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 an injection needle, and more particularly to an injection needle having an opening in its side. [Background technology]

[0002] Reducing the puncture resistance is an important issue for injection needles, and to address this issue, injection needles made of superelastic metals with a wall thickness of 0.3 mm or less have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-225940 Summary of the Invention [Problem to be solved by the invention]

[0004] The injection needle described in Patent Document 1 is a typical injection needle with an opening at the tip. However, so-called side-hole injection needles with an opening on the side of the needle are also used in various fields, including cosmetic surgery. With such side-hole injection needles, the injection needle may be moved back and forth or rotated within the skin to distribute the medicinal solution widely within the skin. This increases the penetration resistance, which may cause internal bleeding or blood vessel damage within the skin. Therefore, reducing the penetration resistance is even more important with side-hole injection needles.

[0005] Therefore, an object of the present invention is to solve the above problems and to provide an injection needle that can reliably reduce puncture resistance even when it has an opening on the side. [Means for solving the problem]

[0006] In one embodiment of the injection needle of the present invention, 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 formed on a side surface of the main body; 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 substantially 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, A rear end chamfer having a gently curved surface is provided at a position that becomes the rear end edge of the concave shape. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an injection needle that can reliably reduce puncture resistance even when it has a side opening. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view schematically showing an injection needle according to one embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view schematically showing a conventional injection needle having a side opening. [Figure 3] 1A-1C are diagrams showing a general method for manufacturing a syringe needle having a side opening. [Figure 4A] 1 is a plan view schematically showing an injection needle according to one embodiment of the present invention. [Figure 4B] FIG. 4B is a side cross-sectional view showing section AA of FIG. 4A. [Figure 5A] FIG. 1 is a plan view schematically showing a conventional injection needle having a side opening. [Figure 5B] FIG. 5B is a side cross-sectional view showing section BB of FIG. 5A. [Figure 6A] 10 is a graph showing changes in puncture resistance value in the outward path when the injection needle is moved back and forth. [Figure 6B] 10 is a graph showing changes in the puncture resistance value on the return path when the injection needle is moved back and forth. [Figure 7A]FIG. 1 is a perspective view showing the position of a cross section perpendicular to the axial direction for calculating the outer area of ​​a 22G injection needle according to the present invention. [Figure 7B] 6B is a line graph showing the change in cross-sectional area, with the horizontal axis representing the axial length from the tip and the vertical axis representing the outer area of ​​the cross section perpendicular to the axial direction shown in FIG. 6A. [Figure 8A] FIG. 1 is a perspective view showing the position of a cross section perpendicular to the axial direction for calculating the outer area of ​​a 30 G injection needle according to the present invention. [Figure 8B] 68 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 area of ​​the cross section perpendicular to the axial direction shown in Figure 67 on the vertical axis. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, specific embodiments of the present invention will be described in detail with reference to the drawings, in which corresponding elements having the same functions are designated by the same reference numerals.

[0010] (Injection needle according to one embodiment of the present invention) First, with reference to Figures 1 to 3, an injection needle according to one embodiment of the present invention will be described in comparison with a conventional injection needle having a side opening. Figure 1 is a perspective view that schematically shows an injection needle according to one embodiment of the present invention. Figure 2 is a perspective view that schematically shows a conventional injection needle having a side opening. Figure 3 is a diagram showing a general method for manufacturing an injection needle having a side opening.

[0011] <Conventional injection needle> For example, in a cosmetic procedure in which a medicinal liquid such as hyaluronic acid is administered intradermally, a so-called side-hole injection needle 60 having a side opening 70 is used, as shown in Figure 2. Such an injection needle 60 comprises a hollow cylindrical main body 62 and a curved tip portion 64 joined to close the tip of the main body 62. The side opening 70 is formed on the side surface of the injection needle 60 near the tip portion 64. The tip portion 64 of the injection needle 60 is spherical, and the medicinal liquid is administered through the side opening 70 formed near the tip portion 64.

[0012] When administering a medicinal solution such as hyaluronic acid, a hole is first made in the skin near the area to be administered using a standard injection needle, and then a side-hole injection needle 60 is inserted into the hole to administer the hyaluronic acid intradermally. The injection needle 60 is moved to administer the hyaluronic acid over a wide area within the skin. This allows the skin surface to expand from within the skin, smoothing 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 within the skin to administer it to the required location. Since the injection needle 60 is moved over a wide area within the skin, there is a risk of internal bleeding or blood vessel damage within the skin. In particular, there are edge portions Ef and Er at the front and rear ends of the side opening 70 (see Figures 2 and 5B), and these edge portions Ef and Er may act as resistance, increasing the puncture resistance.

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

[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 close the tip of the metal block. The metal block joined to one end of the metal circular tube becomes the tip 64 of the injection needle 60. Then, as shown in (c), the main body 62 and tip 64 of the injection needle 60 are polished so that they 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 electric discharge machining. More specifically, as shown in (d), wire electric discharge machining is performed so that the area surrounding the side opening 70 has a substantially arc-shaped concave shape when viewed from the side along the axial direction G with the side opening 70 positioned on top. As a result, when viewed from above with the side opening 70 positioned on top, 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, but since an opening cannot be formed if it extends into the area where the tip 64 exists, it is preferable to form the side opening 70 as close to the tip as possible in an area where there is no mass of the tip 64 inside.

[0018] At this time, in a side view along the axial direction G with the side opening 70 positioned at the top, the intersection F between the upper outline of the main body 62 or the tip end 64 and the front line segment of the substantially arc-shaped concave shape formed by cutting out using wire electric discharge machining forms a protruding edge, forming an edge portion Ef. Similarly, the intersection R between the upper outline of the main body 62 and the rear line segment of the substantially arc-shaped concave shape formed by cutting out using wire electric discharge machining forms a protruding edge, forming an edge portion Er.

[0019] When the injection needle 60 is moved back and forth or rotated inside the skin, these edges Ef and Er may act as resistance, increasing the puncture resistance.

[0020] (Injection needle according to one embodiment of the present invention) To address this issue, the injection needle 10 of this embodiment has a tip chamfered portion 30 with a gently curved surface formed at the edge of the tip end of the concave shape, and a rear chamfered portion 40 with a gently curved surface formed at the edge of the rear end of the concave shape.

[0021] The injection needle 10 according to this embodiment is also manufactured through the steps shown in (a) to (d) of Figure 3. As shown in (a), a metal circular tube that will become the main body 12 of the injection needle 10 is prepared, and 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 12 of the injection needle 10, and the welded metal block becomes the tip 14 of the injection needle 10. Then, as shown in (c), polishing is performed so that the main body 12 and tip 14 of the injection needle 10 are smoothly connected.

[0022] Next, as shown in (d), wire electric discharge machining is performed so that the area surrounding the side opening 20 has a generally arc-shaped concave shape when viewed from the side along the axial direction G with the side opening 20 positioned on top. As a result, when viewed from above with the side opening 20 positioned on top, 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 to the tip as possible in an area where no mass of the tip portion 14 exists inside.

[0023] In this state, when viewed from the side along the axial direction G with the side opening 20 positioned at the top, the intersection F between the upper outline of the main body 12 or the tip 14 and the front line segment of the approximately arc-shaped concave shape formed by cutting out using wire electric discharge machining forms a protruding edge, and the intersection F between the upper outline of the main body 12 and the rear line segment of the approximately arc-shaped concave shape formed by cutting out using wire electric discharge machining forms a protruding edge.

[0024] In this embodiment, as shown in (d), after forming the side opening 20 by wire electric discharge machining, the edge is removed by wire electric discharge machining to form a chamfered portion with a gently curved surface. A leading edge chamfered portion 30 with a gently curved surface is formed at position F, which is the leading edge of the concave shape, and a trailing edge chamfered portion 40 with a gently curved surface is formed at position R, which is the trailing edge of the concave shape.

[0025] More specifically, in this embodiment, wire electric discharge machining is performed so that the leading side chamfer 30 and the trailing side chamfer 40 have a circular arc-like convex shape when viewed from the side along the axial direction G with the side opening 20 positioned at the top. However, the shape is not limited to a circular arc as long as the convex shape is smooth.

[0026] As described above, the injection needle 10 according to this embodiment comprises the hollow cylindrical main body 12, the tip portion 14 having a curved outer shape and joined to close the tip of the main body 12, and the side opening 20 opened in the side of the main body 12. When viewed from the side along the axial direction G with the side opening 20 positioned on top, the area surrounding the side opening 20 has a roughly arc-shaped concave shape, and has a tip side chamfer 30 with a gently curved surface at position F, which is the edge on the tip side of the concave shape, and a rear side chamfer 40 with a gently curved surface at position R, which is the edge on the rear side of the concave shape.

[0027] The injection needle 10 according to this embodiment has a tip side chamfer 30 with a gently curved surface at position F, which is the edge on the tip side, and a rear side chamfer 40 with a gently curved surface at position R, which is the edge on the rear side, so that it is possible to reduce the puncture resistance that occurs when the injection needle 10 is moved inside the skin. By reducing the puncture resistance, it is possible to reduce the possibility of internal bleeding and blood vessel damage inside the skin. As a result, it is possible to provide an injection needle 10 that can reliably reduce puncture resistance even when it has a side opening 20.

[0028] In particular, when the leading-end chamfered portion 30 and the trailing-end chamfered portion 40 have an arc-shaped convex shape when viewed from the side along the axial direction G with the side opening 20 positioned at the top, it is possible to easily and reliably form chamfered portions with gently curved surfaces by wire electric discharge machining or the like.

[0029] Furthermore, when viewed in a plane with the side opening 20 positioned upward, if the side opening 20 has an elliptical or oblong shape extending in the axial direction G, medicinal liquids including hyaluronic acid can be reliably administered over a wide area within the skin.

[0030] (Detailed shape of the injection needle according to one embodiment of the present invention) Next, with reference to Figures 4A to 5B, the shape of the injection needle according to this embodiment will be described in more detail, in comparison with conventional injection needles. Figure 4A is a plan view schematically showing an injection needle according to one embodiment of the present invention. Figure 4B is a side cross-sectional view showing section AA of Figure 4A. Figure 5A is a plan view schematically showing a conventional injection needle having a side opening. Figure 5B is a side cross-sectional view showing section BB of Figure 5A.

[0031] As shown in Fig. 5B, in a conventional injection needle, an edge portion Ef exists on the tip side of the side opening 70, and a rear edge portion Er exists on the rear side of the side opening 70. On the other hand, in the injection needle 10 according to this embodiment, a tip side chamfered portion 30 having a gently curved surface is formed at position F, which is the tip edge, and a rear side chamfered portion 40 having a gently curved surface is formed at position R, which is the rear edge. In Fig. 4A, the outlines of the tip side edge Ef and rear side edge Er removed by wire electric discharge machining are shown by dotted lines.

[0032] In the conventional injection needle 60, the edge portion Ef on the tip side is located at approximately the same height as the outline of the upper side of the main body 12 when viewed from the side along the axial direction G with the side opening 20 positioned at the top. On the other hand, in the injection needle 10 according to the present embodiment, the tip side chamfered portion 30 is formed, and therefore there is a predetermined height distance D between the highest position of the tip side chamfered portion 30 and the outline of the upper side of the main body 12 when viewed from the side along the axial direction G with the side opening 20 positioned at the top. When the conventional tip side edge Ef is present, the distance D = 0 in principle.

[0033] A larger value for this distance D is expected to reduce the penetration resistance that occurs when the injection needle 10 is moved intradermally. In particular, when the injection needle 10 is moved back and forth, a reduction in penetration resistance can be expected on the outward path. In addition, the rear end side chamfered portion 40 smoothly connects to the outer contour of the upper side of the main body 12 to form a concave shape, so a reduction in penetration resistance can be expected on the return path when the injection needle 10 is moved back and forth.

[0034] Next, samples of the injection needle 10 having different distances D were fabricated, and a test was conducted to measure the puncture resistance value, and the relationship between the value of the distance D and the puncture 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 chamfered portion 30, and injection needles 10 with distances D = 0.04 mm, 0.07 mm, and 0.10 mm were fabricated, and the puncture resistance values ​​were measured. The outer diameter of the injection needle 10 was set in the range of 22 G or more and 30 G or less, taking into account the practical range.

[0035] The reason why the distance D is set to the range of 0.04 mm or more and 0.10 mm or less can be explained as follows. Taking into consideration the manufacturing tolerances when forming the tip side chamfer 30 and the fact that a consistent trend is observed even in repeated tests, the minimum value of distance D was set to 0.04 mm. On the other hand, a larger value of distance D is expected to have a lower puncture resistance effect, but considering the outer diameters of injection needles 10 actually used, which are 22 G to 30 G, the thinnest thickness of 30 G is 0.059 mm. Therefore, taking into consideration practical strength, the maximum value of distance D was set to 0.10 mm.

[0036] As shown in Fig. 4A, when viewed from the side along the axial direction G with the side opening 20 positioned at the top, the region surrounding the side opening 20 has a generally arc-shaped concave shape, and as shown in Fig. 4B, the value of the radius Rh of this arc can be, for example, R0.98 mm to R1.0 mm. Furthermore, when the convex shapes of the leading side chamfered portion 30 and the trailing side chamfered portion 40 are arc-shaped, the radii Rf and Rr of this arc can be, for example, R0.75 mm to R1.5 mm.

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

[0038] The membrane to be punctured in the puncture resistance measurement test was made of silicone rubber, and the hardness and thickness were as low as possible. Specifically, a silicone rubber sheet (hardness 5 (durometer A), thickness: 3 mm, Kyowa Kogyo Co., Ltd.) was used. The membrane to be punctured was fixed on the measurement jig so that the puncture point was at the center of an 8 mm diameter hole in the measurement jig. The membrane to be punctured was then repeatedly punctured twice in a back and forth motion. The test speed was 20 mm / min. Since the first puncture showed an effect due to the opening, the data from the second puncture was used.

[0039] [Measurement conditions] Test equipment: Automatic load testing machine (MAX-1KN-P-1) manufactured by Japan Measurement Systems Co., Ltd. Load cell: JCL-M10N (capacity: 10N) Measuring jig: MKT-45 Membrane to be punctured: Silicone rubber sheet (hardness 5 (durometer A), thickness: 3 mm, manufactured by Kyowa Seisakusho) Test speed: 20mm / min Test range: Approximately 10 mm from the tip of the needle just before it comes into contact with the membrane to be punctured

[0040] [Measurement results] The measurement results are shown in Figures 6A and 6B. Figure 6A is a graph showing the change in the penetration resistance value on the outward path when the injection needle is moved back and forth. Figure 6B is a graph showing the change in the penetration resistance value on the return path when the injection needle is moved back and forth. The horizontal axis of the graph shows the displacement of the injection needle tip. The position immediately before the injection needle tip comes into contact with the membrane to be punctured is set to zero. The vertical axis of the graph shows the measured penetration resistance value (N). The measured penetration resistance value is shown with the compression direction as positive.

[0041] The prototype 22G and 30G injection needles with distances D of 0 mm, 0.04 mm, 0.07 mm, and 0.10 mm all showed similar trends as shown in Figures 6A and 6B.

[0042] <Outbound> In the outward path shown in Figure 6A, as the injection needle is moved from the zero position in the puncture direction, the penetration resistance value increases, reaching peak P1, and then repeatedly decreases and increases, resulting in peaks P2, P3, and P4. Peak P1 is thought to be due to axial misalignment caused by the tension of the membrane to be punctured when the injection needle is inserted. Therefore, the penetration resistance value of peak P2 is thought to have a significant effect on the penetration resistance in the outward path. The table below shows the average penetration resistance values ​​and "ratios to D=0" for measured peaks P2 to P4. Note that the "ratios to D=0" in the table below are expressed as a percentage (Y / X), where X is the penetration resistance value at D=0 and Y is the penetration resistance value at D=0.04 mm, 0.07 mm, and 0.10 mm.

[0043] (Table 1) Puncture resistance value (outward path) TIFF0007727324000001.tif47146

[0044] It was found that the prototype 22G and 30G injection needles with distances D = 0.04mm, 0.07mm, and 0.10mm could reduce the value of peak P1 in the outward movement by approximately 10% compared to an injection needle with distance D = 0.

[0045] <Return trip> In the return path shown in Figure 6B, as the injection needle is moved in the return direction from the puncture position in the outward path, there are repeated drops and rises, although not as large as in the outward path, resulting in peaks Q1, Q2, Q3, and Q4. Of these, the penetration resistance value of peak Q3 is thought to have a significant effect on the penetration resistance in the outward path. The average values ​​of the measured penetration resistance values ​​at peaks Q1 to Q4 and their ratios to D=0 are shown in the table below.

[0046] (Table 2) Puncture resistance value (return path) TIFF0007727324000002.tif52133

[0047] It was found that the prototype 30G and 22G injection needles with distances D = 0.04mm, 0.07mm, and 0.10mm could reduce the peak Q3 value on the return path by 10% or more compared to an injection needle with distance D = 0.

[0048] As described above, it has been found that when the outer diameter of main body portion 12 is in the range of 22 G or more and 30 G or less, and when viewed from the side along axial direction G with side opening 20 positioned at the top, the height distance D between the highest position of tip side chamfer 30 and the upper outline of main body portion 12 is in the range of 0.04 mm or more and 0.10 mm or less, the puncture resistance value at second peak P2 on the outward path can be reduced by approximately 10% compared to when distance D = 0, and the puncture resistance value at peak Q3 on the return path can be reduced by 10% or more compared to when distance D = 0.

[0049] Therefore, it was demonstrated that the injection needle 10 having the distance D in the range of 0.04 mm or more and 0.10 mm or less can reliably reduce the puncture resistance that occurs when the injection needle 10 is moved inside the skin.

[0050] (External area of ​​cross section perpendicular to the axial direction) In the above, the shape of the injection needle 10 according to the present embodiment having the tip side chamfered portion 30 is defined by the height distance D between the highest point of the tip side chamfered portion 30 and the upper outline of the main body portion 12, but this is not limiting. For example, it is also possible to define it by the outline area of ​​a cross section perpendicular to the axial direction G. Next, calculation of the outline area of ​​a cross section perpendicular to the axial direction G will be described with reference to Figures 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 area of ​​a 22G injection needle according to the present invention. Fig. 7B is a line graph showing the change in cross-sectional area, with the horizontal axis representing the length in the axial direction from the tip and the vertical axis representing the outer area of ​​the cross section perpendicular to the axial direction shown in Fig. 6A. Fig. 8A is a perspective view showing the position of a cross section perpendicular to the axial direction for calculating the outer area of ​​a 30G injection needle according to the present invention. Fig. 8B is a line graph showing the change in cross-sectional area, with the horizontal axis representing the length in the axial direction from the tip and the vertical axis representing the outer area of ​​the cross section perpendicular to the axial direction shown in Fig. 8A.

[0052] FIG. 7A shows planes 1 to 11 forming a cross section 11 perpendicular to the axial direction of a 22G injection needle 10. The horizontal axis of FIG. 7B represents the distance (unit: mm) in the axial direction G from the tip of the injection needle 10, and the vertical axis represents the outer area (unit: mm) of the cross section perpendicular to the axial direction G. 2 ) are shown. The outline area here refers to the area considered as solid, without subtracting the area of ​​the hollow portion. FIG. 7B is a line graph in which the outline areas of Planes 1 to 11 shown in FIG. 7A are plotted and the plotted points are connected by straight lines. The solid line shows the case where there is no leading side chamfer 30 and there is edge Ef, with distance D=0. The short dotted line shows the case where there is leading side chamfer 30 and distance D=0.04 mm, the dashed dotted line shows distance D=0.07 mm, and the long dotted line shows distance D=0.10 mm.

[0053] Regarding the outer area shown in FIG. 7B, the reduction ratio of the outer area when the leading edge chamfer 30 is provided to the outer area when the edge Ef is provided can be expressed by the following formula. Assuming that there is a leading edge portion Ef, the outer area of ​​a cross section perpendicular to the axial direction G including the edge portion Ef is defined as A, and the outer area of ​​a cross section perpendicular to the axial direction G when there is a leading edge chamfer 30 at the same position in the axial direction G is defined as B, then this can be expressed as (AB) / A. The value of (AB) / A at the position of the leading edge portion Ef can be expressed as the value on plane 3 in the table below. On plane 3, the value of (AB) / A is in the range of greater than 3.0% and less than 7.4%.

[0054] Regarding the outer area shown in FIG. 7B, the reduction ratio of the outer area when rear end side chamfer 40 is provided to the outer area when edge portion Er is provided can be expressed by the following formula. Assuming that there is a leading edge portion Er, the outer area of ​​a cross section perpendicular to the axial direction G including the edge portion Er is defined as C, and the outer area of ​​a cross section perpendicular to the axial direction G when there is a rear end chamfered portion 40 at the same position in the axial direction G is defined as D, then this can be expressed as (CD) / C. The value of (CD) / C at the position of the rear end edge portion Er can be expressed as the value at plane 10 in the table below. At plane 10, the value of (CD) / C is approximately 1.8%.

[0055] (Table 3) Reduction ratio of external area (%) TIFF0007727324000003.tif73147

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

[0057] 8B, the value of (AB) / A, which is the reduction ratio of the outer area when the tip side chamfer 30 is provided to the outer area when the edge portion Ef is provided, can be expressed by the value for Plane 2 in the table below. For Plane 2, the value of (AB) / A is in the range of more than 2.4% and less than 4.8%.

[0058] 8B, the value of (CD) / D, which is the reduction ratio of the outer area when the rear end chamfered portion 40 is provided to the outer area when the edge portion Er is provided, can be expressed by the value at plane 11 in the table below. At plane 11, the value of (CD) / D is in the range of more than 0.1% and less than 0.6%.

[0059] (Table 4) Reduction ratio of external area (%) TIFF0007727324000004.tif73147

[0060] The value of (AB) / A is in the range of greater than 3.0% and less than 7.4% for 22G, and greater than 2.4% and less than 4.8% for G30G. Therefore, if we take the overlapping range of both, the value of (AB) / A is in 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 22 G or more and 30 G or less and that it has an edge portion Ef on the tip side, the outer area of ​​the cross section perpendicular to the axial direction G including the edge portion Ef is A, and the outer area of ​​the cross section perpendicular to the axial direction G when it has a tip side chamfered portion 30 at the same position in the axial direction G is B, when the value of (AB) / A is in the range of more than 3.0% and less than 4.8%, it is possible to reliably reduce the puncture resistance that occurs when the injection needle 10 is moved intradermally, especially in the outward movement.

[0062] Furthermore, the value of (CD) / D is approximately 1.8% at 22 G, and is in the range of greater than 0.1% and less than 0.6% at 30 G. Therefore, if the value of (CD) / D is at least greater than 0.1%, it can be expected that the puncture resistance that occurs when the injection needle 10 is moved intradermally, particularly on the return path, can be reduced.

[0063] Therefore, assuming that the outer diameter of the main body is in the range of 22 G to 30 G and that it has an edge portion Er on the rear end side, the outer area of ​​the cross section perpendicular to the axial direction G including the edge portion Er is C, and the outer area of ​​the cross section perpendicular to the axial direction G when it has a rear end chamfered portion 40 at the same position in the axial direction G is D, if the value of (CD) / C is in the range greater than 0.1%, it is possible to reliably reduce the puncture resistance that occurs when the injection needle 10 is moved intradermally, especially on the return path.

[0064] As mentioned above, A first aspect of the present invention is 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 formed on a side surface of the main body; 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 substantially 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 with a gently curved surface at the position that becomes the edge of the rear end of the concave shape.

[0065] A second aspect of the present invention is a method for producing a composition comprising the steps of: The outer diameter of the main body is in the range of 22G or more and 30G or less, When viewed from the side along the axial direction with the side opening positioned upward, The height direction distance between the highest position of the tip side chamfer and the upper outline of the main body is in the range of 0.04 mm to 0.10 mm.

[0066] A third aspect of the present invention is the first or second aspect, The outer diameter of the main body is in the range of 22G or more and 30G or less, Assuming that the tip end side edge portion is present, the outer area of ​​a cross section perpendicular to the axial direction including the edge portion is defined as A, and as the outer area of ​​a cross section perpendicular to the axial direction in the case where the tip end chamfered portion is present at the same position in the axial direction is defined as B, The value of (AB) / A is in the range of greater than 3.0% and less than 4.8%.

[0067] A fourth aspect of the present invention is any one of the first to third aspects, The outer diameter of the main body is in the range of 22G or more and 30G or less, Assuming that the rear end side edge portion is present, the outer area of ​​a cross section perpendicular to the axial direction including the edge portion is defined as C, and as the outer area of ​​a cross section perpendicular to the axial direction in the case where the rear end side chamfer portion is present at the same position in the axial direction is defined as D, The value of (CD) / C is in the range of more than 0.1%.

[0068] A fifth aspect of the present invention is any one of the first to fourth aspects, When viewed from the side along the axial direction with the side opening positioned upward, The leading edge chamfered portion and the trailing edge chamfered portion have an arcuate convex shape.

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

[0070] Although the embodiments and modes of implementation of the present invention have been described, the disclosed contents may vary in the details of the configuration, and changes in the combination and order of elements in the embodiments and modes of implementation may be realized without departing from the scope and spirit of the claimed invention. [Explanation of symbols]

[0071] 10 Syringe needle 12 Main body 14 Tip 20 Side opening 30 Tip side chamfer 40 Rear end side chamfer 60 Syringe needle 62 Main body 64 Tip 70 Side opening Ef, Er edge part Axial G

Claims

1. An injection needle used to puncture a hole in the skin, insert it into the hole, and move it back and forth to supply a liquid medicine over a wide area, a hollow cylindrical metal body; a metal tip portion having a curved outer shape and joined to close the tip of the main body portion; a side opening formed on a side surface of a cylindrical portion of the main body having the same outer diameter as the tip portion, the cylindrical portion being adjacent to the tip 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 substantially 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, a rear end chamfer having a gently curved surface at a position that becomes an edge on the rear end side of the concave shape, In a plan view of the side opening from above along the axial direction, the outlines of the main body on both sides of the entire area of ​​the side opening extend along the axial direction at the same distance, and 1. The injection needle according to claim 1, wherein the highest position of the tip side chamfer is formed lower than the outline of the upper side of the main body when viewed from the side along the axial direction with the side opening positioned at the top.

2. 2. The injection needle according to claim 1, wherein the tip chamfered portion and the rear chamfered portion have a smooth convex shape obtained by a single wire electric discharge machining operation involving a one-dimensional movement in which the tip of the wire describes a curve, when viewed from the side along the axial direction with the side opening positioned at the top.

3. The outer diameter of the main body is in the range of 22G or more and 30G or less, When viewed from the side along the axial direction with the side opening positioned upward, 2. The injection needle according to claim 1, wherein the height direction distance between the highest position of the tip side chamfer and the upper outline of the main body is in the range of 0.04 mm to 0.10 mm.

4. The outer diameter of the main body is in the range of 22G or more and 30G or less, Assuming that the tip end side edge portion is present, the outer area of ​​a cross section perpendicular to the axial direction including the edge portion is defined as A, and as the outer area of ​​a cross section perpendicular to the axial direction in the case where the tip end side chamfered portion is present at the same position in the axial direction is defined as B, 2. The injection needle according to claim 1, wherein the value of (A-B) / A is in the range of more than 3.0% and less than 4.8%.

5. The outer diameter of the main body is in the range of 22G or more and 30G or less, Assuming that the rear end side edge portion is included, the outer area of ​​a cross section perpendicular to the axial direction including the edge portion is defined as C, and as the outer area of ​​a cross section perpendicular to the axial direction in the case where the rear end side chamfer portion is included at the same position in the axial direction is defined as D, 5. The injection needle according to claim 4, wherein the value of (C-D) / C is in a range greater than 0.1%.

6. When viewed from the side along the axial direction with the side opening positioned upward, 6. The injection needle according to claim 1, wherein the leading end chamfered portion and the rear end chamfered portion have a convex arc shape.

7. In a plan view with the side opening positioned upward, 6. The injection needle according to claim 1, wherein the side opening has an elliptical or oval shape extending in the axial direction.

8. A method for manufacturing an injection needle used to puncture the skin, insert it into a hole made in the skin, and move it back and forth to supply a drug solution over a wide area, comprising: a hollow cylindrical metal body; a metal tip portion having a curved outer shape and joined to close the tip of the main body portion; a side opening formed on a side surface of a cylindrical portion of the main body having the same outer diameter as the tip portion, the cylindrical portion being adjacent to the tip 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 substantially 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, A method for manufacturing an injection needle having a rear end chamfered portion with a gently curved surface at a position that will become an edge on the rear end side of the concave shape, comprising: In a side view along the axial direction with the side opening positioned at the top, the edges are removed by a single wire electric discharge machining in which the tip of the wire moves in a one-dimensional curve, thereby forming smooth convex shapes of the tip side chamfer portion and the rear side chamfer portion; In the manufactured injection needle, in a plan view along the axial direction when the side opening is viewed from above, the outlines of the main body portion on both sides of the entire area of ​​the side opening extend along the axial direction at the same distance, and a tip end of the injection needle having a chamfered portion at a highest position that is lower than an upper outline of the main body when viewed from the side along the axial direction with the side opening portion positioned at the top.

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