TW202235114A - Syringe and syringe barrel - Google Patents

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

Syringes and outer barrels for syringes

The present invention relates to a syringe and an outer barrel for a syringe used for administering a liquid medicine or the like to a human body.

Conventionally, syringes with a relatively small capacity have been used for administration of vaccines, etc., and there are some cases in which the needle tube is directly fixed to the outer cylinder (syringe). The syringe with the needle has the advantage of smaller dead space compared with the syringe with the needle tube connected via the needle connector.

That is, the syringe with a needle has the advantage that the amount of liquid medicine remaining in the syringe is small when the plunger (plunger) inserted into the outer cylinder is pressed to the bottom, and it can be used without waste. Use medicines efficiently.

In general, the fixing of the needle tube to the outer cylinder of the syringe with a needle is by inserting the rear end side of the needle tube into the needle tube insertion part which is a part of the hole provided on the front end of the outer cylinder, so that the adhesive flows into the needle tube. Between the two and proceed. In addition, the positioning of the needle tube in the axial direction is performed by providing a step at the rear end of the needle tube insertion portion (for example, refer to Patent Document 1). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-163642

[Problem to be Solved by the Invention]

However, in general, when the outer cylinder is made of resin, the rear end portion of the needle tube insertion portion is a region that extends in multiple directions of the axial direction and the radial direction of the outer cylinder, and is positioned radially inside the cylindrical member. Areas with poor properties, that is, areas where sink marks or voids are likely to occur during resin molding, so there is a problem that poor molding is likely to occur.

When a molding defect occurs at the rear end portion of the needle tube insertion portion, it is difficult to properly position and fix the needle tube to the outer cylinder. Therefore, the conventional syringes with needles are not only poor in assembly, but also low in productivity due to a decrease in yield.

In view of this fact, the present invention provides a syringe and an outer cylinder for a syringe that can improve productivity. [Technical means to solve the problem]

The syringe of the present invention is characterized in that it is provided with a needle tube and an outer cylinder for fixing the needle tube. The protruding part of the aforementioned needle tube, the needle tube insertion part provided on the aforementioned protruding part and inserted into the aforementioned needle tube, and the flow path connecting the inner space of the aforementioned outer tube body part with the aforementioned needle tube insertion part; the aforementioned flow path has: The position of the aforementioned needle tube insertion portion is a small diameter portion with a smaller diameter or narrower width than the outer diameter of the aforementioned needle tube, and it is provided in such a way as to connect the inner space of the aforementioned outer cylinder body portion with the aforementioned small diameter portion, And compared with the above-mentioned small-diameter portion, it is a large-diameter portion with a larger diameter or wider width; the aforementioned small-diameter portion is arranged on the front side of the front end side of the aforementioned bottom.

The outer cylinder for syringes of the present invention is characterized in that it has: a bottomed cylindrical outer cylinder main body composed of a bottom and a cylinder; a protrusion protruding from the bottom and fixing the needle tube; The needle tube insertion part for inserting the aforementioned needle tube, and the circulation path connecting the inner space of the aforementioned outer tube body part and the aforementioned needle tube insertion part; The small-diameter portion is smaller in diameter or narrower in width, and is provided in such a way as to connect the inner space of the outer cylinder body portion with the small-diameter portion, and is larger in diameter or wider than the small-diameter portion. The large-diameter part with a wider width; the small-diameter part is arranged on the front end side of the front end side of the bottom part.

According to the present invention, the layer thickness near the small-diameter part is appropriately reduced by the large-diameter part, the cooling rate of the small-diameter part and the vicinity of the needle tube insertion part is increased during resin molding, and the front end side of the protruding part and the outer periphery of the bottom On the side, it can suppress the influence of pulling caused by the resin whose temperature has been lowered first, so it can prevent the formation defects such as sink marks or holes in the small diameter part and the needle tube insertion part. This can prevent the lack of fixation of the needle tube to the outer cylinder, so the assembly and yield can be improved, and the productivity of the injection cylinder can be improved.

In addition, in the present invention, it is preferable that the aforementioned large-diameter portion is configured to form a step difference with the aforementioned small-diameter portion.

According to this, since the vicinity of the small-diameter portion can be significantly thinned, it is possible to more effectively prevent molding defects such as sink marks and voids generated in the small-diameter portion and the needle tube insertion portion.

In addition, in the present invention, it is preferable that the aforementioned large-diameter portion has a portion in which the diameter expansion ratio or the widening ratio decreases toward the rear end side.

Thereby, since the vicinity of the small-diameter portion can also be greatly thinned, molding defects such as sink marks and voids generated in the small-diameter portion and the needle tube insertion portion can be more effectively prevented.

Furthermore, in the present invention, it is preferable that the bottom portion is configured such that its thickness gradually decreases toward the large-diameter portion side.

According to this, by reducing the layer thickness in the connecting region between the protrusion and the bottom, it is possible to more effectively prevent formation defects such as sink marks and voids generated in the small-diameter portion and the needle insertion portion.

In addition, in the present invention, the aforementioned bottom preferably has on the side of the rear end: the first tapered surface connected to the aforementioned large-diameter portion, and the second tapered surface on the outer peripheral side of the aforementioned first tapered surface; the aforementioned first tapered surface The taper angle of the tapered surface is larger than the taper angle of the aforementioned second tapered surface.

According to this, the front end surface of the washer at the front end of the piston rod can be properly adhered to the rear end side, and the washer can be deformed so that a part of the front end surface of the washer enters the large-diameter portion, so the space inside the outer cylinder can be further reduced. Efficiently use liquid medicines, etc. that are administered to the human body without using space. [Effect of Invention]

According to the syringe and the outer barrel for the syringe of the present invention, an excellent effect of improving productivity can be achieved.

Embodiments of the present invention are described below with reference to the attached drawings.

Fig. 1A is a front view of a syringe 1 according to an embodiment of the present invention. FIG. 1B is a cross-sectional view along line I-I of FIG. 1A. The syringe 1 is provided with: a needle tube 10, an outer cylinder (syringe) 20 fixing the needle tube 10, a plunger rod (plunger) 30 inserted into the outer cylinder 20, and a gasket 40 mounted on the front end of the plunger rod.

The needle tube 10 is a part that is punctured into a human body or the like. The needle tube 10 is made of appropriate metal such as stainless steel, and a blade surface 11 for sharpening the needle tip is formed at the front end. The size of the needle tube 10 is not particularly limited, and for example, a gauge of 16 to 33 (outer diameter: 1.7 to 0.2 mm) stipulated in ISO9626 can be used.

In addition, the shape of the needle tip of the needle tube 10 is not particularly limited, and it may be needle-punched or back-cut. In addition, the inner and outer diameters of the needle tube 10 can vary in the axial direction.

The outer cylinder 20 is a part that accommodates the liquid medicine etc. which are administered to the human body inside. The outer cylinder 20 is made of suitable transparent or translucent resin such as polypropylene, acrylonitrile-butadiene-styrene (ABS) resin, and polycarbonate, for example. In addition, the outer cylinder 20 has a bottomed cylindrical outer cylinder main body 21 ensuring an internal space for containing liquid medicine and the like, and a cylindrical protruding portion 22 protruding from the front end of the outer cylinder main body 21 .

The outer cylinder body portion 21 is composed of a cylindrical portion 21a having substantially constant inner and outer diameters, and a disc-shaped bottom portion 21b closing the front end side of the cylindrical portion 21a. At the rear end portion of the outer peripheral surface 21a1 of the cylindrical portion 21a, a flange portion 21c that protrudes toward the outer peripheral side and is elliptical in plan view is provided.

The flange portion 21c is a part that the user of the syringe 1 holds with fingers (for example, index finger and middle finger). On the front end side 21c1 of the flange portion 21c, there is provided a C-shaped anti-slip protrusion when viewed from above. 21c2. In addition, planar portions 21c3 for stably placing the syringe 1 on a table or the like are provided on the front and rear end surfaces of the flange portion 21c, respectively.

In addition, on the outer peripheral surface 21a1 of the cylindrical portion 21a, a scale (not shown) indicating the amount of the liquid medicine or the like accommodated is provided. Moreover, the protrusion 21d continuous in the circumferential direction is provided in the rear end part of the inner peripheral surface 21a2 of the cylindrical part 21a. The protrusion 21d is used to prevent the piston core rod 30 and the washer 40 from falling off from the outer cylinder 20 easily.

On the central portion of the front end side surface 21b1 of the bottom portion 21b, the protruding portion 22 protrudes toward the front end side. In addition, around the protruding portion 22, a cylindrical collar 23 for reinforcing the protruding portion 22 and four trapezoidal plate-shaped ribs 24 are provided.

The collar 23 is provided so as to surround the outer periphery of the base end portion of the protruding portion 22 . The ribs 24 are arranged at equal intervals in the circumferential direction between the protruding portion 22 and the collar 23 , and are connected to the protruding portion 22 , the bottom portion 21 b , and the collar 23 . In addition, on the end surface 24a on the outer peripheral side of the rib 24, an engaging recessed portion 24b for engaging with a cover (not shown) for needle protection is provided.

In this embodiment, the productivity of the syringe 1 is improved by carefully examining the shapes of the bottom 21 b and the protrusion 22 in the outer cylinder 20 . The details of the shapes of the bottom portion 21b and the protruding portion 22 will be described later.

The piston rod 30 is inserted into the outer cylinder 20 through an opening on the rear end side of the outer cylinder 20, and is pressed when the medicinal solution is administered. The piston core rod 30 is a rod-shaped member having a cross-shaped cross section, and is made of suitable resin such as polystyrene, polypropylene, and polycarbonate. At the front end of the piston core rod 30, there are provided: the base end side engaged with the washer 40 is a cylindrical engaging portion 31 with a small diameter and a step difference, and a flange that is pressed in contact with the washer 40 during the pressing operation Shaped pressing portion 32 . In addition, at the rear end of the piston core rod 30, there is provided a disk-shaped force-receiving portion 33 that receives the pressing force from the user's fingers (such as the thumb) during the pressing operation.

The gasket 40 seals the rear end side of the outer cylinder 20 and is made of a material having appropriate elasticity, such as thermoplastic elastomer, polysiloxane rubber, and butadiene rubber. FIG. 2A is a front view of gasket 40 . FIG. 2B is a sectional view along line II-II of FIG. 2A .

The gasket 40 is configured in a bottomed cylindrical shape with an open rear end. The outer peripheral surface 41 of the washer 40 is formed so that the middle part 41a in the axial direction has a thinner shape, and the front end side sliding part 41b and the rear end side sliding part 41c are formed to be larger in diameter than the middle part 41a. 21a2 slides.

The outer diameter of the intermediate portion 41a is set smaller than the inner diameter of the cylindrical portion 21a. Moreover, the outer diameter of the front-end side sliding part 41b and the rear-end side sliding part 41c is set larger than the inner diameter of the cylindrical part 21a. Thus, by providing the front-end side sliding part 41b and the rear-end side sliding part 41c, it is possible to simultaneously achieve airtightness and sliding properties.

The outer diameter of the intermediate part 41a may be set substantially the same as the inner diameter of the cylindrical part 21a. The outer diameter of the gasket 40 is reduced as a whole due to the compressive force from the cylindrical portion 21a, so that the intermediate portion 41a and the inner peripheral surface 21a2 of the cylindrical portion 21a do not come into contact even at this time. In addition, the outer diameters of the front end side sliding part 41b and the rear end side sliding part 41c may be set to be substantially the same as each other, or may be set to have different outer diameters in anticipation of deformation after molding.

The front end surface 42 of the gasket 40 is configured in a conical trapezoidal shape, and a dome-shaped recess 42a is provided in the center. In this embodiment, the taper angle of the front end surface 42 is set to about 160°. Thus, by setting the taper angle of the front-end surface 42 large, the protrusion amount of the front-end surface 42 can be reduced and the visibility of the scale provided on the outer peripheral surface 21a1 of the cylindrical part 21a can be improved.

Specifically, the dosage of the medicinal solution can be measured by reading the scale corresponding to the front end position of the contact surface of the front end side sliding part 41b with the inner peripheral surface 21a2, but when the front end surface 42 protrudes a lot, The vicinity of the scale darkens and sometimes becomes difficult to read. In the present embodiment, this loss can be prevented by reducing the protrusion amount of the front end surface.

The inner peripheral surface 43 of the washer 40 is configured such that the inner diameter on the rear end side is smaller than the inner diameter on the front end side so as to engage with the engaging portion 31 of the piston rod 30 . In addition, in the rear end portion of the inner peripheral surface 43, in order to facilitate the insertion of the engaging portion 31, a tapered introduction portion 43a whose diameter gradually increases toward the rear end side is provided. In addition, the rear end surface 44 of the washer 40 is configured as a plane substantially perpendicular to the axis so as to stably contact and press the pressing portion 32 of the piston rod 30 .

FIG. 3 is a sectional view taken along line I-I of FIG. 1A, and is an enlarged view showing the periphery of the bottom 21b and the protruding portion 22. The protruding portion 22 has a tapered diameter-enlarged portion 22a on the base end portion whose outer diameter gradually increases toward the rear end side, and the diameter-enlarged portion 22a is connected to the front end side 21b1 of the bottom portion 21b.

Inside the protruding portion 22, a needle tube insertion portion 25 of a hole into which the rear end side of the needle tube 10 is inserted and fixed is provided. The needle tube insertion part 25 passes through the front end surface 22b of the protruding part 22 in the axial direction, and is composed of a needle tube support part 25a on the rear end side and an adhesive agent storage part 25b on the front end side.

The needle tube supporting portion 25a is configured such that the inner peripheral surface 25a1 has an inner diameter slightly larger than the outer diameter of the needle tube 10, has a substantially constant inner diameter in the axial direction, and has a stepped rear end surface 25a2. That is, the needle tube supporting portion 25a is configured to hold the needle tube 10 in a posture along the axis of the outer cylinder 20 by the inner peripheral surface 25a1, and is formed by abutting the rear end surface 25a2 on the rear end surface 12 of the needle tube 10. Position the needle tube 10 in the axial direction.

The adhesive container 25 b is formed into a tapered shape whose inner diameter gradually expands from the needle tube support 25 a toward the front end, and forms a filling space between the needle tube 10 and the needle tube 10 filled with the adhesive 50 . In this embodiment, two grooves 25b1 continuous in the circumferential direction are provided in the adhesive container 25b, and the hardened adhesive 50 is engaged with the grooves 25b1. Thereby, even if the resin constituting the outer cylinder 20 has poor adhesiveness, the needle tube 10 can be prevented from coming off from the outer cylinder 20 . In addition, of course, appropriate surface treatment or the like may be applied to the adhesive container 25 b to improve adhesiveness.

Inside the protruding portion 22 and the bottom portion 21b, a flow path 26 that communicates the needle tube insertion portion 25 with the inner space of the outer cylinder body portion 21 is provided. This circulation path 26 is a path through which the liquid medicine circulates, and is formed by a small-diameter portion 26a connected to the front end side of the needle tube insertion portion 25, and a large-diameter portion 26b connecting the inner space of the outer cylinder body portion 21 with the small-diameter portion 26a. constitute.

The small-diameter portion 26a is set to be smaller than the outer diameter of the needle tube 10 and larger in inner diameter than the inner diameter of the needle tube 10, and has a substantially constant inner diameter in the axial direction. In this embodiment, the needle tube 10 can be positioned in the axial direction by providing the small-diameter portion 26a and forming the rear end surface 25a2 on the needle tube supporting portion 25a.

The large-diameter portion 26b has a larger inner diameter than the small-diameter portion 26a as a whole, and has a stepped front end surface 26b1. Moreover, the large-diameter portion 26b has: a first rounded portion 26b2 whose diameter gradually increases from the front end surface 26b1 toward the rear end side, and the diameter expansion ratio gradually decreases toward the rear end side; The tapered portion 26b3 whose diameter gradually increases only slightly, and the second rounded portion 26b4 whose diameter gradually increases from the tapered portion 26b3 toward the rear end side and whose diameter expansion rate gradually increases toward the rear end side are constituted.

The large-diameter portion 26b is not only configured as a passage through which the liquid medicine and the like flow, but also has a structure for preventing sink marks or the like from occurring in the needle tube supporting portion 25a, the small-diameter portion 26a and their vicinity when the resin of the outer cylinder 20 is molded. The function of thinning due to poor forming such as pores.

The needle tube supporting portion 25a and the small-diameter portion 26a are portions formed by the center pin of a resin-molded mold, and are areas that have poorer heat dissipation than the front end side of the protruding portion 22 and the outer peripheral side of the bottom portion 21b. Therefore, in the cooling process after the resin is filled in the mold around the needle tube supporting part 25a and the small diameter part 26a, the resin on the front end side of the protruding part 22 and the outer peripheral side of the bottom part 21b are pulled by the resin whose temperature is lowered first. Therefore, sink marks, voids, etc. are likely to occur, and there is a possibility that the needle tube supporting portion 25a and the small diameter portion 26a are not formed into appropriate dimensions and shapes.

In this embodiment, the small-diameter portion 26a and the large-diameter portion 26a are provided in such a manner that the front end surface 26b1 of the large-diameter portion 26b (in other words, the rear end of the small-diameter portion 26a) is located on the front side of the front side surface 21b1 of the bottom portion 21b. The diameter portion 26b can sufficiently reduce the layer thickness near the needle tube support portion 25a and the small diameter portion 26a, can increase the cooling rate of the periphery, and can suppress the pulling caused by the resin whose temperature on the outer peripheral side of the bottom portion 21b is lowered first. The influence affects the needle tube supporting part 25a and the small diameter part 26a. In other words, it is possible to effectively prevent the formation defects such as sink marks and voids in the needle tube supporting portion 25a and the small-diameter portion 26a.

Thereby, since the needle tube supporting part 25a and the small-diameter part 26a are formed in an appropriate size and shape, the needle tube can be properly positioned and fixed to the outer cylinder. That is, the syringe 1 of the present embodiment has both good assemblability and high yield, and is excellent in productivity.

In particular, in this embodiment, a step is provided between the small-diameter portion 26a and the large-diameter portion 26b, and the large-diameter portion 26b is provided with a portion where the diameter expansion ratio gradually decreases toward the rear end side, so that the thickness can be greatly reduced. The vicinity of the small-diameter portion 26a prevents molding failure more effectively. Furthermore, the enlarged diameter portion 22a and the second rounded corner portion 26b4 are provided in correspondence with each other to reduce layer thickness variation in the connection area between the protruding portion 22 and the bottom portion 21b, thereby preventing molding defects more effectively.

The front end side 21b1 of the bottom portion 21b is formed in a planar shape substantially perpendicular to the axis of the outer cylinder 20 . On the other hand, the rear end side 21b2 of the bottom 21b facing the inner space of the outer cylinder main body 21 has a tapered shape in which the thickness in the axial direction gradually decreases from the outer peripheral side to the axial center side (large diameter portion 26b side). In this embodiment, by configuring the bottom portion 21b in this way, the layer thickness in the connection region between the protruding portion 22 and the bottom portion 21b can be reduced, and molding defects can be prevented more effectively.

Furthermore, in this embodiment, it is obtained from two kinds of tapered surfaces of the first tapered surface 21b2a connected to the large-diameter portion 26b and the second tapered surface 21b2b on the outer peripheral side of the first tapered surface 21b2a. The rear end side 21b2 of the bottom 21b is formed, and the taper angle of the first tapered surface 21b2a is set to be larger than the taper angle of the second tapered surface 21b2b, thereby improving the adhesion with the front end surface 42 of the gasket 40 and reducing the dead space .

FIG. 4 is a sectional view taken along line I-I of FIG. 1A , and is an enlarged view showing the periphery of the bottom 21b and the protruding portion 22 in a state where the piston core rod 30 is pressed to the bottom. In the state where the piston rod 30 is pressed to the bottom, the front end surface 42 of the washer 40 is in a state of being properly adhered to the rear end side surface 21b2 of the bottom portion 21b.

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 160° with respect to the taper angle of the front end surface 42 of the gasket 40. 145°, thereby, the front end surface 42 of the gasket 40 and the rear end side surface 21b2 of the bottom 21b are properly adhered to, and no residual liquid will be generated between the two.

In addition, in this embodiment, by providing the first tapered surface 21b2a with a large tapered angle (close to the plane perpendicular to the axis), the peripheral portion of the concave portion 42a of the front end surface 42 of the gasket 40 enters into a large diameter portion 26b to further reduce the dead space in the outer cylinder 20. Furthermore, by providing the second rounded portion 26b4 on the large diameter portion 26b and providing the recessed portion 42a on the front end surface 42 of the gasket 40, the front end surface 42 of the gasket 40 can easily enter the large diameter portion 26b.

In addition, in this embodiment, since the rear end side 21b2 and the large diameter portion 26b of the bottom 21b are not provided with a portion protruding toward the rear end side or a reversely tapered portion, it is possible to attract The air bubbles generated in the liquid medicine etc. are smoothly guided toward the small-diameter portion 26 a and discharged from the tip of the needle tube 10 .

The cross-sectional shape of the needle insertion portion 25 and the flow path 26 is 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 only needs to be narrower than the outer diameter of the needle tube 10 in any direction perpendicular to the axis. In addition, the large-diameter portion 26b only needs to be configured to be wider than the inner diameter of the small-diameter portion 26a in any direction perpendicular to the axis, and is preferably formed in any direction orthogonal to the axis. There is a portion where the expansion rate decreases upward.

In addition, the front end surface 26b1 of the large diameter part 26b may be formed in a tapered shape, or the front end surface 26b1 may be omitted and the first rounded part 26b2 may be connected to the small diameter part 26a. In addition, the rear end side 21b2 of the bottom portion 21b may be constituted by one tapered surface, or may be constituted by a curved surface. In addition, the front-end side surface 21b1 of the bottom part 21b may be comprised in taper shape.

In addition, 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 cylinder 20 by welding or insert molding.

The embodiments of the present invention have been described above, but the syringe and the outer cylinder for syringes of the present invention are not limited to the above embodiments, and various changes can be made without departing from the gist 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-mentioned embodiments, and various known shapes and arrangements can be adopted.

In addition, the functions and effects shown in the above-mentioned embodiments are merely examples of the most suitable functions and effects produced by the present invention, and the functions and effects of the present invention are not limited thereto.

1: Syringe 10: needle tube 12: Rear face 20: Outer cylinder 21: Outer cylinder body 21a: Barrel 21a1: Outer peripheral surface of cylinder 21a2: inner peripheral surface of cylinder 21b: Bottom 21b1: front side of the bottom 21b2: Bottom rear side 21b2a: 1st cone surface 21b2b: 2nd cone surface 21c: Flange 21c1: Front side of flange 21c2: protrusion 21c3: Plane Department 21d: protrusion 22: protrusion 22a: enlarged diameter part 22b: front face 23: Collar 24: Rib 24a: Outer peripheral end face of the rib 24b: engagement recess 25: needle tube insertion part 25a: needle tube support part 25a1: inner peripheral surface 25a2: rear end face 25b: Adhesive container 25b1: slot 26: Circulation path 26a: Small diameter department 26b: Large diameter part 26b1: front face 26b2: 1st fillet 26b3: cone 26b4: The second fillet 30: Piston core rod 31:Catching part 32: Pressing part 33: Receiving part 40: Gasket 41a: middle part 41b: Front side sliding part 41c: rear end side sliding part 42: front face 42a: concave part 43: inner peripheral surface 43a: Import Department 44: Rear face 50: Adhesive

[ Fig. 1A ] is a front view of a syringe according to an embodiment of the present invention. [FIG. 1B] is a sectional view taken along line I-I of FIG. 1A. [Fig. 2A] is a front view of the gasket. [FIG. 2B] is a sectional view taken along line II-II of FIG. 2A. [ Fig. 3 ] is an enlarged cross-sectional view showing the periphery of the bottom and the protrusion. [ Fig. 4 ] is an enlarged cross-sectional view showing the periphery of the bottom portion and the protruding portion in a state where the piston rod is pressed to the bottom.

1: Syringe

10: needle tube

12: Rear face

21: Outer cylinder body

21a: Barrel

21a1: Outer peripheral surface of cylinder

21a2: inner peripheral surface of cylinder

21b: Bottom

21b1: front side of the bottom

21b2: Bottom rear side

21b2a: 1st cone surface

21b2b: 2nd cone surface

22: protrusion

22a: enlarged diameter part

22b: front face

23: Collar

24: Rib

24a: Outer peripheral end face of the rib

24b: engagement recess

25: needle tube insertion part

25a: needle tube support part

25a1: inner peripheral surface

25a2: rear end face

25b: Adhesive container

25b1: slot

26: Circulation path

26a: Small diameter department

26b: Large diameter part

26b1: front face

26b2: 1st fillet

26b3: cone

26b4: The second fillet

50: Adhesive

Claims (6)

A syringe comprising a needle tube and an outer cylinder for fixing the needle tube, The above-mentioned outer cylinder has: a bottomed cylindrical outer cylinder body part composed of a bottom and a cylinder part, and a protruding portion protruding from the bottom and fixing the needle tube; and a needle tube insertion portion provided on the protrusion and inserted into the needle tube; and A circulation path that communicates with the inner space of the outer cylinder main body and the needle tube insertion portion; The flow path has a small-diameter portion that is provided at a position connected to the needle tube insertion portion and has a smaller diameter or narrower width than the outer diameter of the needle tube, and It is provided in such a way as to connect the inner space of the outer cylinder body part with the aforementioned small-diameter part, and is a large-diameter part with a larger diameter or a wider width than the aforementioned small-diameter part; The small-diameter portion is provided on the front end side of the front end side of the bottom portion. The syringe according to claim 1, wherein the large-diameter portion is configured to form a step with the small-diameter portion. The syringe according to claim 1 or 2, wherein the large-diameter portion has a diameter expansion ratio or a widening ratio that decreases toward the rear end side. The syringe according to claim 1, wherein the bottom portion is configured such that its thickness gradually decreases toward the side of the large-diameter portion. The syringe according to claim 4, wherein the bottom portion has on the side of the rear end: a first tapered surface connected to the large-diameter portion, and a second tapered surface on the outer peripheral side of the first tapered surface; The taper angle of the first taper surface is greater than the taper angle of the second taper surface. An outer cylinder for a syringe, comprising: a bottomed cylindrical outer cylinder main body composed of a bottom and a cylinder; and protruding from the bottom and fixing the protruding part of the needle tube, and a needle tube insertion portion provided on the protrusion and inserted into the needle tube; and A circulation path that communicates with the inner space of the outer cylinder main body and the needle tube insertion portion; The flow path has a small-diameter portion that is provided at a position connected to the needle tube insertion portion and has a smaller diameter or narrower width than the outer diameter of the needle tube, and It is provided in such a way as to connect the inner space of the outer cylinder main body with the aforementioned small-diameter portion, and is a large-diameter portion with a larger diameter or a wider width than the aforementioned small-diameter portion; The small-diameter portion is provided on the front end side of the front end side of the bottom portion.

Images