Fastening structure

Abstract

Provided is a fastening structure for fastening a part to be fastened to a fixing part, said fastening structure comprising: a bolt that is inserted through the fixing part and the part to be fastened; a nut that is joined to the bolt with the fixing part and the part to be fastened therebetween; a thermal deformation member that thermally deforms by heating, that is provided between the fixing part and the part to be fastened, and that is provided on the outer side of the bolt in the radial direction; and a receiving member that is provided between the fixing part and the part to be fastened and that extends in the axial direction of the bolt with respect to the thermal deformation member upon receipt of force caused by thermal deformation of the thermal deformation member.

Description

Fastening structure

[0001] The present disclosure relates to a fastening structure.

[0002] Conventionally, a fastener assembly for joining members respectively made of different materials has been known (see, for example, Patent Document 1). In the fastener assembly, a non-metallic member is attached to a metallic member. The fastener assembly includes a fastener, a spacer, a countersunk washer, and a nut, wherein the spacer absorbs a difference in thermal expansion coefficients between the different types of members.

[0003] Japanese Unexamined Patent Application Publication No. 2005-330960

[0004] In a fastener assembly such as that disclosed in Patent Document 1, when a fastener such as a bolt is heated, thermal elongation of the bolt in the axial direction causes a reduction in the fastening force applied to the members. In Patent Document 1, although the spacer absorbs the difference in thermal expansion coefficient between different types of members, thermal elongation of the bolt in the axial direction is not taken into consideration.

[0005] Accordingly, an object of the present disclosure is to provide a fastening structure that can suitably maintain the fastening between a fixed portion and a fastened member even when the bolt thermally elongates.

[0006] The fastening structure of the present disclosure, which is a fastening structure for fastening a fastened member to a fixed portion, includes: a bolt inserted through the fixed portion and the fastened member; a nut coupled to the bolt with the fixed portion and the fastened member interposed therebetween; a thermally deformable member provided between the fixed portion and the fastened member, provided radially outward of the bolt, and thermally deformable when heated; and a receiving member provided between the fixed portion and the fastened member, that receives a force generated by thermal deformation of the thermally deformable member, and extends in the axial direction of the bolt relative to the thermally deformable member.

[0007] According to the present disclosure, fastening between the fixed portion and the fastened member can be suitably maintained even when the bolt thermally elongates.

[0008] Figure 1 is a schematic diagram of a fastening structure according to the first embodiment. Figure 2 is a diagram of the pressing surface and pressure receiving surface according to the first embodiment. Figure 3 is a schematic diagram of a fastening structure according to the second embodiment. Figure 4 is a schematic diagram of a fastening structure according to the third embodiment. Figure 5 is a schematic diagram of a fastening structure according to the fourth embodiment. Figure 6 is a schematic diagram of a fastening structure according to the fifth embodiment.

[0009] Embodiments relating to this disclosure will be described in detail below with reference to the drawings. However, these embodiments do not limit this disclosure. Furthermore, some components in the embodiments described below are substituted or substantially identical to those easily substituted by those skilled in the art. Moreover, the components described below can be combined as appropriate, and if there are multiple embodiments, each embodiment can be combined.

[0010] [First Embodiment] The fastening structure 1 according to the first embodiment fastens a fastened part 5 to a fixed part 3. The fixed part 3 is, for example, a mounting part provided on the main body of the device and is made of a metal material. The fastened part 5 is, for example, an outer plate and is made of heat-resistant ceramic or ceramic matrix composite material. In other words, the fixed part 3 and the fastened part 5 are made of different materials and have different coefficients of thermal expansion. Note that if the fixed part 3 and the fastened part 5 are made of different materials, the fixed part 3 may be an outer plate.

[0011] (Fastening Structure) Figure 1 is a schematic diagram of a fastening structure according to the first embodiment. The fastening structure 1 comprises a bolt 11, a nut 12, a ring member 13, and a heat insulating material 14. A hole 3a is formed in the fixing part 3 through which the bolt 11 is inserted, and similarly, a hole 5a is formed in the fastened part 5 through which the bolt 11 is inserted.

[0012] The bolt 11 is inserted through the hole 3a of the fixing part 3 and the hole 5a of the fastened part 5, and is mechanically fastened to the fixing part 3 by the nut 12. The bolt 11 has a head 11a and a threaded portion 11b connected to the head 11a. The tip of the threaded portion 11b of the bolt 11 is inserted through the fastened part 5 and the fixing part 3 in that order, and the head 11a is positioned in relation to the fastened part 5.

[0013] The nut 12 is provided on the outside of the fixing portion 3, that is, on the opposite side of the fastened portion 5, with the fixing portion 3 in between. The nut 12 is mechanically coupled to the tip side of the threaded portion 11b of the bolt 11.

[0014] The ring member 13 is provided between the fixing portion 3 and the fastened portion 5. The ring member 13 is made of a metal material and is a thermally deformable member that expands when heated. The ring member 13 is formed in an annular shape and expands in diameter due to thermal expansion. The ring member 13 is inserted through the bolt 11 and is positioned radially outside the threaded portion 11b of the bolt 11. The radially outer side of the ring member 13 protrudes outward. The radially outer surface of the ring member 13 is a pressing surface 13a that presses against the heat insulating material 14, which will be described later. The pressing surface 13a is a tapered surface that has its apex at the center in the axial direction of the ring member 13 and slopes radially inward toward both sides in the axial direction. In other words, the pressing surface 13a has a V-shaped wedge shape.

[0015] The thermal insulation material 14 is provided between the fixing part 3 and the fastened part 5. The thermal insulation material 14 is made of, for example, ceramic or ceramic matrix composite material and provides insulation between the fixing part 3 and the fastened part 5. Since the thermal insulation material 14 has a smaller coefficient of thermal expansion than the ring member 13, thermal deformation due to heating is unlikely to occur. The thermal insulation material 14 acts as a receiving member that receives pressure due to the thermal expansion of the ring member 13. The thermal insulation material 14 is provided on both sides of the ring member 13 in the axial direction and has a fixing-side thermal insulation material 21 provided on the fixing part 3 side and a fastened-side thermal insulation material 22 provided on the fastened part 5 side.

[0016] The fixed-side insulation material 21 is formed in an annular shape. The fixed-side insulation material 21 is inserted through the bolt 11 and is positioned radially outward of the ring member 13, and also positioned on the fixed portion 3 side relative to the ring member 13. The radially inward surface of the fixed-side insulation material 21 is a pressure-receiving surface 21a that receives pressure from the ring member 13. The pressure-receiving surface 21a of the fixed-side insulation material 21 is in surface contact with the pressure-receiving surface 13a of the ring member 13 on the fixed portion 3 side. In other words, the pressure-receiving surface 21a of the fixed-side insulation material 21 has a complementary shape to the pressure-receiving surface 13a of the ring member 13 on the fixed portion 3 side, and is a tapered surface that inclins radially inward toward the fixed portion 3 side in the axial direction.

[0017] The fastened-side insulation material 22 is formed in an annular shape. The fastened-side insulation material 22 is inserted through the bolt 11 and is positioned radially outward of the ring member 13, and also positioned on the fastened-side 5 side relative to the ring member 13. The radially inward surface of the fastened-side insulation material 22 is a pressure-receiving surface 22a that receives pressure from the ring member 13. The pressure-receiving surface 22a of the fastened-side insulation material 22 is in surface contact with the pressure-receiving surface 13a of the ring member 13 on the fastened-side 5 side. In other words, the pressure-receiving surface 22a of the fastened-side insulation material 22 has a complementary shape to the pressure-receiving surface 13a of the ring member 13 on the fastened-side 5 side, and is a tapered surface that inclins radially inward toward the fastened-side 5 side in the axial direction.

[0018] Here, the axial length of the ring member 13 is shorter than the axial length of the thermal insulation material 14, that is, shorter than the sum of the axial length of the fixed-side thermal insulation material 21 and the axial length of the fastened-side thermal insulation material 22.

[0019] In the fastening structure 1 described above, when the outside of the fastened portion 5 becomes a high-temperature environment, the fastening structure 1, including the bolt 11 and the ring member 13, is heated. When the bolt 11 is heated, it expands due to thermal expansion in the axial direction. Also, when the ring member 13 is heated, it expands in the radial direction. When the ring member 13 expands in diameter, the pressing surface 13a of the ring member 13 presses against the pressure-receiving surface 21a of the fixed-side insulation material 21 and the pressure-receiving surface 22a of the fastened-side insulation material 22. When the fixed-side insulation material 21 and the fastened-side insulation material 22 are pressed by the ring member 13, the fixed-side insulation material 21 and the fastened-side insulation material 22 move away from the ring member 13 in the axial direction. In other words, as the fixed-side insulation material 21 and the fastened-side insulation material 22 move away from each other in the axial direction, they stretch in accordance with the thermal expansion of the bolt 11. Therefore, even when the fastening structure 1 is exposed to a high-temperature environment, the space between the fixed part 3 and the fastened part 5 is filled without any gaps by the ring member 13, the fixed-side insulation material 21, and the fastened-side insulation material 22.

[0020] Next, the inclination angle between the pressing surface 13a and the pressure-receiving surface 22a will be explained with reference to Figure 2. Figure 2 is a diagram of the pressing surface and the pressure-receiving surface according to the first embodiment. The radial direction perpendicular to the axial direction is defined as 0 degrees, and the angle between the radial direction and the pressing surface 13a and the pressure-receiving surface 22a is defined as the inclination angle θ. Note that the pressing surface 13a and the pressure-receiving surface 22a have the same inclination angle θ. Also, in Figure 2, for the sake of simplicity, the portion of the ring member 13 on the fastened portion 5 side and the fastened side insulation material 22 are partially shown. Note that the portion of the ring member 13 on the fixed portion 3 side and the fixed side insulation material 21 have a configuration that is inverted vertically from Figure 2.

[0021] In Figure 2, the amount of radial deformation due to thermal expansion of the ring member 13 is constant at all inclination angles θ. When the inclination angle θ is large (for example, θ = 80 deg), the amount of axial movement of the fastened-side insulation material 22 is large relative to the amount of radial deformation due to thermal expansion of the ring member 13. When the inclination angle θ is medium (for example, θ = 60 deg), the amount of axial movement of the fastened-side insulation material 22 is medium relative to the amount of radial deformation due to thermal expansion of the ring member 13. When the inclination angle θ is small (for example, θ = 45 deg), the amount of axial movement of the fastened-side insulation material 22 is small relative to the amount of radial deformation due to thermal expansion of the ring member 13. From the above, by setting the inclination angle θ to an appropriate angle, it is possible to set the amount of movement of the fixed-side insulation material 21 and the fastened-side insulation material 22 required in response to the thermal expansion of the bolt 11 to an appropriate amount.

[0022] [Second Embodiment] Next, a second embodiment will be described with reference to Figure 3. Figure 3 is a schematic diagram of the fastening structure according to the second embodiment. In the second embodiment, in order to avoid redundant descriptions, the parts that differ from the first embodiment will be described, and parts that have the same configuration as the first embodiment will be denoted by the same reference numerals.

[0023] (Fastening Structure) In the fastening structure 30 of the second embodiment, the axial length of the ring member 33 is longer than the axial length of the heat insulating material 14, that is, longer than the sum of the axial length of the fixed-side heat insulating material 21 and the axial length of the fastened-side heat insulating material 22. Therefore, the ring member 33, which is made of a metal material, can receive the load when the bolt 11 and nut 12 are fastened.

[0024] [Third Embodiment] Next, the third embodiment will be described with reference to Figure 4. Figure 4 is a schematic diagram of the fastening structure according to the third embodiment. In the third embodiment as well, in order to avoid redundant descriptions, the parts that differ from the first and second embodiments will be described, and parts that have the same configuration as the first and second embodiments will be denoted by the same reference numerals.

[0025] (Fastening Structure) In the fastening structure 40 of the third embodiment, the pressing surface 13a and the pressure receiving surfaces 21a and 22a have different shapes from those of the first embodiment. In the fastening structure 1 of the first embodiment, the pressing surface 13a and the pressure receiving surfaces 21a and 22a were tapered surfaces, but in the fastening structure 40 of the third embodiment, the pressing surface 43a and the pressure receiving surfaces 41a and 42a are curved surfaces.

[0026] In the fastening structure 40 of the third embodiment, the ring member 43 is formed in an annular shape with a circular cross-section. Furthermore, the pressing surface 43a of the ring member 43 is a curved surface with a smaller radius of curvature than the pressure-receiving surfaces 41a and 42a that protrude outward (become convex). The pressure-receiving surfaces 41a and 42a of the fixed-side insulation material 41 and the fastened-side insulation material 42 are curved surfaces with a larger radius of curvature than the pressing surface 43a that retracts radially outward (becomes concave). Therefore, when the ring member 43 is heated and expands radially, the pressing surface 43a of the ring member 43 presses against the pressure-receiving surface 41a of the fixed-side insulation material 41 and the pressure-receiving surface 42a of the fastened-side insulation material 42.

[0027] [Fourth Embodiment] Next, the fourth embodiment will be described with reference to Figure 5. Figure 5 is a schematic diagram of the fastening structure according to the fourth embodiment. In the fourth embodiment as well, in order to avoid redundant descriptions, the parts that differ from the first to third embodiments will be described, and parts that have the same configuration as the first to third embodiments will be denoted by the same reference numerals.

[0028] (Fastening Structure) In the fastening structure 50 of the fourth embodiment, the heat insulating material 14 is a single component. In the fourth embodiment, for example, only the fixed-side heat insulating material 21 is provided. The ring member 53 has a pressing surface 53a that presses against the fixed-side heat insulating material 21, and the pressing surface 53a is a tapered surface that is inclined radially inward toward the fixed portion 3 in the axial direction.

[0029] In the fastening structure 50 described above, when the outside of the fastened portion 5 becomes a high-temperature environment, the fastening structure 1, including the bolt 11 and the ring member 53, is heated. When the bolt 11 is heated, it expands axially due to the heat. Also, when the ring member 53 is heated, it expands radially. When the ring member 53 expands, the pressing surface 53a of the ring member 53 presses against the pressure-receiving surface 21a of the fixed-side insulation material 21. When the fixed-side insulation material 21 is pressed by the ring member 53, the fixed-side insulation material 21 moves in a direction away from the ring member 53 in the axial direction. In other words, as the fixed-side insulation material 21 and the ring member 53 move away from each other in the axial direction, the fixed-side insulation material 21 and the ring member 53 expand in accordance with the thermal expansion of the bolt 11. For this reason, even when the fastening structure 1 is exposed to a high-temperature environment, the space between the fixed portion 3 and the fastened portion 5 is filled without any gaps by the ring member 53 and the fixed-side insulation material 21.

[0030] [Fifth Embodiment] Next, the fifth embodiment will be described with reference to Figure 6. Figure 6 is a schematic diagram of the fastening structure according to the fifth embodiment. In the fifth embodiment as well, in order to avoid redundant descriptions, the parts that differ from the first to fourth embodiments will be described, and parts that have the same configuration as the first to fourth embodiments will be denoted by the same reference numerals.

[0031] (Fastening Structure) In the fastening structure 60 of the fifth embodiment, the heat insulating material 14 is a single component. In the fifth embodiment, for example, only the heat insulating material 22 to be fastened is provided. The ring member 63 has a pressing surface 63a that presses against the heat insulating material 22 to be fastened, and the pressing surface 63a is a tapered surface that is inclined radially inward toward the fastened portion 5 in the axial direction.

[0032] In the fastening structure 60 described above, when the outside of the fastened portion 5 becomes a high-temperature environment, the fastening structure 60, including the bolt 11 and the ring member 63, is heated. When the bolt 11 is heated, it expands axially due to the heat. Also, when the ring member 63 is heated, it expands radially. When the ring member 63 expands, the pressing surface 63a of the ring member 63 presses against the pressure-receiving surface 22a of the fastened-side insulation material 22. When the fastened-side insulation material 22 is pressed by the ring member 63, the fastened-side insulation material 22 moves axially away from the ring member 63. In other words, as the fastened-side insulation material 22 and the ring member 63 move axially away from each other, they expand in accordance with the thermal expansion of the bolt 11. For this reason, even when the fastening structure 60 is exposed to a high-temperature environment, the space between the fixed portion 3 and the fastened portion 5 is filled without gap by the ring member 63 and the fastened-side insulation material 22.

[0033] In the first to fifth embodiments, the heat insulating material 14 functioned as a receiving member that received pressure from the ring member 13. However, the receiving member is not particularly limited to the heat insulating material 14, and may be a spacer, washer, or other member.

[0034] Furthermore, in the first to fifth embodiments, the ring members 13, 33, 43, 53, and 63 were arranged radially on the inside (bolt 11 side) of the heat insulating material 14. However, if it is possible to press and stretch the heat insulating material 14, the ring members 13, 33, 43, 53, and 63 may be arranged radially on the outside of the heat insulating material 14.

[0035] As described above, the fastening structures 1, 30, 40, 50, and 60 described in the first to fifth embodiments can be understood, for example, as follows.

[0036] The fastening structures 1, 30, 40, 50, and 60 according to the first embodiment are fastening structures 1, 30, 40, 50, and 60 that fasten a fastened portion 5 to a fixed portion 3, and include a bolt 11 inserted through the fixed portion 3 and the fastened portion 5, a nut 12 that connects to the bolt 11 with the fixed portion 3 and the fastened portion 5 in between, a heat-deformable member (ring member 13, 33, 43, 53, and 63) provided between the fixed portion 3 and the fastened portion 5 and located radially outward of the bolt 11, which deforms when heated, and a receiving member (insulating material 14) provided between the fixed portion 3 and the fastened portion 5, which receives the force due to the heat deformation of the heat-deformable member and extends in the axial direction of the bolt 11 relative to the heat-deformable member.

[0037] With this configuration, even if the bolt 11 expands axially due to heat, the receiving member extends relative to the thermally deformable member, thereby filling the gap between the fixing part 3 and the fastened part 5. Therefore, even if the bolt 11 expands due to heat, the fastening between the fixing part 3 and the fastened part 5 can be maintained effectively.

[0038] In a second embodiment, in the fastening structures 1, 30, 40, 50, and 60 according to the first embodiment, the receiving member has a fixed-side receiving member (fixed-side heat insulating material 21) provided on the fixed-part 3 side and a fastened-side receiving member (fastened-side heat insulating material 22) provided on the fastened-part 5 side relative to the fixed-side receiving member, and the thermal deformation member moves the fixed-side receiving member and the fastened-side receiving member apart in the axial direction during thermal deformation.

[0039] With this configuration, the fixed-side receiving member and the fastened-side receiving member extend relative to the thermally deformable member, thereby more effectively filling the gap between the fixed part 3 and the fastened part 5. Furthermore, if the fixed-side receiving member and the fastened-side receiving member are made of insulating material, the space between the fastened part and the thermally deformable member can be insulated, and the space between the thermally deformable member and the fixed part can be insulated, resulting in high thermal insulation performance.

[0040] As a third aspect, in the fastening structures 1, 30, 40, 50, 60 according to the first or second aspect, the receiving member is provided radially outward of the thermally deformable member, and a radially inward surface facing the thermally deformable member serves as pressure receiving surfaces 21a, 22a, 41a, 42a that receive a force caused by thermal deformation of the thermally deformable member. In the thermally deformable member, a radially outer surface facing the receiving member serves as pressing surfaces 13a, 43a that press the receiving member. The thermally deformable member thermally expands radially outward to press the receiving member, thereby elongating the receiving member relative to the thermally deformable member in the axial direction of the bolt 11.

[0041] According to this configuration, the thermally deformable member thermally expands radially outward, and the pressing surfaces 13a, 43a of the thermally deformable member press the pressure receiving surfaces 21a, 22a, 41a, 42a of the receiving member, whereby the receiving member can be elongated relative to the thermally deformable member in the axial direction of the bolt 11.

[0042] As a fourth aspect, in the fastening structures 1, 30, 50, 60 according to the third aspect, in the thermally deformable member, the pressing surface 13a is a tapered surface inclined relative to the axial direction, and in the receiving member, the pressure receiving surfaces 21a, 22a are tapered surfaces that are in surface contact with the pressing surface 13a.

[0043] According to this configuration, the pressing force of the thermally deformable member in the radial direction can be appropriately converted into elongation of the receiving member in the axial direction.

[0044] As a fifth aspect, in the fastening structure 40 according to the third aspect, in the thermally deformable member, the pressing surface 43a is a convex curved surface, and in the receiving member, the pressure receiving surfaces 41a, 42a are concave curved surfaces having a larger radius of curvature than the pressing surface 43a.

[0045] According to this configuration, when the thermally deformable member applies pressure in the radial direction, the receiving member can be smoothly elongated in the axial direction.

[0046] As a sixth aspect, in the fastening structures 1, 30, 40, 50, 60 according to any one of the first to fifth aspects, the receiving member is a heat insulating material.

[0047] With this configuration, the receiving member can provide insulation between the fixing part 3 and the fastened part 5.

[0048] 1, 30, 40, 50, 60 Fastening structure 3 Fixing part 5 Fastened part 11 Bolt 12 Nut 13, 33, 43, 53, 63 Ring member 13a, 43a Pressing surface 14 Insulation material 21 Fixing side insulation material 22 Fastened side insulation material 21a, 22a, 41a, 42a Pressure receiving surface

Claims

1. A fastening structure for fastening a part to be fastened to a fixed part, comprising: a bolt inserted through the fixed part and the part to be fastened; a nut that connects to the bolt, sandwiching the fixed part and the part to be fastened; a heat-deformable member provided between the fixed part and the part to be fastened and located radially outward from the bolt, which deforms when heated; and a receiving member provided between the fixed part and the part to be fastened, which receives the force caused by the heat deformation of the heat-deformable member and extends in the axial direction of the bolt relative to the heat-deformable member.

2. The fastening structure according to claim 1, wherein the receiving member comprises a fixed-side receiving member provided on the fixed-part side and a fastened-side receiving member provided on the fastened-part side relative to the fixed-side receiving member, and the thermal deformation member moves such that the fixed-side receiving member and the fastened-side receiving member separate in the axial direction during thermal deformation.

3. The fastening structure according to claim 1, wherein the receiving member is provided on the radially outer side of the thermal deformation member, and the radially inner surface facing the thermal deformation member is a pressure receiving surface that receives force due to the thermal deformation of the thermal deformation member, the radially outer surface of the thermal deformation member facing the receiving member is a pressing surface that presses against the receiving member, and the thermal deformation member expands radially outward due to thermal expansion and presses against the receiving member, thereby elongating the receiving member relative to the thermal deformation member in the axial direction of the bolt.

4. The fastening structure according to claim 3, wherein the heat-deformable member has a tapered surface on which the pressing surface is inclined with respect to the axial direction, and the receiving member has a tapered surface on which the pressure-receiving surface is in surface contact with the pressing surface.

5. The fastening structure according to claim 3, wherein the heat-deformable member has a curved surface with a convex pressing surface, and the receiving member has a curved surface with a concave pressure-receiving surface having a larger radius of curvature than the pressing surface.

6. The fastening structure according to claim 1, wherein the receiving member is an insulating material.

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