Fastening structure
The fastening structure addresses fretting wear by ensuring surface contact through differential rigidity, enhancing friction and preventing relative movement between fastened members.
Patent Information
- Application Number
- JP2024011926
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-01-30
- Publication Date
- 2025-08-12
AI Technical Summary
Fretting wear occurs in fastening structures due to manufacturing and assembly errors, leading to relative movement and contact between non-surface-contacting portions of fastened members, which is not effectively addressed by conventional methods that increase cost or are infeasible.
A fastening structure design where the rigidity of the first member surrounding the through hole is lower than the second member, allowing deformation and surface contact upon tightening, thereby preventing fretting.
Components come into surface contact, increasing frictional force and preventing relative movement, thus suppressing fretting wear.
Smart Images
Figure 2025117197000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a fastening structure for fastening a plurality of members together using fastening members such as bolts. [Background technology]
[0002] Fig. 7 is a perspective view showing an outline of the structure in which compressor 103 is attached to engine 101, Fig. 8 is a side view, and Fig. 9 is a front view. A hanger 102 for hanging is attached to engine 101. A bracket 104 is attached to compressor 103, and bracket 104 is fastened to the side of hanger 102 with bolts 105. Details of other fastening parts for attaching compressor 103 to engine 101 are omitted. Summary of the Invention [Problem to be solved by the invention]
[0003] As the vehicle is driven, i.e., the engine is used repeatedly, wear called fretting may occur on the contact surface between the bracket 104 and the hanger 102. Fretting is wear caused by members rubbing against each other.
[0004] To prevent fretting, the following measures are generally considered: (1) increasing the number of fastening members to increase the surface pressure between the members, (2) increasing the tightening torque of the fastening members to increase the surface pressure between the members, (3) forming a protective layer to prevent wear on the fastening surfaces of the members, and (4) applying a lubricant to prevent wear on the fastening surfaces of the members. However, all of these measures increase the cost of fastening, and may not be feasible depending on the shape and material of the members.
[0005] The inventors of the present disclosure have identified the main cause of fretting occurring in a fastening structure in which multiple members are fastened together with fastening members as follows.
[0006] 10 is a diagram showing a cross section of the fastening structure. Through holes 62, 72 are formed in the first member 61 and the second member 71, respectively, and the first member 61, 71 are fastened together by a bolt 81 and a nut 82 inserted through the through holes 62, 72.
[0007] Even if the opposing surfaces of the two members 61, 71 are designed to be in surface contact, due to manufacturing errors or assembly errors of the members 61, 71, even when the bolts are tightly tightened as in the example of Figure 10, the abutting surfaces of the two members 61, 71 may not be in surface contact, and only some abutting portions 63, 73 of the two members 61, 71 may abut, leaving a gap G in the other parts.
[0008] When both members 61, 71 are placed in a vibrating environment in this fastened state, the abutting portions 63, 73 are unlikely to move relative to each other, whereas the portions 64, 74 across the gap G are likely to move relative to each other. When both portions 64, 74 move relative to each other, they come into contact and rub against each other, causing fretting.
[0009] An object of the present disclosure is to provide a fastening structure in which multiple components are fastened together with fastening members, in which fretting does not occur. [Means for solving the problem]
[0010] The fastening structure of the present disclosure is a fastening structure having a first member having a through hole, a second member, and a fastening member that is inserted into the through hole and fastens the first member and the second member, wherein the rigidity of the portion of the first member surrounding the through hole is lower than the rigidity of the portion of the second member that is fastened by the fastening member. [Effects of the Invention]
[0011] According to the present disclosure, components fastened by fastening members are deformed by the fastening force of the fastening members, and the fastened components come into surface contact with each other, thereby suppressing the occurrence of fretting. [Brief explanation of the drawings]
[0012] [Figure 1] 4A and 4B are diagrams showing a fastened state of a first member and a second member. [Figure 2] FIG. 3 is a cross-sectional view of a first member. [Figure 3] FIG. 10 is a diagram showing a first modified example. [Figure 4] FIG. 10 is a diagram showing a second modified example. [Figure 5] FIG. [Figure 6] 10A and 10B are diagrams showing a fastened state of the bracket and the hanger. [Figure 7] FIG. 2 is a diagram showing a state in which a compressor is attached to an engine. [Figure 8] FIG. 8 is a side view of FIG. [Figure 9] FIG. 8 is a front view of FIG. [Figure 10] FIG. 1 illustrates a conventional technique. DETAILED DESCRIPTION OF THE INVENTION
[0013] Hereinafter, fastening structures according to embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below all show comprehensive or specific examples. Furthermore, each drawing is a schematic diagram and is not necessarily an exact illustration. Furthermore, in each drawing, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.
[0014] Fig. 1 is a diagram schematically illustrating a structure in which a first member 1 and a second member 11 of this embodiment are fastened with a bolt 21 and a nut 22, which are a type of fastening member. The top of Fig. 1 shows the state before the bolt is tightened (lightly tightened state), and the bottom of Fig. 1 shows the state after the bolt is tightened (tightly tightened state). Fig. 2 is a diagram illustrating the first member 1.
[0015] The first member 1 and the second member 11 have through holes 2 and 12, respectively, and bolts 21 are inserted into the through holes 2 and 12. The opposing surfaces of the first member 1 and the second member 11 are not parallel to each other, and the abutting portion 6 of the first member 1 and the abutting portion 16 of the second member 11 abut on each other around the through holes 2 and 12, with a gap G remaining in other areas.
[0016] The through hole 2 of the first member 1 has a large diameter portion 3 on the side closer to the second member 11 (the right side of the figure) and a small diameter portion 4 on the side farther from the second member 11 (the left side of the figure). As a result, the area around the through hole 2 of the first member 1 that faces the second member 11 is a thin-walled portion 7, and is less rigid than the second member 11.
[0017] As shown in the bottom of Figure 1, when the bolt 21 and nut 22 are tightly tightened, the thin-walled portion 7 of the first member 1 is deformed by the fastening force, and the first member 1 and the second member 11 come into surface contact around the through holes 2, 12. The surface contact between the two members 1, 11 increases the frictional force between the two members 1, 11, and prevents the two members 1, 11 from moving relative to each other even when they are placed in a vibrating environment, thereby suppressing the occurrence of fretting.
[0018] 3 shows a first modified example of the first member 1. In this modified example, instead of forming a large diameter portion and a small diameter portion in the through hole 2, the first member 1 has a thin-walled portion 7 around the through hole 2 (top of FIG. 3). As a result, when the bolt 21 and nut 22 are tightly tightened, the thin-walled portion 7 of the first member 1 is deformed by the fastening force, and the first member 1 and the second member 11 come into surface contact around the through holes 2, 12 (bottom of FIG. 3).
[0019] Figure 4 shows a second modified example of the first member 1. In this modified example, the thickness of the portion of the first member 1 around the through hole 2 is the same as in the example of the prior art (Figure 10), but a material with low rigidity, such as an aluminum alloy, is used as the material for the first member 1 (top of Figure 4). As a result, when the bolt 21 and nut 22 are tightly tightened, the second member 11 does not deform, but the first member 1 deforms due to the fastening force, and the first member 1 and second member 11 come into surface contact around the through holes 2, 12 (bottom of Figure 4).
[0020] 5 is a cross-sectional view of a fastening portion of a bracket 31 attached to a compressor, which is used when attaching the compressor to an engine. A through-hole 32 is formed in the bracket 31, and a large-diameter portion 33 and a small-diameter portion 34 are formed in the through-hole 32. A thin-walled portion 37 is formed around the large-diameter portion 33.
[0021] The inner diameters of the large diameter portion 33 and the small diameter portion 34 and the outer diameter of the thin-walled portion 37 are designed based on the material of the bracket 31, etc. For example, if the material of the bracket 31 is FC250 cast iron, it is preferable that the inner diameter of the large diameter portion 33 is 15 mm, the inner diameter of the small diameter portion 34 is 11.8 mm, the outer diameter of the thin-walled portion 37 is 22 mm, and the thickness of the thin-walled portion 37 is 3.5 mm.
[0022] 6 is a cross-sectional view of a structure in which a bracket 31 (first member) and a hanger 41 (second member) for suspending an engine (not shown) are fastened together with a bolt 51. The hanger 41 has an internal thread 42 into which the bolt 51 screws. When the bracket 31 and hanger 41 are fastened together with the bolt 51, the thin-walled portion 37 around the through hole 32 is deformed by the fastening force, and the bracket 31 and hanger 41 come into surface contact. This makes it possible to suppress the occurrence of fretting on the contact surface between the bracket 31 and hanger 41.
[0023] As described above, according to the present disclosure, components fastened by fastening members are deformed by the fastening force of the fastening members, and the fastened components come into surface contact with each other, thereby suppressing the occurrence of fretting. [Industrial Applicability]
[0024] This is suitable for use when multiple members are fastened together using a fastening member. [Explanation of symbols]
[0025] 1 First member 2 through holes 3 Large diameter section 4 Small diameter section 6 Contact part 7 Thin-walled section 11 Second member 12 Through holes 16 Contact part 21 volts 22 Nut
Claims
1. a first member having a through hole; A second member; a fastening member that is inserted into the through hole and fastens the first member and the second member; A fastening structure having The rigidity of a portion of the first member around the through hole is lower than the rigidity of a portion of the second member fastened by the fastening member. Fastening structure.
2. the second member has a through hole; The fastening member is inserted through the through-holes of the first member and the second member. The fastening structure according to claim 1 .
3. a first member having a through hole; A second member; a fastening member that is inserted into the through hole and fastens the first member and the second member; A fastening structure having At least one of the first member and the second member is deformed by the fastening force of the fastening member, so that the first member and the second member are in surface contact with each other. Fastening structure.
4. the first member is a bracket for attaching the compressor to the engine, the second member is a hanger for suspending the engine; The fastening structure according to any one of claims 1 to 3.
5. A portion of the first member around the through hole is formed as a thin-walled portion. The fastening structure according to any one of claims 1 to 3.
6. The through hole is formed as a large diameter portion on a side closer to the second member and a small diameter portion on a side farther from the second member, so that a portion of the first member around the through hole is formed as a thin-walled portion. The fastening structure according to any one of claims 1 to 3.
7. a material of a portion of the first member around the through hole has lower rigidity than a portion of the second member fastened by the fastening member; The fastening structure according to any one of claims 1 to 3.