Interlocking structure

Abstract

To provide a fitting structure actualizing appropriate fitting in work for assembling cylindrical members without the need for positioning.SOLUTION: The fitting structure includes a first cylindrical member (100) and a second cylindrical member (200), the first cylindrical member (100) including a plurality of engaging claws (110), each of the plurality of engaging claws (110) having an arm part (111), and a head part (112) defining a guide part (C112) as a recessed part, the guide part (C112) being constructed to guide a portion (212) of the end of the second cylindrical member (200) in a peripheral direction (Am30), the second cylindrical member (200) having a plurality of recessed parts (C211) as many as the plurality of engaging claws (110), and a guided part (212) to be guided in the peripheral direction (Am30) by the guide part (C112) when fitted to the first cylindrical member (100).SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In members of a fitting structure such as fuel pipes and valves, for example, as described in Patent Document 1, a structure including fitting claws and a fitting groove may be used. Specifically, this structure is composed of a cylindrical member provided with fitting claws and a cylindrical member provided with a fitting groove. These cylindrical members are fitted by arranging the fitting claws in the fitting groove through an assembly operation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using the above fitting structure, the assembly operation requires accurate positioning by an operator of the cylindrical member provided with fitting claws and the cylindrical member provided with a fitting groove. If the fitting claws and the fitting groove are not properly aligned during the assembly operation, the following problems may occur. That is, the operator of the assembly operation may not be able to fit the cylindrical members, or the cylindrical members may be in a semi-fitted state because the fitting claws are fixed at positions other than the fitting groove.

[0005] Therefore, in the assembly operation of two cylindrical members, a fitting structure that can be properly fitted without requiring accurate positioning of the cylindrical members by an operator has been demanded.

Means for Solving the Problems

[0006] The present disclosure can be realized in the following forms.

[0007] (1) According to a first embodiment of the present disclosure, a mating structure is provided. This mating structure is a cylindrical member mating structure in which a first cylindrical member and a second cylindrical member are combined such that their central axes coincide. The first cylindrical member is mated with the second cylindrical member with a portion of the end of the second cylindrical member accepted, and comprises a plurality of engaging claws, which are arranged along the circumferential direction of the first cylindrical member and each engages with the portion of the end of the second cylindrical member. Each of the plurality of engaging claws comprises an arm supported at one end, which extends along the insertion direction in which the second cylindrical member is inserted into the first cylindrical member and is elastically deformable along the radial direction of the first cylindrical member, and a head connected to the tip of the arm, which protrudes more toward the first central axis of the first cylindrical member than the arm, and which defines a guide portion, which is a recess provided on the side facing the first central axis. The guide portion is configured to guide the portion of the end of the second cylindrical member in the circumferential direction. The second cylindrical member comprises a plurality of recesses equal to the plurality of engaging claws, each of which receives the plurality of engaging claws when the second cylindrical member is fitted with the first cylindrical member, and a guided portion provided in the insertion direction relative to the plurality of recesses, protruding outward in the radial direction of the second cylindrical member, and being guided by the guide portion in the circumferential direction when the second cylindrical member is fitted with the first cylindrical member. In this configuration, when the second cylindrical member is fitted with the first cylindrical member, the guided portion of the second cylindrical member is guided in the circumferential direction by the guide portion. Therefore, precise positioning of the second cylindrical member and the first cylindrical member by the worker is not required during the assembly work of the second cylindrical member and the first cylindrical member. (2) In the fitting structure of the above embodiment, the first cylindrical member further comprises a first fitting opening located at one end of the first cylindrical member in the direction of the first central axis into which the second cylindrical member is inserted, a first other opening located at the other end of the first cylindrical member in the direction of the first central axis, and a plurality of protrusions. The guide portion further extends from the end of the head in the direction opposite to the insertion direction along the insertion direction and comprises a pair of first guide end edges defining the circumferential ends of the guide portion, wherein the distance between the pair of first guide end edges in the circumferential direction decreases along the insertion direction. The plurality of protrusions project from the inner wall of the first cylindrical member, and in the circumferential direction, on both sides of each of the plurality of engaging claws, the end of the first fitting opening and the other first opening closer to the first fitting opening is positioned in the first fitting opening with respect to the extension line of the pair of first guide end edges, and the end is an inclined surface, and the end is positioned so that the further the projection is from the engaging claw in the circumferential direction, the closer it is to the first fitting opening from the extension line. The guided portion may be provided with a pair of second guide end edges that define both ends of the guided portion in the circumferential direction, and the distance between the pair of second guide end edges in the circumferential direction decreases along the insertion direction. In this configuration, the guided portion is guided circumferentially by multiple projections even between multiple engaging claws in the circumferential direction. Furthermore, the pair of second guide ends have a different inclination from the extension line of the pair of first guide ends that serve as the reference for the guide. Therefore, the guided portion is not guided while in contact at multiple points, and thus the guidance is not hindered compared to when it is in contact at multiple points. Moreover, since the ends of each of the multiple projections form an inclined surface, the possibility of hindering the guidance is reduced compared to when it is guided by multiple ends of projections. In other words, the guided portion is easily guided. (3) In the fitting structure of the above embodiment, the first cylindrical member further comprises a first fitting opening located at one end of the first cylindrical member in the direction of the first central axis into which the second cylindrical member is inserted, and a first other opening and a plurality of protrusions located at the other end of the first cylindrical member in the direction of the first central axis. The guide portion further extends from the end of the head in the direction opposite to the insertion direction along the insertion direction and comprises a pair of first guide end edges defining the circumferential ends of the guide portion, and the distance between the pair of first guide end edges in the circumferential direction decreases along the insertion direction. The plurality of protrusions project from the inner wall of the first cylindrical member, and in the circumferential direction, on both sides of each of the plurality of engaging claws, the end of the first fitting opening and the other opening closer to the first fitting opening is positioned in relation to the extension line of the pair of first guide end edges, and the further a protrusion is from the engaging claw in the circumferential direction, the closer its end is to the first fitting opening relative to the extension line. The guided portion may further include a pair of second guide end edges that define both ends of the guided portion in the circumferential direction, and the circumferential distance between the pair of second guide end edges decreases along the insertion direction. In this configuration, the guided portion is guided circumferentially by multiple projections even between multiple engaging claws in the circumferential direction. Furthermore, the pair of second guide ends have a different inclination from the extension line of the pair of first guide ends that serve as the reference for the guide. Therefore, the guided portion is not guided while in contact at multiple points, and thus the guidance is not hindered compared to when multiple points are in contact. In other words, the guided portion is easily guided. (4) In the fitting structure of the above form, the shape of each of the plurality of protrusions may further be such that it extends from the first fitting opening toward the first other opening. This configuration makes it easier to ensure the durability of the multiple protrusions against forces from the insertion direction by the guided portion, and also makes it easier to form them within a limited area in the circumferential direction. (5) In the above-described configuration of the interlocking structure, the spacing between adjacent protrusions among the plurality of protrusions may be greater than the circumferential spacing between each of the pair of second guide end edges. In this configuration, the guided portion strikes the projection when the second cylindrical member rotates relative to the first cylindrical member. In other words, the projection prevents the second cylindrical member from rotating relative to the first cylindrical member when the two cylindrical members are locked together. (6) A second embodiment of the present disclosure provides a fitting structure for cylindrical members in which a first cylindrical member and a second cylindrical member are fitted together such that their central axes coincide. The first cylindrical member is fitted to the second cylindrical member with a portion of its end received by the second cylindrical member and comprises a plurality of engaging claws, which are arranged along the circumferential direction of the first cylindrical member and each engage with the portion of the end of the second cylindrical member. Each of the plurality of engaging claws comprises an arm supported at one end, extending along the insertion direction in which the first cylindrical member is inserted into the second cylindrical member and being elastically deformable along the radial direction of the first cylindrical member, and a head connected to the tip of the arm, projecting in the opposite direction to the first central axis of the first cylindrical member than the arm, and defining a guide portion which is a recess provided on the side opposite to the side facing the first central axis. The guide portion is configured to guide the portion of the end of the second cylindrical member in the circumferential direction. The second cylindrical member comprises a plurality of recesses equal to the plurality of engaging claws, each of which receives the plurality of engaging claws when the second cylindrical member is fitted with the first cylindrical member, and a guided portion provided in the insertion direction relative to the plurality of recesses, protruding inward in the radial direction of the second cylindrical member, and being guided by the guide portion in the circumferential direction when the second cylindrical member is fitted with the first cylindrical member. In this configuration, when the first cylindrical member is inserted into the second cylindrical member, the guided portion of the second cylindrical member is guided in the circumferential direction by the guide portion when the second cylindrical member and the first cylindrical member are fitted together. Therefore, precise positioning of the second cylindrical member and the first cylindrical member by the worker is not required during the assembly work of the second cylindrical member and the first cylindrical member. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram showing the fitting structure of the cylindrical member 10 as a first embodiment of the present disclosure. [Figure 2] This is a perspective view of the first cylindrical member 100. [Figure 3] This is a perspective view of the engaging claw 110. [Figure 4] This is a perspective view of the second cylindrical member 200. [Figure 5] This is an explanatory diagram showing the cylindrical member 10 unfolded from the central axis CL in Figure 1. [Figure 6] This is a cross-sectional view of the VI-VI section in Figure 5. [Figure 7] This is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110 during the guiding process. [Figure 8] This is an explanatory diagram showing the insertion state up to the projection 120. [Figure 9] This is an explanatory diagram showing the insertion state up to the first guide end C112a of the pair. [Figure 10] Figure 9 is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110. [Figure 11] This is an explanatory diagram showing the insertion state up to the guide section C112. [Figure 12] Figure 11 is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110. [Figure 13] Figure 12 is a cross-sectional view of the XIII-XIII section. [Figure 14] This is a cross-sectional view of the engaged portion 210 and the engaging claw 110, showing the elastic deformation of the arm portion 111. [Figure 15]Cross-sectional view of the engaged portion 210 in the engaged state and the engaging claw 110. [Figure 16] Explanatory drawing showing a plurality of protrusions 120a of the second embodiment. [Figure 17] Explanatory drawing showing a plurality of protrusions 120b of the third embodiment.

Mode for Carrying Out the Invention

[0009] A. First Embodiment: A1. Structure of the Cylindrical Member: FIG. 1 is an explanatory drawing showing the fitting structure of the cylindrical member 10 as the first embodiment of the present disclosure. In the following description, for ease of understanding, directions are set based on the central axis CL of the cylindrical member 10. As the directions along the central axis CL, the directions of arrow Am10 and arrow Am20 are set. The direction of arrow Am10 is also referred to as the insertion direction Am10, which will be described later. The direction of arrow Am20 is the opposite direction of the direction of arrow Am10. As the direction around the central axis CL, the circumferential direction Am30 is set. Further, in the circumferential direction Am30, as one direction, the direction of arrow Am31 is set. The direction of arrow Am31 is the clockwise direction when viewed from the direction of arrow Am10.

[0010] The cylindrical member 10 is a member in which two cylindrical members are connected. The cylindrical member 10 is composed of a first cylindrical member 100 and a second cylindrical member 200. The cylindrical member 10 is combined such that the central axes CL of the first cylindrical member 100 and the second cylindrical member 200 coincide with each other. The cylindrical member 10 is, for example, a connection portion of a pipe having a flow path. That is, the cylindrical member 10 connects the respective flow paths of the first cylindrical member 100 and the second cylindrical member 200.

[0011] Figure 2 is a perspective view of the first cylindrical member 100. The first cylindrical member 100 fits with the second cylindrical member 200 with a portion of the end of the second cylindrical member 200 accepted. This portion of the end is the guided portion 212. The guided portion 212 will be described in detail later. In other words, the first cylindrical member 100 fits with the second cylindrical member 200 when the second cylindrical member 200 is inserted into it. The shape of the first cylindrical member 100 is cylindrical with a first central axis CL1. The first central axis CL1 coincides with the central axis CL of the cylindrical member 10 when the first cylindrical member 100 and the second cylindrical member 200 are combined. The first cylindrical member 100 includes a plurality of engaging claws 110, a plurality of projections 120, a first fitting opening 101c, and a first other opening 102c. For example, the first cylindrical member 100 is a pipe having a flow path C103. As shown in Figure 1, the first cylindrical member 100 is fitted with the second cylindrical member 200 by a plurality of engaging claws 110, thereby connecting to the flow path C203 of the second cylindrical member 200.

[0012] As shown in Figure 2, the first fitting opening 101c is located at one end of the first cylindrical member 100 in the direction of the first central axis CL1, and is the opening into which the second cylindrical member 200 is inserted. The first other opening 102c is located at the other end of the first cylindrical member 100 in the direction of the first central axis CL1. The direction of the first central axis CL1 is parallel to the first central axis CL1. That is, the insertion direction Am10 is the direction from the first fitting opening 101c toward the first other opening 102c. The first fitting opening 101c is circular and has an inner diameter d1 that is larger than the outer diameter D2 of the second fitting opening 201c of the second cylindrical member 200. Furthermore, the first cylindrical member 100 has an inner diameter d1 that is larger than the outer diameter D2 of the second cylindrical member 200 within the range into which the second cylindrical member 200 is inserted from the first fitting opening 101c.

[0013] Figure 3 is a perspective view of the engaging claws 110. Each of the multiple engaging claws 110 engages with a portion of the end of the second cylindrical member 200. This portion of the end is a recess C211, which will be described later. The multiple engaging claws 110 are arranged along the circumferential direction Am30 of the first cylindrical member 100. For example, as shown in Figure 2, the multiple engaging claws 110 are arranged at four equally spaced positions along the circumferential direction Am30. Each of the multiple engaging claws 110 comprises an arm portion 111 that can be elastically deformed along the radial direction Am40 of the first cylindrical member 100, and a head portion 112 connected to the tip of the arm portion 111, as shown in Figure 3. More specifically, the engaging claw 110 has one end 111c of the arm portion 111 supported by the inner wall 104c and extends along the insertion direction Am10. That is, the engaging claw 110 is surrounded by a gap on all sides except for the one end 111c of the arm portion 111.

[0014] The arm portion 111 is elastically deformable for fitting. The arm portion 111 is supported at one end 111c and extends along the insertion direction Am10 in which the second cylindrical member 200 is inserted into the first cylindrical member 100. Thus, the arm portion 111 can bend radially in the direction Am40, which is perpendicular to the first central axis CL1, with the support portion as the fulcrum.

[0015] The head portion 112 engages with the recess C211 of the second cylindrical member 200. The recess C211 will be described in detail later. The head portion 112 is connected to the tip of the arm portion 111. The head portion 112 protrudes further than the arm portion 111 toward the first central axis CL1 of the first cylindrical member 100. The head portion 112 defines a guide portion C112, which is a recess provided on the side facing the first central axis CL1. More specifically, when the first cylindrical member 100 and the second cylindrical member 200 are combined, the head portion 112 is located in the space of the recess C211 of the second cylindrical member 200. For this reason, the head portion 112 has a smaller volume than the space of the recess C211 in the second cylindrical member 200. The amount of protrusion t10 of the head portion 112 will be described in detail later. Therefore, the head portion 112 is housed in the recess C211 of the second cylindrical member 200, thereby fitting the first cylindrical member 100 and the second cylindrical member 200 together.

[0016] The guide portion C112 is configured to guide a portion 212 of the end of the second cylindrical member 200 in the circumferential direction Am30. More specifically, the guide portion C112 guides the head 112 to the position of the recess C211 in the circumferential direction Am30 by guiding the guided portion 212 of the second cylindrical member 200. The guide portion C112 is a recess provided on the side opposite to the first central axis CL1. Furthermore, the guide portion C112 extends along the insertion direction Am10 from the end 112a of the head 112 in the direction Am20 opposite to the insertion direction Am10. The guide portion C112 includes a pair of first guide end edges C112a that define both ends of the guide portion C112 in the circumferential direction Am30. More specifically, the guide portion C112 is a triangular pyramidal recess. The bottom of the guide portion C112 is located in the center of the head 112 in the circumferential direction Am30. The bottom of the guide portion C112 is called the first vertex C112b. Of the three faces that define the triangular pyramidal recess of the guide portion C112, two faces face the head portion 112. That is, the guide surface C112r is connected to the arm portion 111 via a pair of first guide edges C112a. These two faces facing the head portion 112 are called the guide surface C112r.

[0017] The pair of first guide edges C112a guide the guided portion 212 of the second cylindrical member 200 for fitting. Furthermore, the pair of first guide edges C112a determine the direction of guidance for the guided portion 212. The distance S1 between the pair of first guide edges C112a in the circumferential direction Am30 decreases along the insertion direction Am10. In the pair of first guide edges C112a, the intersection of the two sides is located in the center of the head 112 in the circumferential direction Am30. This intersection is called the first vertex C112b. That is, the pair of first guide edges C112a are edges that spread out from the first vertex C112b toward the first fitting opening 101c. The pair of first guide edges C112a extend in a straight line along the inner wall 104c of the first cylindrical member 100. The extension line obtained by extending the pair of first guide edges C112a beyond the range of the head 112 is called the first guide line C112ag. The first guide line C112ag is a line obtained by extending the pair of first guide edges C112a along the inner wall 104c of the first cylindrical member 100. The first guide line C112ag will be described in detail later. The interior angle of the pair of first guide edges C112a and the interior angle of the two guide lines is called the first interior angle R1. The first interior angle R1 will be described in detail later.

[0018] The width of the guide surface C112r decreases in the circumferential direction Am30 toward the interior of the first cylindrical member 100. Therefore, the guide surface C112r has a vertex at the position closest to the first central axis CL1 of the first cylindrical member. This vertex is called the third vertex C112c. The two faces of the guide surface C112r are configured symmetrically with respect to a straight line from the third vertex C112c to the first vertex C112b. Furthermore, the guide surface C112r bends along this straight line, defining a groove. This groove is called the guide groove C112d. Therefore, the guide groove C112d is formed along the first central axis CL1 of the first cylindrical member 100 in the circumferential direction Am30. The guide groove C112d guides the guided portion 212 along the direction of the first central axis CL1. The guiding function of the guide groove C112d will be explained later.

[0019] The multiple protrusions 120 guide the guided portion 212 of the second cylindrical member 200. As shown in Figure 2, the multiple protrusions 120 project from the inner wall 104c of the first cylindrical member 100. The multiple protrusions 120 are arranged on both sides of each of the multiple engaging claws 110 in the circumferential direction Am30. Furthermore, the spacing S2 between adjacent protrusions 120 is greater than the spacing S3 between each of the pair of second guide ends 212a in the circumferential direction Am30. The spacing S2 of the multiple protrusions 120 will be explained later. The shape of each of the multiple protrusions 120 is such that it extends from the first fitting opening 101c toward the first other opening 102c. More specifically, the shape of each of the multiple projections 120 extends along the direction of the first central axis CL1, and the dimension in the direction of the first central axis CL1 is larger than the dimensions in the circumferential direction Am30 and the radial direction Am40. That is, the projections 120 have the shape of a rib with a longitudinal direction in the direction of the first central axis CL1. With this configuration, the multiple projections 120 can be easily formed within a limited range in the circumferential direction Am30, and their durability against forces from the insertion direction Am10 by the guided portion 212 can be easily ensured. Furthermore, the length of the projections 120 in the direction of the first central axis CL1 is longer than the length from one end 111c of the arm portion 111 to the end 112a of the head portion 112. Therefore, when the guided portion 212, which will be described later, is positioned at the location of the engaging claw 110, the projections 120 on both sides prevent movement in the circumferential direction Am30. This function will be described in detail later.

[0020] Furthermore, the guide end 120c on the first fitting opening 101c side of the projection 120 is a curved surface. This end is called the guide end 120c. Therefore, the guide end 120c is susceptible to force from the insertion direction Am10 on its inclined surface. This inclined surface has an inclination in the circumferential direction Am30 with respect to the insertion direction Am10. Therefore, an object in contact with the guide end 120c moves along the inclined surface of the guide end 120c. The object in contact with the guide end 120c is the guided portion 212 of the second cylindrical member 200. The guided portion 212 will be described in detail later. The guide end 120c and the guided portion 212 are in a state where they can move relative to each other in the circumferential direction Am30. Therefore, the movement of the guided portion 212 on the inclined surface of the guide end 120c is a relative movement with respect to the guide end 120c.

[0021] Figure 4 is a perspective view of the second cylindrical member 200. The second cylindrical member 200 is fitted to the first cylindrical member 100 by being inserted into it. The shape of the second cylindrical member 200 is cylindrical with a second central axis CL2. The second central axis CL2 coincides with the central axis CL of the cylindrical member 10 when the first cylindrical member 100 and the second cylindrical member 200 are combined. The second cylindrical member 200 includes a guided portion 212, a plurality of recesses C211, a second fitting opening 201c, a second other opening 202c, and a step 213. The configuration of the guided portion 212, the recesses C211, and the step 213 is also called the engaged portion 210. For example, the second cylindrical member 200 is a pipe having a flow path C203. As shown in Figure 1, the second cylindrical member 200 is fitted with the first cylindrical member 100 by a plurality of recesses C211, thereby connecting to the flow path C103 of the first cylindrical member 100.

[0022] The second fitting opening 201c is located at one end of the second cylindrical member 200 in the direction of the second central axis CL2, as shown in Figure 4, and is an opening into which the second cylindrical member 100 is inserted. The second other opening 202c is located at the other end of the second cylindrical member 200 in the direction of the second central axis CL2. The direction of the second central axis CL2 is parallel to the second central axis CL2. That is, the insertion direction Am10 is the direction from the second other opening 202c toward the second fitting opening 201c. The second fitting opening 201c is circular and has an outer diameter D2 that is smaller than the inner diameter d1 of the first fitting opening 101c of the first cylindrical member 100. Furthermore, the second cylindrical member 200 also has an outer diameter D2 that is smaller than the inner diameter d1 of the first cylindrical member 100, even within the range into which the second cylindrical member 200 is inserted from the second fitting opening 201c.

[0023] The multiple recesses C211 are the same number as the multiple engaging claws 110, and each of the multiple engaging claws 110 is received when the second cylindrical member 200 is fitted with the first cylindrical member 100. More specifically, the recesses C211 have a space capable of accommodating the heads 112 of the engaging claws 110 in order to fit with them. The recesses C211 are, for example, holes with bottoms. The recesses C211 are located from the intersection point 212b of the pair of second guide ends 212a of the guided portion 212 to the second other opening 202c. That is, the recesses C211 are located from the second vertex 212b of the guided portion 212 along the direction of the second central axis CL2 toward the second other opening 202c.

[0024] The guided portion 212 is positioned in the insertion direction Am10 relative to the plurality of recesses C211 and protrudes outward in the radial direction Am40 of the second cylindrical member 200. Furthermore, when the second cylindrical member 200 is fitted with the first cylindrical member 100, it is guided by the guide portion C112 in the circumferential direction Am30. In addition, the guided portion 212 prevents the second cylindrical member 200 from rotating relative to the first cylindrical member 100 when fitted. The guided portion 212 includes a pair of second guide end edges 212a that define both ends of the second cylindrical member 200 in the circumferential direction Am30. More specifically, the guided portion 212 protrudes from the outer wall 204c of the second cylindrical member 200, thus forming a step in the outer wall 204c.

[0025] The pair of second guide edges 212a are the edges between the guided portion 212 and the outer wall 204c. The pair of second guide edges 212a are configured such that the spacing S3 in the circumferential direction Am30 decreases along the insertion direction Am10. The spacing S2 will be explained later. At the pair of second guide edges 212a, the intersection of the two edges is located in the center of the guided portion 212 in the circumferential direction Am30. This intersection is called the second vertex 212b. Therefore, the pair of second guide edges 212a are edges that extend from the second vertex 212b toward the second other opening 202c. The pair of second guide edges 212a extend in a straight line along the outer wall 204c of the second cylindrical member 200. The interior angle of this edge is called the third interior angle R3. The length L of the second guide edges 212a and the third interior angle R3 will be explained in detail later. Between the second vertex 212b and the end 201ca of the second fitting opening 201c, there exists the area of ​​the outer wall 204c of the second cylindrical member 200. In this configuration, the second cylindrical member 200 enters the guiding process after being inserted into the first cylindrical member 100, thus preventing it from coming out of the first cylindrical member 100 during the guiding process.

[0026] The step 213 prevents the second cylindrical member 200 from rotating relative to the first cylindrical member 100 when the first cylindrical member 100 and the second cylindrical member 200 are assembled. The step 213 is located on both sides of the guided portion 212 in the circumferential direction Am30. Furthermore, the step 213 is located on the side of the second other opening 202c that is closer to the guided portion 212 in the direction of the second central axis CL2. The step 213 is a step that extends from the second fitting opening 201c toward the second other opening 202c. More specifically, the step 213 is a step that aligns parallel to the longitudinal direction of the projection 120 when the first cylindrical member 100 and the second cylindrical member 200 are assembled. Furthermore, in this assembled state, the step 213 is located between the multiple projections 120 on both sides of the guided portion 212 in the circumferential direction Am30. The function of step 213 will be explained in detail later.

[0027] A2. Structure of each part for positioning: Figure 5 is an explanatory diagram showing the cylindrical member 10 unfolded from the central axis CL in Figure 1. The explanatory diagram in Figure 5 shows the positional relationship between the engaged portion 210 and the engaging claw 110 as viewed from the central axis CL. In Figure 5, for the sake of ease of understanding the technology, the direction in which the head 112 protrudes and the direction in which the opening of the recess C211 is shown as being in the same direction. In the explanatory diagram in Figure 5, the direction in which the projection 120 protrudes is also the same direction as the direction in which the head 112 protrudes. However, in actual fitting, the direction in which the head 112 protrudes and the direction in which the opening of the recess C211 are in opposite directions. Also, the cylindrical member 10 in Figure 5 is in the same state as the cylindrical member 10 in Figure 1. That is, the second cylindrical member 200 is inserted into the first cylindrical member 100 up to the second vertex 212b of the engaged portion 210.

[0028] Figure 6 is a cross-sectional view of the VI-VI section in Figure 5. In Figure 6, the protruding direction of the head 112 and the protruding direction of the projection 120 are opposite to each other, just as in the actual fitted state. In the following description, the cross-sectional views of the engaged portion 210 and the engaging claw 110 are similarly illustrated. As mentioned above, the engaged portion 210 is the portion that protrudes from the outer wall 204c of the second cylindrical member 200. The projection 120 is the portion that protrudes from the inner wall 104c of the first cylindrical member 100. As shown in Figure 6, the projection 120 is positioned to overlap when viewed from the insertion direction Am10, at a distance t30 between the inner wall 104c of the first cylindrical member 100 and the outer wall 204c of the second cylindrical member 200. More specifically, the protrusion amount t20 of the guided portion 212 and the protrusion amount t10 of the projection 120 are smaller than the distance t30 from the inner wall 104c of the first cylindrical member 100 to the outer wall 204c of the second cylindrical member 200. Therefore, the guided portion 212 comes into contact with the projection 120 when the second cylindrical member 200 is inserted into the first cylindrical member 100.

[0029] Figure 7 is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110 during the guiding process. The structure of each part performing the guiding will be explained using Figure 7 as an example. The explanatory diagram in Figure 7 shows a pair of engaged portions 210 and engaging claws 110. Although the positional relationship between the engaged portion 210 and the engaging claw 110 in Figure 7 is different from the positional relationship in Figure 5, the method of illustrating the head 112 and the recess C211 is the same. In the following explanation, the explanatory diagrams showing the positional relationship between the engaged portion 210 and the engaging claw 110 are illustrated in the same way. In Figure 7, the engaged portion 210 is shown positioned at the location of the projection 120 in the circumferential direction Am30.

[0030] The fitting of the cylindrical members 10 is performed by the head 112 of the first cylindrical member 100 being received into the recess C211 of the second cylindrical member 200. Furthermore, the fitting of the cylindrical members 10 is performed by combining the first cylindrical member 100 and the second cylindrical member 200 with their central axes CL aligned. Therefore, fitting requires the head 112 and the recess C211 to be fitted by movement along the direction of the central axis CL. In other words, fitting requires the circumferential positions Am30 of the head 112 and the recess C211 to be aligned. Accordingly, in Figure 7, the circumferential positions Am30 of the head 112 and the recess C211 are not aligned, so positioning is required.

[0031] As described above, the multiple projections 120 are arranged on both sides of each of the multiple engaging claws 110. Furthermore, the ends of the multiple projections 120 that are closer to the first fitting opening 101c of the first fitting opening 101c and the first other opening 102c are in relation to the extension line C112ag of the pair of first guide edge sides C112a. On the side of section 101c Furthermore, the multiple protrusions 120 are arranged such that the end of the protrusion 120 that is further away from the engaging claw 110 in the circumferential direction Am30 is closer to the first fitting opening 101c from the extension line C112ag.

[0032] More specifically, the arrangement of the multiple protrusions 120 is determined based on the first interior angle R1 by the first guide line C112ag and the third interior angle R3 of the pair of second guide ends 212a. For example, each of the multiple protrusions 120 consists of two parts, a first protrusion 120x and a second protrusion 120y, as shown in Figure 7. The first protrusion 120x and the second protrusion 120y are arranged on one side of the engaging claw 110 in the circumferential direction Am30. As shown in Figure 7, the side closer to the engaging claw 110 is called the first protrusion 120x, and the other side is called the second protrusion 120y. The end of the protrusion 120 on the side of the first fitting opening 101c is called the guide end 120c. Therefore, the guide ends 120c of the first protrusion 120x and the second protrusion 120y are called the first guide end 120cx and the second guide end 120cy, respectively. Furthermore, the line connecting the first vertex C112b of the guide section C112 and the guide end 120c is called the second guide line C120cg. In addition, the interior angle of the second guide line C120cg extending on both sides of the engaging claw 110 in the circumferential direction Am30 is called the second interior angle R2. In this case, the second interior angle R2 is set to be smaller than the first interior angle R1 formed by the first guide line C112ag. Furthermore, as mentioned above, the distance S3 between the pair of second guide end sides 212a in the circumferential direction Am30 decreases along the insertion direction Am10. The third interior angle R3 is set to be less than or equal to the first interior angle R1 and larger than the second interior angle R2. For example, the first interior angle R1, the second interior angle R2, and the third interior angle R3 are 120 degrees, 110 degrees, and 120 degrees, respectively.

[0033] The projection 120 is further positioned such that the distance L1 between the projection 120 and the distance L2 between the projection 120 and the guide portion C112 is shorter than the length L3 of the second guide end 212a. Therefore, the guided portion 212 comes into contact with either the projection 120 or the guide portion C112 during the insertion process. More specifically, the guided portion 212 is guided while in contact with either the guide portion C112 or one of the guide end 120c. Therefore, when the guided portion 212 moves toward the insertion direction Am10, it moves toward the circumferential direction Am30 along the second guide line C120cg formed by the projection 120. Thus, the guided portion 212 is guided to the first vertex C112b of the guide portion C112. Furthermore, because the third interior angle R3 of the guided portion 212 is smaller than the second interior angle R2, the surface with the pair of second guide edges 212a comes into contact with the projection 120 before the second vertex 212b comes into contact with the projection 120. In other words, the engaged portion 210 comes into contact with the projection 120 and the guide portion C112 from the inclined surface of the guided portion 212. Therefore, the engaged portion 210 is more susceptible to force in the circumferential direction Am30 compared to when contact is made from the tip. With this configuration, the guided portion 212 is guided in the circumferential direction Am30 by the multiple projections 120 even between the multiple engaging claws 110 in the circumferential direction Am30. Furthermore, the pair of second guide edges 212a have a different inclination from the extension line C112ag of the pair of first guide edges C112a that serve as the reference for the guide. Therefore, since the guided portion 212 is not guided while in contact at multiple points, the guidance is not hindered compared to when it is in contact at multiple points. In other words, the guided portion is easily guided.

[0034] A3. Positioning operation of fitting using cylindrical members: The fitting of the first cylindrical member 100 and the second cylindrical member 200 is performed as follows. The fitting of the first cylindrical member 100 and the second cylindrical member 200 is performed with the second cylindrical member 200 fixed to the first cylindrical member 100. For example, the fitting is performed with the second cylindrical member 200 fixed to a base that can rotate in the circumferential direction Am30. The worker performing the fitting inserts the first cylindrical member 100 into the second cylindrical member 200 which is fixed to the base. That is, the worker performs the insertion by applying an external force to the first cylindrical member 100 in the insertion direction Am10 toward the second cylindrical member 200 so that the first central axis CL1 and the second central axis CL2 coincide. Therefore, the second cylindrical member 200 can rotate even if it is subjected to a rotational force in the circumferential direction Am30 from insertion to fitting.

[0035] Furthermore, in the following description, the fitting of the first cylindrical member 100 and the second cylindrical member 200 is an example similar to the fitting structure in Figures 5 and 7. That is, four sets of engaged portion 210 and engaging claw 110 are provided. First projections 120x and second projections 120y are provided on both sides of the engaging claw 110.

[0036] In the initial operation, as shown in Figure 1, the second fitting opening 201c of the second cylindrical member 200 is inserted into the first fitting opening 101c of the first cylindrical member 100 along the direction of the central axis CL. The engaged portion 210 of the second cylindrical member 200 is formed at a position away from the second fitting opening 201c. Therefore, as shown in Figure 1, during the insertion process, the second cylindrical member 200 is inserted into the first cylindrical member 100 up to the extent of the outer wall 204c from the second fitting opening 201c to the engaged portion 210.

[0037] In Figure 1, the second vertex 212b of the guided portion 212 is located at the second guide end 120cy of the second projection 120y in the circumferential direction Am30. Therefore, as the insertion process progresses, the guided portion 212 comes into contact with the second guide end 120cy, as described above. The guide end 120c is a curved surface with respect to the second vertex 212b. Therefore, the guided portion 212 moves along the slope of the guide end 120c. That is, the second cylindrical member 200 is inserted while rotating relative to the first cylindrical member 100. In the following description, the case in which the second cylindrical member 200 rotates toward the circumferential direction Am31, which is a constant direction in the circumferential direction Am30, relative to the first cylindrical member 100 will be described as an example.

[0038] Figure 8 is an explanatory diagram showing the state in which the guided portion 212 has been inserted up to the second projection 120y. In the next operation, as the second cylindrical member 200 is further inserted into the first cylindrical member 100, the second vertex 212b of the guided portion 212 passes through the contacted second guide end 120cy. Therefore, the second vertex 212b of the guided portion 212 is positioned on the second guide line C120cg, as shown in Figure 7. Consequently, the guided portion 212 moves along the second guide line C120cg. That is, the second cylindrical member 200 is further inserted into the first cylindrical member 100 while rotating toward the circumferential direction Am31.

[0039] Figure 9 is an explanatory diagram showing the state in which the guided portion 212 is inserted between the second projection 120y and the guide portion C112. Furthermore, Figure 10 is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110 in Figure 9. In the next operation, as the second cylindrical member 200 is inserted into the first cylindrical member 100, the second vertex 212b of the guided portion 212 reaches the guide portion C112 in the circumferential direction Am30. The guided portion 212 is guided in a state in contact with the guide portion C112 and one of the multiple projections 120. Therefore, the guided portion 212 passes the second guide end 120cy by moving along the second guide line C120cg.

[0040] Figure 11 is an explanatory diagram showing the state in which the guided portion 212 has been inserted up to the guide portion C112. Furthermore, Figure 12 is an explanatory diagram showing the positional relationship between the engaged portion 210 and the engaging claw 110 in Figure 9. However, in Figure 12, the pairs of engaged portion 210 and engaging claw 110 are shown as in Figure 5, representing all pairs in the circumferential direction Am30. In the next operation, as the second cylindrical member 200 is further inserted into the first cylindrical member 100, the second vertex 212b of the guided portion 212 reaches the first vertex C112b of the guide portion C112 along the pair of first guide end edges C112a. Thus, in the circumferential direction Am30, the positions of the second vertex 212b and the first vertex C112b coincide. That is, in the circumferential direction Am30, the head 112 of the first cylindrical member 100 and the recess C211 of the second cylindrical member 200 coincide.

[0041] In Figure 12, the guided portion 212 is positioned with projections 120 on both sides in the circumferential direction Am30. Furthermore, as shown in Figure 12, the distance S2 between adjacent projections 120 is greater than the distance S3 between each of the pair of second guide ends 212a in the circumferential direction Am30. Therefore, the pair of second guide ends 212a are positioned between the projections 120. Consequently, even when the guided portion 212 is subjected to a force in the circumferential direction Am30 from its positioned state, it will still contact the projections 120. In other words, this prevents the second cylindrical member 200 from rotating relative to the first cylindrical member 100. The length of the projection 120 in the direction of its first central axis CL1 is longer than the length from one end 111c of the arm portion 111 to the end 112a of the head portion 112. Therefore, the projection 120 prevents rotation even when the engaged portion 210 moves further in the insertion direction Am10, resulting in a locked state.

[0042] Figure 13 is a cross-sectional view of the XIII-XIII section in Figure 12. In the circumferential direction Am30, the positions of the second vertex 212b and the first vertex C112b coincide, so that the guided portion 212 and the head portion 112 are positioned to overlap when viewed from the insertion direction Am10.

[0043] Figure 14 is a cross-sectional view of the engaged portion 210 and the engaging claw 110 showing the elastic deformation of the arm portion 111. In the next operation, as the second cylindrical member 200 is further inserted into the first cylindrical member 100, the guide groove C112d of the engaging claw 110 guides the guided portion 212 in the insertion direction Am10 while maintaining its position in the circumferential direction Am30. As a fitting operation, the guided portion 212 pushes the arm portion 111 toward the radial direction Am40 of the first cylindrical member 100. As a result, the space in the insertion direction Am10 expands due to the deformation of the arm portion 111, and the second cylindrical member 200 is further inserted in the insertion direction Am10.

[0044] Figure 15 is a cross-sectional view of the engaged portion 210 and the engaging claw 110 in the fitted state. In the next operation, the second cylindrical member 200 is further inserted into the first cylindrical member 100, causing the recess C211 to reach the head 112, thereby fitting them together. Thus, the fitting of the cylindrical member 10 is completed when the first cylindrical member 100 and the second cylindrical member 200 are combined.

[0045] With this configuration, when the second cylindrical member 200 is fitted with the first cylindrical member 100, the guided portion 212 of the second cylindrical member 200 is guided by the guide portion C112 in the circumferential direction Am30. Therefore, in the assembly work of the second cylindrical member 200 and the first cylindrical member 100, precise positioning of the second cylindrical member 200 and the first cylindrical member 100 by the worker is not required.

[0046] Furthermore, in this configuration, the guided portion 212 is guided in the circumferential direction Am30 by the multiple projections 120 even between the multiple engaging claws 110 in the circumferential direction Am30. Moreover, the second guide end 212a has a different inclination from the extension line C112ag of the pair of first guide end halves C112a that serve as the reference for the guide. Therefore, the guided portion 212 is not guided while in contact at multiple points, and thus the guidance is not hindered compared to when it is in contact at multiple points. In other words, the guided portion 212 is easily guided.

[0047] Furthermore, by adopting this configuration, the multiple protrusions 120 can be easily formed within a limited range in the circumferential direction Am30, while also ensuring durability against forces from the insertion direction Am10 by the guided portion 212.

[0048] Furthermore, in this configuration, the guided portion 212 will come into contact with the projection 120 when the second cylindrical member 200 rotates relative to the first cylindrical member 100. In other words, the projection 120 prevents the second cylindrical member 200 from rotating relative to the first cylindrical member 100 when the two members are locked together.

[0049] B. Second Embodiment: Figure 16 is an explanatory diagram showing the multiple protrusions 120a of the second embodiment. In the cylindrical member 10 of the second embodiment, the configuration of the multiple protrusions 120a differs from that of the multiple protrusions 120 of the first embodiment. Other aspects of the cylindrical member 10 of the second embodiment are the same as those of the cylindrical member 10 of the first embodiment. The differences from the first embodiment will be explained below. Note that Figure 16 shows a configuration in which the multiple protrusions 120 of the first embodiment are replaced with the multiple protrusions 120a of the second embodiment, as shown in the explanatory diagram of Figure 12 showing the positional relationship between the engaged portion 210 and the engaging claw 110. In Figure 16, some reference numerals have been omitted from Figure 12 to facilitate understanding of the technology.

[0050] In the multiple protrusions 120a of the second embodiment, the end of the first fitting opening 102c that is closer to the first fitting opening 101c is arranged such that, with respect to the circumferential direction Am30, the end of the protrusion 120a that is farther from the engaging claw 110 and closer to the first fitting opening 101c is closer to the first fitting opening 101c from the extension line C112ag of the first guide end edge C112a. That is, as shown in Figure 16, the multiple protrusions 120a include an inclined surface 120ac formed from the end of the protrusion 120a on the first fitting opening 101c side.

[0051] The multiple protrusions 120a are arranged such that, in the circumferential direction Am30, one protrusion 120a is positioned on each side of the multiple engaging claws. More specifically, each of the multiple protrusions 120a is a state in which the first protrusion 120x and the second protrusion 120y in the first embodiment are integrated. Therefore, the end of the protrusion 120a on the first fitting opening 101c side corresponds to the first guide end 120cx and the second guide end 120cy in the first embodiment. Thus, the protrusion 120a has an inclined surface 120ac along the second guide line C120cg in the first embodiment. Therefore, in the multiple protrusions 120a of the second embodiment, similar to the multiple protrusions 120 of the first embodiment, the guided portion 212 is guided in the circumferential direction Am30 by the multiple protrusions 120a even between the multiple engaging claws 110 in the circumferential direction Am30.

[0052] In this configuration, since the ends of the multiple protrusions 120a form an inclined surface 120ac, the possibility of obstruction to the guide can be reduced compared to when the guide is provided by multiple ends of the protrusions 120a.

[0053] C. Third Embodiment: Figure 17 is an explanatory diagram showing a plurality of protrusions 120b of the third embodiment. The shape of each of the plurality of protrusions 120a of the second embodiment may be a shape that extends from the end of the portion that forms the inclined surface 120ac in the insertion direction Am10 toward the first fitting opening 101c toward the first other opening 102c, as shown in the third embodiment of Figure 17. The portion that extends from the end of the portion that forms the inclined surface 120ac toward the first fitting opening 101c toward the first other opening 102c is called the straight portion 120bs. That is, the protrusion 120b of the third embodiment is formed by the portion of the inclined surface 120ac and the straight portion 120bs so as to form the contour of the protrusion 120a of the second embodiment.

[0054] By adopting this configuration, the amount of material required to form the projection 120b can be reduced compared to the projection 120a in the second embodiment.

[0055] D. Fourth Embodiment: In the interlocking structure of the cylindrical members of the fourth embodiment, the first cylindrical member is fitted with the second cylindrical member with a portion of the end of the first cylindrical member being received by the second cylindrical member.

[0056] The cylindrical member of the fourth embodiment has a mating structure in which the first cylindrical member and the second cylindrical member are combined so that their central axes coincide, similar to the embodiments described above. However, in the cylindrical member of the fourth embodiment, the first cylindrical member is fitted with the second cylindrical member with a portion of the end of the first cylindrical member being received by the second cylindrical member. That is, in the cylindrical member of the fourth embodiment, the second fitting opening of the second cylindrical member is circular and has an inner diameter larger than the outer diameter of the first fitting opening of the first cylindrical member. Therefore, in the cylindrical member of the fourth embodiment, the first cylindrical member, which has an engaging claw, is inserted into the second cylindrical member, which has a recess for receiving the engaging claw.

[0057] The first cylindrical member of the fourth embodiment is provided with a plurality of engaging claws that engage with a portion of the end of the second cylindrical member. The plurality of engaging claws of the fourth embodiment are arranged along the circumferential direction of the first cylindrical member, similar to the first embodiment.

[0058] In the fourth embodiment, each of the multiple engaging claws is supported at one end and includes an arm that extends along the insertion direction in which the first cylindrical member is inserted into the second cylindrical member and is elastically deformable along the radial direction of the first cylindrical member. Furthermore, the engaging claw includes a head connected to the tip of the arm and projecting in the opposite direction to the direction toward the first central axis of the first cylindrical member. The head defines a guide portion, which is a recess provided on the side opposite to the side facing the first central axis. The guide portion is configured to guide a portion of the end of the second cylindrical member in the circumferential direction.

[0059] The second cylindrical member of the fourth embodiment comprises a plurality of recesses equal to the number of engaging claws, and a guided portion. The plurality of recesses each receive the plurality of engaging claws when the second cylindrical member is fitted with the first cylindrical member. The guided portion is positioned in the insertion direction relative to the plurality of recesses and protrudes inward in the radial direction of the second cylindrical member. Furthermore, the guided portion is guided by the guide portion in the circumferential direction when the second cylindrical member is fitted with the first cylindrical member.

[0060] In other words, in the fourth embodiment, the first cylindrical member and the second cylindrical member are formed in the opposite direction to the first embodiment in their respective radial directions, in which the protruding and recessed parts are located.

[0061] Therefore, in the fourth embodiment, the guided portion of the second cylindrical member is configured to be guided on the outside of the first cylindrical member by a plurality of protrusions and a guide portion of the head of the engaging claw. In the first embodiment, the guided portion 212 of the second cylindrical member 200 is guided on the inside of the first cylindrical member 100 by a plurality of protrusions 120 and a guide portion C112 of the head 112.

[0062] In this configuration, when the cylindrical member of the fourth embodiment is engaged by inserting the first cylindrical member, which has engaging claws, into the second cylindrical member, which has recesses for receiving the engaging claws, the guided portion of the second cylindrical member is guided.

[0063] E. Other embodiments: E1. Other Embodiments 1: (1) In the above embodiment, the cylindrical member 10 is a pipe. However, the cylindrical member 10 is not necessarily limited to a pipe. The cylindrical member 10 can be any member that requires a cylindrical fitting structure. For example, the cylindrical member 10 may be a valve having a cylindrical shape as part of its overall shape.

[0064] (2) In the above embodiment, the recess C211 is a hole with a bottom. However, since the recess C211 is to fit with the head 112, it is sufficient if it is a space that can accommodate the head 112. For example, the recess C211 may be a through hole.

[0065] (3) In the above embodiment, the cylindrical member 10 is provided with four engaging claws 110 and the same number of recesses C211 as the engaging claws 110. That is, the cylindrical member 10 is provided with four sets of engaging claws 110 and recesses C211. However, there may be multiple sets of engaging claws 110 and recesses C211. For example, there may be six sets of engaging claws 110 and recesses C211.

[0066] E2. Other Embodiments 2: (1) In the above embodiment, the projection 120 consists of two projections, a first projection 120x and a second projection 120y, on one side of the engaging claw 110 in the circumferential direction Am30. However, the projection 120 may consist of three or four projections on one side of the engaging claw 110 in the circumferential direction Am30.

[0067] (2) In the above embodiment, the circumferential distance S1 of the pair of first guide edges C112a is defined by the pair of first guide edges C112a. However, this distance S1 may be defined by three edges. For example, the three edges may consist of a pair of first guide edges C112a as two edges and a third edge connecting them. Thus, the circumferential distance S1 of the pair of first guide edges C112a may also be defined by the length of the third edge.

[0068] (3) In the above embodiment, the first interior angle R1, the second interior angle R2, and the third interior angle R3 are set to 120 degrees, 110 degrees, and 120 degrees, respectively. However, the relationship between each angle is not limited to this condition. The third interior angle R3 only needs to be set to an angle that is less than or equal to the first interior angle R1 and greater than the second interior angle R2.

[0069] (4) In the above embodiment, the projection 120 is provided based on the extension line C112ag of the pair of first guide end sides C112a of the guide portion C112. However, for example, the projection 120 may be positioned based on a line that extends along the inner wall 104c at an internal angle of 120 degrees from the tip of the head 112 toward the first fitting opening 101c.

[0070] (5) In the above embodiment, the circumferential distance S3 of the pair of second guide edges 212a is defined by the pair of second guide edges 212a. However, this distance S3 may be defined by three edges. For example, the three edges may consist of a pair of second guide edges 212a as two edges and a third edge connecting them. The third edge is a curved portion defined by making the tip of the guided portion 212 a curved surface. The circumferential distance S3 of the pair of second guide edges 212a may also be defined by the degree of curvature of the third edge.

[0071] (6) In the above embodiment, the pair of second guide ends 212a are assumed to extend in a straight line along the outer wall 204c of the second cylindrical member 200. However, the pair of second guide ends 212a may have curved portions having a curvature greater than that of the outer wall 204c of the second cylindrical member 200. The pair of first guide ends C112a are assumed to extend in a straight line along the inner wall 104c of the first cylindrical member 100. However, the pair of first guide ends C112a may have curved portions having a curvature greater than that of the inner wall 104c of the first cylindrical member 100.

[0072] E3. Other Embodiments 3: (1) In the above embodiment, the shape of the projection 120 is such that it extends from the first fitting opening 101c toward the first other opening 102c. However, the shape of the projection 120 does not have to be a straight line extending from the first fitting opening 101c toward the first other opening 102c. For example, the shape of the projection 120 may be such that the end on the side of the first other opening 102c in the direction of the first central axis CL1 is curved toward the circumferential direction Am30.

[0073] E4. Other Embodiments 4: (1) In the above embodiment, the spacing S2 between adjacent projections 120 among the plurality of projections 120 is set to be larger than the spacing S3 between each of the pair of second guide end edges 212a in the circumferential direction Am30. However, the spacing S2 may be the same as the spacing S3. For example, the guided portion 212 can have the spacing S2 and the spacing S3 the same by setting the amount of protrusion t20 of the guided portion 212 to such an extent that it does not come into contact with the projections 120 at the end of the pair of second guide end edges 212a that is close to the second other opening 202c.

[0074] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features of the embodiments corresponding to the technical features in each form described in the Summary of the Disclosure section can be replaced or combined as appropriate to solve some or all of the above problems, or to achieve some or all of the above effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of Symbols]

[0075] 10...Cylindrical member, 100...First cylindrical member, 101c...First fitting opening, 102c...First other opening, 104c...Inner wall, 110...Engaging claw, 111...Arm, 111c...One end, 112...Head, 112a...End, 120, 120a, 120b...Projection, 120c...Guide end, 120cx...First guide end, 120cy...Second guide End portion, 120x...First projection, 120y...Second projection, 200...Second cylindrical member, 201c...Second fitting opening, 201ca...End portion, 202c...Second other opening, 204c...Outer wall, 210...Engaged portion, 212...Guided portion, 212a...Second guide end edge, 212b...Second vertex, 213...Step, Am10...Insertion direction, Am20... Direction, Am30...Circumferential direction, Am31...Circumferential direction, Am40...Radial direction, C103...Flow path, C112...Guide section, C112a...First guide end, C112ag...First guide line, C112b...First vertex, C112c...Third vertex, C112d...Guide groove, C112r...Guide surface, C120cg...Second guide line, C203...Flow path, C211...recess, CL...central axis, CL1...first central axis, CL2...second central axis, D2...outer diameter, L1...spacing, L2...spacing, R1...first interior angle, R2...second interior angle, R3...third interior angle, S1...spacing, S2...spacing, S3...spacing, d1...inner diameter, t10...projection amount, t20...projection amount, t30...spacing, 120ac...inclined surface, 120bc...straight section

Claims

1. A cylindrical member fitting structure in which a first cylindrical member and a second cylindrical member are combined such that their central axes coincide, The first cylindrical member is The second cylindrical member is fitted with the second cylindrical member while a portion of the end of the second cylindrical member is received, The set comprises a plurality of engaging claws, each of which is arranged along the circumferential direction of the first cylindrical member and engages with the portion of the end of the second cylindrical member, Each of the aforementioned multiple engaging claws is An arm portion is supported at one end, extends along the insertion direction in which the second cylindrical member is inserted into the first cylindrical member, and is elastically deformable along the radial direction of the first cylindrical member, The head is connected to the tip of the arm and protrudes further than the arm toward the first central axis of the first cylindrical member, and defines a guide portion which is a recess provided on the side facing the first central axis, The guide portion is configured to guide a portion of the end of the second cylindrical member in the circumferential direction. The second cylindrical member is The plurality of recesses are the same number as the plurality of engaging claws, and each of the plurality of recesses receives the plurality of engaging claws when the second cylindrical member is fitted with the first cylindrical member, A fitting structure comprising: a guided portion provided in the insertion direction relative to the plurality of recesses, protruding outward in the radial direction of the second cylindrical member, and being guided by the guide portion in the circumferential direction when the second cylindrical member is fitted with the first cylindrical member.

2. The fitting structure according to claim 1, The first cylindrical member further comprises, A first fitting opening is located at one end of the first cylindrical member in the direction of the first central axis, into which the second cylindrical member is inserted, The first other opening located at the other end of the first cylindrical member in the direction of the first central axis, It has multiple protrusions, The aforementioned guide section further, It extends from the end of the head in the direction opposite to the insertion direction along the insertion direction, and has a pair of first guide end edges that define both ends of the guide portion in the circumferential direction, and the distance between the pair of first guide end edges in the circumferential direction decreases along the insertion direction, The aforementioned multiple protrusions are, The first cylindrical member protrudes from the inner wall, and in the circumferential direction, on both sides of each of the multiple engaging claws, the end of the first fitting opening and the other first opening closer to the first fitting opening are positioned on the first fitting opening side with respect to the extension line of the pair of first guide end edges, The end of the inclined surface is an inclined surface, and the inclined surface is formed by the end of the projection that is further away from the engaging claw in the circumferential direction and closer to the first fitting opening from the extension line, The guided portion is, A fitting structure comprising a pair of second guide end edges defining both ends of the guided portion in the circumferential direction, wherein the distance between the pair of second guide end edges in the circumferential direction decreases along the insertion direction.

3. The fitting structure according to claim 1, The first cylindrical member further comprises, A first fitting opening is located at one end of the first cylindrical member in the direction of the first central axis, into which the second cylindrical member is inserted, The first other opening located at the other end of the first cylindrical member in the direction of the first central axis, It has multiple protrusions, The aforementioned guide section further, It extends from the end of the head in the direction opposite to the insertion direction along the insertion direction, and has a pair of first guide end edges that define both ends of the guide portion in the circumferential direction, and the distance between the pair of first guide end edges in the circumferential direction decreases along the insertion direction, The aforementioned multiple protrusions are, The first cylindrical member protrudes from the inner wall, and in the circumferential direction, on both sides of each of the multiple engaging claws, the end of the first fitting opening and the other first opening closer to the first fitting opening are positioned on the first fitting opening side with respect to the extension line of the pair of first guide end edges, The further the projection is from the engaging claw in the circumferential direction, the more the end closest to the first fitting opening is positioned to move closer to the first fitting opening from the extension line. The guided portion further, A fitting structure comprising a pair of second guide end edges defining both ends of the guided portion in the circumferential direction, wherein the distance between the pair of second guide end edges in the circumferential direction decreases along the insertion direction.

4. The fitting structure according to claim 2 or claim 3, The fitting structure further comprises the shape of each of the plurality of protrusions, which extends from the first fitting opening toward the other first fitting opening.

5. The fitting structure according to claim 4, further, A fitting structure in which the distance between adjacent protrusions among the plurality of protrusions is greater than the distance between each of the pair of second guide end edges in the circumferential direction.

Images