Needle assembly

Abstract

Provided is a needle assembly having a novel structure allowing air on the side closer to the needle tip than a valve body to be discharged while preventing blood from leaking.　The needle assembly 10 is provided with: a hollow needle body 12; a cylindrical valve housing 14 provided on the base end side of the needle body 12; and a valve body 44 housed in the inner cavity 16 of the valve housing 14 and switching between communication and blocking of the inner cavity 16 in the valve housing 14. The needle assembly 10 is provided with an air bleeding path 48 that traverses the valve housing 14. The air bleeding path 48 communicates with the inner cavity 16 of the valve housing 14 on the side closer to the needle tip of the needle body 12 than the valve body 44. Provided midway along the air bleeding path 48 is a liquid accumulation portion 50 having a locally increased cross-sectional area.

Description

[Technical field]

[0001] The present invention relates to a needle assembly, for example an indwelling needle with a valve. [Background technology]

[0002] Conventionally, some needle assemblies, such as intravenous indwelling needles, are provided with a valve body to prevent backflow of blood. The needle assembly has a structure in which, for example, the valve body is housed in the inner cavity of a valve housing connected to the base end side of the needle body. As a result, when the needle assembly is inserted into a vein, for example, the valve body prevents blood that has entered the inner cavity of the valve housing from flowing out to the outside. An example of a needle assembly provided with such a valve body is disclosed in Japanese Patent Application Laid-Open No. 2002-263197 (Patent Document 1).

[0003] Incidentally, when a valve body that blocks the inner cavity of the valve housing is provided, it is necessary to vent air in order to fill the area of ​​the inner cavity of the valve housing on the needle tip side of the valve body with blood when the needle body is inserted into a blood vessel, etc. In Patent Document 1, therefore, an air vent groove is formed penetrating the outer circumferential surface of the valve body in the axial direction, and this air vent groove allows air on the needle tip side of the valve body to be vented to the base end side through an air vent passage formed between the valve body and the valve housing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-263197 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, forming an air vent passage between the valve body and the valve housing may result in an insufficient air vent passage. In other words, since the valve body is an elastic body that can switch between communicating and blocking the inner cavity of the valve housing by deformation, the outer surface of the valve body in particular may become distorted after assembly into the valve housing, which may cause the cross-sectional shape and cross-sectional area of ​​the air vent passage to change. This may result in a problem that air cannot be vented stably.

[0006] An object of the present invention is to provide a needle assembly of a novel structure that can prevent blood leakage while discharging air from the needle tip side relative to the valve body. [Means for solving the problem]

[0007] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0008] The first aspect is a needle assembly comprising a hollow needle body, a cylindrical valve housing provided on the base end side of the needle body, and a valve body received in the inner cavity of the valve housing for switching between communication and blocking of the inner cavity of the valve housing, wherein an air vent passage is provided through the valve housing and communicates with the inner cavity of the valve housing on the needle tip side of the needle body relative to the valve body, and a liquid reservoir portion with a partially enlarged cross-sectional area is provided midway through the air vent passage.

[0009] In the needle assembly constructed according to this aspect, the air vent passage is provided penetrating the valve housing which is harder than the valve body, so that the cross-sectional shape and cross-sectional area of ​​the air vent passage are stable.

[0010] By providing a liquid reservoir with an increased cross-sectional area in the air vent passage, the progress of blood that has entered the air vent passage by capillary action is blocked in the liquid reservoir, thereby preventing blood that has entered the region of the valve housing on the needle tip side from the valve body from leaking out through the air vent passage to the outside.

[0011] In a second aspect, in the needle assembly described in the first aspect, the air vent passages are provided at a plurality of positions in the circumferential direction of the valve housing.

[0012] With a needle assembly constructed according to this aspect, air can be efficiently discharged through the multiple air vent passages. Also, the cross-sectional area of ​​each air vent passage can be reduced while ensuring the total cross-sectional area of ​​the air vent passages necessary for discharging air, thereby preventing blood from entering the air vent passages.

[0013] A third aspect is the needle assembly according to the first or second aspect, wherein the liquid reservoir is formed into an annular shape that is continuous in the circumferential direction of the valve housing.

[0014] With a needle assembly constructed according to this aspect, the volume of the liquid reservoir can be increased, making it possible to more effectively prevent blood from leaking through the air vent passage.

[0015] A fourth aspect is a needle assembly according to any one of the first to third aspects, wherein the valve housing comprises a first component and a second component connected to the base end side of the first component, and the air vent passage is formed between the first and second components.

[0016] In a needle assembly constructed according to this aspect, by forming an air vent passage between the first and second component members, the cross-sectional shape and cross-sectional area of ​​the air vent passage can be designed with greater freedom than when an air vent passage is formed through a single component. In particular, by reducing the cross-sectional area of ​​the air vent passage, the amount of blood that enters the air vent passage can be reduced.

[0017] In a fifth aspect, in the needle assembly described in the fourth aspect, the second component is fitted into the inner periphery of the first component to connect them, and the liquid reservoir is formed by a recess that opens onto the outer periphery of the part of the second component that is fitted into the first component.

[0018] In a needle assembly constructed according to this aspect, the second component is fitted into the inner periphery of the first component, so that the opening of the recess provided in the second component is covered by the first component to form a liquid reservoir, and the liquid reservoir can be easily formed between the second component and the first component.

[0019] By forming the recess for forming the liquid reservoir portion so that it opens into the outer peripheral surface of the second component, the recess can be formed with precision, and leakage of blood through the air vent passage can be more effectively prevented.

[0020] In a sixth aspect, in the needle assembly described in the fourth or fifth aspect, the base end portion of the first component is provided with a support surface which extends radially inward and is superimposed on at least one of the valve body and the second component, a groove which forms the air vent passage is opened into the support surface, and an operating member which is inserted into the valve housing from the base end side causes the valve body to deform toward the tip end, thereby closing the air vent passage.

[0021] With a needle assembly constructed according to this aspect, an air vent passage can be realized more stably than when an air vent passage is formed by providing a groove in the valve body. Also, because the end of the air vent passage is formed in the vicinity of the valve, when the operating member is inserted from the base end of the valve housing, the air vent passage and the inner cavity of the valve housing can be reliably brought into a non-communicating state, and even if the pressure inside the valve housing increases, that pressure is unlikely to act on the air vent passage, preventing the liquid in the air vent passage from leaking to the outside.

[0022] In a seventh aspect, the needle assembly according to any one of the first to sixth aspects further includes a cap member that is inserted into the valve housing from the base end side to block the inner cavity of the valve housing and deforms the valve body toward the tip side to block the air vent passage with the valve body, and the cap member is detachable from the valve housing.

[0023] With a needle assembly constructed according to this aspect, for example, when the needle is left in a state in which it is inserted into a patient's blood vessel, the cap member can be inserted into the inner cavity of the valve housing and attached to close the inner cavity of the valve housing and the air vent passage, thereby preventing blood from leaking through the inner cavity of the valve housing and the air vent passage, and making it possible, for example, to maintain the needle assembly in a retained state for a relatively long period of time.

[0024] An eighth aspect is a needle assembly comprising a hollow needle body, a cylindrical valve housing provided on the base end side of the needle body, and a valve body accommodated in the inner cavity of the valve housing for switching between communication and blocking of the inner cavity of the valve housing, wherein a retaining portion is provided protruding from the inner surface of the valve housing, the retaining portion is provided partially in the circumferential direction of the valve housing, and has an inclined surface that is inclined so that the protruding height increases toward the valve body side.

[0025] In a needle assembly constructed according to this aspect, the holding portion has an inclined surface, so that by moving the valve body from the base end toward the needle tip in the inner cavity of the valve housing, the valve body is guided by the inclined surface of the holding portion and easily overcomes the holding portion, and the valve body can be easily inserted axially into the inner cavity of the valve housing.

[0026] Since the retaining portion is provided partially in the circumferential direction of the valve housing, the contact area between the valve body and the retaining portion is small when the valve body is guided by sliding against the inclined surface of the retaining portion, so that the force required to insert the valve body axially into the bore of the valve housing is reduced, making it easier to attach the valve body to the valve housing. Effect of the Invention

[0027] According to the present invention, in the needle assembly, it is possible to prevent blood leakage while discharging air on the needle tip side relative to the valve body. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a front view of a needle assembly according to a first embodiment of the present invention; [Diagram 2] FIG. 2 is a longitudinal sectional view of the needle assembly shown in FIG. 1, which corresponds to the II-II section of FIG. [Diagram 3] FIG. 2 is an enlarged view of the III-III cross section of FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view taken along the line IV-IV of FIG. [Diagram 5] FIG. 2 is a longitudinal sectional view of the needle assembly shown in FIG. 1, showing a state in which the valve body is opened by the plunger; [Figure 6] FIG. 2 is a longitudinal sectional view showing a state in which a cap member is attached to the needle assembly shown in FIG. [Figure 7] FIG. 1 is a longitudinal cross-sectional view of a needle assembly according to a second embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0030] 1 to 4 show an indwelling needle 10 as a first embodiment of a needle assembly constructed according to the present invention. The indwelling needle 10 has a structure in which a valve housing 14 is connected to the base end side of a cannula 12 serving as a needle body. In the following description, the tip side generally refers to the left side in FIG. 2, which is the needle tip side of the cannula 12, and the base end side generally refers to the right side in FIG. 2, which is the opposite side to the needle tip of the cannula 12. In addition, the axial direction generally refers to the left-right direction in FIG. 2, which is the needle axial direction of the cannula 12.

[0031] The cannula 12 is hollow and cylindrical, and is made of, for example, a soft synthetic resin. The cannula 12 may have a tapered outer circumferential surface at the tip (not shown) that gradually reduces in diameter toward the tip. In addition, a plurality of through holes may be formed in the peripheral wall of the tip of the cannula 12 to facilitate the flow of liquids, such as blood, into the cannula 12. The cannula 12 may be hard, and may be made of, for example, a metal.

[0032] The valve housing 14 is generally cylindrical and has an inner cavity 16 that penetrates in the axial direction. The valve housing 14 is harder than a valve body 44, which will be described later, and is formed, for example, from a hard synthetic resin. The valve housing 14 includes a first component member 18 that is connected to the cannula 12, and a second component member 20 that is connected to the first component member 18, as shown in FIG.

[0033] The first component 18 has a tip 22 that is tapered and tubular in shape with a smaller diameter toward the tip. The cannula 12 is inserted into the tip 22 of the first component 18 from the tip side, and the cannula 12 is fixed to the inner circumferential surface of the tip 22. The valve housing 14 of this embodiment is a needle fixing part, and the cannula 12 is directly connected to the first component 18 that constitutes the tip part. The first component 18 also has a substantially cylindrical connecting tube part 24 that protrudes from the tip 22 to the base end side. The connecting tube part 24 is thinner and has a larger inner diameter than the base end of the tip 22, and the inner circumferential part of the base end surface of the tip 22 is an annular support surface 25 located on the inner circumference than the tip of the connecting tube part 24. The support surface 25 is provided at the base end part of the tip 22 of the first component 18 and extends radially inward.

[0034] A groove 26 is formed in the inner peripheral surface and the support surface 25 of the connecting tube portion 24 of the first component member 18. The groove 26 is provided partially in the circumferential direction of the first component member 18. The groove 26 extends linearly in the radial direction on the support surface 25, and extends linearly in the axial direction on the inner peripheral surface of the connecting tube portion 24. One end of the groove 26 reaches the inner peripheral end of the support surface 25, and the other end reaches the base end of the connecting tube portion 24. The number of grooves 26 is not particularly limited, but is preferably a plurality, and in this embodiment, eight grooves 26 are arranged at approximately equal intervals in the circumferential direction.

[0035] The second component 20 has a generally cylindrical shape, and a male threaded portion 28 protruding to the outer periphery is provided at the base end. The base end portion on the inner circumferential surface of the second component 20 is set with a female luer taper that becomes smaller in diameter toward the tip side, so as to fit closely to the outer circumferential surface of the male connector 52 described later.

[0036] The second component member 20 is provided with a positioning portion 30 that protrudes toward the outer periphery at an axially intermediate portion. The positioning portion 30 gradually increases in protruding height toward the tip. The positioning portion 30 is provided around the entire circumference, and as shown in FIG. 3, communication grooves 32 are provided at multiple locations in the circumferential direction.

[0037] A first holding portion 34 and a second holding portion 36 protrude from the inner peripheral surface of the second component member 20 as holding portions. The first holding portion 34 is provided partially in the circumferential direction of the second component member 20 and extends linearly in the axial direction. A plurality of the first holding portions 34 are provided in the circumferential direction of the second component member 20 at intervals from each other, and in this embodiment, eight first holding portions 34 are arranged at equal intervals in the circumferential direction of the second component member 20. The protruding end surface of the first holding portion 34 is an inclined surface 38 that inclines toward the inner circumference toward the tip side in the axial direction, and the protruding height increases toward the tip side in the axial direction, which is the side where the valve body 44 described later is disposed. In this embodiment, the inclined surface 38 is inclined at a substantially constant inclination angle, but the inclination angle may change gradually or in stages. The axial length of the first holding portion 34 is longer than the axial length of the valve body 44 described later.

[0038] The second retaining portion 36 is partially provided in the circumferential direction of the second component member 20 and extends linearly in the axial direction. A plurality of the second retaining portions 36 are provided in the circumferential direction of the second component member 20 at intervals, and in this embodiment, eight second retaining portions 36 are arranged at equal intervals in the circumferential direction of the second component member 20. The second retaining portions 36 are arranged away from the first retaining portion 34 toward the tip side, and a valve body accommodating portion 40 is provided between the first retaining portion 34 and the second retaining portion 36 in the axial direction. The protruding end surface of the first retaining portion 34 and the protruding end surface of the second retaining portion 36 are both positioned protruding inward from the inner peripheral surface of the peripheral wall of the valve body accommodating portion 40. The protruding height of the second retaining portion 36 is approximately constant in the axial direction. The axial length of the first retaining portion 34 is longer than the axial length of the second retaining portion 36. The protruding height of the first holding portion 34 and the protruding height of the second holding portion 36 may be different from each other, but in this embodiment, they are set to be approximately the same.

[0039] The second retaining portion 36 is disposed at a position spaced apart from the first retaining portion 34 in the circumferential direction of the second component member 20, and in this embodiment, the first retaining portion 34 and the second retaining portion 36 are alternately disposed in the circumferential direction. This allows the inner circumferential surface of the second component member 20 including the first retaining portion 34 and the second retaining portion 36 to be molded by a simple mold structure divided in the axial direction when the second component member 20 is manufactured by molding such as injection molding. That is, the end face of the first retaining portion 34 on the valve body accommodating portion 40 side and both side end faces and the protruding end face of the second retaining portion 36 can be molded by the mold on the tip side, and the both side end faces and the protruding end face of the first retaining portion 34 and the end face of the second retaining portion 36 on the valve body accommodating portion 40 side can be molded by the mold on the base side.

[0040] A recess 42 is open on the outer peripheral surface of the second component 20. The recess 42 is provided at the tip portion of the second component 20 that is fitted into the connecting tube portion 24 of the first component 18. The recess 42 is disposed in the middle of the tip portion of the second component 20 away from the axial tip, and is preferably located in the axial center of the tip portion of the second component 20. The recess 42 in this embodiment is annular and extends continuously in the circumferential direction. The cross-sectional shape of the recess 42 is not particularly limited, but is substantially semicircular in this embodiment. The recess 42 is disposed on the base end side in the axial direction relative to the valve body accommodating portion 40. It is desirable that the radial depth dimension of the recess 42 is greater than the depth dimension of the recessed groove 26 of the first component 18.

[0041] The valve body 44 is accommodated in the inner circumference of the second component member 20. The valve body 44 is an elastic body made of rubber or the like, has a generally disk shape, and has a notch 46 penetrating therethrough in the axial direction. The shape of the notch 46 is not limited, but for example, it is radial, and in this embodiment, it is radial extending in three directions from the center to the outer periphery. It is desirable that the outer diameter of the valve body 44 is larger than the inner diameter of the second component member 20 in the valve body accommodating portion 40.

[0042] The valve body 44 is inserted into the second component 20 from the base end. The base end opening of the second component 20 has a larger diameter than the valve body 44, so that the valve body 44 can be easily inserted into the base end opening of the second component 20. The valve body 44 moves toward the tip side along the inner circumference of the second component 20, passes over the first holding portion 34 toward the tip side, and is inserted into the valve body accommodating portion 40. When passing over the first holding portion 34, the valve body 44 abuts against the inclined surface 38, which is the protruding end surface of the first holding portion 34, and passes over the first holding portion 34 while being gradually compressed by the inclined surface 38. As a result, the valve body 44 passes over the first holding portion 34 smoothly without getting caught in the first holding portion 34, and is guided to the valve body accommodating portion 40.

[0043] Since the first retaining portion 34 is longer in the axial direction than the valve body 44, the first retaining portion 34 is not pressed locally against the outer peripheral surface of the valve body 44, and the outer peripheral surface of the valve body 44 is pressed against the inclined surface 38 of the first retaining portion 34 over a wide range. Furthermore, since the first retaining portion 34 is longer than the second retaining portion 36, the inclination angle of the inclined surface 38 of the first retaining portion 34 is reduced, making it easier to insert the valve body 44 into the valve body accommodating portion 40. Furthermore, since the second retaining portion 36 is short, the length of the second component member 20 can be shortened, and the valve housing 14 can be made compact in the axial direction.

[0044] The first retaining portion 34 and the second retaining portion 36 are located on both axial sides of the valve body 44 inserted into the valve body accommodating portion 40. The valve body 44 is positioned relative to the second component member 20, with its movement toward the base end being restricted by engagement with the first retaining portion 34 and its movement toward the tip end being restricted by engagement with the second retaining portion 36. In the valve housing 14 of this embodiment, the first retaining portion 34 and the second retaining portion 36 that position the valve body 44 are both provided on the second component member 20, and the valve body 44 is held in a positioned state by the second component member 20 as the valve body 44 climbs over the first retaining portion 34. According to such a structure of the first retaining portion 34 and the second retaining portion 36, the valve body 44 can be easily positioned and held by a single member without sandwiching the valve body 44 between two members.

[0045] When the valve element 44 reaches the valve element accommodating portion 40, it is released from contact with the first holding portion 34, and the compressive deformation caused by the contact with the first holding portion 34 is released. Since the inner diameter dimension of the valve element accommodating portion 40 is smaller than the outer diameter dimension of the valve element 44, the valve element 44 is disposed in the valve element accommodating portion 40 in a state compressed in the radial direction. As a result, the inner surfaces of the notches 46 are in close contact with each other, the notches 46 are sealed liquid-tight, and the inner cavity of the second component member 20 is blocked by the valve element 44.

[0046] The second component 20, to which the valve body 44 is attached, is connected to the first component 18 by fitting its tip portion into the connecting tube portion 24 of the first component 18. In this way, the valve housing 14 is formed by the first component 18 and the second component 20. The inner cavity of the first component 18 and the inner cavity of the second component 20 are connected to form the inner cavity 16 of the valve housing 14 that penetrates in the axial direction. The cannula 12 is provided so as to protrude from the valve housing 14 to the tip side, and the valve body 44 is housed in the inner cavity 16 of the valve housing 14, thereby forming the indwelling needle 10 of this embodiment.

[0047] In the connected state of the first component 18 and the second component 20, the tip surface of the second component 20 abuts against the support surface 25 of the first component 18. In addition, in the connected state of the first component 18 and the second component 20, the tip surface of the positioning portion 30 is overlapped with the base end surface of the first component 18. Therefore, it is possible to confirm from the outside by visual inspection or the like that the second component 20 is properly inserted into the first component 18. In addition, the positioning portion 30 is provided near an air vent passage 48 described later, and also functions as a cover portion that prevents the air vent passage 48 from being blocked by a user's finger when the user grips the outer surface of the valve housing 14. In addition, the communication groove 32 provided in the positioning portion 30 extends in the axial direction, and prevents the air vent passage 48 from being blocked by a user's finger when the user grips the outer surface of the valve housing 14. This eliminates the need to provide a separate cover to prevent the communication groove 32 from being covered by fingers, thereby preventing an increase in size of the valve housing 14. Note that a separate cover for covering the communication groove 32 can also be provided.

[0048] An air vent passage 48 is formed between the overlapping surfaces of the first component 18 and the second component 20 of the valve housing 14, penetrating the valve housing 14. That is, the opening of the recessed groove 26 provided in the first component 18 is covered by the second component 20 to form a tunnel-shaped passage. One end of this tunnel-shaped passage opens on the inner circumferential surface of the valve housing 14 on the tip side of the valve body 44 and communicates with the bore 16 of the valve housing 14, and the other end opens on the outer circumferential surface of the valve housing 14 through the communicating groove 32 of the second component 20 and opens to the external space A. As a result, the recessed groove 26 forms an air vent passage 48 that allows air to flow between the region of the bore 16 of the valve housing 14 on the tip side of the valve body 44 and the external space A. The air vent passages 48 are provided at a plurality of locations in the circumferential direction of the valve housing 14. Because the air vent passage 48 is provided between the overlapping surfaces of the first component member 18 and the second component member 20, it is easier to ensure the passage length and blood leakage is more effectively prevented than, for example, when the air vent passage 48 is formed by a through hole formed in the first component member 18 or the second component member 20. It is desirable for the air vent passage 48 to restrict the infiltration of blood while allowing air to pass through, and the amount of infiltrating blood can be reduced by, for example, reducing the cross-sectional area of ​​the passage by flattening the cross-sectional shape of the passage.

[0049] In addition, an experiment was conducted to confirm the leakage of liquid through the air vent passage 48 by applying an air pressure of up to 40 mmHg. As a result, it was found that, preferably, in the air vent passage 48 having a bottom surface with an arc-shaped cross section, the depth is greater than 0.04 mm and smaller than 0.06 mm, and the cross-sectional area of ​​the passage is 0.0087 mm 2 Larger than 0.0158mm 2It has been confirmed that the range is smaller than the range described above. In this range, air can be effectively discharged through the air vent passage 48 while preventing leakage of liquid through the air vent passage 48. Even if the internal pressure of the first component member 18 increases and a small amount of liquid flows into the air vent passage 48, the liquid reservoir section 50 described below retains the liquid inside and prevents the liquid from flowing out from the liquid reservoir section 50 to the air vent passage 48 at the base end. More preferably, the air vent passage 48 has a bottom surface with an arc-shaped cross section, and has a depth of 0.05 mm and a passage cross-sectional area of ​​0.0122 mm. 2 It was confirmed that this was the case.

[0050] The recess 42 opening on the outer peripheral surface of the second component member 20 is covered by the connecting tube portion 24 of the first component member 18. As a result, a ring-shaped liquid reservoir portion 50 that is continuous in the circumferential direction is formed by the recess 42. The liquid reservoir portion 50 is formed over the entire circumference between the overlapping surfaces of the connecting tube portion 24 of the first component member 18 and the second component member 20, and is therefore connected to the air vent passage 48 at multiple points in the circumferential direction. In other words, the liquid reservoir portion 50 is provided partially midway in the passage length direction of the air vent passage 48. In a cross section perpendicular to the passage length direction of the air vent passage 48, the cross-sectional area of ​​the recess 42 is larger than the cross-sectional area of ​​the recessed groove 26, and therefore the liquid reservoir portion 50 is formed with a cross-sectional area larger than that of the air vent passage 48. Since the liquid reservoir 50 is connected to the air vent passage 48, if the liquid reservoir 50 is regarded as a part of the air vent passage 48, the air vent passage 48 is partially expanded in the liquid reservoir 50 to increase the cross-sectional area. In short, the liquid reservoir 50 is formed in the air vent passage 48 by forming a part of the flow path extending in the axial direction whose cross-sectional area is larger than the surrounding area. In particular, the liquid reservoir 50 is deeper in the overlapping direction of the first component member 18 and the second component member 20 than the air vent passage 48 outside the liquid reservoir 50. The liquid reservoir 50 in this embodiment is provided between the overlapping surfaces of the inner circumferential surface of the first component member 18 and the outer circumferential surface of the second component member 20, and is disposed in the middle of the part of the air vent passage 48 that extends linearly in the axial direction. In particular, in this embodiment, the liquid reservoir 50 is disposed approximately in the center of the part of the air vent passage 48 that extends linearly in the axial direction. The axial length of the liquid reservoir 50 is shorter than the axial length of the axially extending air vent passage 48 other than the liquid reservoir 50. Note that the liquid reservoir 50 may be formed to have a certain degree of length, and may be formed to extend in the axial direction longer than the axial length of the axially extending air vent passage 48 other than the liquid reservoir 50, for example.

[0051] The indwelling needle 10 thus constructed is, for example, inserted into a blood vessel to form a circuit for infusion, blood collection, etc. That is, first, an inner needle (not shown) inserted into the cannula 12 from the base end side through the slit 46 of the valve body 44 is inserted into the blood vessel together with the cannula 12 as an outer needle. Next, the inner needle is removed, and the indwelling needle 10 including the cannula 12 is left in a punctured state in the blood vessel.

[0052] When the cannula 12 is inserted into a blood vessel and the inner needle is withdrawn, blood enters the lumen 16 of the valve housing 14 through the cannula 12, but because the slit 46 in the valve body 44 is sealed, the blood remains in the lumen 16 of the valve housing 14 on the distal side of the valve body 44. Furthermore, air filling the lumen 16 on the distal side of the valve body 44 is discharged to the external space A through the air vent passage 48 when blood is introduced into the lumen 16. As a result, the lumen 16 on the distal side of the valve body 44 is filled with blood, preventing air from entering.

[0053] The blood filling the cavity 16 on the distal side of the valve body 44 does not flow into the air vent passage 48 with force because the cross-sectional area of ​​the air vent passage 48 is small, but it gradually enters the air vent passage 48 due to capillary action. Here, the blood that has entered the air vent passage 48 is prevented from moving due to capillary action in the liquid reservoir 50 provided in the middle of the air vent passage 48, and is prevented from moving toward the proximal side of the liquid reservoir 50. By providing the liquid reservoir 50 in this manner, even if a filter is not provided in the air vent passage 48, the blood is prevented from reaching the proximal opening of the air vent passage 48, and the leakage of blood through the air vent passage 48 to the external space A is prevented while preventing the valve housing 14 from becoming large. Therefore, the indwelling needle 10 is suitable for infusion such as drip infusion, blood collection, pediatric use, and the like, in which a reduction in the size of the valve housing 14 is particularly required. It is also possible to provide a filter for the air vent passage 48 that allows air to pass through and restricts the passage of blood.

[0054] In this embodiment, the liquid reservoir 50 is formed in a continuous annular shape around the entire circumference, so that the volume of the liquid reservoir 50 is large. Therefore, even if blood gradually enters the liquid reservoir 50, leakage of blood to the outside is prevented for a time sufficient for practical use of the indwelling needle 10. That is, blood is prevented from leaking out through the air vent passage 48 from the time when the inner needle is removed from the cannula 12 and blood is introduced into the lumen 16 of the valve housing 14 until the male connector 52 described below is connected and the air vent passage 48 is blocked by the valve body 44. In addition, if the liquid reservoir 50 is annular, the air vent passage 48 and the liquid reservoir 50 can be communicated without positioning the liquid reservoir 50 with respect to the air vent passage 48 that is partially provided in the circumferential direction. Note that the liquid reservoir 50 does not have to be annular, and can be, for example, a spot-like shape provided only in parts corresponding to the air vent passages 48 in the circumferential direction of the valve housing 14.

[0055] As shown in FIG. 5, in the indwelling needle 10, when a male connector 52 serving as an operating member is connected to the valve housing 14, the notch 46 of the valve body 44 is pushed open by the plunger 54, and the inner cavity 16 of the valve housing 14 and the inner cavity of the male connector 52 are connected through the inner cavity of the plunger 54.

[0056] The male connector 52 is substantially cylindrical, with a tapered male luer taper set on the outer circumferential surface. The male connector 52 is inserted into the inner cavity 16 of the valve housing 14 from the base end side, so that it comes into close contact with the inner circumferential surface of the valve housing 14, on which the female luer taper is set. The male connector 52 is, for example, a male connector for a syringe, an infusion circuit, or the like. The male connector 52 may include a locking portion (not shown) that screws into the male thread portion 28 of the valve housing 14.

[0057] The plunger 54 is cylindrical and can be inserted into the bore 16 of the valve housing 14, and the outer circumferential surface of the tip portion is a tapered surface. The plunger 54 may be positioned radially in the bore 16 of the valve housing 14 by, for example, a ring member 56 attached to the inner circumferential surface of the valve housing 14 (see FIG. 5). In this case, the plunger 54 is axially slidable relative to the ring member 56, and the plunger 54 is guided in the axial direction by the ring member 56. Then, the plunger 54 is pressed against the valve body 44 from the base end side, so that the slit 46 of the valve body 44 is pushed open by the plunger 54 and released. The plunger 54 is pressed toward the tip side by the male connector 52, which is inserted into the bore 16 of the valve housing 14 from the base end side of the plunger 54, and the valve body 44 is deformed toward the tip side.

[0058] When the plunger 54 pushes open the slit 46, the valve body 44 elastically deforms so as to roll up toward the tip side and is pressed against the inner circumferential surface of the valve housing 14. The opening of the air vent passage 48 on the inner cavity 16 side, which is located on the tip side of the valve body 44, is sealed by the valve body 44, and the air vent passage 48 is blocked when the valve body 44 is in an open state. As a result, when the valve body 44 is opened and the external flow path including the inner cavity of the male connector 52 is connected to the inner cavity 16 of the valve housing 14, blood flowing through the inner cavity 16 does not leak into the external space A through the air vent passage 48. In addition, air in the external space A is prevented from mixing into the inner cavity 16 through the air vent passage 48.

[0059] In this embodiment, the structure in which the notch 46 of the valve body 44 is opened by the plunger 54 has been described, but the plunger 54 is not essential. For example, the male connector 52 may be directly pressed against the base end surface of the valve body 44, so that the notch 46 of the valve body 44 is pushed open by the male connector 52.

[0060] Incidentally, the indwelling needle 10 can be fitted with a cap member 57 as shown in Fig. 6. When the indwelling needle 10 is left indwelling without connecting the male connector 52 of an infusion circuit, syringe, or the like to the lumen 16 with the cannula 12 inserted into a blood vessel, for example, the attachment of the cap member 57 can prevent blood leakage.

[0061] The cap member 57 is a hard member made of, for example, synthetic resin. The cap member 57 has a structure in which a cylindrical locking tube portion 58 and a columnar or truncated cone-shaped cap body 59 are connected to each other at the base end. The locking tube portion 58 has a screw thread protruding from its inner circumferential surface so as to be capable of screwing into the male screw portion 28 of the valve housing 14.

[0062] The cap body 59 has a tapered shape with a diameter that decreases from the base end to the tip. The base end portion of the cap body 59 has a tapered outer peripheral surface that corresponds to the inner peripheral surface of the valve housing 14, and is capable of fitting into the valve housing 14. The tip portion of the cap body 59 has a larger inclination angle with respect to the axial direction than the inner peripheral surface of the valve housing 14, and is spaced inward from the inner peripheral surface of the valve housing 14. The tip portion of the cap body 59 has a step halfway in the axial direction, and the tip side of the step has a smaller diameter than the base end side.

[0063] 6, the cap member 57 is attached to the indwelling needle 10. That is, the cap member 57 is disposed on approximately the same center axis as the second component member 20 of the valve housing 14, and the cap body 59 is inserted into the second component member 20 from the base end side, and the locking tube portion 58 is screwed into the male thread portion 28 provided at the base end of the second component member 20.

[0064] By fastening the male thread portion 28 and the lock tube portion 58, the cap body 59 moves toward the tip side, and the tip portion of the cap body 59 is inserted into the notch 46 of the valve body 44. As a result, the notch 46 is blocked by the cap body 59, and the lumen 16 of the valve housing 14 is blocked by the cap body 59, preventing blood leakage through the lumen 16 of the valve housing 14. In addition, the opening of the air vent passage 48 on the lumen 16 side is blocked by the valve body 44 which has been pushed and deformed by the cap body 59, preventing blood leakage through the air vent passage 48. The tip portion of the cap body 59 is tapered at a larger rate of change than the base end portion, and the tip has a sufficiently small diameter, making it easy to insert into the notch 46.

[0065] For example, when it is desired to leave the indwelling needle 10 in a blood vessel with the cannula 12 inserted without connecting it to an external flow path such as an infusion line or a syringe, the indwelling needle 10 can prevent blood leakage by attaching the cap member 57 to the valve housing 14.

[0066] By fitting the base end portion of the cap body 59 into the valve housing 14, leakage of blood through the lumen 16 of the valve housing 14 is also prevented by overlapping the cap body 59 and the valve housing 14. In addition, the fitting of the base end portion of the cap body 59 into the valve housing 14 prevents rattling between the cap member 57 and the valve housing 14, so that the attachment state of the cap member 57 is stable, and stable closure of the lumen 16 of the valve housing 14 and the air vent passage 48 is achieved.

[0067] In the present embodiment, the cap member 57 has the locking tube portion 58 and the cap body 59 integrally formed, but the locking tube portion 58 and the cap body 59 may be formed separately and connected by being fixed. Also, the locking tube portion 58 is not essential to the cap member. If the locking tube portion 58 is not provided, the cap body 59 can be attached to the valve housing 14, for example, by pushing it axially into the bore 16.

[0068] For example, after infusion or administration of medicine by connecting the male connector 52 to the indwelling needle 10, it is possible to remove the male connector 52 from the indwelling needle 10 and attach the cap member 57 to the indwelling needle 10, thereby leaving the indwelling needle 10 with the lumen 16 and air vent passage 48 blocked inserted in the blood vessel. Then, by removing the cap member 57 from the indwelling needle 10 and connecting another male connector 52 to the indwelling needle 10, infusion or administration of medicine can be performed again.

[0069] The cap member 57 can be removed from the valve housing 14 by pulling the cap body 59 out of the valve housing 14 after releasing the engagement between the male thread portion 28 and the locking tube portion 58. In this manner, the cap member 57 is detachably attached to the valve housing 14.

[0070] 7 shows an indwelling needle 60 as a second embodiment of a needle assembly constructed in accordance with the present invention. In the following description, the same members and parts as those in the first embodiment are denoted by the same reference numerals in the drawings and description thereof will be omitted.

[0071] The indwelling needle 60 has a structure in which a valve body 44 is sandwiched between a first component member 18 and a second component member 64 that constitute a valve housing 62. The second component member 64 has a structure similar to that of the second component member 20 of the first embodiment, except for the tip portion including the second holding portion 36 and the first holding portion 34. The second component member 64 also has a valve body accommodating portion 40 whose tip portion has an expanded diameter, and the valve body accommodating portion 40 located at the axial tip of the second component member 64 is open toward the needle tip.

[0072] The plunger 54 and the valve body 44 are inserted from the tip side of the second component member 64. An annular convex portion 65 extends on the inner peripheral surface of the second component member 64, and the annular convex portion 65 abuts against the plunger 54, thereby preventing the plunger 54 from slipping out from the base end side of the second component member 64. The second component member 64 containing the plunger 54 is inserted from the base end side into the connecting tube portion 24 of the first component member 18 and connected to the first component member 18. Since the valve body 44 is contained in the valve body containing portion 40 of the second component member 64, when the first component member 18 and the second component member 64 are assembled, the valve body 44 is prevented from sliding against one of the components 18 (64) and being fixed in an unintended deformed state. The support surface 25 of the first component member 18 has an outer peripheral portion overlapped with the tip surface of the second component member 64, and an inner peripheral portion overlapped with the tip surface of the valve body 44. As a result, the valve body 44 is sandwiched in the axial direction between the support surface 25 of the first component member 18 and the first holding portion 34 of the second component member 64 , and is positioned with respect to the valve housing 62 .

[0073] An air vent passage 66 penetrating the valve housing 62 is formed by covering the opening of the groove 26 of the first component member 18. In this embodiment, the groove 26 of the first component member 18 has a portion that opens to the inner circumferential portion of the support surface 25 covered by the valve body 44, and a portion that opens to the outer circumferential portion of the support surface 25 and the inner circumferential surface of the connecting tube portion 24 covered by the second component member 64. As a result, the air vent passage 66 includes a first portion 68 formed by the groove 26 being covered by the valve body 44, and a second portion 70 formed by the groove 26 being covered by the second component member 64. The air vent passage 66 communicates with the inner cavity 16 of the valve housing 62 at a first portion 68 extending between the overlapping surfaces of the first component member 18 and the valve body 44, and is open to the external space A through the communicating groove 32 of the valve housing 62 at a second portion 70 extending between the overlapping surfaces of the first component member 18 and the second component member 64. The liquid reservoir portion 50 is provided midway through the second portion 70 of the air vent passage 66, and the wall portion of the liquid reservoir portion 50 is formed by the valve housing 62, not the valve body 44.

[0074] According to such an indwelling needle 60, in a structure in which the valve body 44 is sandwiched between the first component member 18 and the second component member 64, the first portion 68 of the air vent passage 66 is formed between the first component member 18 and the valve body 44, so that the first portion 68 can be easily formed. Furthermore, the second portion 70 of the air vent passage 66 is formed penetrating the valve housing 62, which is harder than the valve body 44, so that changes in the passage cross-sectional shape and the passage cross-sectional area are suppressed, and air is stably discharged and blood leakage is prevented. Moreover, since the valve housing 62 is formed by the first component member 18 and the second component member 64 and the second portion 70 of the air vent passage 66 extends between the overlapping surfaces of the first component member 18 and the second component member 64, it is easy to form an air vent passage 66 with a small cross-sectional area.

[0075] The tip surface of the valve body 44 and the support surface 25 of the first component member 18 are both flat, and a first portion 68 of the air vent passage 66 is formed between the overlapping surfaces of the surfaces having a linear cross-sectional shape. The first portion 68 of the air vent passage 66 is constituted by a recessed groove formed in the first component member 18, and therefore the stability of the shape of the air vent passage 66 is increased compared to when the air vent passage 66 is provided in the valve body 44 which is easily deformed. Note that the air vent passage 66 is provided in the overlapping surface between the surfaces of the valve body 44 and the first component member 18 having a linear cross-sectional shape, but the air vent passage 66 may be provided between overlapping surfaces that do not have a linear cross-sectional shape, such as in a concave-convex fit portion. For example, claws extending in the base end direction and recessed grooves 26 for the air vent passage 66 may be alternately provided on the periphery of the support surface 25 of the first component 18, and an annular groove may be provided on the tip surface of the valve body 44, so that the air vent passage 66 is formed on the support surface 25 of the first component 18 while the claws and the annular groove are engaged with each other to improve the fixing force between the first component 18 and the valve body 44.

[0076] Since the air vent passage 66 extends so as to be open toward the base end, in a valve housing 62 in which the second component 64 is fitted into the inner periphery of the first component 18 from the base end side, the second portion 70 of the air vent passage 66 is easily formed between the overlapping surfaces of the first component 18 and the second component 64.

[0077] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the specific description. For example, although it is preferable that a plurality of air vent passages 48 are provided in the circumferential direction of the valve housing 14, only one air vent passage 48 may be provided.

[0078] The air vent passage 48 is desirably formed between overlapping surfaces of a plurality of members, but may be formed, for example, by a through hole that penetrates at least a part of one member. Specifically, for example, in the indwelling needle 60 shown in FIG. 5, the second part of the air vent passage 48 may be formed by a through hole that penetrates the first component member 18 in the radial direction. Also, in the structure of FIG. 2, a through hole that penetrates the second component member 20 in the radial direction near the valve body 44 may be formed, and the through hole may be used as the air vent passage 48. Also, a part of the air vent passage 48 may be formed by utilizing a recessed groove provided on the tip surface of the valve body 44. Also, in addition to the air vent passage 48 according to the present application, an air vent passage may be further formed between the inner surface of the valve housing 14 and the outer surface of the valve body 44.

[0079] In the embodiment described above, one end of the air vent passage 48 is connected to the bore 16 further distal than the valve body 44, and the other end is open to the external space A at the outer periphery of the valve housing 14, but, for example, the air vent passage may be connected to the bore 16 on both sides of the valve body 44. That is, in the structure of FIG. 2, a through hole constituting the other end of the air vent passage may be provided penetrating the second component member 20 in the radial direction, and the through hole may be connected to the bore 16 further proximal than the valve body 44, so that the air vent passage is opened to the external space A through the proximal opening of the bore 16. By forming the air vent passage 48 to extend in the axial direction, the length of the air vent passage 48 can be increased, thereby reducing the occurrence of liquid leaking to the outside. Therefore, the axial length of the air vent passage 48 is preferably longer than the inner diameter of the valve housing 14 on the distal side of the valve body 44, longer than the diameter of the valve body 44, longer than the diameter of the plunger 54, or longer than the inner diameter of the valve housing 14 on the proximal side of the valve body 44. In particular, it is preferable that the air vent passage 48 extends toward the side where an operating member such as a male connector is inserted, thereby ensuring a long air vent passage 48. In this case, the liquid reservoir 50 is preferably provided in an intermediate portion on the air vent passage 48, and is preferably provided in a portion of the valve housing 14 where the plunger 54 is located radially inward.

[0080] The liquid reservoir 50 is not limited to an annular shape, and may be provided in spots in the circumferential direction of the valve housing 14, and may be positioned in the circumferential direction with respect to the air vent passage 48. A plurality of liquid reservoirs 50 may be provided in the passage length direction of the air vent passage 48, and blood leakage can be more effectively prevented by providing a plurality of liquid reservoirs 50 on one air vent passage 48. The plurality of liquid reservoirs 50 may differ from each other in structure, shape, volume, and the like. The liquid reservoir 50 is preferably formed on the air vent passage 48 that extends linearly in the axial direction, and is preferably smaller in length and larger in width and depth than the air vent passage 48. In addition, the maximum cross-sectional area of ​​the liquid reservoir 50 in a cross section perpendicular to the passage length direction of the air vent passage 48 is preferably at least twice the cross-sectional area of ​​the air vent passage 48. It is preferable to provide the liquid reservoir 50 on the base end side of the air vent passage 48, since this makes it difficult for blood or other liquid to leak to the outside. In particular, by providing it in the middle part of the air vent passage 48 extending in the axial direction, it is possible to realize a configuration in which liquid is less likely to reach the liquid reservoir section 50, and even if an amount of liquid flows in that exceeds the capacity of the liquid reservoir section 50, the liquid will not immediately leak out to the outside.

[0081] The recessed groove 26 constituting the air vent passage 48 may be formed on the tip surface and outer peripheral surface of the second component member 20. The recess 42 constituting the liquid reservoir portion 50 may be formed on the inner peripheral surface of the first component member 18. It is also possible to form the liquid reservoir portion 50 by providing recesses on both the inner surface of the first component member 18 and the outer surface of the second component member 20. The position of the liquid reservoir portion 50 is not particularly limited, and it may be formed on the tip surface of the second component member 20, for example. However, since it is preferable that the volume of the liquid reservoir portion 50 is large, it is preferable that the liquid reservoir portion 50 is formed between the inner peripheral surface of the first component member 18 and the outer peripheral surface of the second component member 20, where a large volume can be easily ensured.

[0082] The valve body 44 may be attached to the first component member 18 constituting the needle tip side of the valve housing 14. In this case, for example, the first holding portion 34 and the second holding portion 36 may be provided on the inner peripheral surface of the first component member 18. In the embodiment, the valve body accommodating portion 40 is provided on the second component member 20, but the valve body accommodating portion 40 may be provided on the first component member 18 instead of the second component member 20, or may be formed by both the first component member 18 and the second component member 20. In order to increase the fixing force between the valve body 44 and the valve housing 14, an annular groove may be provided on the tip surface of the valve body 44 and a convex portion to be inserted into the annular groove may be provided on the valve housing 14, an annular groove may be provided on the base end surface of the valve body 44 and a convex portion to be inserted into the annular groove may be provided on the valve housing 14, or annular grooves may be provided on the tip and base end surfaces of the valve body 44 and the convex portions may be inserted therein.

[0083] The valve housing 14 may be configured by combining three or more members, or may be configured by one member. The valve housing 14 may be made of a transparent material or an opaque material. In the embodiment, the positioning portion 30 is also a cover portion that prevents the user's finger from blocking the air vent passage 48, but the cover portion may be provided separately from the positioning portion 30.

[0084] The valve housing 14 may have a structure including a needle fixing part connected to the needle body and a valve housing connected to the needle fixing part by a flexible tube, as shown in, for example, FIG. 14 of WO 2019 / 027024. That is, the first component and the second component may constitute the valve housing, the tube may be connected to the tip part of the first component, and the tip part of the tube may be connected to the needle fixing part. In this way, the first component is not limited to being directly connected to the needle body. In FIG. 14 of WO 2019 / 027024, the tube connecting the needle fixing part and the valve housing extends from the needle fixing part toward the base end side, but for example, in cases where the inner cavity of the needle fixing part branches and opens to the side, the tube connected to the valve housing may extend to the side of the needle fixing part. In addition, a sharp metal needle may be fixed to the tip of the valve housing 14 to make a structure in which an inner needle is not required.

[0085] The method of fixing the first component 18 and the second component 20 is not limited to fitting as shown in the above embodiment, and may be ultrasonic welding, adhesion, locking, screwing, etc. For example, a convex portion may be provided on the outer surface of the second component 20, and a through hole may be provided in the first component 18, and the convex portion may engage with the through hole to fix the first component 18 and the second component 20. In addition, when the first component 18 and the second component 20 are fitted together, the first component 18 may be fitted into the second component 20. In addition, in the above embodiment, the recessed groove 26 constituting the air vent passage 48 is formed in the first component 18, and the recess 42 constituting the liquid reservoir 50 is formed in the second component 20, and the first component 18 and the second component 20 are fixed so that the air vent passage 48 and the liquid reservoir 50 communicate with each other. However, for example, by forming both the groove 26 that constitutes the air vent passage 48 and the recess 42 that constitutes the liquid reservoir portion 50 in only one of the first component member 18 or the second component member 20, an air vent passage 48 equipped with a liquid reservoir portion 50 may be formed regardless of the axial positions of the first component member 18 and the second component member 20.

[0086] The first holding portion 34 may be provided closer to the needle tip side than the valve body 44 , and the second holding portion 36 may be provided closer to the base end side than the valve body 44 .

[0087] A safety mechanism for preventing accidental puncture may also be provided in the lumen 16 of the valve housing 14. The safety mechanism covers and protects the tip of the inner needle when the inner needle is pulled out of the valve housing 14, and may employ various known structures, for example, those exemplified in JP 2002-85558 A, JP 4510619 A, and US Pat. No. 4,929,241. When the safety mechanism is disposed in the plunger, it may be located between the plunger and the inner needle, and may be held in place by engaging with the inner surface of the plunger so as not to be unintentionally removed from the valve housing. For example, an annular protrusion or recess may be provided on the inner surface of the plunger, and a part of the safety mechanism may be engaged with the annular protrusion or recess so that the safety mechanism does not unintentionally come off from the valve housing, and the annular protrusion or recess may be disengaged from a part of the safety mechanism by pulling out the inner needle, allowing the safety mechanism to be removed from the valve housing. In addition, the safety mechanism may be retained in the valve housing by engaging with the inner cavity 16 of the valve housing 14 on the base end side of the plunger 54, or may be retained in the valve housing by being assembled to the outside of the valve housing 14, and various known safety mechanisms can be provided. [Explanation of symbols]

[0088] 10 Indwelling needle (needle assembly first embodiment) 12 Cannula (needle body) 14 Valve housing 16 lumen 18 First component 20 Second component 22 Tip 24 Connecting cylinder part 25 Support surface 26 Groove 28 Male thread 30 Positioning part 32 Communication groove 34 First holding part (holding part) 36 Second holding part 38 Slope 40 Valve body receiving portion 42 Recess 44 Valve body 46 Cutting 48 Air vent passage 50 Liquid reservoir 52 Male connector 54 Pusher 56 Ring member 57 Cap member 58 Lock cylinder 59 Cap body 60 Indwelling needle (needle assembly second embodiment) 62 Valve housing 64 Second component 65 Circular convex part 66 Air vent passage 68 Part 1 70 Part 2 A. External space

Claims

1. A needle assembly comprising: a hollow needle body; a cylindrical valve housing provided on a base end side of the needle body; and a valve body accommodated in an inner cavity of the valve housing for switching between communication and blocking of the inner cavity of the valve housing, an air vent passage penetrating the valve housing is provided, and the air vent passage is connected to the inner cavity of the valve housing on the needle tip side of the needle body relative to the valve body; The needle assembly has a liquid reservoir portion partially enlarged in cross-sectional area provided in the air vent passage.

2. 2. The needle assembly according to claim 1, wherein the air vent passages are provided at a plurality of locations in the circumferential direction of the valve housing.

3. 3. The needle assembly according to claim 1, wherein the liquid reservoir is annular and extends continuously in the circumferential direction of the valve housing.

4. 4. The needle assembly according to claim 1, wherein the valve housing comprises a first component member and a second component member connected to a proximal end side of the first component member, and the air vent passage is formed between the first component member and the second component member.

5. 5. The needle assembly according to claim 4, wherein the second component is fitted into and connected to the inner periphery of the first component, and the liquid reservoir is formed by a recess opening onto the outer periphery of the portion of the second component that is fitted into the first component.

6. 6. The needle assembly according to claim 4 or 5, wherein a support surface is provided at a base end portion of the first component member, extending radially inward and superimposed on at least one of the valve body and the second component member, a groove forming the air vent passage is opened into the support surface, and an operating member is inserted into the valve housing from the base end side to deform the valve body towards the tip end side, thereby causing the valve body to close the air vent passage.

7. A needle assembly comprising: a hollow needle body; a cylindrical valve housing provided on a base end side of the needle body; and a valve body accommodated in an inner cavity of the valve housing for switching between communication and blocking of the inner cavity of the valve housing, A retaining portion is provided protruding from an inner peripheral surface of the valve housing, The retaining portion is provided partially in the circumferential direction of the valve housing, and has an inclined surface that is inclined so that a protruding height increases toward the valve body. A needle assembly in which the valve body has an outer circumferential surface that abuts against the inner circumferential surface of the valve housing over its entire periphery in a radially compressed state.

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