate thickness of the first member 1 is, for example, 3 mm. The plate thickness of the second member 2 is, for example, 1.6 mm. As an example, the four corners and the front - rear - left - right centers of the rectangular plate - shaped first member 1 and the four corners and the front - rear - left - right centers of the rectangular plate - shaped second member 2 are fastened by fasteners.

[0018] The width W of the movable part 7 is, for example, 12 mm. The length L of the movable part 7 is, for example, 40 mm.

[0019] In the above material and dimension examples, when the ambient temperature of the first member 1 and the second member 2 changes from 25°C to 40°C, the maximum stress generated in the mounting portion 6 of the first member 1 is about 13 MPa. In the simulation result when the cut 5 and the movable part 7 are not formed in the second member 2, the maximum stress generated in the mounting portion 6 of the first member 1 is about 16 MPa. Also, in the above material and dimension examples, when the ambient temperature of the first member 1 and the second member 2 changes from 20°C to -5°C, the maximum stress generated in the mounting portion 6 of the first member 1 is about 10 MPa. In the simulation result when the cut 5 and the movable part 7 are not formed in the second member 2, the maximum stress generated in the mounting portion 6 of the first member 1 is about 25 MPa. Thus, by forming the cut 5 and the movable part 7 in the second member 2, the stress concentration occurring in the mounting portion 6 of the first member 1 can be suppressed.

[0020] As described above, according to the present embodiment, by forming the cut 5 and the movable part 7 in the second member 2, it is possible to suppress the stress concentration occurring in the fastening portion due to thermal deformation without providing additional parts. Thereby, damage and reduction of the life of the member can be avoided. Also, since no additional parts are required, the part cost and the assembly man-hours can be reduced. Also, since no space for installing additional parts is required, an increase in the product volume can be avoided. Further, the member mounting structure according to the present embodiment can be realized only by an additional process of making a cut 5 in the second member 2. Also, without the need to modify the first member 1, a change in appearance can be avoided.

[0021] FIG. 4 is an exploded perspective view showing a modified example of the member mounting structure according to Embodiment 1. In the modified example of FIG. 4, a cut 51 is formed in the second member 2 instead of the cut 5. The movable portion 7 formed by the cut 51 includes a tip portion constituting the tip end portion of the movable portion 7 and a base portion constituting the base portion of the movable portion 7. This tip portion is in contact with the mounting portion 6 of the first member 1 and is fixed to the mounting portion 6 by a fastener. In this modified example, the width W1 of the base portion is smaller than the width W of the tip portion. In this modified example, even if the length L1 of the movable portion 7 is made shorter than the length L in the above-described embodiment, the effect of suppressing stress concentration can be sufficiently obtained.

[0022] Also, as shown in FIGS. 2 and 4, a round hole portion 10 may be formed at the base of the movable portion 7. Thereby, stress concentration at the base of the movable portion 7 can be suppressed.

[0023] Embodiment 2. Next, Embodiment 2 will be described. FIG. 5 is an exploded perspective view showing the relationship between the first member 1 and the second member 2 constituting the member mounting structure according to Embodiment 2. FIG. 6 is a cross-sectional view taken along the line SB-SB in FIG. 5. FIG. 6(a) shows the normal state. FIGS. 6(b) and 6(c) show the states during thermal deformation. For parts that are the same as or corresponding to those in Embodiment 1, the description will be simplified and omitted. In FIG. 5, illustrations of fasteners such as bolts 3 and nuts 4 are omitted.

[0024] In the present embodiment, instead of the movable portion 7 formed by the cut 5 in Embodiment 1, a peninsula-shaped movable portion 8 is formed. The peninsula-shaped movable portion 8 is fastened to the mounting portion 6 by a fastener. The peninsula-shaped movable portion 8 is displaceable together with the mounting portion 6. According to the present embodiment, by forming the movable portion 8, similarly to Embodiment 1, stress concentration generated in the fastening portion due to thermal deformation can be suppressed without providing additional parts.

[0025] Also, as shown in FIG. 5, an R portion 11 may be formed at the base of the movable portion 8. Thereby, stress concentration at the base of the movable portion 8 can be suppressed.

[0026] Also, FIG. 7 is an exploded perspective view showing a modified example of the member mounting structure according to the second embodiment. In this modified example, a peninsula-shaped movable portion 81 is formed on the second member 2 instead of the peninsula-shaped movable portion 8. The peninsula-shaped movable portion 81 includes a tip portion that constitutes the tip of the movable portion 81 and a base portion that constitutes the base of the movable portion 81. This tip portion is in contact with the mounting portion 6 of the first member 1 and is fixed to the mounting portion 6 by a fastening member. In this modified example, the width W1 of the base portion is smaller than the width W of the tip portion. In this modified example, even if the length L1 of the movable portion 81 is made shorter than the length L of the movable portion 8 in the above-described embodiment, the effect of suppressing stress concentration can be sufficiently obtained.

[0027] Embodiment 3. Next, Embodiment 3 will be described. FIG. 8 is an exploded perspective view showing the relationship between the first member 1 and the second member 2 constituting the member mounting structure according to Embodiment 3. FIG. 9 is a cross-sectional view taken along the line SC-SC in FIG. 8. FIG. 9(a) shows the normal state. FIGS. 9(b) and 9(c) show the state during thermal deformation. For parts that are the same as or corresponding to those in the above-described embodiments, the description will be simplified and omitted. In FIG. 8, illustration of fastening members such as the bolt 3 and the nut 4 is omitted.

[0028] In the present embodiment, the first member 1 is flat plate-shaped. In the present embodiment, the concave mounting portion 6 is not formed on the first member 1. Fastening members such as the bolt 3 are attached to the flat surface of the flat plate-shaped first member 1. For example, the bolt 3 is inserted into a screw fastening portion 9 which is a through hole formed in the flat surface of the flat plate-shaped first member 1. The second member 2 is formed with a peninsula-shaped movable portion 8 in the same manner as in the second embodiment. The movable portion 8 is fastened to the flat plate-shaped first member 1 by a fastening member. By this movable portion 8, stress concentration generated in the screw fastening portion 9 can be suppressed.

[0029] In this embodiment, as shown in FIG. 9 and the like, the first member 1 and the second member 2 are in close contact with each other. The configuration of this embodiment is preferably applied to products that require sealing performance such as waterproofness or dustproofness.

[0030] FIG. 10 is an exploded perspective view showing a modified example of the member mounting structure according to Embodiment 3. In this modified example, a peninsula-shaped movable portion 81 is formed on the second member 2 instead of the peninsula-shaped movable portion 8. The peninsula-shaped movable portion 81 includes a tip portion that constitutes the tip end portion of the movable portion 81 and a base portion that constitutes the base portion of the movable portion 81. This tip portion is in contact with the mounting portion 6 of the first member 1 and is fixed to the mounting portion 6 by a fastener. In this modified example, the width W1 of the base portion is smaller than the width W of the tip portion. In this modified example, even if the length L1 of the movable portion 81 is made shorter than the length L of the movable portion 8 in the above-described embodiment, the effect of suppressing stress concentration can be sufficiently obtained.

Explanation of Reference Numerals

[0031] 1 First member, 2 Second member, 3 Bolt, 4 Nut, 5 Notch, 6 Mounting portion, 7 Movable portion, 8 Movable portion, 9 Threaded fastening portion, 10 Round hole portion, 11 R portion, 51 Notch, 81 Movable portion

Claims

1. A member mounting structure for fastening a first member and a second member having a coefficient of linear expansion smaller than that of the first member with a fastener, a concave mounting portion to which the fastener is attached is formed on the first member, a movable portion is formed on the second member by a cut, the movable portion is fastened to the mounting portion by the fastener and is displaceable together with the mounting portion, and a round hole portion is formed at the base of the movable portion. The member mounting structure is characterized by this.

2. A member mounting structure for fastening a first member and a second member having a coefficient of linear expansion smaller than that of the first member with a fastener, a concave mounting portion to which the fastener is attached is formed on the first member, a movable portion is formed on the second member by a cut, the movable portion is fastened to the mounting portion by the fastener and is displaceable together with the mounting portion, the movable portion includes a tip portion constituting the tip portion of the movable portion and a root portion constituting the root portion of the movable portion, the tip portion is fixed in contact with the first member by the fastener, and the width of the root portion is smaller than the width of the tip portion. The member mounting structure is characterized by this.

3. A member mounting structure for fastening a first member and a second member having a coefficient of linear expansion smaller than that of the first member with a fastener, a concave mounting portion to which the fastener is attached is formed on the first member, a peninsula-shaped movable portion is formed on the second member, the movable portion is fastened to the mounting portion by the fastener and is displaceable together with the mounting portion, the movable portion includes a tip portion constituting the tip portion of the movable portion and a root portion constituting the root portion of the movable portion, the tip portion is fixed in contact with the first member by the fastener, A member mounting structure, characterized in that the width of the base portion is smaller than the width of the tip portion.

4. A member mounting structure for fastening a first member and a second member having a smaller coefficient of linear expansion than the first member with a fastener, The first member is flat, and the fastener is attached to the flat surface of the first member. A semi - peninsula - shaped movable portion is formed on the second member. The movable portion is fastened to the first member by the fastener and is displaceable together with the first member. The movable portion includes a tip portion constituting the tip of the movable portion and a base portion constituting the base of the movable portion. The tip portion is fixed in contact with the first member by the fastener. A member mounting structure, characterized in that the width of the base portion is smaller than the width of the tip portion.

5. The member mounting structure according to claim 3 or claim 4, characterized in that an R portion is formed at the base of the movable portion.

6. The movable portion includes a tip portion constituting the tip of the movable portion and a base portion constituting the base of the movable portion. The tip portion is fixed in contact with the first member by the fastener. The member mounting structure according to claim 1, characterized in that the width of the base portion is smaller than the width of the tip portion.

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