Syringes and syringe barrels

Abstract

Provided are a syringe and a syringe barrel that can raise productivity. The syringe 1 according to the present invention comprises a needle tube 10 and a barrel 20 to which the needle tube 10 is fixed. The barrel 20 has: a barrel body 21 that is in the shape of a bottomed cylinder and that is composed of a bottom portion 21b and a cylinder portion 21a; a projecting portion 22, which is installed in a protruding manner on the bottom portion 21b and to which the needle tube 10 is fixed; a needle tube insertion portion 25, which is provided on the projecting portion 22 and into which the needle tube 10 is inserted; and a flow passage 26 through which the interior space of the barrel body 21 and the needle tube insertion portion 25 communicate. The flow passage 26 has a small-diameter portion 26a that is provided at a position connecting to the needle tube insertion portion 25 and that is smaller in diameter or narrower than the outside diameter of the needle tube 10, and a large-diameter portion 26b that is provided so as to connect the interior space of the barrel body 21 and the small-diameter portion 26a and that is larger in diameter or wider than the small-diameter portion 26a. The small-diameter portion 26a is provided further toward the distal-end side than a distal-end-side surface 21b1 of the bottom portion 21b.

Description

[Technical Field]

[0001] The present invention relates to a syringe and a syringe barrel used for administering a medicinal solution or the like to a human body or the like. [Background technology]

[0002] Conventionally, some relatively small-capacity syringes used for administering vaccines, etc. have needles directly attached to the outer cylinder (barrel). These needle-equipped syringes have the advantage of having less dead space than syringes whose needles are connected via a Luer connector.

[0003] In other words, a syringe with a needle has the advantage that when the plunger inserted into the outer cylinder is fully pressed, the amount of medicinal liquid remaining in the syringe is small, making it possible to use the medicinal liquid efficiently without waste.

[0004] Generally, in a needle syringe, the needle is fixed to the outer cylinder by inserting the rear end of the needle into a needle insertion portion, which is part of a hole provided at the tip of the outer cylinder, and then adhering them by pouring adhesive between the two. In addition, the needle is positioned in the axial direction by providing a step at the rear end of the needle insertion portion (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-163642 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the outer tube is generally made of resin, and the rear end portion of the needle tube insertion section is an area that extends in multiple directions, including the axial and radial directions of the outer tube, and is located in an area inside the tubular member with poor heat dissipation, i.e., an area where sink marks and voids are likely to occur during resin molding, which creates the problem of molding defects being prone to occur.

[0007] If the rear end of the needle insertion portion is poorly molded, it becomes difficult to properly position the needle and secure it to the outer cylinder. As a result, conventional syringes with needles are not only difficult to assemble, but also have low productivity due to a reduced yield.

[0008] In view of the above circumstances, the present invention aims to provide a syringe and a syringe barrel that can increase productivity. [Means for solving the problem]

[0009] The syringe of the present invention comprises a needle tube and an outer cylinder to which the needle tube is fixed, the outer cylinder having a bottomed, cylindrical outer cylinder main body portion consisting of a bottom portion and a cylindrical portion, a protruding portion protruding from the bottom portion and to which the needle tube is fixed, a needle tube insertion portion provided on the protruding portion and into which the needle tube is inserted, and a flow passage connecting an internal space of the outer cylinder main body portion with the needle tube insertion portion, the flow passage having a small diameter portion provided at a position connected to the needle tube insertion portion and having a diameter or width smaller than the outer diameter of the needle tube, and a large diameter portion provided to connect the internal space of the outer cylinder main body portion with the small diameter portion and having a diameter or width larger than the small diameter portion, the small diameter portion being provided on the distal side of the distal end side of the bottom portion The bottom portion is configured so that its thickness gradually decreases toward the large diameter portion, and the bottom portion has, at its rear end side, a first tapered surface that is connected to the large diameter portion and a second tapered surface that is closer to the outer periphery than the first tapered surface, and the taper angle of the first tapered surface is larger than the taper angle of the second tapered surface. It is characterized by:

[0010] The syringe outer cylinder of the present invention comprises a cylindrical outer cylinder main body having a bottom and a cylindrical portion, a protruding portion protruding from the bottom and to which a needle tube is fixed, a needle tube insertion portion provided on the protruding portion and into which the needle tube is inserted, and a flow passage connecting an internal space of the outer cylinder main body with the needle tube insertion portion, the flow passage having a small diameter portion provided at a position connected to the needle tube insertion portion and having a diameter or width smaller than the outer diameter of the needle tube, and a large diameter portion provided so as to connect the internal space of the outer cylinder main body with the small diameter portion and having a diameter or width larger than the small diameter portion, the small diameter portion being provided on the distal side of the distal end side of the bottom portion. The bottom portion is configured so that its thickness gradually decreases toward the large diameter portion, and the bottom portion has, at its rear end side, a first tapered surface that is connected to the large diameter portion and a second tapered surface that is closer to the outer periphery than the first tapered surface, and the taper angle of the first tapered surface is larger than the taper angle of the second tapered surface. It is characterized by:

[0011] According to the present invention, the large diameter portion appropriately reduces the wall thickness near the small diameter portion, improving the cooling rate near the small diameter portion and the needle insertion portion during resin molding, and suppressing the effects of tension caused by the resin whose temperature drops first at the tip side of the protrusion and the outer periphery of the bottom portion, thereby preventing molding defects such as sink marks and voids that occur in the small diameter portion and the needle insertion portion. This makes it possible to prevent problems with fixing the needle to the outer cylinder, improving assembly ease and yield and increasing syringe productivity.

[0012] In the present invention, the large diameter portion is preferably configured to form a step between itself and the small diameter portion.

[0013] This allows for greater weight reduction in the vicinity of the small diameter portion, making it possible to more effectively prevent molding defects such as sink marks and voids that occur in the small diameter portion and the needle tube insertion portion.

[0014] In the present invention, it is preferable that the large diameter portion has a portion where the diameter expansion rate or width expansion rate decreases toward the rear end side.

[0015] This also makes it possible to remove more weight near the small diameter portion, making it possible to more effectively prevent molding defects such as sink marks and voids that occur in the small diameter portion and the needle tube insertion portion.

[0016] In the present invention, the bottom portion is configured so that the thickness gradually decreases toward the large diameter portion. will be done.

[0017] This reduces the thickness of the connecting region between the protrusion and the bottom, and more effectively prevents molding defects such as sink marks and voids that occur in the small diameter portion and the needle tube insertion portion.

[0018] In the present invention, the bottom portion has a first tapered surface connected to the large diameter portion and a second tapered surface on the rear end side surface that is closer to the outer periphery than the first tapered surface, and the taper angle of the first tapered surface is larger than the taper angle of the second tapered surface. big.

[0019] This allows the tip surface of the gasket at the tip of the plunger to be properly adhered to the rear end side surface, and the gasket can be deformed so that part of the tip surface of the gasket enters the large diameter portion, thereby further reducing dead space inside the outer tube and allowing for efficient use of medicinal solutions, etc., administered to the human body, etc. [Effects of the Invention]

[0020] The syringe and syringe barrel of the present invention have the excellent effect of enabling increased productivity. [Brief explanation of the drawings]

[0021] [Figure 1] 1A is a front view of a syringe according to one embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line II in FIG. [Figure 2] 2A is a front view of the gasket, and FIG. 2B is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 4 is an enlarged cross-sectional view showing the periphery of the bottom and the protrusion. [Figure 4] FIG. 10 is an enlarged cross-sectional view showing the bottom and the protrusion periphery in a state where the plunger is fully pressed. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0023] Fig. 1A is a front view of a syringe 1 according to one embodiment of the present invention, and Fig. 1B is a cross-sectional view taken along line II in Fig. 1A. Syringe 1 includes a needle tube 10, an outer cylinder (barrel) 20 to which needle tube 10 is fixed, a pusher (plunger) 30 inserted into outer cylinder 20, and a gasket 40 attached to the tip of the pusher.

[0024] The needle tube 10 is the part that is inserted into the human body, etc. The needle tube 10 is made of an appropriate metal such as stainless steel, and has a cutting edge 11 formed at the tip to sharpen the needle tip. The size of the needle tube 10 is not particularly limited, and for example, a needle tube of 16 to 33 gauge (outer diameter: 1.7 to 0.2 mm) specified in ISO 9626 can be used.

[0025] The shape of the needle tip of the needle tube 10 is not particularly limited, and may be lancet-shaped or back-cut. The needle tube 10 may have inner and outer diameters that change in the axial direction.

[0026] The outer cylinder 20 is a portion that contains a medicinal solution or the like to be administered to the human body. The outer cylinder 20 is made of an appropriate transparent or translucent resin, such as polypropylene, acrylonitrile butadiene styrene (ABS) resin, or polycarbonate. The outer cylinder 20 has a cylindrical outer cylinder main body 21 with a bottom that defines an internal space for containing the medicinal solution or the like, and a cylindrical protrusion 22 that protrudes from the tip of the outer cylinder main body 21.

[0027] The outer tube main body 21 is composed of a cylindrical tube portion 21a with a substantially constant inner and outer diameter, and a disk-shaped bottom portion 21b that closes the tip side of the tube portion 21a. A flange portion 21c that is elliptical in plan view and protrudes toward the outer periphery is provided at the rear end of the outer circumferential surface 21a1 of the tube portion 21a.

[0028] The flange portion 21c is a portion on which the user of the syringe 1 places his / her fingers (for example, the index finger and middle finger), and a protrusion 21c1 at the tip end side surface of the flange portion 21c is formed in a C-shape in a plan view to prevent slipping. c Furthermore, flat surfaces 21c3 are provided on the front and rear end surfaces of flange portion 21c, respectively, for stably placing syringe 1 on a desk or the like in a horizontal position.

[0029] The outer peripheral surface 21a1 of the cylindrical portion 21a is provided with a scale (not shown) that indicates the amount of medicinal solution or the like contained therein. In addition, the rear end of the inner peripheral surface 21a2 of the cylindrical portion 21a is provided with a circumferentially continuous protrusion 21d. This protrusion 21d is intended to prevent the plunger 30 and the gasket 40 from easily falling off the outer cylinder 20.

[0030] A protrusion 22 is provided at the center of the tip side surface 21b1 of the bottom 21b so as to protrude toward the tip side. A cylindrical collar 23 and four trapezoidal plate-like ribs 24 are provided around the periphery of the protrusion 22 to reinforce the protrusion 22.

[0031] Collar 23 is provided to surround the outer periphery of the base end of protrusion 22. Ribs 24 are arranged at equal intervals in the circumferential direction between protrusion 22 and collar 23, and are connected to protrusion 22, bottom portion 21b, and collar 23. In addition, end surface 24a on the outer periphery of rib 24 is provided with engaging recesses 24b that engage with a needle protection cap (not shown).

[0032] In this embodiment, the productivity of the syringe 1 is improved by devising the shapes of the bottom portion 21b and the protruding portion 22 of the outer cylinder 20. The shapes of the bottom portion 21b and the protruding portion 22 will be described in detail later.

[0033] The plunger 30 is inserted into the outer tube 20 from an opening at the rear end thereof and is pressed when administering a medicinal solution or the like. The plunger 30 is a rod-shaped member with a cross-shaped cross section and is made of an appropriate resin, such as polystyrene, polypropylene, or polycarbonate. The distal end of the plunger 30 is provided with a stepped cylindrical engagement portion 31 with a small diameter at the proximal end that engages with the gasket 40, and a flange-shaped pressing portion 32 that contacts and presses the gasket 40 during pressing. The rear end of the plunger 30 is provided with a disk-shaped force-receiving portion 33 that receives the pressing force of the user's finger (e.g., thumb) during pressing.

[0034] Gasket 40 seals the rear end side of outer cylinder 20 and is made of a material having appropriate elasticity, such as a thermoplastic elastomer, silicone rubber, or butadiene rubber. Fig. 2A is a front view of gasket 40, and Fig. 2B is a cross-sectional view taken along line II-II in Fig. 2A.

[0035] The gasket 40 is configured in a cylindrical shape with a bottom and an open rear end. The outer peripheral surface 41 of the gasket 40 has a narrowed axial middle portion 41a, and a front sliding portion 41b and a rear sliding portion 41c, which are configured with larger diameters than the middle portion 41a, slide against the inner peripheral surface 21a2 of the tubular portion 21a.

[0036] The outer diameter of the intermediate portion 41a is set to be smaller than the inner diameter of the tubular portion 21a. The outer diameters of the front-end sliding portion 41b and the rear-end sliding portion 41c are set to be larger than the inner diameter of the tubular portion 21a. By providing the front-end sliding portion 41b and the rear-end sliding portion 41c in this manner, it is possible to achieve both sealing performance and slidability.

[0037] The outer diameter of the intermediate portion 41a may be set to be approximately the same as the inner diameter of the tubular portion 21a. Since the outer diameter of the gasket 40 is reduced overall by the compressive force received from the tubular portion 21a, it is possible to prevent contact between the intermediate portion 41a and the inner circumferential surface 21a2 of the tubular portion 21a, even in this case. The outer diameters of the front-end sliding portion 41b and the rear-end sliding portion 41c may be set to be approximately the same as each other, or may be set to be different in anticipation of deformation after molding, etc.

[0038] The tip surface 42 of the gasket 40 is configured in a truncated cone shape, with a dome-shaped recess 42a provided in the center. In this embodiment, the taper angle of the tip surface 42 is set to approximately 160°. By setting the taper angle of the tip surface 42 to a large value in this manner, the amount of protrusion of the tip surface 42 is reduced, and the visibility of the scale provided on the outer peripheral surface 21a1 of the tubular portion 21a can be improved.

[0039] Specifically, the dosage of the medicinal solution is measured by reading the scale corresponding to the tip position of the contact surface of the tip-side sliding portion 41b with the inner circumferential surface 21a2, but if the amount of protrusion of the tip surface 42 is large, the area around the scale may become dark and difficult to read. In this embodiment, this problem is prevented by reducing the amount of protrusion of the tip surface.

[0040] The inner diameter of the inner circumferential surface 43 of the gasket 40 is smaller at the rear end side than at the front end side so as to engage with the engaging portion 31 of the plunger 30. A tapered introduction portion 43a that gradually increases in diameter toward the rear end side is provided at the rear end of the inner circumferential surface 43 to facilitate insertion of the engaging portion 31. A rear end surface 44 of the gasket 40 is formed in a flat shape that is approximately perpendicular to the axis, so as to be in stable contact with and pressed by the pressing portion 32 of the plunger 30.

[0041] 1A, and is an enlarged cross-sectional view taken along line II of the bottom portion 21b and the vicinity of the protruding portion 22. The protruding portion 22 has a tapered enlarged diameter portion 22a at its base end, the outer diameter of which gradually increases toward the rear end, and the enlarged diameter portion 22a is connected to the tip side surface 21b1 of the bottom portion 21b.

[0042] A needle tube insertion section 25, which is a hole into which the rear end side of the needle tube 10 is inserted and fixed, is provided inside the protruding section 22. The needle tube insertion section 25 is drilled along the axial direction from the tip surface 22b of the protruding section 22, and is composed of a needle tube support section 25a on the rear end side and an adhesive storage section 25b on the tip side.

[0043] The needle tube support portion 25a has an inner peripheral surface 25a1 that is slightly larger than the outer diameter of the needle tube 10 and has a substantially constant inner diameter in the axial direction, and has a stepped rear end surface 25a2. That is, the needle tube support portion 25a is configured to hold the needle tube 10 in a position along the axis of the outer tube 20 by means of the inner peripheral surface 25a1, and to position the needle tube 10 in the axial direction by bringing the rear end surface 25a2 into contact with the rear end surface 12 of the needle tube 10.

[0044] The adhesive accommodating portion 25b is configured in a tapered shape with an inner diameter gradually increasing from the needle tube support portion 25a toward the distal end, and a filling space into which the adhesive 50 is filled is formed between the adhesive accommodating portion 25b and the needle tube 10. In this embodiment, two circumferentially continuous grooves 25b1 are provided in the adhesive accommodating portion 25b, and the hardened adhesive 50 engages with the grooves 25b1. This makes it possible to prevent the needle tube 10 from falling off the outer tube 20 even when the adhesiveness of the resin constituting the outer tube 20 is poor. Needless to say, the adhesiveness may be improved by applying an appropriate surface treatment to the adhesive accommodating portion 25b, for example.

[0045] A flow passage 26 is provided inside the protruding portion 22 and the bottom portion 21b, connecting the needle tube insertion portion 25 with the internal space of the outer tube main body 21. This flow passage 26 is a passage through which a medicinal solution or the like flows, and is composed of a small diameter portion 26a on the tip side connected to the needle tube insertion portion 25, and a large diameter portion 26b connecting the internal space of the outer tube main body 21 with the small diameter portion 26a.

[0046] The small diameter portion 26a has an inner diameter that is smaller than the outer diameter of the needle tube 10 and larger than the inner diameter of the needle tube 10, and is set to a substantially constant inner diameter in the axial direction. In this embodiment, by providing the small diameter portion 26a, a rear end surface 25a2 is formed in the needle tube support portion 25a, and it is possible to position the needle tube 10 in the axial direction.

[0047] The large diameter portion 26b has an inner diameter larger than that of the small diameter portion 26a overall and has a stepped tip surface 26b1. The large diameter portion 26b further includes a first rounded portion 26b2 that gradually increases in diameter from the tip surface 26b1 toward the rear end and gradually decreases in diameter expansion rate toward the rear end, a tapered portion 26b3 that gradually increases in diameter slightly from the first rounded portion 26b2 toward the rear end, and a second rounded portion 26b4 that gradually increases in diameter from the tapered portion 26b3 toward the rear end and gradually increases in diameter expansion rate toward the rear end.

[0048] The large diameter portion 26b is configured not only to function as a passage for the flow of medicinal liquids, etc., but also to function as a recess to prevent molding defects such as sink marks and voids that occur in the needle tube support portion 25a, the small diameter portion 26a, and their vicinity during resin molding of the outer tube 20.

[0049] The needle tube support portion 25a and the small diameter portion 26a are formed by a core pin of a resin molding die, and are regions with poorer heat dissipation than the tip side of the protrusion 22 and the outer periphery of the bottom 21b. Therefore, in the cooling process after the resin is filled into the die, the areas around the needle tube support portion 25a and the small diameter portion 26a are pulled by the resin on the tip side of the protrusion 22 and the outer periphery of the bottom 21b, which have cooled down first, and sink marks, voids, and the like are likely to occur, and the needle tube support portion 25a and the small diameter portion 26a may not be molded into the appropriate dimensions.

[0050] In this embodiment, the small diameter portion 26a and the large diameter portion 26b are provided so that the tip surface 26b1 of the large diameter portion 26b (in other words, the rear end of the small diameter portion 26a) is located more tip-side than the tip side surface 21b1 of the bottom portion 21b, thereby sufficiently reducing the wall thickness in the vicinity of the needle tube support portion 25a and the small diameter portion 26a, improving the cooling rate in the vicinity, and making it possible to suppress the influence of tension caused by the resin whose temperature has dropped earlier on the outer periphery of the bottom portion 21b from affecting the needle tube support portion 25a and the small diameter portion 26a. In other words, it is possible to effectively prevent molding defects such as sink marks and voids in the needle tube support portion 25a and the small diameter portion 26a.

[0051] As a result, needle support portion 25a and small-diameter portion 26a are molded to have appropriate dimensions and shapes, making it possible to appropriately position the needle and fix it to the outer cylinder. In other words, syringe 1 of this embodiment has excellent assembly properties and a high yield, making it highly productive.

[0052] In particular, in this embodiment, by providing a step between the small diameter portion 26a and the large diameter portion 26b and by providing a portion in the large diameter portion 26b where the diameter expansion rate gradually decreases toward the rear end, it is possible to remove a large amount of material near the small diameter portion 26a and more effectively prevent molding defects. Furthermore, by providing the expanded diameter portion 22a and the second rounded portion 26b4 in correspondence with each other, it is possible to reduce the change in thickness in the connection region between the protrusion 22 and the bottom portion 21b, and it is also possible to more effectively prevent molding defects.

[0053] A tip side surface 21b1 of the bottom portion 21b is formed in a flat shape that is approximately perpendicular to the axis of the outer cylinder 20. On the other hand, a rear side surface 21b2 of the bottom portion 21b that faces the internal space of the outer cylinder main body 21 is formed in a tapered shape that gradually reduces its thickness in the axial direction from the outer periphery toward the axis (toward the large diameter portion 26b). In this embodiment, by forming the bottom portion 21b in this manner, the thickness of the connection region between the protrusion 22 and the bottom portion 21b is reduced, making it possible to more effectively prevent molding defects.

[0054] Furthermore, in this embodiment, the rear end side surface 21b2 of the bottom portion 21b is composed of two types of tapered surfaces: a first tapered surface 21b2a that connects to the large diameter portion 26b, and a second tapered surface 21b2b that is closer to the outer periphery than the first tapered surface 21b2a.In addition, by setting the taper angle of the first tapered surface 21b2a larger than the taper angle of the second tapered surface 21b2b, adhesion with the tip surface 42 of the gasket 40 is improved and dead space is reduced.

[0055] 1A, and is an enlarged view of the periphery of the bottom portion 21b and the protrusion 22 when the plunger 30 is fully pressed. When the plunger 30 is fully pressed, the tip surface 42 of the gasket 40 is in appropriate contact with the rear end side surface 21b2 of the bottom portion 21b.

[0056] In this embodiment, the taper angle of the first tapered surface 21b2a is set to approximately 174° and the taper angle of the second tapered surface 21b2b is set to approximately 145°, while the taper angle of the tip surface 42 of the gasket 40 is approximately 160°, so that the tip surface 42 of the gasket 40 is properly brought into close contact with the rear end side surface 21b2 of the bottom 21b, preventing residual liquid from remaining between the two.

[0057] In this embodiment, by providing first tapered surface 21b2a with a large taper angle (close to a plane perpendicular to the axis), the peripheral edge of recess 42a in tip surface 42 of gasket 40 is allowed to fit into large diameter portion 26b, further reducing dead space within outer cylinder 20. In addition, by providing second rounded portion 26b4 in large diameter portion 26b and providing recess 42a in tip surface 42 of gasket 40, tip surface 42 of gasket 40 can be easily fitted into large diameter portion 26b.

[0058] In addition, in this embodiment, the rear end side surface 21b2 of the bottom 21b and the large diameter portion 26b do not have any parts that protrude toward the rear end or parts that are tapered in the opposite direction, so that air bubbles generated when aspirating a medicinal solution or the like can be smoothly guided toward the small diameter portion 26a and discharged from the tip of the needle tube 10.

[0059] The cross-sectional shapes of the needle tube insertion portion 25 and the flow path 26 are not limited to a circular shape, and various shapes such as an elliptical shape or a polygonal shape can be adopted. In this case, the small diameter portion 26a may be configured to be narrower than the outer diameter of the needle tube 10 in any direction perpendicular to the axis. The large diameter portion 26b may be configured to be wider than the inner diameter of the small diameter portion 26a in any direction perpendicular to the axis, and preferably has a portion where the expansion rate decreases in any direction perpendicular to the axis.

[0060] Furthermore, the tip surface 26b1 of the large diameter portion 26b may be tapered, or the tip surface 26b1 may be omitted and the first rounded portion 26b2 may be connected to the small diameter portion 26a. Furthermore, the rear end side surface 21b2 of the bottom portion 21b may be formed as a single tapered surface or as a curved surface. Furthermore, the tip side surface 21b1 of the bottom portion 21b may be tapered.

[0061] Furthermore, the adhesive containing portion 25b may be omitted from the needle tube insertion portion 25, and the needle tube 10 may be fixed to the outer tube 20 by welding or insert molding.

[0062] Although the embodiments of the present invention have been described above, the syringe and syringe barrel of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the shape and arrangement of each part of the syringe 1 are not limited to those shown in the above-described embodiments, and various known shapes and arrangements can be adopted.

[0063] Furthermore, the actions and effects shown in the above-described embodiments are merely a list of the most preferable actions and effects resulting from the present invention, and the actions and effects of the present invention are not limited to these. [Explanation of symbols]

[0064] 1 syringe 10 needle tube 20 outer cylinder 21 outer cylinder main body 21a Cylinder part 21b bottom 21b1 Bottom tip side 21b2 Rear end side of bottom 21b2a First tapered surface 21b2b Second tapered surface 22 Protrusion 25 Needle tube insertion part 26 Distribution path 26a Small diameter section 26b Large diameter section

Claims

1. a needle tube and an outer cylinder to which the needle tube is fixed, The outer cylinder is a bottomed cylindrical outer cylinder main body portion consisting of a bottom portion and a cylindrical portion; a protrusion provided on the bottom portion to which the needle tube is fixed; a needle tube insertion portion provided on the protruding portion and into which the needle tube is inserted; a flow passage communicating an internal space of the outer tube main body portion with the needle tube insertion portion; and The flow path is a small diameter portion provided at a position connected to the needle tube insertion portion, the small diameter portion having a diameter or width smaller than an outer diameter of the needle tube; a large diameter portion that is provided so as to connect an internal space of the outer tube main body portion and the small diameter portion, and that has a larger diameter or a wider width than the small diameter portion, the small diameter portion is provided closer to the tip than the tip side surface of the bottom portion, the bottom portion is configured so that the thickness gradually decreases toward the large diameter portion, the bottom portion has, at a rear end side surface, a first tapered surface connected to the large diameter portion and a second tapered surface located on an outer circumferential side of the first tapered surface; A syringe, wherein the taper angle of the first tapered surface is greater than the taper angle of the second tapered surface.

2. The syringe according to claim 1, A syringe characterized in that the large diameter portion is configured to form a step between the large diameter portion and the small diameter portion.

3. The syringe according to claim 1 or 2, The syringe is characterized in that the large diameter portion has a portion in which the diameter expansion rate or width expansion rate decreases toward the rear end side.

4. a bottomed cylindrical outer cylinder main body portion consisting of a bottom portion and a cylindrical portion; a protrusion provided on the bottom portion to which a needle tube is fixed; a needle tube insertion portion provided on the protruding portion and into which the needle tube is inserted; a flow passage communicating an internal space of the outer tube main body portion with the needle tube insertion portion; Equipped with The flow path is a small diameter portion provided at a position connected to the needle tube insertion portion, the small diameter portion having a diameter or width smaller than an outer diameter of the needle tube; a large diameter portion that is provided so as to connect an internal space of the outer tube main body portion and the small diameter portion, and that has a larger diameter or a wider width than the small diameter portion, the small diameter portion is provided closer to the tip than the tip side surface of the bottom portion, the bottom portion is configured so that the thickness gradually decreases toward the large diameter portion, the bottom portion has, at a rear end side surface, a first tapered surface connected to the large diameter portion and a second tapered surface located on an outer circumferential side of the first tapered surface; The syringe outer barrel, wherein the taper angle of the first tapered surface is larger than the taper angle of the second tapered surface.

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