Multi-layer cylindrical body

Abstract

To provide a multi-layer cylindrical body capable of realizing both of an ease of assembling of a component part and an excellent appearance.SOLUTION: A multi-layer cylindrical body 1 comprises: a first cylindrical body 10; and a second cylindrical body 20 arranged in a cylinder of the first cylindrical body 10. The first cylindrical body 10 includes: a first cylinder end part 11 constructing a cylinder end surface 11b; and a first main body part 12 where an inner peripheral surface 12a is offset in an outer direction from an inner peripheral surface 11a of the first cylinder end part 11. The second cylindrical body 20 includes: a second cylinder end part 21 constructing a cylinder end surface 21b; a second main body part 22 that is positioned at a position where an outer peripheral surface 22a is offset in an outer direction from an outer peripheral surface 21a of the second cylinder end part 21; and a cantilever beam engagement part 27 that can be elastically deformed so as to be provided to the second main body part 22. Both of the first and second cylinder end parts 11 and 21 are arranged so as to overlap an inner side and an outer side of the multi-layer cylindrical body. The engagement part 27 is pressed and contacted to the inner peripheral surface 12a of the first main body part 12.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a multi-layered cylindrical body including a first cylindrical body (outer cylinder) and a second cylindrical body (inner cylinder) disposed inside the first cylindrical body. [Background technology]

[0002] Conventionally, charging connectors that are installed in vehicles such as electric vehicles and plug-in hybrid vehicles have been proposed to supply power (charge) to batteries mounted on the vehicles from outside the vehicle (see, for example, Patent Document 1). This type of connector has terminals and a housing that accommodates the terminals, and is generally called a charging inlet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-003340 A Summary of the Invention [Problem to be solved by the invention]

[0004] The housing constituting the above-mentioned type of connector (charging inlet) may have a multi-layer structure in which multiple resin cylindrical bodies are arranged to overlap in the radial direction. For example, when an inner tube and an outer tube are assembled so that they overlap in the radial direction, the wider the gap between them, the easier the assembly is, but the more the aesthetic appearance of the housing as a finished product is impaired. On the other hand, the narrower the gap between them, the more the aesthetic appearance of the housing can be improved, but the more difficult the assembly is. In particular, in the case of a housing having a cylindrical shape long in the axial direction such as a charging inlet housing, if the above-mentioned gap is narrowed, depending on the size of the shape variation (in other words, the design dimensional tolerance) that inevitably occurs during the manufacturing process, the inner tube and the outer tube are strongly pressed against each other, which increases the force required for assembly (so-called insertion force), and the deformation of both tubes and the whitening of the resin due to the deformation may occur. In this way, with a multi-layered cylindrical body, it is generally difficult to achieve both ease of assembly of components and excellent aesthetics.

[0005] An object of the present invention is to provide a multi-layered tubular body that is easy to assemble and has excellent aesthetic appearance. [Means for solving the problem]

[0006] In order to achieve the above object, the multi-layered tubular body according to the present invention has the following features.

[0007] A multi-layered cylindrical body including a first cylindrical body and a second cylindrical body disposed inside the first cylindrical body, The first cylindrical body is a first cylindrical end portion constituting a cylindrical end surface of the first cylindrical body, and a first main body portion whose inner circumferential surface is offset outwardly from the first cylindrical body relative to the inner circumferential surface of the first cylindrical end portion, The second cylindrical body is a second cylindrical end portion constituting a cylindrical end surface of the second cylindrical body, a second main body portion whose outer circumferential surface is offset outwardly from the second cylindrical body relative to the outer circumferential surface of the second cylindrical end portion, and a cantilever-shaped engagement portion provided on the second main body portion and capable of elastic deformation; The first tube end portion and the second tube end portion are arranged so as to overlap each other on the inside and outside of the multi-layered tube, The engagement portion is in pressing contact with an inner circumferential surface of the first main body portion. It is a multi-layered cylindrical body. Effect of the Invention

[0008] According to the multi-layered tubular body of the present invention, the first tube end and the first main body of the first tube are configured so that their respective inner circumferential surfaces are offset from each other. As a result, in molding the first tube, the first tube end can be molded strictly with a small dimensional tolerance, and the first main body can be molded with a large dimensional tolerance. In other words, the shape accuracy of the mold for molding the first tube can be made different on either side of the boundary between the first tube end and the first main body. The same is true for the second tube. As a result, at the location where the first tube end and the second tube end overlap, even if the gap between them is designed to be small, the dimensional tolerance is small, so that the aesthetic appearance can be improved while suppressing deformation and whitening of the first tube end and the second tube end. On the other hand, at the location where the first main body and the second main body overlap, the gap between them can be designed to be large, absorbing the large dimensional tolerance and facilitating assembly. Furthermore, the engaging portion provided on the second main body portion of the second cylindrical body presses against the first main body portion, thereby suppressing misalignment between the two (so-called rattle). In addition, since the engaging portion has a cantilever shape, the engaging portion does not press the first main body portion too strongly compared to a case where a simple protruding engaging portion is provided, and deformation and whitening of the first main body portion and the second main body portion can be suppressed. Therefore, the multi-layered cylindrical body of this configuration can achieve both ease of assembly of components and excellent aesthetics.

[0009] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a perspective view showing a multi-layered cylindrical body according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view of the multi-layered cylindrical body shown in FIG. [Diagram 3] FIG. 3 is an exploded perspective view of the multi-layered cylindrical body shown in FIG. [Figure 4] FIG. 4 is a perspective view of the multi-layered cylindrical body shown in FIG. 1 as viewed from the rear side. [Diagram 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 6 is an enlarged view of part B in FIG. [Figure 7] FIG. 7 is an enlarged view of part C in FIG. [Figure 8] FIG. 8 is an exploded perspective view of a multi-layered cylindrical body according to a modified example. [Figure 9] FIG. 9 is a front view of the inner cylinder shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Embodiment> Hereinafter, a multilayer cylindrical body 1 according to an embodiment of the present invention will be described with reference to the drawings. The multilayer cylindrical body 1 is a part of a housing used in a charging connector (also called a charging inlet) installed in a vehicle such as an electric vehicle or a plug-in hybrid vehicle in order to supply (charge) power from outside the vehicle to a battery mounted on the vehicle. As shown in Figs. 1 to 5, the multilayer cylindrical body 1 is composed of an outer tube 10, an inner tube 20 disposed inside the outer tube 10, and a male screw 30 that fastens the outer tube 10 and the inner tube 20 together.

[0012] For ease of explanation, the following definitions are used for "front," "rear," "left," "right," "upper," and "lower" as shown in FIG. 1 etc. The "front-rear direction," "left-right direction," and "up-down direction" are mutually perpendicular. The front-rear direction coincides with the axial direction of the multi-layered cylindrical body 1. Below, each of the components that make up the multi-layered cylindrical body 1 will be explained in order. Furthermore, for each of the outer tube 10 and the inner tube 20, the circumferential direction of the cylindrical body will be simply referred to as the "circumferential direction," and the thickness direction of the cylindrical body will be referred to as the "radial direction."

[0013] First, the outer tube 10 will be described. The outer tube 10 is a resin molded body. The outer tube 10 is a cylindrical body extending in the front-rear direction, and as shown in Figures 3 and 5, the outer tube 10 integrally includes an outer tube end portion 11, an outer tube main body portion 12 located on the rear side of the outer tube end portion 11, a connecting portion 13 connecting the outer tube end portion 11 and the outer tube main body portion 12, and a flange portion 14 extending radially outward from the rear end portion of the outer tube main body portion 12.

[0014] The outer cylinder end 11 is a cylindrical body extending in the front-rear direction, and constitutes the front end portion of the outer cylinder 10 extending in the front-rear direction. The outer cylinder end 11 has a shape obtained by connecting a pair of left and right notched edges extending in the front-rear direction in a "partial elongated hole-shaped cylindrical portion obtained by cutting out the left-right central portion of the upper wall of a long hole-shaped cylindrical portion extending in the front-rear direction and long in the left-right direction" and a pair of left and right notched edges extending in the front-rear direction in a "partial cylindrical portion obtained by cutting out the lower end portion of a cylindrical portion extending in the front-rear direction". The thickness of the outer cylinder end 11 is constant over the entire area.

[0015] The outer tube main body 12 is a cylindrical body extending in the front-rear direction, and constitutes almost the entire area in the front-rear direction except for the front end portion of the outer tube 10 extending in the front-rear direction. When viewed in the front-rear direction, the outer tube main body 12 has a similar shape obtained by expanding the shape of the outer tube end 11 radially outward over the entire circumferential area. For this reason, as shown in FIG. 5, the inner circumferential surface 12a of the outer tube main body 12 is offset radially outward from the inner circumferential surface 11a of the outer tube end 11 over the entire circumferential area. This allows the outer tube end 11 to be molded strictly with a small dimensional tolerance, and the outer tube main body 12 to be molded with a large dimensional tolerance. In other words, the shape accuracy of the mold for molding the outer tube 10 can be made different on both sides of the boundary (i.e., the connecting portion 13) between the outer tube end 11 and the outer tube main body 12. The thickness of the outer cylinder main body portion 12 is constant over the entire area, and is the same as the thickness of the outer cylinder end portion 11 .

[0016] The connecting portion 13 is a portion that radially connects the rear end of the outer tube end portion 11 and the front end of the outer tube main body portion 12 over the entire circumferential area, and is an annular portion that extends radially over the entire circumferential area. The thickness of the connecting portion 13 is constant over the entire area and is the same as the thickness of the outer tube end portion 11.

[0017] The flange portion 14 is a flat plate-like portion that extends radially outward from the rear end of the outer tube main body portion 12, and has a rectangular outer shape when viewed from the front-rear direction. Each of the four corners of the flange portion 14 is provided with a female screw portion 15 into which a male screw 30 is screwed.

[0018] Next, the inner tube 20 will be described. The inner tube 20 is a resin molded body. The inner tube 20 is a cylindrical body extending in the front-rear direction, and has a shape similar to a similar shape obtained by shrinking the shape of the outer tube 10 radially inward over the entire circumferential area so that it can be placed inside the outer tube 10. Specifically, as shown in Figures 3 and 5, the inner tube 20 integrally includes an inner tube end portion 21, an inner tube main body portion 22 located on the rear side of the inner tube end portion 21, a connecting portion 23 connecting the inner tube end portion 21 and the inner tube main body portion 22, and a flange portion 24 extending radially outward from the rear end portion of the inner tube main body portion 22.

[0019] The inner cylinder end 21 is a cylindrical body extending in the front-rear direction, and constitutes the front end portion of the inner cylinder 20 extending in the front-rear direction. The inner cylinder end 21 has a similar shape obtained by shrinking the shape of the outer cylinder end 11 radially inward over the entire circumferential area when viewed from the front-rear direction so that the inner cylinder end 21 can be arranged so as to overlap radially within the outer cylinder end 11. The wall thickness of the inner cylinder end 21 is constant over the entire area.

[0020] The inner cylinder body 22 is a cylindrical body extending in the front-rear direction, and constitutes substantially the entire area in the front-rear direction except for the front end portion of the inner cylinder 20 extending in the front-rear direction. The inner cylinder body 22 has a similar shape obtained by shrinking the shape of the outer cylinder body 12 radially inward over the entire circumferential area when viewed from the front-rear direction so that it can be arranged in the outer cylinder body 12, and has a similar shape obtained by expanding the shape of the inner cylinder end 21 radially outward over the entire circumferential area (excluding the slit 25 and the engagement portion 27 described later). Therefore, as shown in FIG. 5, the outer peripheral surface 22a of the inner cylinder body 22 is offset radially outward from the outer peripheral surface 21a of the inner cylinder end 21 over the entire circumferential area. This allows the inner cylinder 20 to be molded by precisely molding the inner cylinder end 21 with a small dimensional tolerance, and molding the inner cylinder body 22 with a large dimensional tolerance. In other words, the shape precision of the mold for molding the inner tube 20 can be made different on either side of the boundary (i.e., the connecting portion 23) between the inner tube end portion 21 and the inner tube main body portion 22. The thickness of the inner tube main body portion 22 is constant throughout and is the same as the thickness of the inner tube end portion 21 (excluding the slit 25 and the engagement portion 27 described below).

[0021] The connecting portion 23 is a portion that radially connects the rear end of the inner cylinder end portion 21 and the front end of the inner cylinder main body portion 22 over the entire circumferential area, and is an annular portion that extends radially over the entire circumferential area. The thickness of the connecting portion 23 is constant over the entire area and is the same as the thickness of the inner cylinder end portion 21.

[0022] The flange portion 24 is a flat plate-like portion that extends radially outward from the rear end of the inner cylinder main body portion 22, and has a rectangular outer shape when viewed from the front-rear direction. Each of the four corners of the flange portion 24 is provided with a through hole 28 into which a male screw 30 is inserted, corresponding to the female screw portion 15 of the flange portion 14.

[0023] As shown in Fig. 3 and Fig. 4, a pair of slits 25 are formed at the rear end of the inner tube main body 22 at each of the upper end, lower end, left end, and right end (four locations) of the inner tube main body 22, spaced apart in the circumferential direction and extending forward from the rear end of the inner tube main body 22. Furthermore, a pair of slits 25 and a through hole 26 are formed in each portion of the flange portion 24 corresponding to the four locations, so as to connect to the rear end of the inner tube main body 22 located between the pair of slits 25 and to extend radially outward from the rear end. As a result, a cantilever-shaped engagement portion 27 is defined between each pair of slits 25 at the rear end of the inner tube main body 22, with the front end and the rear end being fixed ends and free ends, respectively.

[0024] The engaging portions 27 are elastically deformable in the radial direction. Compared to other portions of the inner tube body portion 22, the engaging portions 27 are thickened so as to protrude radially outward, except for the portion near the fixed end, as shown in Figs. 5 and 7, and the outer peripheral surface of the engaging portions 27 is located radially outward from the outer peripheral surface 22a of the inner tube body portion 22. Therefore, when the inner tube 20 is disposed in the outer tube 10, each engaging portion 27 is in pressing contact with the rear end of the inner peripheral surface 12a of the outer tube body portion 12 (see Figs. 5 and 7). Each component constituting the multi-layered tube 1 has been described above.

[0025] Next, an assembly procedure for the multilayer tubular body 1 will be described. To assemble the multilayer tubular body 1, first, the inner tube 20 is placed inside the outer tube 10. For this purpose, the inner tube 20 is inserted into the outer tube 10 from the rear side. This insertion is continued until the connecting portion 23 of the inner tube 20 abuts against the connecting portion 13 of the outer tube 10 and the flange portion 24 of the inner tube 20 abuts against the flange portion 14 of the outer tube 10, as shown in FIG.

[0026] When the inner cylinder 20 is completely placed in the outer cylinder 10, the outer cylinder end 11 and the inner cylinder end 21 are arranged so as to overlap in the radial direction, and the outer cylinder main body 12 and the inner cylinder main body 22 are arranged so as to overlap in the radial direction, as shown in Fig. 5. As shown in Fig. 6, the radial gap L1 between the inner peripheral surface 11a of the outer cylinder end 11 and the outer peripheral surface 21a of the inner cylinder end 21 is smaller than the radial gap L2 between the inner peripheral surface 12a of the outer cylinder main body 12 and the outer peripheral surface 22a of the inner cylinder main body 22. This is because, as described above, in the molding of the outer cylinder 10, the outer cylinder end 11 is molded strictly with a small dimensional tolerance, and the outer cylinder main body 12 is molded with a large dimensional tolerance, and, in the molding of the inner cylinder 20, the inner cylinder end 21 is molded strictly with a small dimensional tolerance, and the inner cylinder main body 22 is molded with a large dimensional tolerance. As a result, at the location where the outer tube end 11 and the inner tube end 21 overlap, the dimensional tolerance is small even if the gap L1 between the two is designed to be small, improving the aesthetics while suppressing deformation and whitening of the outer tube end 11 and the inner tube end 21. On the other hand, at the location where the outer tube main body portion 12 and the inner tube main body portion 22 overlap, the gap L2 between the two can be designed to be large, absorbing the large dimensional tolerance and making assembly easier.

[0027] Furthermore, when the inner tube 20 is completely placed in the outer tube 10, as shown in Fig. 5 and Fig. 7, each of the engagement parts 27 is in pressing contact with the rear end of the inner peripheral surface 12a of the outer tube main body part 12 while being slightly elastically deformed radially inward. This makes it possible to suppress positional deviation (so-called rattling) between the outer tube main body part 12 and the inner tube main body part 22. In addition, since each of the engagement parts 27 has a cantilever shape, the engagement parts 27 do not press the inner peripheral surface 12a of the outer tube main body part 12 excessively strongly compared to the case where a simple protruding engagement part is provided, and therefore deformation and whitening of the outer tube main body part 12 and the inner tube main body part 22 can be suppressed.

[0028] Furthermore, when the inner tube 20 is completely placed inside the outer tube 10, the tube end surface 11b of the outer tube 10 (outer tube end surface 11) and the tube end surface 21b of the inner tube 20 (inner tube end surface 21) are flush with each other at a common position in the front-to-rear direction, as shown in Figures 5 and 6. This allows the outer tube end surface 11 and the inner tube end surface 21 to be assembled with a small gap L1, and the tube end surfaces 11b, 21b are flush with each other, further improving the aesthetic appearance of the multilayered tube 1.

[0029] Once the placement of the inner tube 20 inside the outer tube 10 is completed as described above, each of the four male screws is then inserted from the rear into the corresponding through-holes 28 of the flange portion 24, and screwed into the corresponding female threaded portion 15 of the flange portion 14 with a predetermined torque. This fastens the outer tube 10 and the inner tube 20 together. This completes the assembly of the multi-layered cylindrical body 1, and the multi-layered cylindrical body 1 shown in FIG. 1 is obtained.

[0030] <Actions and Effects> As described above, according to the multi-layered cylindrical body 1 of the present embodiment, the outer tube end 11 and the outer tube main body 12 of the outer tube 10 are configured such that their respective inner circumferential surfaces 11a, 12a are offset from each other. As a result, in molding the outer tube 10, the outer tube end 11 can be molded strictly with a small dimensional tolerance, and the outer tube main body 12 can be molded with a large dimensional tolerance. In other words, the shape accuracy of the mold for molding the outer tube 10 can be made different on either side of the boundary between the outer tube end 11 and the outer tube main body 12. The same is true for the inner tube 20. As a result, at the location where the outer tube end 11 and the inner tube end 21 overlap, even if the gap L1 between them is designed to be small, the dimensional tolerance is small, so that the appearance can be improved while suppressing deformation and whitening of the outer tube end 11 and the inner tube end 21. On the other hand, at the location where the outer tube main body 12 and the inner tube main body 22 overlap, the gap L2 between them can be designed to be large, absorbing the large dimensional tolerance and facilitating assembly. Furthermore, the engagement portion 27 provided on the inner tube main body portion 22 of the inner tube 20 presses against the outer tube main body portion 12, thereby suppressing misalignment between the two (so-called rattle). In addition, since the engagement portion 27 has a cantilever shape, the engagement portion 27 does not press the outer tube main body portion 12 excessively strongly compared to a case where a simple protruding engagement portion is provided, and therefore deformation and whitening of the outer tube main body portion 12 and the inner tube main body portion 22 can be suppressed. Therefore, the multilayer cylindrical body 1 according to this embodiment can achieve both ease of assembly of components and excellent aesthetic appearance.

[0031] Furthermore, according to the multi-layered cylindrical body 1 of this embodiment, the cylindrical end surface 11b of the outer cylinder 10 and the cylindrical end surface 21b of the inner cylinder 20 are arranged flush with each other. As a result, the outer cylinder end portion 11 and the inner cylinder end portion 21 are assembled with a small gap L1, and the cylindrical end surfaces 11b, 21b are arranged flush with each other, which further improves the aesthetic appearance of the multi-layered cylindrical body 1.

[0032] <Other forms> The present invention is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and appropriate modifications, improvements, etc. are possible. In addition, the material, shape, size, number, arrangement location, etc. of each component in the above-described embodiments are arbitrary as long as the present invention can be achieved, and are not limited.

[0033] For example, in the above embodiment, the outer tube 10 (outer tube end portion 11+outer tube main body portion 12) and the inner tube 20 (inner tube end portion 21+inner tube main body portion 22) have a cylindrical shape composed of curved surfaces as a whole, combining the above-mentioned "partial elongated hole-shaped cylindrical portion" and the above-mentioned "partial cylindrical portion". In contrast, as shown in Figures 8 and 9, the outer tube main body portion 12 of the outer tube 10 and the inner tube main body portion 22 of the inner tube 20 may have a cylindrical shape composed of flat surfaces as a whole, combining two upper and lower angular tube portions, one in place of the above-mentioned "partial elongated hole-shaped cylindrical portion" and the other in place of the above-mentioned "partial cylindrical portion".

[0034] As described above, when the outer tube body 12 and the inner tube body 22 have a cylindrical shape composed entirely of flat surfaces, it is easier to design the dimensional tolerances at each point of the outer tube 10 (outer tube body 12) and the inner tube 20 (inner tube body 22) in actual design than in the above embodiment. This improves the productivity of the multilayered tube 1.

[0035] Here, the features of the above-mentioned embodiment of the multilayer cylindrical body 1 according to the present invention will be briefly summarized and listed in the following [1] to [3].

[0036] [1] A multi-layered cylindrical body (1) comprising a first cylindrical body (10) and a second cylindrical body (20) disposed inside the first cylindrical body (10), The first cylindrical body (10) is a first cylindrical end portion (11) constituting a cylindrical end surface (11b) of the first cylindrical body (10); and a first main body portion (12) having an inner peripheral surface (12a) offset outwardly from an inner peripheral surface (11a) of the first cylindrical end portion (11), The second cylindrical body (20) is the second cylindrical body (20) has a second cylindrical end (21) constituting a cylindrical end surface (21b) of the second cylindrical body (20); a second main body portion (22) whose outer peripheral surface (22a) is offset outwardly of the second cylindrical body (20) from an outer peripheral surface (21a) of the second cylindrical end (21); and a cantilever-shaped engagement portion (27) provided on the second main body portion (22) and capable of elastic deformation; the first cylindrical end portion (11) and the second cylindrical end portion (21) are arranged so as to overlap with each other on the inside and outside of the multilayer cylindrical body (1); The engagement portion (27) is in pressing contact with the inner circumferential surface (12a) of the first main body portion (12). Multilayer cylinder (1).

[0037] According to the multi-layered cylindrical body of the above-mentioned configuration [1], the first cylindrical end portion and the first main body portion of the first cylindrical body are configured so that their respective inner circumferential surfaces are offset from each other. As a result, in molding the first cylindrical body, the first cylindrical end portion can be molded strictly with a small dimensional tolerance, and the first main body portion can be molded with a large dimensional tolerance. In other words, the shape accuracy of the mold for molding the first cylindrical body can be made different on either side of the boundary between the first cylindrical end portion and the first main body portion. The same is true for the second cylindrical body. As a result, at the location where the first cylindrical end portion and the second cylindrical end portion overlap, even if the gap between the two portions is designed to be small, the dimensional tolerance is small, so that the aesthetic appearance can be improved while suppressing deformation and whitening of the first cylindrical end portion and the second cylindrical end portion. On the other hand, at the location where the first main body portion and the second main body portion overlap, the gap between the two portions can be designed to be large, absorbing the large dimensional tolerance and facilitating assembly. Furthermore, the engaging portion provided on the second main body portion of the second cylindrical body presses against the first main body portion, thereby suppressing misalignment between the two (so-called rattle). In addition, since the engaging portion has a cantilever shape, the engaging portion does not press the first main body portion too strongly compared to a case where a simple protruding engaging portion is provided, and deformation and whitening of the first main body portion and the second main body portion can be suppressed. Therefore, the multi-layered cylindrical body of this configuration can achieve both ease of assembly of components and excellent aesthetics.

[0038] [2] In the multilayer tubular body (1) described in [1] above, The first cylindrical body (10) has a square cylindrical shape in which the inner circumferential surface of the first main body portion (12) is formed of a flat surface, The second cylindrical body (20) has a square cylindrical shape in which the outer circumferential surface of the second main body portion (22) is formed of a flat surface. Multilayer cylinder (1).

[0039] According to the multi-layered tubular body of the configuration [2] above, the first tubular body and the second tubular body have a rectangular tubular shape. This makes it easier to design the dimensional tolerances of each part of the first tubular body and the second tubular body in actual design, compared to when the first tubular body and the second tubular body have a cylindrical shape, for example. This improves the productivity of the multi-layered tubular body.

[0040] [3] In the multilayer tubular body (1) described in [1] above, The first cylindrical body (10) and the second cylindrical body (20) are a cylindrical end surface (11b) of the first cylindrical body (10) and a cylindrical end surface (21b) of the second cylindrical body (20) are disposed flush with each other at a common position in the axial direction of the multi-layer cylindrical body (1); Multilayer cylinder (1).

[0041] According to the multi-layered tubular body having the above-mentioned configuration [3], the tubular end surface of the first tubular body and the tubular end surface of the second tubular body are arranged flush with each other. This allows the first tubular end portion and the second tubular end portion to be assembled with a small gap, and the tubular end surfaces to be arranged flush with each other, thereby further improving the aesthetic appearance of the multi-layered tubular body. [Explanation of symbols]

[0042] 1 Multilayer cylindrical body 10 Outer cylinder (first cylindrical body) 11 Outer tube end (first tube end) 11a Inner surface 11b Cylinder end surface 12 Outer cylinder main body portion (first main body portion) 12a Inner surface 20 Inner cylinder (second cylindrical body) 21 Inner tube end (second tube end) 21a Outer surface 21b End face of cylinder 22 Inner cylinder body part (2nd body part) 22a Outer surface 27 Department

Claims

1. A multi-layered cylindrical body including a first cylindrical body and a second cylindrical body disposed inside the first cylindrical body, The first cylindrical body is a first cylindrical end portion constituting a cylindrical end surface of the first cylindrical body, and a first main body portion whose inner circumferential surface is offset outwardly from the first cylindrical body relative to the inner circumferential surface of the first cylindrical end portion, The second cylindrical body is a second cylindrical end portion constituting a cylindrical end surface of the second cylindrical body, a second main body portion whose outer circumferential surface is offset outwardly from the second cylindrical body relative to the outer circumferential surface of the second cylindrical end portion, and a cantilever-shaped engagement portion provided on the second main body portion and capable of elastic deformation; The first cylinder end portion and the second cylinder end portion are arranged so as to overlap each other on the inside and outside of the multi-layered cylinder body, The engagement portion is in pressing contact with an inner circumferential surface of the first main body portion. Multilayer cylindrical body.

2. The multi-layered tubular body according to claim 1, The first cylindrical body has a square tube shape in which an inner circumferential surface of the first main body portion is formed of a flat surface, The second cylindrical body has a square cylindrical shape in which the outer circumferential surface of the second main body portion is formed of a flat surface. Multilayer cylindrical body.

3. The multi-layered tubular body according to claim 1, The first cylindrical body and the second cylindrical body are A cylindrical end surface of the first cylindrical body and a cylindrical end surface of the second cylindrical body are disposed flush with each other at a common position in the axial direction of the multi-layered cylindrical body. Multilayer cylindrical body.

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