Member fitting structure

Abstract

To provide a fitting structure for components that improves the joint strength between components with a simple structure and allows the fitted components to be easily disassembled. [Solution] This disclosure provides a fitting structure 30 for members in which a first member 10 formed in a hollow or solid shape is fitted to a second member 20 formed in a hollow shape, wherein the inner diameter of the end 22 of the second member 20 gradually expands, the end 11 of the first member 10 is fitted inside the end 22 of the second member 20, and the end 22 of the second member 20 is elastically deformed radially outward.

Description

Technical Field

[0001] The present disclosure relates to a fitting structure of members.

Background Art

[0002] Patent Document 1 discloses a pipe joint joining method including a joint fitting formed with an annular bulging portion and a diameter-expanded portion in which a sealing material such as an O-ring is fitted, inserting a pipe into the diameter-expanded portion and bringing the tip portion of the pipe into close contact with the sealing material, and partially pressing the outer periphery of the diameter-expanded portion to form a plurality of recesses.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the joining strength between the joint fitting and the pipe is improved by the recesses, but the processing of the recesses requires labor. Further, when the recesses are formed, it becomes difficult to disassemble the fitted members. The present disclosure solves such problems and provides a fitting structure of members that improves the joining strength between members with a simple structure and enables easy disassembly of the fitted members.

Means for Solving the Problems

[0005] The present disclosure is a fitting structure of members in which a first member formed in a hollow shape or a solid shape and a second member formed in a hollow shape are fitted, the end portion of the second member has a gradually expanding inner diameter, the end portion of the first member is fitted inside the end portion of the second member, and the end portion of the second member is elastically deformed radially outward. With such a structure, the joining strength between members can be improved with a simple structure, and the fitted members can be easily disassembled.

[0006] The inner diameter of the end portion of the first member is formed to be larger than the inner diameter of the central portion of the second member. This structure improves the joint strength between members with a simple structure and allows the fitted members to be easily disassembled.

[0007] This disclosure relates to a fitting structure for members comprising a first member formed in a hollow shape and a second member formed in a hollow shape, wherein the outer diameter of the end of the second member gradually decreases, the end of the second member is fitted inside the end of the first member, and the end of the second member is elastically deformed radially inward. This structure allows for improved joint strength between components with a simple structure, and also enables easy disassembly of the fitted components. [Effects of the Invention]

[0008] This disclosure provides a fitting structure for members that improves the joint strength between members with a simple structure and allows the fitted members to be easily disassembled. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view of the first member and the second member before fitting, showing the fitting structure of the members according to Embodiment 1. [Figure 2] This is a cross-sectional view showing the fitting structure of the members according to Embodiment 1. [Figure 3] This is a partial cross-sectional view showing the fitting structure of the members according to Embodiment 1. [Figure 4] This is a cross-sectional view showing the fitting structure of the members according to Embodiment 2. [Modes for carrying out the invention]

[0010] The embodiments of this disclosure will be described below with reference to Figures 1 to 4. Figure 1 is a cross-sectional view of the first member and the second member before fitting, showing the fitting structure of the members of Embodiment 1. Figure 2 is a cross-sectional view showing the fitting structure of the members of Embodiment 1. Figure 3 is a partial cross-sectional view showing the fitting structure of the members of Embodiment 1. Figure 4 is a cross-sectional view showing the fitting structure of the members of Embodiment 2.

[0011] Embodiment 1 The member fitting structure 30 according to Embodiment 1 is composed of a first member 10 and a second member 20. The first member 10 and the second member 20 before fitting will be described with reference to Figure 1.

[0012] The first member 10 is a tube formed into a cylindrical shape by extrusion of an aluminum alloy material. That is, the first member 10 is formed in a hollow shape. The first member 10 has the same inner and outer diameters in the axial direction. However, the first member 10 may be formed in a solid shape instead of being hollow. Also, the inner and outer diameters of the first member 10 may expand or contract in the axial direction.

[0013] The second member 20 is an electric resistance welded steel pipe formed from a hot-rolled steel sheet into a cylindrical shape using a roll. In other words, the second member 20 is hollow. The second member 20 has a central portion 21 formed in the axial center and an end portion 22 formed at the axial end. The central portion 21 has the same inner and outer diameter in the axial direction. On the other hand, the end portion 22 gradually expands in both inner and outer diameters from the central portion 21 side towards the tip side. The inner and outer diameters of the end portion 22 expand linearly, that is, in an inverse taper shape. The inner and outer diameters of the end portion 22 expand at an angle θ1 with respect to the axial direction of the central portion 21. Note that the end portion 22 does not need to expand linearly; it may expand in a curved shape.

[0014] The inner diameter D11 of the first member 10 is larger than the inner diameter D21 of the central portion 21 of the second member 20. Also, the outer diameter D12 of the first member 10 is smaller than the inner diameter D22 of the tip of the end portion 22 of the second member 20.

[0015] Next, the fitting structure of the members according to Embodiment 1 will be described using Figures 2 and 3. As shown in Figure 2, the end portion 11 of the first member 10 is fitted inside the end portion 22 of the second member 20 to form the fitting structure 30 of the members.

[0016] The end 22 of the second member 20 is elastically deformed radially outward. That is, when the end 11 of the first member 10 is inserted inside the end 22 of the second member 20, the end 11 of the first member 10 is inserted up to the range where the end 22 of the second member 20 elastically deforms radially outward. Due to the elastic deformation of the end 22 of the second member 20 radially outward, the inner diameter and the outer diameter of the end 22 are such that the angle θ2 with respect to the axial direction of the central portion 21 becomes larger than the angle θ1 before fitting. The outer peripheral surface 11a of the end 11 of the first member 10 and the inner peripheral surface 22a of the end 22 of the second member 20 are in contact with each other at the contact surface 31.

[0017] Due to the elastic deformation of the end 22 of the second member 20 radially outward, a restoring force is generated radially inward. Specifically, a restoring force is generated in a direction (direction A shown in FIG. 3) perpendicular to the inner peripheral surface 22a of the end 22 of the second member 20. The restoring force generated in the end 22 of the second member 20 is divided into two forces and acts on the end 11 of the first member 10.

[0018] One is that a clamping force F1 generated in a direction (direction B shown in FIG. 3) perpendicular to the axial direction of the second member 20 acts on the end 11 of the first member 10. The clamping force F1 is expressed by the following formula (1). F1 = kx cos θ2 ··· Formula (1) kx is the magnitude of the restoring force generated in the end 22 of the second member 20.

[0019] The other is that at the contact surface 31, a frictional force F2 acts in a direction (direction C shown in FIG. 3) parallel to the inner peripheral surface 22a of the end 22 of the second member 20. The frictional force F2 is expressed by the following formula (2). F2 = μN ··· Formula (2) μ is the coefficient of friction between the inner peripheral surface 22a of the end 22 of the second member 20 and the outer peripheral surface 11a of the end 11 of the first member 10. N is the normal reaction force generated at the contact surface 31.

[0020] These clamping forces F1 and frictional force F2 allow the first member 10 and the second member 20 to fit together with high joint strength. Furthermore, by pulling out either the first member 10 or the second member 20 with a force greater than or equal to the frictional force F2, the first member 10 and the second member 20 can be easily separated. After separation, the end portion 22 of the second member 20 returns to its original shape and can be reused.

[0021] Embodiment 2 Next, the fitting structure 40 of the member according to Embodiment 2 will be described with reference to Figure 4. The fitting structure 40 is composed of a first member 10 and a second member 50. The first member 10 has the same configuration as that of Embodiment 1, so its description will be omitted.

[0022] The second member 50 is an electric resistance welded steel pipe formed from a hot-rolled steel sheet into a cylindrical shape using a roll. In other words, the second member 50 is hollow. The second member 50 has a central portion 51 formed in the axial center and an end portion 52 formed at the axial end. The central portion 51 has the same inner and outer diameter in the axial direction. On the other hand, the end portion 52 gradually decreases in both inner and outer diameter from the central portion 51 side towards the tip side. The inner and outer diameters of the end portion 52 decrease linearly, i.e., in a tapered manner. Note that the end portion 52 does not need to decrease linearly; it may decrease in a curved manner.

[0023] The inner diameter D11 of the first member 10 is smaller than the inner diameter D51 of the central portion 51 of the second member 50. Also, the inner diameter D11 of the first member 10 is larger than the outer diameter D52 of the end portion 52 of the second member 50. However, the inner diameter D11 of the first member 10 may be larger than the inner diameter D51 of the central portion 51 of the second member 50.

[0024] The end portion 52 of the second member 50 is fitted inside the end portion 11 of the first member 10, forming a fitting structure 40.

[0025] The end portion 52 of the second member 50 is elastically deformed radially inward. That is, when inserting the end portion 52 of the second member 50 into the end portion 11 of the first member 10, the end portion 52 of the second member 50 is inserted to the extent that it elastically deforms radially inward. The inner circumferential surface 11b of the end portion 11 of the first member 10 and the outer circumferential surface 52a of the end portion 52 of the second member 50 are in contact at the contact surface 41.

[0026] The end portion 52 of the second member 50 undergoes elastic deformation radially inward, which generates a restoring force radially outward. Specifically, a restoring force is generated perpendicular to the outer circumferential surface 52a of the end portion 52 of the second member 50. The restoring force generated at the end portion 52 of the second member 50 acts on the end portion 11 of the first member 10 as two separate forces.

[0027] One such force is a pressing force F3 generated perpendicular to the axial direction of the second member 50, which acts on the end portion 11 of the first member 10. The pressing force F3 can be expressed by equation (1), similar to the clamping force F1 in Embodiment 1.

[0028] Another factor is that a frictional force F4 acts on the contact surface 41 in a direction parallel to the outer circumferential surface 52a of the end portion 52 of the second member 50. The frictional force F4 can be expressed by equation (2), similar to the frictional force F2 in Embodiment 1.

[0029] These pressing forces F3 and frictional forces F4 allow the first member 10 and the second member 50 to fit together with high joint strength. Furthermore, by pulling out either the first member 10 or the second member 50 with a force greater than or equal to the frictional force F4, the first member 10 and the second member 50 can be easily separated. After separation, the end portion 52 of the second member 50 returns to its original shape and can be reused.

[0030] In the above embodiment, the first and second members were both cylindrical in shape, but their cross-sections may be rectangular or polygonal. Also, although the first and second members were both pipes, either one may be a joint.

[0031] In the above embodiment, the first member is made of an aluminum alloy and the second member is made of an iron alloy, but the first member may be made of an iron alloy and the second member of an aluminum alloy, or both the first and second members may be made of an iron alloy or an aluminum alloy.

[0032] The materials for the first and second components may be metals other than aluminum or iron, such as titanium, and resins such as polyvinyl chloride, polypropylene, polyethylene, and phenolic resins, as well as polymers such as butadiene rubber, can also be used.

[0033] To improve insertability between the first member and the second member, a triangular or arc-shaped chamfer may be provided at the tip of the end of the first member.

[0034] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from its spirit. [Explanation of Symbols]

[0035] 10. First component 11...end 20, 50... Second component 21, 51...center 22, 52...end 30, 40... Fitting structure of components

Claims

1. A fitting structure for members comprising a first member formed in a hollow or solid shape and a second member formed in a hollow shape, The end of the second member gradually widens in inner diameter. The end of the first member is fitted inside the end of the second member. The end of the second member is elastically deformed radially outward. A fitting structure for components.

2. The inner diameter of the end portion of the first member is formed to be larger than the inner diameter of the central portion of the second member. The fitting structure for the member according to claim 1.

3. A fitting structure for members, comprising a first member formed in a hollow shape and a second member formed in a hollow shape, The outer diameter of the end of the second member gradually decreases. The end of the second member is fitted inside the end of the first member. The end of the second member is elastically deformed radially inward. A fitting structure for components.

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