male connector

Abstract

In the present invention, a male member (11) is surrounded by an outer cylinder (15). A female screw (16) is formed on the inner surface of the outer cylinder (15). The thread groove of the female screw (16) is constituted from a bottom part (53) and a pair of flanks (55a, 55b). The female screw (16) has, in the vicinity of the end (59) of the thread groove on the base end side of the outer cylinder (15), an incomplete thread part (51) in which the bottom part (53) of the thread groove is displaced so as to approach the axis (1a) of a male connector (1) with increasing proximity to the end (59).

Description

[Technical Field]

[0001] The present invention relates to a male connector, and more particularly to a male connector having a male member and a female screw surrounding the male member. [Background technology]

[0002] Enteral nutrition is known as a method for administering liquids, including nutrients and medicines, to patients who are no longer able to take food orally. In enteral nutrition, a catheter is inserted into the digestive tract (e.g., the stomach) from outside the body and left indwelling in the patient. Known catheters include a nasal catheter inserted through the patient's nose and a gastrostomy catheter inserted into a gastrostomy fistula formed in the patient's abdomen. The liquid is stored in a container. A connector consisting of a male connector and a female connector is used to form a flow path for the liquid from the container to the catheter. This connector is composed of a male connector 910 shown in Figures 18A and 18B and a female connector 920 shown in Figures 19A and 19B.

[0003] 18A and 18B has a cylindrical male member 911 and an outer tube 915 that surrounds the male member 911. The base end of the male member 911 and the base end of the outer tube 915 are connected via a flange 918 that protrudes like a brim from the base end of the male member 911. The outer peripheral surface of the male member 911 has a male tapered surface 912 whose outer diameter decreases toward the tip of the male member 911. The male member 911 is provided with a flow path 919 that penetrates the male member 911 along its longitudinal direction. A female thread 916 is provided on the inner peripheral surface of the outer tube 915 that faces the male member 911.

[0004] 19A and 19B has a hollow cylindrical female member 921. The inner peripheral surface of the female member 921 has a female tapered surface 922 whose inner diameter increases toward the tip of the female member 921. A helical protrusion (male thread) 926 is provided on the outer peripheral surface of the female member 921.

[0005] The male connector 910 is connected to the female connector 920 by inserting the male member 911 into the female member 921 and threading the female thread 916 into the helical protrusion 926. The male tapered surface 912 of the male member 911 and the female tapered surface 922 of the female member 921 have the same diameter and taper angle, so they are tapered and fitted together liquid-tight.

[0006] In enteral nutrition, the female connector 920 is used as the connector on the upstream side (container side) in the direction of flow of the liquid, and the male connector 910 is used as the connector on the downstream side (patient side).

[0007] In the male connector 910, an outer tube 915 surrounds a male member 911, and a female thread 916 is provided on the inner circumferential surface of the outer tube 915. After enteral nutrition, liquid is likely to remain in the gap 914 between the male member 911 and the outer tube 915. When the male connector 910 is provided at the upstream end of a catheter inserted into a patient, the male connector 910 is left in the patient together with the catheter for an extended period of time. Liquid remaining in the gap 914 can deteriorate the hygiene of the male connector 910.

[0008] Patent Document 1 describes a wiping tip for cleaning a male connector 910. The wiping tip has a tubular portion made of water-absorbent foam or nonwoven fabric. The tubular portion is inserted into a gap 914 between a male member 911 and an outer tube 915. Any liquid remaining in the gap 914 (particularly the thread groove of a female thread 916) is absorbed by the tubular portion and wiped away. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2017-099738 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-119837 Summary of the Invention [Problem to be solved by the invention]

[0010] Because the radial distance between male member 911 and outer tube 915 of male connector 910 is very narrow, it is difficult to insert the cylindrical portion of Patent Document 1 deeply into gap 914. Furthermore, a narrow and deep thread groove (narrow deep groove) 957 (see FIG. 18B) exists near flange 918. Although the cylindrical portion is configured to be deformable, it is difficult to insert the cylindrical portion into narrow deep groove 957 and wipe off any liquid inside narrow deep groove 957. For this reason, it is difficult to thoroughly clean the thread groove deep in gap 914 of male connector 910, even if a cleaning tool like the cylindrical portion is used.

[0011] An object of the present invention is to provide a male connector that is easy to clean while ensuring compatibility with conventional male connectors. [Means for solving the problem]

[0012] The first male connector of the present invention comprises a cylindrical male member having a flow path formed therein, an outer tube surrounding the male member, and a female thread formed helically on the inner surface of the outer tube facing the male member from the tip of the outer tube toward the base end of the outer tube. The thread groove of the female thread is composed of a bottom and a pair of flanks that face each other in the axial direction of the male connector, sandwiching the bottom. The female thread has an incomplete thread portion near the end of the thread groove on the base end side of the outer tube, where the bottom of the thread groove is displaced toward the axis of the male connector as it approaches the end.

[0013] The second male connector of the present invention comprises a cylindrical male member having a flow path formed therein, an outer tube surrounding the male member, a female thread formed on the inner surface of the outer tube facing the male member, spiraling from the tip of the outer tube to the base end of the outer tube, and a flange connecting the base end of the male member to the base end of the outer tube. The female thread comprises a complete thread portion having a constant thread groove depth and an incomplete thread portion that continues to the complete thread portion at the base end of the outer tube and whose thread groove depth decreases toward the end of the thread groove at the base end of the outer tube. The thread groove in the complete thread portion is composed of a bottom portion, a pair of flanks that face each other in the axial direction of the male connector across the bottom portion, and a corner of an arc-shaped cross section that connects the bottom portion to the pair of flanks. The thread groove in the incomplete thread portion is composed of an arc-shaped cross section that smoothly connects to the flange. The radius of curvature of the arcuate cross section of the incomplete thread portion is greater than the radius of curvature of the corner of the complete thread portion. [Effects of the Invention]

[0014] According to the present invention, there is no narrow and deep thread groove (narrow deep groove) near the end of the thread groove, which makes the male connector of the present invention easy to clean.

[0015] The incomplete thread portion does not affect the connection of the male connector of the present invention to the female connector, so the male connector of the present invention is compatible with conventional male connectors in terms of connection with female connectors. [Brief explanation of the drawings]

[0016] [Figure 1] Fig. 1A is a perspective view of a male connector according to a first embodiment of the present invention, and Fig. 1B is a cross-sectional perspective view of the male connector. [Figure 2] FIG. 2 is a plan view of the male connector according to the first embodiment of the present invention, with the male member omitted. [Figure 3] 3A to 3F are cross-sectional views taken along the lines 3A-3A to 3F-3F in FIG. [Figure 4]FIG. 4 is an enlarged cross-sectional view of FIG. 3B. [Figure 5] FIG. 5 is a plan view of a conventional male connector in which the male member is omitted. [Figure 6] 6A to 6F are cross-sectional views taken along the lines 6A-6A to 6F-6F in FIG. [Figure 7] FIG. 7 is an enlarged cross-sectional view of FIG. 6B. [Figure 8] FIG. 8 is a plan view of a male connector according to a second embodiment of the present invention, with the male member omitted. [Figure 9] 9A to 9F are cross-sectional views taken along the lines 9A-9A to 9F-9F in FIG. [Figure 10] FIG. 10 is an enlarged cross-sectional view of FIG. 9B. [Figure 11] FIG. 11 is a plan view of a male connector according to a third embodiment of the present invention, in which the male member is omitted. [Figure 12] 12A to 12F are cross-sectional views taken along the lines 12A-12A to 12F-12F in FIG. [Figure 13] FIG. 13 is an enlarged cross-sectional view of FIG. 12B. [Figure 14] FIG. 14 is a plan view of a male connector according to a fourth embodiment of the present invention, in which the male member is omitted. [Figure 15] 15A to 15F are cross-sectional views taken along the lines 15A-15A to 15F-15F in FIG. [Figure 16] FIG. 16 is an enlarged cross-sectional view of FIG. 15C. [Figure 17] FIG. 17 is a cross-sectional view of a male connector according to a fifth embodiment of the present invention. [Figure 18] Fig. 18A is a perspective view of a conventional male connector, and Fig. 18B is a cross-sectional view taken along a plane including the axis of the male connector. [Figure 19] Fig. 19A is a perspective view of a conventional female connector, and Fig. 19B is a cross-sectional view taken along a plane including the axis of the female connector. DETAILED DESCRIPTION OF THE INVENTION

[0017] The first male connector of the present invention may further include a flange connecting the base end of the male member and the base end of the outer tube. In the incomplete thread portion, the flange may not be connected to the flank of the pair of flanks closest to the tip of the outer tube. According to this aspect, a narrow, deep groove is reliably prevented from being formed near the end of the thread groove. This is advantageous for facilitating cleaning of the male connector.

[0018] In one aspect of the first male connector of the present invention, the female thread may further include a complete thread portion, the distance of the bottom of which is constant from the axis, continuous with the incomplete thread portion, closer to the tip of the outer tube than the incomplete thread portion. The width of the thread groove at the incomplete thread portion may be wider than the width of the bottom of the complete thread portion. According to this aspect, a narrow, deep groove is reliably prevented from being formed near the end of the thread groove. This is advantageous for facilitating cleaning of the male connector.

[0019] In one aspect of the first male connector of the present invention, the incomplete thread portion may have a first corner portion having an arc-shaped cross section formed so as to be continuous with the bottom portion. The radius of curvature of the first corner portion may be 0.6 mm or more. This aspect is advantageous for facilitating cleaning of the incomplete thread portion. The first corner portion is preferably formed on the base end side (flange side) of the outer tube relative to the bottom portion, and more preferably, is formed on both the base end side (flange side) of the outer tube and the tip end side of the outer tube relative to the bottom portion.

[0020] In one aspect of the first male connector of the present invention, the female thread may further have a complete thread portion, continuous with the incomplete thread portion, located closer to the tip of the outer tube than the incomplete thread portion and having a constant distance from the axis of the bottom portion. The complete thread portion may have a second corner portion with an arc-shaped cross section formed so as to be continuous with the bottom portion. The radius of curvature of the second corner portion may be 0.6 mm or more. This aspect is advantageous for facilitating cleaning of the complete thread portion. The second corner portion is preferably formed on either the base end side (flange side) of the outer tube or the tip end side of the outer tube relative to the bottom portion, and more preferably on both sides.

[0021] In one aspect of the first male connector of the present invention, the female thread may further include a complete thread portion, the distance of the bottom portion from the axis of the complete thread portion being constant, and continuous with the complete thread portion, located closer to the tip of the outer tube than the incomplete thread portion. The incomplete thread portion may have a first corner portion having an arc-shaped cross section that is continuous with the bottom portion. The complete thread portion may have a second corner portion having an arc-shaped cross section that is continuous with the bottom portion. The radius of curvature of the first corner may be larger than the radius of curvature of the second corner. This aspect is advantageous for facilitating cleaning of the incomplete thread portion and ensuring compatibility with conventional male connectors for connection to female connectors. The first corner portion having a relatively large radius of curvature is preferably formed on the base end side (flange side) of the outer tube relative to the bottom, and more preferably on both the base end side (flange side) and the tip end side of the outer tube relative to the bottom.

[0022] In one aspect of the second male connector of the present invention, the radius of curvature of the arc-shaped cross section of the incomplete thread portion may be 0.6 mm or more. This aspect is advantageous in that it makes it easier to clean the incomplete thread portion.

[0023] In one aspect of the second male connector of the present invention, the arc-shaped cross section of the incomplete thread portion may connect the flange and the apex of the female thread. According to this aspect, the thread groove of the incomplete thread portion is substantially defined by the arc-shaped cross section. This is advantageous in that it makes it easier to clean the incomplete thread portion.

[0024] In one aspect of the second male connector of the present invention, the radius of curvature of the arc-shaped cross section of the incomplete thread portion may be constant over the entire length of the incomplete thread portion. This aspect is advantageous for simplifying the configuration of the incomplete thread portion.

[0025] In one aspect of the first and second male connectors of the present invention, the male connector may include a flange connecting the base end of the male member and the base end of the outer tube. A third corner having an arc-shaped cross section with a curvature radius of 0.6 mm or more may be formed between the base end of the male member and the flange. This aspect is advantageous for facilitating cleaning of the base end of the male member.

[0026] The present invention will be described in detail below, illustrating preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. For the sake of convenience, the drawings referred to in the following description show simplified views of the main components constituting the embodiments of the present invention. Therefore, the present invention may include any components not shown in the following drawings. Furthermore, within the scope of the present invention, the components shown in the following drawings may be modified or omitted. In the drawings referred to in the description of each embodiment, components corresponding to components shown in the drawings referred to in the preceding embodiment are designated by the same reference numerals as those in the drawings of the preceding embodiment. Duplicate descriptions of such components are omitted, and the descriptions of the preceding embodiment should be taken into consideration as appropriate.

[0027] In the present invention, the "axis" of a member (e.g., a male connector) refers to the central axis of the member. The "axis" passes through the center of a circle included in the member and / or coincides with the central axis of a cylinder or cone (taper) included in the member. The direction along a straight line perpendicular to the axis is called the "radial direction." In the radial direction, the side closer to the axis is called the "inner" side, and the side farther from the axis is called the "outer" side. The direction of rotation around the axis is called the "circumferential direction." In the present invention, "cross section" refers to a cross section along a plane including the axis of the member, unless otherwise specified.

[0028] In the present invention, "arcuate cross section" means that the shape of the cross section along the plane including the axis of the male connector is an arc. "Corner of arcuate cross section" means that the surface of the corner is configured as a curved surface such that the corner forms an arc in the cross section along the plane including the axis of the male connector. "Radius of curvature" means the radius of curvature of the arc in the cross section along the plane including the axis of the male connector.

[0029] (Embodiment 1) Fig. 1A is a perspective view of a male connector 1 according to a first embodiment of the present invention as seen from above, and Fig. 1B is a cross-sectional perspective view of male connector 1 taken along a plane including axis 1a thereof.

[0030] The male connector 1 has a cylindrical male member 11 at one end and a connecting tube 21 at the other end, which are arranged coaxially with the axis 1a. A flow path 19 passes through the male connector 1 along the axis 1a from the male member 11 to the connecting tube 21. An outer tube 15 surrounds the male member 11.

[0031] The male member 11 has a long, thin rod shape. The outer peripheral surface of the male member 11 is provided with a male tapered surface 12, the outer diameter of which decreases as it approaches the tip of the male member 11. The male member 11 has a tip tapered surface 13, which is located closer to the tip of the male tapered surface 12 than the male tapered surface 12 and has a larger taper angle than the male tapered surface 12. The tip of the male member 11 (part or all of the tip tapered surface 13) protrudes in the direction of the axis 1a beyond the tip of the outer tube 15. The fact that the male member 11 protrudes beyond the outer tube 15 is advantageous for facilitating connection of the male connector 1 to the female connector 920 (see Figures 19A and 19B).

[0032] A flange 18 protrudes radially outward from the base end of the male member 11. An outer tube 15 extends from the circular outer peripheral edge of the flange 18 toward the same side as the male member 11 (the tip end side of the male connector 1). The outer tube 15 has a substantially cylindrical shape and is arranged coaxially with the male member 11. The outer tube 15 is spaced radially from the male member 11 across a gap 14. A female thread 16 is provided on the inner peripheral surface of the outer tube 15 facing the male member 11.

[0033] The connecting tube 21 has a hollow cylindrical shape and is connected to the male member 11. The grip portion 23 is provided integrally with the connecting tube 21 so as to surround the connecting tube 21. The grip portion 23 has a substantially quadrangular prism shape with a substantially rectangular cross section along a plane perpendicular to the axis 1a. The grip portion 23 makes it easy for the operator to apply a rotational force around the axis 1a to the male connector 1. In the present invention, the shape of the grip portion 23 is arbitrary. The grip portion 23 may have a thin plate shape along a plane including the axis 1a. The male connector 1 does not have to have the grip portion 23.

[0034] A flexible, hollow tube 29 extends from the connecting tube 21. The tube 29 is inserted into the connecting tube 21 and fixed thereto with an adhesive or the like. The flow path 19 of the male connector 1 communicates with the inner cavity of the tube 29. The tube 29 may be a nasal catheter inserted through the patient's nasal cavity into the stomach or esophagus. Alternatively, the tube 29 may be a tube (extension tube) connected to a nasal catheter.

[0035] The male connector 1 can be integrally molded as a single component using a hard material. The hard material preferably has a degree of mechanical strength (rigidity) that prevents it from being substantially deformed by external forces. Specific examples of hard materials that can be used include resin materials such as polypropylene, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polyacetal, polystyrene, polyamide, polyethylene, and rigid polyvinyl chloride. The male connector 1 may also be formed by combining multiple separately manufactured components (e.g., two components: the outer tube 15 and the portion excluding the outer tube 15). In this case, the materials constituting the multiple components may be the same or different, and each may be selected from the hard materials listed above.

[0036] The male connector 1 is compatible with the conventional male connector 910 shown in Figures 18A and 18B. Therefore, the male connector 1 can be repeatedly connected to and disconnected from the female connector 920 of Figures 19A and 19B. That is, the male connector 1 can be connected to the female connector 920 by inserting the male member 11 into the female member 921 and threading the female thread 16 into the helical protrusion 926. The male tapered surface 12 of the male member 11 and the female tapered surface 922 of the female member 921 have the same diameter and taper angle, so they are tapered to fit together liquid-tightly.

[0037] The male connector 1 of the first embodiment differs from the conventional male connector 910 (see FIGS. 18A and 18B) in terms of the female thread 16. This will be explained below.

[0038] FIG. 2 is a plan view of the male connector 1 of the first embodiment, as seen from the tip side. In FIG. 2, the male member 11 and the flow path 19 are omitted. FIGS. 3A to 3F are cross-sectional views of the male connector 1 taken along the cross sections 3A-3A to 3F-3F in FIG. 2. The cross sections 3A-3A to 3F-3F include the axis 1a of the male connector 1, and are rotated clockwise around the axis 1a by 30 degrees. In FIGS. 3A to 3F, only the portion of the male connector 1 above the flange 18 is shown. In addition, in FIGS. 3A to 3F, the male member 11 and the flow path 19 are omitted so that the shape of the female thread 16 can be seen.

[0039] A female screw 16 is provided on the inner peripheral surface of the outer tube 15. The female screw 16 extends continuously in a spiral shape from the tip of the outer tube 15 (the upper end of the outer tube 15 in FIGS. 3A to 3F) to the base end of the outer tube 15 (the end on the flange 18 side). The female screw 16 includes a screw groove and a screw thread that are alternately arranged in the direction of the axis 1a in a cross section along a plane including the axis 1a of the male connector 1. Of the two ends of the spirally continuous screw groove, the end on the tip side of the outer tube 15 is referred to as the "start end" of the screw groove, and the end on the base end side of the outer tube 15 is referred to as the "end end" 59 of the screw groove. In the present invention, the end end 59 of the screw groove refers to the point where the screw groove disappears. In the first embodiment, the female screw 16 is a double-start screw. Therefore, the female screw 16 includes two spiral screw grooves (or two screw threads) that are adjacent to each other in the direction of the axis 1a. The female thread 16 has two-fold rotational symmetry with respect to the axis 1a (i.e., when the female thread 16 is rotated 180 degrees around the axis 1a, it coincides with the female thread 16 before rotation). However, in the present invention, the female thread 16 is not limited to a double-start thread, and may be a single-start thread or a multiple-start thread with three or more starts.

[0040] The female thread 16 has a complete thread portion 52 located on the distal end side of the outer tube 15 and an incomplete thread portion 51 located on the proximal end side of the outer tube 15. The complete thread portion 52 constitutes the majority of the female thread 16 and includes the starting end of the female thread 16. The incomplete thread portion 51 is continuous with the complete thread portion 52 on the proximal end side of the outer tube 15 and includes the terminal end 59 of the female thread 16. The complete thread portion 52 and the incomplete thread portion 51 differ in the cross-sectional shape of the thread groove of the female thread 16. Figures 3A to 3F show the complete thread portion 52 and the incomplete thread portion 51 for one of the two thread grooves that constitute the female thread 16. The cross section of Figure 3A passes through the boundary between the complete thread portion 52 and the incomplete thread portion 51.

[0041] FIG. 4 is a cross-sectional view of the male connector 1, enlarged from FIG. 3B. In a cross section including the axis 1a, the female thread 16 of the fully threaded portion 52 has a root 53 located at the outermost position in the radial direction, a crest 54 located at the innermost position in the radial direction, and flanks 55a and 55b connecting adjacent roots 53 and crests 54. The roots 53 and crests 54 include straight lines parallel to the axis 1a in a cross section including the axis 1a. The "root diameter" of the female thread 16 is defined by the root 53. The "inner diameter" of the female thread 16 is defined by the crest 54. The flank (first flank) 55a is located on the base end side (flange 18 side) of the root 53, and the flank (second flank) 55b is located on the tip end side of the root 53. The flanks 55a and 55b face each other in the direction of the axis 1a, sandwiching the root 53 therebetween. A corner 69a having an arcuate cross section is formed between the bottom 53 and the flank 55a, and a corner 69b having an arcuate cross section is formed between the bottom 53 and the flank 55b. The corners 69a and 69b smoothly connect the bottom 53 to the flanks 55a and 55b. Both the corners 69a and 69b have a radius of curvature R9. Although there are no limitations on the radius of curvature R9, it is preferable that the radius of curvature R9 be 0.3 mm or less, and more preferably 0.2 mm or less.

[0042] The thread groove of the female thread 16 is composed of a bottom portion 53, corner portions 69a, 69b smoothly connected to the bottom portion 53, and flanks 55a, 55b smoothly connected to the corner portions 69a, 69b, and has an approximately trapezoidal cross-sectional shape overall. The thread grooves are arranged at a constant pitch from the crest portion 54 in the direction of the axis 1a. The flanks 55a and 55b function as thread surfaces and are represented as straight lines of the same length in a cross section including the axis 1a. The flanks 55a and 55b are inclined with respect to a line perpendicular to the axis 1a (i.e., the radial direction), and the absolute values of the angles (flank angles) of the flanks 55a and 55b relative to the line are the same. In the present invention, the term "flank length" refers to the length of the straight flank in a cross section including the axis 1a. The term "thread groove width" refers to the dimension of the thread groove in the direction of the axis 1a at the point closest to the axis 1a. In the fully threaded portion 52, the "width of the thread groove" is approximately equal to the distance in the axial direction 1a between adjacent crests 54 on either side of the thread groove. The "depth of the thread groove" refers to the radial distance between the deepest part of the thread groove (the point farthest from the axis 1a) and the crest 54. The cross-sectional shape of the thread groove and the dimensions of each part of the thread groove, including the width and depth, are constant over the entire length of the thread groove in the fully threaded portion 52.

[0043] The thread groove extends continuously from the complete thread portion 52 to the incomplete thread portion 51. As can be seen by comparing Figures 3A and 3B, in the incomplete thread portion 51, the bottom portion 53 is displaced radially so as to approach the axis of the male connector 1 as it approaches the end 59 of the thread groove. In other words, in the incomplete thread portion 51, the thread groove of the female thread 16 gradually becomes shallower as it approaches the end 59. Then, at the end 59, the bottom portion 53 reaches the same radial position as the top portion 54, and the thread groove disappears. The part of the female thread 16 where the bottom portion 53 of the thread groove is displaced radially (or the part where the depth of the thread groove changes) is the incomplete thread portion 51.

[0044] In incomplete thread portion 51, flanks 55a, 55b become shorter as bottom portion 53 moves radially closer to the axis of male connector 1 toward terminal end 59. However, similar to complete thread portion 52, in incomplete thread portion 51, corners 69a, 69b with an arc-shaped cross section having a radius of curvature R9 smoothly connect bottom portion 53 and flanks 55a, 55b.

[0045] In the incomplete thread portion 51, the flange 18 is connected to the flank 55a (see FIG. 3A). On the proximal side of the thread groove, there is no crest 54, particularly no crest 54 having the same inner diameter as the crest 54 of the complete thread portion 52. The flank 55a gradually becomes shorter as it approaches the end 59. Just before the end 59, the flank 55a may be substantially absent, and the flange 18 may be connected to the base 53 via a corner 69a (see FIG. 4).

[0046] For comparison, a female screw 916 provided on a conventional male connector 910 (see FIGS. 18A and 18B) will be described. FIG. 5 is a plan view of the male connector 910 as seen from the tip side. As with FIG. 2, the male member 911 and the flow path 919 are omitted from FIG. 5 for simplicity's sake. FIGS. 6A to 6F are cross-sectional views of the male connector 910 taken along the cross sections 6A-6A to 6F-6F in FIG. 5. The cross sections 6A-6A to 6F-6F include the axis 910a of the male connector 910 and are rotated clockwise around the axis 910a by 30 degrees. The cross sections 6A-6A to 6F-6F in FIG. 5 correspond, in order, to the cross sections 3A-3A to 3F-3F in FIG. 2. FIGS. 6A to 6F show only the portion of the male connector 910 above the flange 918. 6A to 6F, the male member 911 and the flow path 919 are omitted so that the shape of the female screw 916 can be seen.

[0047] 7 is an enlarged cross-sectional view of the male connector 910 of FIG. 6B. Like the male thread 16 of embodiment 1, the female thread 916 has a complete thread portion 952 and an incomplete thread portion 951. The complete thread portion 952 is the same as the complete thread portion 52 of embodiment 1. The female thread 916 differs from the female thread 16 of embodiment 1 with respect to the incomplete thread portion 951, as will be explained below.

[0048] The cross section of FIG. 6A, like FIG. 3A, passes through the boundary between the complete thread portion 952 and the incomplete thread portion 951 of one of the two thread grooves that make up the double-start thread. In FIG. 6A, like FIG. 3A, the flange 918 is connected to the flank 55a. In FIG. 6B, the flange 918 is connected to the corner portion 69a. In FIG. 6C, the flange 918 is connected to the root portion 53. In FIG. 6D, the flange 918 is connected to the flank 55b. In this way, in the incomplete thread portion 951, as one approaches the terminal end 59 of the thread groove, the flange 918 is connected to the flank 55a (see FIG. 6A), the corner portion 69a (see FIG. 6B), the root portion 53 (see FIG. 6C), the corner portion 69b, and the flank 55b (see FIG. 6D) in this order. Thereafter, the flank 55b gradually becomes shorter. Then, at the terminal end 59 of the female thread 916, the flank 55b disappears, the flange 918 connects to the crest portion 54, and the thread groove disappears.

[0049] As described above, in the incomplete thread portion 951 of the conventional male connector 910, the crest 54 of the female thread 916 approaches the flange 918, narrowing the width of the thread groove as it approaches the terminal end 59. At the terminal end 59, the crest 54 connects to the flange 918, the width of the thread groove becomes zero, and the thread groove disappears. In the incomplete thread portion 951, the distance from the axis of the bottom 53 of the thread groove (or the depth of the thread groove) remains constant as long as the bottom 53 exists (see FIGS. 6A to 6C). In the portion where the bottom 53 disappears and the flange 918 connects to the flank 55b, the thread groove gradually becomes shallower as it approaches the terminal end 59 (see FIG. 6D). For this reason, the incomplete thread portion 951 has a narrow and deep thread groove (hereinafter referred to as a "narrow and deep groove") 957 near the terminal end 59 (or the flange 918) (see FIGS. 6C and 6D). When enteral nutrition is performed using the male connector 910 and liquid adheres to the narrow, deep groove 957 of the incomplete thread portion 951, it is difficult to completely remove the liquid from the narrow, deep groove 957 by simply washing with water or even by using a cleaning tool such as the cylindrical portion or brush of Patent Document 1.

[0050] In contrast, in the incomplete thread portion 51 of the male connector 1 of the first embodiment, the bottom portion 53 displaces closer to the axis 1a as it approaches the end 59. At the end 59, the bottom portion 53 reaches the same radial position as the top portion 54, and the thread groove disappears. In the incomplete thread portion 51, the flange 18 may be connected to the bottom portion 53, but is not connected to the flank 55b on the tip side. Therefore, the width of the thread groove is wide up to the end 59 (or the flange 18). Preferably, the width of the thread groove at any position in the incomplete thread portion 51 is wider than the width of the bottom portion 53 (dimension in the direction of the axis 1a) at the complete thread portion 52. In this way, the thread groove becomes shallower while maintaining the desired width, and reaches the end 59. The incomplete thread portion 51 does not have a narrow and deep thread groove like the narrow and deep groove 957 (see FIGS. 6C and 6D) formed in the incomplete thread portion 951 of the conventional male connector 910. Therefore, even if liquid adheres to the thread groove of the incomplete thread portion 51 when using the male connector 1 for enteral nutrition, the liquid can be easily washed away by rinsing with water, etc. Furthermore, when a cleaning tool such as the cylindrical portion or brush of Patent Document 1 is inserted into the gap 14, the cleaning tool easily penetrates the wide and shallow thread groove of the incomplete thread portion 51, deforms to fit closely to the inner surface that defines the thread groove, and slides on the inner surface of the thread groove. The thread groove of the incomplete thread portion 51 can be thoroughly cleaned using the cleaning tool. Therefore, the male connector 1 of this embodiment 1 is easy to clean and is advantageous for maintaining good hygiene.

[0051] Like the incomplete thread portion 951 of the conventional male connector 910, the incomplete thread portion 51 does not participate in threading with the helical protrusion 926 (see FIGS. 19A and 19B) of the female connector 920. In the incomplete thread portion 51, even if the radial position of the bottom portion 53 is closer to the axis 1a than the complete thread portion 52, this does not affect the connection of the male connector 1 to the female connector 920. Therefore, the male connector 1 is compatible with the conventional male connector 910 in terms of connection with the female connector 920.

[0052] (Embodiment 2) The second embodiment differs from the first embodiment in terms of the incomplete thread portion 51. The second embodiment will be described focusing on the differences from the first embodiment.

[0053] The external shape of the male connector 2 according to the second embodiment is generally the same as that of the male connector 1 according to the first embodiment (see FIGS. 1A and 1B), and is therefore omitted from the illustration. FIG. 8 is a plan view of the male connector 2 as seen from the tip side. As with FIG. 2, the male member 11 and the flow path 19 are omitted from FIG. 8. FIGS. 9A to 9F are cross-sectional views of the male connector 2 taken along the cross sections 9A-9A to 9F-9F in FIG. 8. The cross sections 9A-9A to 9F-9F include the axis 1a of the male connector 2 and are rotated clockwise around the axis 1a by 30 degrees. FIGS. 9A to 9F show only the portion of the male connector 2 above the flange 18. Furthermore, the male member 11 and the flow path 19 are omitted from FIGS. 9A to 9F so that the shape of the female thread 16 can be seen. As in the first embodiment, in the second embodiment, the bottom portion 53 of the incomplete thread portion 51 is displaced so as to approach the axis 1a of the male connector 2 as it approaches the end 59.

[0054] FIG. 10 is an enlarged cross-sectional view of FIG. 9B. Unlike the first embodiment, the second embodiment has a corner 61a with a circular arc-shaped cross section having a relatively large radius of curvature R1 formed between the bottom 53 and the flange 18 in the incomplete thread portion 51. The corner 61a smoothly connects the bottom 53 and the flange 18. The radius of curvature R1 is not limited, but is preferably 0.6 mm or more, and even 0.8 mm or more. The upper limit of the radius of curvature R1 is not limited, but is preferably equal to or less than the depth of the thread groove in the complete thread portion 52 of the female thread 16, and even preferably equal to or less than half of that depth. As shown in FIGS. 9A and 9B, the corner 61a with the radius of curvature R1 is continuously formed along the entire length of the incomplete thread portion 51. Furthermore, even in the region beyond the end 59 of the thread groove, a corner 67 having an arcuate cross section with a relatively large radius of curvature is formed between the apex 54 and the flange 18 so as to smoothly connect the apex 54 and the flange 18 (see FIGS. 9C and 9D). The radius of curvature of the corner 67 is not limited, but is preferably 0.6 mm or more, and further preferably 0.8 mm or more, and can be set to the same as the radius of curvature R1, for example.

[0055] Thus, in the second embodiment, the incomplete thread portion 51 has a corner 61a with an arc-shaped cross section having a relatively large radius of curvature R1, which is formed so as to be continuous with the bottom portion 53. Even if liquid adheres to the corner 61a when enteral nutrition is performed using the male connector 2, the liquid can be easily washed away with water or the like. Furthermore, when a cleaning tool such as the cylindrical portion or brush of Patent Document 1 is inserted into the gap 14, the cleaning tool easily deforms to adhere to the surface of the corner 61a and can slide over the surface of the corner 61a. The corner 61a can be thoroughly cleaned using the cleaning tool. Therefore, the male connector 2 of the second embodiment is easier to clean than the male connector 1 of the first embodiment, and is advantageous for maintaining good hygiene.

[0056] In the second embodiment, a corner 69b having an arc-shaped cross section with a relatively small radius of curvature R9 is provided between the bottom 53 and the flank 55b of the incomplete thread portion 51, as in the first embodiment (see FIG. 10). However, the present invention is not limited to this. Instead of the corner 69b, a corner having an arc-shaped cross section with a relatively large radius of curvature R1 may be provided between the bottom 53 and the flank 55b (or the top 54) of the incomplete thread portion 51.

[0057] The fully threaded portion 52 of the second embodiment is the same as the fully threaded portion 52 of the first embodiment. That is, the fully threaded portion 52 has corners 69a, 69b of an arc-shaped cross section having a relatively small radius of curvature R9 that are continuous with the bottom portion 53 (see FIG. 10 ). This is advantageous in reducing the possibility that the helical protrusion 926 of the female connector 920 will collide with the corners 69a, 69b of the fully threaded portion 52 when the male connector 2 is connected to the female connector 920 ( FIGS. 19A and 19B ). Because the fully threaded portion 52 is relatively easier to clean than the incomplete threaded portion 51, even if the fully threaded portion 52 has corners 69a, 69b of an arc-shaped cross section having a relatively small radius of curvature R9, the thread groove of the fully threaded portion 52 is unlikely to become unsanitary.

[0058] In the above example, the incomplete thread portion 51 does not substantially have a flank 55a (see FIG. 7), and the corner portion 61a smoothly connects the bottom portion 53 and the flange 18, but the present invention is not limited to this. For example, in the incomplete thread portion 51, the flange 18 may be connected to the flank 55a as in the first embodiment, and a corner portion 61a with an arc-shaped cross section having a relatively large radius of curvature R1 may be provided between the flank 55a and the bottom portion 53 so as to smoothly connect the flank 55a and the bottom portion 53.

[0059] Except for the above, the present embodiment 2 is the same as the embodiment 1. The description of the embodiment 1 also applies to the present embodiment 2.

[0060] (Embodiment 3) The third embodiment differs from the first embodiment in terms of the complete thread portion 52 and the incomplete thread portion 51. The third embodiment will be described focusing on the differences from the first embodiment.

[0061] The external shape of the male connector 3 according to the third embodiment is generally the same as that of the male connector 1 according to the first embodiment (see FIGS. 1A and 1B), and is therefore omitted from the illustration. FIG. 11 is a plan view of the male connector 3 as seen from the tip side. As with FIGS. 2 and 8, the male member 11 and the flow path 19 are omitted in FIG. 11. FIGS. 12A to 12F are cross-sectional views of the male connector 3 taken along the cross sections 12A-12A to 12F-12F in FIG. 11. The cross sections 12A-12A to 12F-12F include the axis 1a of the male connector 3 and are rotated clockwise around the axis 1a by 30 degrees. FIGS. 12A to 12F show only the portion of the male connector 3 above the flange 18. Furthermore, the male member 11 and the flow path 19 are omitted in FIGS. 12A to 12F so that the shape of the female thread 16 can be seen. As in the first embodiment, in the third embodiment, the bottom portion 53 of the incomplete thread portion 51 is displaced so as to approach the axis 1a of the male connector 3 as it approaches the end 59.

[0062] FIG. 13 is a cross-sectional view of the male connector 3, enlarged from FIG. 12B. In this third embodiment, instead of the corners 69a and 69b (see FIG. 4) having a relatively small radius of curvature R9 of the first embodiment, corners 61a and 61b having a relatively large radius of curvature R1 are provided along the entire length of the thread groove of the female thread 16. The radius of curvature R1 is not limited, but is preferably 0.6 mm or greater, and more preferably 0.8 mm or greater. The upper limit of the radius of curvature R1 is not limited, but is preferably equal to or less than the depth of the thread groove of the fully threaded portion 52 of the female thread 16, and more preferably equal to or less than half of that depth. The radius of curvature R1 is set so that the corners 69a and 69b of the fully threaded portion 52 do not collide with the helical protrusion 926 of the female connector 920 when the male connector 1 is connected to the female connector 920 (see FIGS. 19A and 19B).

[0063] In the second embodiment, the corner 61a having the radius of curvature R1 is provided only on the flange 18 (base end) side relative to the bottom 53 in the incomplete thread portion 51 (see FIG. 10). In contrast, in the third embodiment, the corners 61a and 61b having the radius of curvature R1 are provided on both the flange 18 (base end) side and the tip side relative to the bottom 53 in the incomplete thread portion 51 and the complete thread portion 52.

[0064] More specifically, corner portion 61b, which has a circular arc-shaped cross section and a relatively large radius of curvature R1, smoothly connects bottom portion 53 and flank 55b along the entire length of the thread groove of female thread 16. Corner portion 61a, which has a circular arc-shaped cross section and a relatively large radius of curvature R1, smoothly connects bottom portion 53 and flange 18 (or flank 55a) in incomplete thread portion 51, and smoothly connects bottom portion 53 and flank 55a in complete thread portion 52.

[0065] Thus, in the third embodiment, corners 61a, 61b with a circular arc-shaped cross section having a relatively large radius of curvature R1 are formed along the entire length of the thread groove of the female thread 16, continuing to the bottom 53. Even if liquid adheres to the corners 61a, 61b when performing enteral nutrition using the male connector 3, the liquid can be easily washed away with water or the like. Furthermore, when a cleaning tool such as the cylindrical portion or brush of Patent Document 1 is inserted into the gap 14, the cleaning tool easily deforms to adhere closely to the surfaces of the corners 61a, 61b, allowing it to slide over the surfaces of the corners 61a, 61b. The corners 61a, 61b can be thoroughly cleaned using the cleaning tool. Therefore, the male connector 3 of the third embodiment is easier to clean than the male connectors 1, 2 of the first and second embodiments, and is advantageous for maintaining good hygiene.

[0066] Except for the above, the present embodiment 3 is the same as the embodiments 1 and 2. The explanations of the embodiments 1 and 2 are similarly applied to the present embodiment 3.

[0067] (Embodiment 4) The fourth embodiment differs from the first embodiment in terms of the incomplete thread portion 51. The fourth embodiment will be described focusing on the differences from the first embodiment.

[0068] The external shape of the male connector 4 according to the fourth embodiment is generally the same as that of the male connector 1 according to the first embodiment (see FIGS. 1A and 1B), and is therefore omitted from the illustration. FIG. 14 is a plan view of the male connector 4 as seen from the tip side. As with FIGS. 2, 8, and 11, the male member 11 and the flow path 19 are omitted in FIG. 14. FIGS. 15A to 15F are cross-sectional views of the male connector 4 taken along the cross sections 15A-15A to 15F-15F in FIG. 14. The cross sections 15A-15A to 15F-15F include the axis 1a of the male connector 4 and are rotated clockwise around the axis 1a by 30 degrees. FIGS. 15A to 15F show only the portion of the male connector 4 above the flange 18. Furthermore, the male member 11 and the flow path 19 are omitted in FIGS. 15A to 15F so that the shape of the female thread 16 can be seen.

[0069] FIG. 16 is a cross-sectional view of the male connector 4, enlarged from FIG. 15C. Unlike Embodiments 1 to 3, in Embodiment 4, the incomplete thread portion 51 does not substantially have flanks 55a, 55b having linear cross sections. The thread groove of the incomplete thread portion 51 is configured with an arc-shaped cross section 63 smoothly connected to the flange 18. The radius of curvature R3 of the arc-shaped cross section 63 is greater than the radius of curvature R9 of the corners 69a, 69b of the complete thread portion 52. Specifically, the radius of curvature R3 is 0.6 mm or greater, preferably 0.8 mm or greater. There is no upper limit to the radius of curvature R3, but it is preferably equal to or less than the depth of the thread groove in the complete thread portion 52 of the female thread 16. The arc-shaped cross section 63 is provided continuously over the entire length of the incomplete thread portion 51. The radius of curvature R3 may vary over the entire length of the incomplete thread portion 51, but is preferably constant. The arc-shaped cross section 63 defines the deepest part of the thread groove in the incomplete thread portion 51. The arc-shaped cross section 63 connects the flange 18 and the apex 54. As in the first embodiment, in the incomplete thread portion 51, the depth of the thread groove becomes shallower as it approaches the terminal end 59 of the thread groove. In other words, in the fourth embodiment, the incomplete thread portion 51 is the part of the female thread 16 where the depth of the thread groove becomes shallower as it approaches the terminal end 59.

[0070] In the fourth embodiment, the thread groove of the incomplete thread portion 51 is configured with an arc-shaped cross section 63 having a radius of curvature R3 greater than the radius of curvature R9 of the corners 69a, 69b of the complete thread portion 52. The arc-shaped cross section 63 displaces toward the axis of the male connector 4 as it approaches the terminal end 59. At the terminal end 59, the thread groove disappears. In the incomplete thread portion 51, the width of the thread groove narrows toward the terminal end 59, but in parallel with this, the thread groove becomes shallower. Therefore, the incomplete thread portion 51 does not have a narrow and deep thread groove like the narrow and deep groove 957 (see FIGS. 6C and 6D) formed in the incomplete thread portion 951 of the conventional male connector 910. Even if liquid adheres to the arc-shaped cross section 63 when enteral nutrition is performed using the male connector 4, the liquid can be easily washed away by rinsing with water, etc. Furthermore, when a cleaning tool such as the cylindrical portion or brush of Patent Document 1 is inserted into gap 14, the cleaning tool easily penetrates into the wide, shallow thread groove of incomplete thread portion 51, easily deforms to fit closely to the surface of arc-shaped cross section 63 that defines the thread groove, and slides over the surface of arc-shaped cross section 63. Incomplete thread portion 51 can be thoroughly cleaned using the cleaning tool. Therefore, male connector 4 of this embodiment 4 is easy to clean and advantageous for maintaining good hygiene.

[0071] Like the incomplete thread portion 951 of the conventional male connector 910, the incomplete thread portion 51 does not participate in threading with the helical protrusion 926 (see FIGS. 19A and 19B) of the female connector 920. Even though the thread groove of the incomplete thread portion 51 is configured with an arc-shaped cross section 63 having a relatively large radius of curvature R3 and the thread groove becomes shallower as it approaches the end 59, this does not affect the connection of the male connector 4 to the female connector 920. Therefore, the male connector 4 is compatible with the conventional male connector 910 in terms of connection with the female connector 920.

[0072] Except for the above, the fourth embodiment is the same as the first embodiment. The description of the first embodiment also applies to the fourth embodiment.

[0073] In the fourth embodiment, the thread groove of the complete thread portion 52 may have corners 61a and 61b having an arc-shaped cross section with a relatively large radius of curvature R1, instead of the corners 69a and 69b, as described in the third embodiment. In this case, the same effects as those of the third embodiment are achieved.

[0074] (Embodiment 5) 17 is a cross-sectional view of a male connector 5 according to a fifth embodiment of the present invention. Male connector 5 differs from the third embodiment in the shape of the base end of male member 11. The fifth embodiment will be described, focusing on the differences from the third embodiment.

[0075] In the fifth embodiment, a corner 65 having an arc-shaped cross section with a relatively large radius of curvature R5 is formed between the base end of the male member 11 and the flange 18. The corner 65 smoothly connects the male member 11 and the flange 18. The radius of curvature R5 is 0.6 mm or more, and preferably 0.8 mm or more. There is no upper limit to the radius of curvature R5, but it is preferably equal to or less than the pitch of the female thread 16, more preferably equal to or less than 1 / 2, and particularly preferably equal to or less than 1 / 3 of the pitch of the female thread 16.

[0076] In the fifth embodiment, the male member 11 and the flange 18 are smoothly connected by a corner 65 having a relatively large radius of curvature R5. Even if liquid adheres to the corner 65 when enteral nutrition is performed using the male connector 5, the liquid can be easily washed away by rinsing with water, etc. Furthermore, when a cleaning tool such as the cylindrical part or brush of Patent Document 1 is inserted into the gap 14, the cleaning tool easily deforms to adhere to the surface of the corner 65 and can slide over the surface of the corner 65. The corner 65 can be thoroughly cleaned using the cleaning tool. Therefore, the male connector 5 of the fifth embodiment is easy to clean and advantageous for maintaining good hygiene.

[0077] Except for the above, the fifth embodiment is the same as the third embodiment. The description of the third embodiment also applies to the fifth embodiment.

[0078] The corner portion 65 of the fifth embodiment may be applied to the male connectors 1, 2, and 4 of the first, second, and fourth embodiments. In this case, the same effects as those of the fifth embodiment are achieved.

[0079] The above-mentioned embodiments 1 to 5 are merely examples, and the present invention is not limited to the above-mentioned embodiments, and can be modified as appropriate.

[0080] In the above-described first to fifth embodiments, the flange 18 is a flat plate extending in the radial direction, but the present invention is not limited to this. For example, the flange 18 may be formed along a conical surface that is coaxial with the axis of the male connector, and more specifically, along a conical surface that widens in diameter toward the tip side of the male connector (the side opposite the connecting tube 21).

[0081] A through-hole that connects the gap 14 to the outside may be formed in the flange 18 and / or the outer cylinder 15 (see, for example, Patent Document 2).

[0082] Although the corners 61a, 61b, 65, 67, 69a, and 69b in the above-described first to fifth embodiments have arc-shaped cross sections, the corners of the present invention are not limited thereto. For example, some or all of the corners 61a, 61b, 65, 67, 69a, and 69b may have an inclined straight line (i.e., a linear cross section) in a cross section along a plane including the axis 1a. The "inclined straight line" may be a straight line connecting both ends of the arc that constitutes the arc-shaped cross section. In a cross section along a plane including the axis 1a, the length of the straight line that constitutes the corner having a linear cross section can be varied depending on the radius of curvature of the arc that constitutes the corner having an arc-shaped cross section.

[0083] The male connector of the present invention may be used for purposes other than enteral nutrition. [Industrial Applicability]

[0084] The present invention can be widely used in the medical field, particularly as a male connector for use in enteral nutrition, and is particularly suitable for use as a male connector provided at the upstream end of a catheter that is inserted into a patient and left in the patient for an extended period of time. [Explanation of symbols]

[0085] 1,2,3,4,5 male connector 1a Male connector shaft 11 Male member 12 Male tapered surface 14 Gap 15 outer cylinder 16 female thread 18 flange 19 Flow path 51 Incomplete thread 52 Fully threaded 53 Bottom of thread groove 54 Top of female thread 55a, 55b Thread groove flank 59 Thread groove end 61a, 61b Corner of screw groove 63 Circular cross section of screw groove 65 Corner between the base end of the male member and the flange 69a, 69b Corner of screw groove

Claims

1. a cylindrical male member having a flow path formed therein; an outer cylinder surrounding the male member; A male connector having a female screw formed in a spiral shape from the tip end of the outer tube to the base end of the outer tube on an inner surface of the outer tube facing the male member, The thread groove of the female screw is composed of a bottom portion and a pair of flanks that face each other in the axial direction of the male connector with the bottom portion in between, The female screw has an incomplete thread portion near the end of the thread groove on the base end side of the outer cylinder, in which the bottom of the thread groove is displaced so as to approach the axis of the male connector as it approaches the end, A male connector characterized in that the female thread further has a complete thread portion, which is located at a constant distance from the axis of the bottom, and is continuous with the incomplete thread portion, closer to the tip of the outer tube than the incomplete thread portion.

2. The male connector further includes a flange connecting a base end of the male member and a base end of the outer tube, 2. The male connector according to claim 1, wherein the flange is not connected to the flank on the tip side of the outer cylinder in the incomplete thread portion.

3. A male connector as described in claim 1 or 2, wherein the width of the thread groove at the incomplete thread portion is wider than the width of the bottom at the complete thread portion.

4. The incomplete thread portion has a first corner portion having an arc-shaped cross section formed so as to be continuous with the bottom portion, 4. The male connector according to claim 1, wherein the radius of curvature of the first corner portion is 0.6 mm or more.

5. In the fully threaded portion, a second corner portion having an arc-shaped cross section is formed so as to be continuous with the bottom portion, 5. The male connector according to claim 4, wherein the radius of curvature of the second corner portion is 0.6 mm or more.

6. In the incomplete thread portion, a first corner portion having an arc-shaped cross section is formed so as to be continuous with the bottom portion, a second corner portion having an arc-shaped cross section is formed in the fully threaded portion so as to be continuous with the bottom portion, 5. The male connector according to claim 1, wherein the radius of curvature of the first corner portion is larger than the radius of curvature of the second corner portion.

7. a cylindrical male member having a flow path formed therein; an outer cylinder surrounding the male member; a female screw formed in a spiral shape from the tip end of the outer cylinder toward the base end of the outer cylinder on an inner surface of the outer cylinder facing the male member; A male connector comprising a flange connecting a base end of the male member and a base end of the outer tube, The female thread includes a complete thread portion having a constant depth of the thread groove, and an incomplete thread portion that is continuous with the complete thread portion on the base end side of the outer tube and whose depth of the thread groove becomes shallower as it approaches the terminal end of the thread groove on the base end side of the outer tube, The thread groove in the complete thread portion is composed of a bottom portion, a pair of flanks facing each other in the axial direction of the male connector across the bottom portion, and a corner portion of an arc-shaped cross section connecting the bottom portion and the pair of flanks, The thread groove of the incomplete thread is configured with an arc-shaped cross section smoothly connected to the flange, A male connector, characterized in that the radius of curvature of the arc-shaped cross section of the incomplete thread portion is larger than the radius of curvature of the corner of the complete thread portion.

8. The male connector according to claim 7, wherein the radius of curvature of the arc-shaped cross section of the incomplete thread portion is 0.6 mm or more.

9. The male connector according to claim 7 or 8, wherein the arcuate cross section of the incomplete thread portion connects the flange and the apex of the female thread.

10. The male connector according to any one of claims 7 to 9, wherein the radius of curvature of the arc-shaped cross section of the incomplete thread portion is constant over the entire length of the incomplete thread portion.

11. the male connector includes a flange connecting a base end of the male member and a base end of the outer tube, A male connector according to any one of claims 1 to 10, wherein a third corner portion having an arc-shaped cross section with a curvature radius of 0.6 mm or more is formed between the base end of the male member and the flange.

Images