Injection needle

Abstract

To provide an injection needle with which penetration resistance can be reduced even when an opening is provided on a side surface thereof.SOLUTION: Provided is an injection needle 10 that comprises: a hollow cylindrical body 12; a tip part 14 having a curved outline and joined so as to close the tip of the body 12; and a side opening 20 formed on the side surface of the body 12, wherein, in a side view along the axial direction G in the state where the side opening 20 is positioned above, the area surrounding the side opening 20 has an approximately arcuate concave shape, and has a tip side edge 30 with gently curved surface at a position that is the tip edge of the concave shape and a rear end side edge 40 with gently curved surface at a position that is the rear end edge of the concave shape.SELECTED DRAWING: Figure 4B

Description

Technical Field

[0001] The present invention relates to a syringe needle, particularly a syringe needle having an opening on its side surface.

Background Art

[0002] Reducing the piercing resistance is an important issue for syringe needles. To address this issue, a syringe needle made of superelastic metal with a wall thickness of 0.3 mm or less has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The syringe needle described in Patent Document 1 is a general syringe needle having an opening at its tip. However, so-called side-hole syringe needles having an opening on the side surface of the syringe needle are also used in various fields including plastic surgery. In such side-hole syringe needles, in order to widely spread the drug solution in the dermis, the syringe needle may be moved back and forth or rotated in the dermis. Therefore, the piercing resistance increases, and there is a risk of internal bleeding and blood vessel damage in the dermis. Thus, in side-hole syringe needles, it is more important to reduce the piercing resistance.

[0005] Therefore, an object of the present invention is to solve the above problems and provide a syringe needle capable of reliably reducing the piercing resistance even when having an opening on the side surface.

Means for Solving the Problems

[0006] In the syringe needle according to one embodiment of the present invention, a hollow cylindrical main body portion, and A tip portion having a curved outer shape joined so as to close the tip of the main body portion, A side opening formed on the side surface of the main body portion, and comprising, In a side view along the axial direction with the side opening disposed upward, the region surrounding the side opening has a substantially arc-shaped concave shape, It has a tip side surface taking portion having a smooth curved surface at a position that is the edge on the tip side of the concave shape, At a position that is the edge on the rear end side of the concave shape, it has a rear end side surface taking portion having a smooth curved surface.

Advantages of the Invention

[0007] According to the present invention, even when there is a side opening, it is possible to provide an injection needle capable of reliably reducing the piercing resistance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Mode for Carrying Out the Invention

[0009] Next, specific embodiments of the present invention will be described in detail with reference to the drawings. In each figure, corresponding members having the same function are denoted by the same reference numerals.

[0010] (Injection needle according to one embodiment of the present invention) First, with reference to FIGS. 1 to 3, an injection needle according to one embodiment of the present invention will be described while comparing it with a conventional injection needle having a side opening. FIG. 1 is a perspective view schematically showing an injection needle according to one embodiment of the present invention. FIG. 2 is a perspective view schematically showing a conventional injection needle having a side opening. FIG. 3 is a view showing a general manufacturing method of an injection needle having a side opening.

[0011] <Conventional injection needle> For example, in a cosmetic procedure for administering a drug solution such as hyaluronic acid intradermally, a so-called side hole injection needle 60 having a side opening 70 as shown in FIG. 2 is used. Such an injection needle 60 includes a hollow cylindrical main body 62 and a tip 64 having a curved outer shape joined so as to close the tip of the main body 62. And a side opening 70 is formed in the side surface near the tip 64 of the injection needle 60. The tip 64 of the injection needle 60 is spherical, and the drug solution is administered from the side opening 70 formed near the tip 64.

[0012] When administering a chemical solution such as hyaluronic acid, first puncture the skin near the area to be administered with a common injection needle to make a hole, and then insert the side hole injection needle 60 into the hole to administer hyaluronic acid intradermally. The administration of hyaluronic acid is carried out by moving the injection needle 60 to administer it over a wide area intradermally. Thereby, it is possible to swell the skin surface from the intradermal layer to stretch out wrinkles.

[0013] At this time, in order to administer hyaluronic acid over a wide area, the side hole injection needle 60 is moved back and forth or rotated intradermally to administer it to the necessary locations. Since the injection needle 60 is moved widely intradermally, there is a risk of internal bleeding and blood vessel damage occurring intradermally. In particular, edge portions Ef, Er are present on the tip side and the rear end side of the side opening portion 70 (see FIGS. 2 and 5B), and there is a risk that these edge portions Ef, Er will act as resistance and increase the piercing resistance.

[0014] <Method for manufacturing an injection needle having a side opening> Next, with reference to FIG. 3, a method for manufacturing such an injection needle 60 having a side opening will be described. First, as shown in (a), a metal circular tube that will be the main body portion 62 of the injection needle is prepared. Examples of the material of the metal circular tube include stainless steels such as SUS304 and 316. Examples of the standard dimensions of the circular tube include 22G: outer diameter 0.7075 mm, thickness 0.105 mm to 30G: outer diameter 0.3105 mm, thickness 0.059 mm, but it is not limited thereto. The length of the metal circular tube is determined according to the length of the injection needle to be manufactured. Examples of the length range include 38 mm to 70 mm, but it is not limited thereto.

[0015] Next, as shown in (b), a metal block is welded to one end of the metal circular tube. The metal block has a curved outer shape and is joined so as to block the tip of the metal block. The metal block joined to one end of this metal circular tube becomes the tip portion 64 of the injection needle 60. Then, as shown in (c), polishing is performed so that the main body portion 62 and the tip portion 64 of the injection needle 60 are smoothly connected.

[0016] Next, an elliptical or oval side opening 70 is formed on the side surface of the injection needle 60 by wire electrical discharge machining. More specifically, as shown in (d), wire electrical discharge machining is performed such that in a side view along the axial direction G with the side opening 70 disposed upward, the region surrounding the side opening 70 has a substantially arc-shaped concave shape. As a result, in a plan view with the side opening 70 disposed upward, the side opening 70 has an elliptical or oval shape extending in the axial direction G.

[0017] The side opening 70 is preferably formed at a position close to the tip. However, if it reaches the region where the tip portion 64 exists, an opening cannot be formed. Therefore, in a region where there is no mass of the tip portion 64 inside, it is preferable to form the side opening 70 as close to the tip side as possible.

[0018] At this time, in a side view along the axial direction G with the side opening 70 disposed upward, the intersection F between the outer contour line above the main body portion 62 or the tip portion 64 and the front line segment of the substantially arc-shaped concave shape formed by cutting out by wire electrical discharge machining becomes a protruding edge shape, and an edge portion Ef is formed. Similarly, the intersection R between the outer contour line above the main body portion 62 and the rear line segment of the substantially arc-shaped concave shape formed by cutting out by wire electrical discharge machining becomes a protruding edge shape, and an edge portion Er is formed.

[0019] When the injection needle 60 is moved back and forth or rotated intradermally, there is a risk that these edge portions Ef and Er become a resistance and the piercing resistance increases.

[0020] (Injection needle according to one embodiment of the present invention) To address this, in the injection needle 10 according to the present embodiment, a tip side surface taking portion 30 having a gentle curved surface is formed at a position that becomes the edge on the tip side of the concave shape, and a rear end side surface taking portion 40 having a gentle curved surface is formed at a position that becomes the edge on the rear end side of the concave shape.

[0021] The injection needle 10 according to this embodiment also undergoes the manufacturing process shown in FIGS. 3(a) to 3(d). As shown in (a), a metal circular tube that will become the main body portion 12 of the injection needle 10 is prepared. As shown in (b), a metal block is welded to one end of the metal circular tube. As a result, the metal circular tube becomes the main body portion 12 of the injection needle 10, and the welded metal block becomes the tip portion 14 of the injection needle 10. Then, as shown in (c), polishing is performed so that the main body portion 12 and the tip portion 14 of the injection needle 10 are smoothly connected.

[0022] Next, as shown in (d), wire electrical discharge machining is performed so that in a side view along the axial direction G with the side opening 20 disposed upward, the region surrounding the side opening 20 has a substantially arc-shaped concave shape. As a result, in a plan view with the side opening 20 disposed upward, the side opening 70 has an elliptical or oval shape extending in the axial direction G. In this case, it is preferable to form the side opening 20 as close as possible to the tip side in a region where there is no mass of the tip portion 14 inside.

[0023] In this state, in a side view along the axial direction G with the side opening 20 disposed upward, the intersection F between the outer contour line on the upper side of the main body portion 12 or the tip portion 14 and the front line segment of the substantially arc-shaped concave shape formed by cutting away with wire electrical discharge machining becomes a protruding edge shape, and the intersection F between the outer contour line on the upper side of the main body portion 12 and the rear line segment of the substantially arc-shaped concave shape formed by cutting away with wire electrical discharge machining becomes a protruding edge shape.

[0024] In this embodiment, after forming the side opening 20 by wire electrical discharge machining as shown in (d), this edge is removed by wire electrical discharge machining to form a chamfered portion having a smooth curved surface. A front-end chamfered portion 30 having a smooth curved surface is formed at the position F that becomes the edge on the tip side of the concave shape, and a rear-end chamfered portion 40 having a smooth curved surface is formed at the position R that becomes the edge on the rear-end side of the concave shape.

[0025] More specifically, in the present embodiment, wire electrical discharge machining is performed such that, in a side view along the axial direction G with the side opening 20 disposed upward, the tip side surface chamfering portion 30 and the rear end side surface chamfering portion 40 have an arcuate convex shape. However, as long as it has a smooth convex shape, it is not limited to an arc.

[0026] As described above, in the injection needle 10 according to the present embodiment, a hollow cylindrical main body portion 12, a tip portion 14 having a curved outer shape joined so as to close the tip of the main body portion 12, and a side opening 20 formed in the side surface of the main body portion 12 are provided. In a side view along the axial direction G with the side opening 20 disposed upward, the region surrounding the side opening 20 has a substantially arcuate concave shape, and has a tip side surface chamfering portion 30 having a smooth curved surface at a position F that is the edge on the tip side of the concave shape, and a rear end side surface chamfering portion 40 having a smooth curved surface at a position R that is the edge on the rear end side of the concave shape.

[0027] In the injection needle 10 according to the present embodiment, a tip side surface chamfering portion 30 having a smooth curved surface is formed at a position F that is the edge on the tip side, and a rear end side surface chamfering portion 40 having a smooth curved surface is formed at a position R that is the edge on the rear end side. Therefore, the piercing resistance generated when the injection needle 10 is moved intradermally can be reduced. By reducing the piercing resistance, the possibility of internal bleeding and blood vessel damage within the skin can be reduced. Thereby, even in the case of having the side opening 20, an injection needle 10 capable of reliably reducing the piercing resistance can be provided.

[0028] In particular, when, in a side view along the axial direction G with the side opening 20 disposed upward, the tip side surface chamfering portion 30 and the rear end side surface chamfering portion 40 have an arcuate convex shape, a chamfering portion having a smooth curved surface can be easily and reliably formed by wire electrical discharge machining or the like.

[0029] Also, when, in a plan view with the side opening 20 disposed upward, the side opening 20 has an elliptical or oval shape extending in the axial direction G, a chemical solution such as hyaluronic acid can be reliably administered over a wide range within the skin.

[0030] (Detailed Shape of Hypodermic Needle According to One Embodiment of the Present Invention) Next, with reference to FIGS. 4A to 5B, a more detailed description of the shape of the hypodermic needle according to this embodiment will be given while comparing it with a conventional hypodermic needle. FIG. 4A is a plan view schematically showing a hypodermic needle according to one embodiment of the present invention. FIG. 4B is a side cross-sectional view showing the cross-section A-A of FIG. 4A. FIG. 5A is a plan view schematically showing a conventional hypodermic needle having a side opening. FIG. 5B is a side cross-sectional view showing the cross-section B-B of FIG. 5A.

[0031] As shown in FIG. 5B, in a conventional hypodermic needle, an edge portion Ef exists on the tip side of the side opening portion 70, and a side edge portion Er exists on the rear end side of the side opening portion 70. On the other hand, in the hypodermic needle 10 according to this embodiment, a tip side surface taking portion 30 having a smooth curved surface is formed at a position F that becomes the tip side edge, and a rear end side surface taking portion 40 having a smooth curved surface is formed at a position R that becomes the rear end side edge. In FIG. 4A, the outer shapes of the tip side edge portion Ef and the side edge portion Er on the rear end side, which are removed by wire electrical discharge machining, are shown by dotted lines.

[0032] In a side view along the axial direction G with the side opening portion 20 disposed upward, in the conventional hypodermic needle 60, the tip side edge portion Ef is at substantially the same height position as the upper outer contour line of the main body portion 12. On the other hand, in the hypodermic needle 10 according to this embodiment, due to the formation of the tip side surface taking portion 30, in a side view along the axial direction G with the side opening portion 20 disposed upward, there is a predetermined distance D in the height direction between the highest position of the tip side surface taking portion 30 and the upper outer contour line of the main body portion 12. When the conventional tip side edge portion Ef exists, in principle, the distance D = 0.

[0033] It is expected that a larger value of this distance D can reduce the piercing resistance generated when moving the hypodermic needle 10 intradermally. In particular, when the hypodermic needle 10 is moved back and forth, a reduction in the piercing resistance in the forward path can be expected. Also, in the rear end side surface taking portion 40, since it smoothly connects to the upper outer contour line of the main body portion 12 to form a concave shape, a reduction in the piercing resistance in the return path when the hypodermic needle 10 is moved back and forth can be expected.

[0034] Next, samples of the injection needle 10 having different distances D were prototyped, and a test was conducted to measure the piercing resistance value, and the relationship between the value of the distance D and the piercing resistance value was examined. In this measurement test, a conventional injection needle 60 (distance D = 0) having an edge portion Ef without the tip side surface taking portion 30 and injection needles 10 with distances D = 0.04 mm, 0.07 mm, and 0.10 mm were prototyped and the piercing resistance values were measured. The outer diameter of the injection needle 10 was set in the range of 22G or more and 30G or less in consideration of a practical range.

[0035] The reason for setting the range of the distance D in the range of 0.04 mm or more and 0.10 mm or less can be explained as follows. Considering the manufacturing tolerance when forming the tip side surface taking portion 30 and that a certain tendency is stably shown even in repeated tests, the minimum value of the distance D was set to 0.04 mm. On the other hand, the greater the value of the distance D, the more the reduction effect of the piercing resistance can be expected. However, considering the outer diameter of the injection needle 10 actually used, which is 22G to 30G, in the case of 30G with the thinnest wall thickness, the thickness is 0.059 mm. Therefore, considering practical strength, the maximum value of the distance D was set to 0.10 mm.

[0036] As shown in FIG. 4A, in a side view along the axial direction G in a state where the side opening 20 is arranged upward, the region surrounding the side opening 20 has a substantially arc-shaped concave shape. As shown in FIG. 4B, as the value of the radius Rh of this arc, R0.98 mm to R1.0 mm can be exemplified. Further, when the convex shapes of the tip side surface taking portion 30 and the rear end side surface taking portion 40 are arc-shaped, as the radius Rf and radius Rr of this arc, R0.75 mm to R1.5 mm can be exemplified.

[0037] (Measurement test of piercing resistance value) As samples of the injection needle 10 having different distances D, for the 22G and 30G injection needles at both ends in the range of 22G or more and 30G or less, samples with distances D = 0 mm, 0.04 mm, 0.07 mm, and 0.10 mm were prototyped, and five measurement tests were conducted for each to obtain the average value.

[0038] The film to be punctured used in the puncture resistance measurement test was silicone rubber, and the one with the lowest possible hardness and the thinnest thickness was used. Specifically, a silicone rubber sheet (hardness 5 (Durometer A), thickness: 3 mm, manufactured by Kyowa Kogyo Co., Ltd.) was used. Also, the film to be punctured was fixed on the measurement jig so that the puncture location would be at the center of the 8-mm diameter hole of the measurement jig. Then, the film to be punctured was repeatedly punctured back and forth twice. The test speed was set at 20 mm / min. Since an influence was seen due to the opening during the first puncture, the data from the second puncture was adopted.

[0039] [Measurement Conditions] Test apparatus: Automatic load tester (MAX-1KN-P-1) manufactured by Nihon Sokkei System Co., Ltd. Load cell: JCL-M10N (capacity: 10 N) Measurement jig: MKT-45 Film to be punctured: Silicone rubber sheet (hardness 5 (Durometer A), thickness: 3 mm, manufactured by Kyowa Seisakusho) Test speed: 20 mm / min Test range: Approximately 10 mm from immediately before the tip of the injection needle contacts the film to be punctured

[0040] [Measurement Results] The measurement results are shown in FIGS. 6A and 6B. FIG. 6A is a graph showing the change in the puncture resistance value in the forward path when the injection needle is moved back and forth. FIG. 6B is a graph showing the change in the puncture resistance value in the return path when the injection needle is moved back and forth. The horizontal axis of the graph indicates the displacement amount of the tip of the injection needle. The position immediately before the tip of the injection needle contacts the film to be punctured is set to zero. The vertical axis of the graph indicates the measured puncture resistance value (N). Note that the measured puncture resistance value is shown with the compression direction being positive.

[0041] In all of the trial-produced 22G and 30G injection needles with distances D = 0 mm, 0.04 mm, 0.07 mm, and 0.10 mm, the same tendency as shown in FIGS. 6A and 6B was exhibited.

[0042] <Forward Path> In the forward path shown in FIG. 6A, as the injection needle is moved in the piercing direction from the zero position, the piercing resistance value increases. After reaching the peak P1, it repeats decreasing and increasing, and peaks P2, P3, and P4 occur. Here, peak P1 is considered to be due to the axial displacement caused by the tension of the membrane to be pierced when the injection needle is inserted. Therefore, the piercing resistance value of peak P2 is considered to greatly affect the piercing resistance in the forward path. The average value of the piercing resistance values at peaks P2 to P4 measured and the "ratio to D = 0" are shown in the following table. Note that the "ratio to D = 0" in the following table is expressed as a percentage of Y / X, where X is the piercing resistance value of D = 0 and Y is the piercing resistance values of D = 0.04 mm, 0.07 mm, and 0.10 mm.

[0043] (Table 1) Piercing resistance value (forward path) TIFF2025089591000002.tif47146

[0044] It was found that for the prototype 22G and 30G injection needles with distances D = 0.04 mm, 0.07 mm, and 0.10 mm, the value of peak P1 in the forward path can be reduced by about 10% compared to the injection needle with D = 0.

[0045] <Return path> In the return path shown in FIG. 6B, as the injection needle is moved in the direction of returning from the position pierced in the forward path, although not as large as in the forward path, it repeats decreasing and increasing, and peaks Q1, Q2, Q3, and Q4 occur. Among these, the piercing resistance value of peak Q3 is considered to greatly affect the piercing resistance in the forward path. The average value of the through-resistance values at peaks Q1 to Q4 measured and the "ratio to D = 0" are shown in the following table.

[0046] (Table 2) Piercing resistance value (return path) TIFF2025089591000003.tif52133

[0047] It was found that in the trial-produced injection needles with a distance D of 0.04 mm, 0.07 mm, and 0.10 mm for 30G and 22G, the value of peak Q3 in the return path could be reduced by 10% or more compared to the injection needle with a distance D of 0.

[0048] As described above, when the outer diameter of the main body 12 is in the range of 22G or more and 30G or less, and in a side view along the axial direction G with the side opening 20 arranged upward, the height direction distance D between the highest position of the tip side gripping portion 30 and the upper outer contour line of the main body 12 is in the range of 0.04 mm or more and 0.10 mm or less, the piercing resistance value at the second peak P2 in the forward path can be reduced by about 10% compared to the case where the distance D = 0, and the piercing resistance value at the peak Q3 in the return path can be reduced by 10% or more compared to the case where the distance D = 0. It was found.

[0049] Therefore, it was demonstrated that in the injection needle 10 where the distance D is in the range of 0.04 mm or more and 0.10 mm or less, the piercing resistance generated when moving the injection needle 10 intradermally can be surely reduced.

[0050] (Outer contour area of the cross-section perpendicular to the axial direction) In the above, the shape of the injection needle 10 according to this embodiment having the tip side gripping portion 30 was defined by the height direction distance D between the highest position of the tip side gripping portion 30 and the upper outer contour line of the main body 12, but it is not limited thereto. For example, it is also conceivable to define it by the outer contour area of the cross-section perpendicular to the axial direction G. Next, the calculation of the outer contour area of the cross-section perpendicular to the axial direction G will be described with reference to FIGS. 7A to 8B.

[0051] FIG. 7A is a perspective view showing the position of a cross-section perpendicular to the axial direction for calculating the outer surface area in a 22G injection needle according to the present invention. FIG. 7B is a line graph showing the change in cross-sectional area with the axial length from the tip on the horizontal axis and the outer surface area of the cross-section perpendicular to the axial direction shown in FIG. 6A on the vertical axis. FIG. 8A is a perspective view showing the position of a cross-section perpendicular to the axial direction for calculating the outer surface area in a 30G injection needle according to the present invention. FIG. 8B is a line graph showing the change in cross-sectional area with the axial length from the tip on the horizontal axis and the outer surface area of the cross-section perpendicular to the axial direction shown in FIG. 8A on the vertical axis.

[0052] FIG. 7A shows planes 1 to 11 that form 11 cross-sections perpendicular to the axial direction in the 22G injection needle 10. The horizontal axis in FIG. 7B indicates the axial distance G (unit: mm) from the tip of the injection needle 10, and the vertical axis indicates the outer surface area of the cross-section perpendicular to the axial direction G (unit: mm 2 ). The outer surface area referred to here is the area regarded as solid without subtracting the area of the hollow part. In FIG. 7B, a line graph is shown in which the outer surface areas in planes 1 to 11 shown in FIG. 7A are plotted and the plotted points are connected by a straight line. The case where the distance D = 0 without the tip side chamfering portion 30 and having the edge portion Ef is shown by a solid line, the case where the distance D = 0.04 mm with the tip side chamfering portion 30 is shown by a short dotted line, the distance D = 0.07 mm is shown by a one-dot chain line, and the distance D = 0.10 mm is shown by a long dotted line.

[0053] Regarding the outer surface area shown in FIG. 7B, the reduction ratio of the outer surface area with the tip side chamfering portion 30 to the outer surface area with the edge portion Ef can be expressed by the following formula. Assuming that there is an edge portion Ef on the tip side, let the outer surface area of the cross-section perpendicular to the axial direction G including the edge portion Ef be A, and the outer surface area of the cross-section perpendicular to the axial direction G with the tip side chamfering portion 30 at the same position in the axial direction G be B, then it can be expressed as (A - B) / A. The value of (A - B) / A at the position of the edge portion Ef on the tip side can be represented by the value in plane 3 of the following table. In plane 3, the value of (A - B) / A is in the range greater than 3.0% and less than 7.4%.

[0054] Regarding the outer surface area shown in FIG. 7B, the reduction ratio of the outer surface area with the rear-end side chamfer 40 to the outer surface area with the edge portion Er can be expressed by the following formula. Assuming that there is an edge portion Er at the tip side, let the outer surface area of the cross-section perpendicular to the axial direction G including the edge portion Er be C, and when there is a rear-end side chamfer 40 at the same position in the axial direction G, let the outer surface area of the cross-section perpendicular to the axial direction G be D. Then it can be expressed as (C - D) / C. The value of (C - D) / C at the position of the edge portion Er on the rear-end side can be represented by the value in the following table for plane 10. In plane 10, the value of (C - D) / C is approximately 1.8%.

[0055] (Table 3) Reduction ratio of outer surface area (%) TIFF2025089591000004.tif73147

[0056] The same applies to the injection needle 10 of 30G. FIG. 8B is a line graph showing the outer surface areas in planes 1 to 11 shown in FIG. 8A, with the plotted points connected by straight lines.

[0057] Regarding the outer surface area shown in FIG. 8B, the value of (A - B) / A, which is the reduction ratio of the outer surface area with the tip-side chamfer 30 to the outer surface area with the edge portion Ef, can be represented by the value in the following table for plane 2. In plane 2, the value of (A - B) / A is in the range greater than 2.4% and less than 4.8%.

[0058] Regarding the outer surface area shown in FIG. 8B, the value of (C - D) / D, which is the reduction ratio of the outer surface area with the rear-end side chamfer 40 to the outer surface area with the edge portion Er, can be represented by the value in the following table for plane 11. In plane 11, the value of (C - D) / C is in the range greater than 0.1% and less than 0.6%.

[0059] (Table 4) Reduction ratio of outer surface area (%) TIFF2025089591000005.tif73147

[0060] The value of (A - B) / A is greater than 3.0% and within the range of less than 7.4% at 22G, and is greater than 2.4% and within the range of less than 4.8% at 30G. Therefore, if the overlapping range of the two is taken, the value of (A - B) / A is within the range of greater than 3.0% and less than 4.8%.

[0061] Therefore, assuming that the outer diameter of the main body 12 is in the range of 22G or more and 30G or less, and the outer profile area of the cross-section perpendicular to the axial direction G including the edge portion Ef having the edge portion Ef on the tip side is A, and the outer profile area of the cross-section perpendicular to the axial direction G when having the tip side chamfered portion 30 at the same position in the axial direction G is B, when the value of (A - B) / A is in the range of greater than 3.0% and less than 4.8%, the piercing resistance generated when moving the injection needle 10 intradermally, especially in the forward path, can be surely reduced.

[0062] Also, the value of (C - D) / D is about 1.8% at 22G, and is in the range of greater than 0.1% and less than 0.6% at 30G. Therefore, if the value of (C - D) / D is greater than at least 0.1%, it can be expected to reduce the piercing resistance generated when moving the injection needle 10 intradermally, especially in the return path.

[0063] Therefore, assuming that the outer diameter of the main body is in the range of 22G or more and 30G or less, and the outer profile area of the cross-section perpendicular to the axial direction G including the edge portion Er having the edge portion Er on the rear end side is C, and the outer profile area of the cross-section perpendicular to the axial direction G when having the rear end side chamfered portion 40 at the same position in the axial direction G is D, when the value of (C - D) / C is in the range of greater than 0.1%, the piercing resistance generated when moving the injection needle 10 intradermally, especially in the return path, can be surely reduced.

[0064] As described above, The first aspect of the present invention is a hollow cylindrical main body portion, a tip portion having a curved outer shape joined so as to close the tip of the main body portion, a side opening formed in the side surface of the main body portion, and comprising In a side view along the axial direction with the side opening disposed upward, the region surrounding the side opening has a substantially arc-shaped concave shape, and has a tip side surface taking portion having a smooth curved surface at a position that is the edge on the tip side of the concave shape, and is an injection needle having a rear end side surface taking portion having a smooth curved surface at a position that is the edge on the rear end side of the concave shape.

[0065] A second aspect of the present invention is, in the first aspect, the outer diameter of the main body portion is in the range of 22G or more and 30G or less, in a side view along the axial direction with the side opening disposed upward, the height direction distance between the highest position of the tip side surface taking portion and the upper outer contour line of the main body portion is in the range of 0.04 mm or more and 0.10 mm or less.

[0066] A third aspect of the present invention is, in the first or second aspect, the outer diameter of the main body portion is in the range of 22G or more and 30G or less, assuming that the edge portion on the tip side is present, let the outer contour area of the cross section perpendicular to the axial direction including the edge portion be A, and let the outer contour area of the cross section perpendicular to the axial direction with the tip side surface taking portion at the same axial position be B, the value of (A - B) / A is in the range greater than 3.0% and less than 4.8%.

[0067] A fourth aspect of the present invention is, in any one of the first to third aspects, the outer diameter of the main body portion is in the range of 22G or more and 30G or less, assuming that the edge portion on the rear end side is present, let the outer contour area of the cross section perpendicular to the axial direction including the edge portion be C, and let the outer contour area of the cross section perpendicular to the axial direction with the rear end side surface taking portion at the same axial position be D, the value of (C - D) / C is in the range greater than 0.1%.

[0068] A fifth aspect of the present invention is, in any one of the first to fourth aspects, In a side view along the axial direction with the side opening disposed upward, the tip side surface attachment portion and the rear end side surface attachment portion have an arc-shaped convex shape.

[0069] A sixth aspect of the present invention is, in any one of the first to fifth aspects, in a plan view with the side opening disposed upward, the side opening has an elliptical or oval shape extending in the axial direction.

[0070] Although the embodiments and aspects of the present invention have been described, the disclosed content may change in the details of the configuration, and changes in the combination and order of elements in the embodiments and aspects can be realized without departing from the scope and spirit of the claimed invention.

Explanation of Reference Numerals

[0071] 10 Syringe needle 12 Main body portion 14 Tip portion 20 Side opening 30 Tip side surface attachment portion 40 Rear end side surface attachment portion 60 Syringe needle 62 Main body portion 64 Tip portion 70 Side opening Ef, Er Edge portion Axial direction G

Claims

[Claim 1] A hollow cylindrical main body; A tip portion having a curved outer shape and joined to close the tip of the main body portion; A side opening portion formed on a side surface of the main body portion; Equipped with When viewed from the side in the axial direction with the side opening disposed on top, a region surrounding the side opening has a generally arc-shaped concave shape, a tip side chamfer having a gently curved surface at a position that becomes an edge on the tip side of the concave shape; The injection needle has a rear end chamfer having a gently curved surface at a position that forms an edge on the rear end side of the concave shape.

Images