Surgical Bur

Abstract

To provide a surgical bur capable of providing high cutting performance while improving operability and of accurate cutting.SOLUTION: A cutting part 11 of a surgical bur 10 includes: a ridge line formed across a rotation axial line of an axial direction end of the cutting part 11 when seen from an end side of a shaft part 13; a first main blade BL1 which is connected to one end of the ridge line and extends to a rear end in an axial direction connected to the shaft part 13 of the cutting part 11; and a second main blade BL3 which is connected to the other end of the ridge line and extends to the rear end in the axial direction of the cutting part 11 so that it becomes rotational symmetrical with the first main blade based on the rotation axial line. The first main blade BL1 has a first tip blade BL1A formed from the one end of the ridge line in an end area of the cutting part 11, and the second main blade BL3 has a second tip blade BL3A formed from the other end of the ridge line in the end area of the cutting part 11. The first tip blade BL1A and the second tip blade BL3A are arranged within the same plane orthogonal to the rotation axial line of the cutting part 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a surgical burr. [Background technology]

[0002] Known surgical burs used in bone surgery instruments are one type of medical instrument used in surgical procedures (Patent Documents 1 to 3). Surgical burs include a shaft and a cutting section provided at the tip of the shaft and having multiple blades. The multiple blades are formed as cutting blades for resecting tissue such as bone, and the shaft is fixed to a drive shaft such as a handpiece. During a surgical procedure, the drive shaft is operated to rotate the surgical burr, and the cutting section is pressed against the tissue to be removed, causing the tissue to be resected by the rotating cutting blades. Such surgical burrs are used in a variety of surgical procedures, such as orthopedic surgery, neurosurgery, spinal surgery, and ear, nose, and throat surgery, or in procedures for selectively removing portions of tissue. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-502943 [Patent Document 2] Special Publication No. 2016-527003 [Patent Document 3] Special Publication No. 2019-531140 Summary of the Invention [Problem to be solved by the invention]

[0004] As in the above-mentioned Patent Documents 1 to 3, various ingenious surgical burrs have been proposed to perform smooth surgical operations. Surgical burrs are required to combine high cutting performance of the cutting part with accurate operability during surgery in order to respond appropriately to various surgical situations. For example, rebound that occurs when the cutting part is pressed against the bone needs to be sufficiently suppressed to perform accurate surgical operations. However, suppression of this rebound tends to be in a trade-off relationship with cutting performance, and further improvements are desired. Therefore, there is an urgent need to develop a surgical burr that is easy for surgeons to handle and has higher cutting performance.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a surgical burr that provides improved operability, high cutting performance, and enables more accurate cutting. [Means for solving the problem]

[0006] The surgical burr according to the present invention has the following configuration. A surgical burr having a shaft portion that rotates around a rotation axis line and a ball-shaped cutting portion provided at a tip of the shaft portion, The cutting portion is a ridgeline formed at an axial tip of the cutting portion across the rotation axis when the cutting portion is viewed from the tip side of the shaft portion; a first main cutting edge connected to one end of the ridge line and extending toward an axial rear end connected to the shank of the cutting portion; a second main cutting edge connected to the other end of the ridge line and extending toward the axial rear end of the cutting portion so as to be rotationally symmetrical to the first main cutting edge with respect to the rotation axis; Equipped with the first main cutting edge has a first tip cutting edge formed from one end of the ridge line in a tip region of the cutting portion, the second main cutting edge has a second tip cutting edge formed from the other end of the ridge line in a tip region of the cutting portion, The first tip cutting edge and the second tip cutting edge are arranged in the same plane perpendicular to the rotation axis of the cutting part. Surgical burr. [Effects of the Invention]

[0007] According to the present invention, high cutting performance can be obtained while improving operability, and more accurate cutting becomes possible. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a surgical operation system. [Figure 2] FIG. 2 is a diagram of a surgical burr. [Figure 3] FIG. 3 is a perspective view of the cutting portion of a surgical burr. [Figure 4] FIG. 4 is a front view of the cutting portion of the surgical burr. [Figure 5] FIG. 5 is a side view of the cutting portion of the surgical burr. [Figure 6] FIG. 6 is an enlarged view of the axial tip of the cutting part. [Figure 7] FIG. 7 is a partially enlarged perspective view of the axial tip of the cutting portion. [Figure 8] FIG. 8 is a cross-sectional view of the cutting portion taken along line VIII-VIII shown in FIG. [Figure 9] FIG. 9 is an explanatory diagram schematically illustrating the cutting edges of the first cutting blade, the second cutting blade, the third cutting blade, and the fourth cutting blade when the cutting portion is viewed from the axial tip. [Figure 10] FIG. 10 is a side view of the cutting portion of the surgical burr. [Figure 11] FIG. 11 is a cross-sectional view taken along line AA of the cut portion shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line BB of the cut portion shown in FIG. [Figure 13] FIG. 13 is a cross-sectional view taken along line CC of the cut portion shown in FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along line DD of the cutting portion shown in FIG. [Figure 15] 15 is a cross-sectional view taken along line EE of the cut portion shown in FIG. [Figure 16]FIG. 16 is an explanatory diagram showing a state in which the cutting part is pressed perpendicularly against the cutting object. [Figure 17] FIG. 17 is an explanatory diagram showing a state in which cutting is performed while the rear end side in the axial direction of the inclined cutting part is pressed against the cutting object. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a surgical operation system that is a bone surgery instrument is exemplified as a medical device that uses the surgical burr according to the present invention, but the invention is not limited to this and may also be a medical device for other purposes such as dentistry.

[0010] <Surgical System> FIG. 1 is a schematic diagram of a surgical operation system 100. As shown in FIG. The surgical system 100 includes a control unit 101, a handpiece 103, and It comprises a connection cable 105 that connects the handpiece 103 to the control unit 101, and a foot switch 107.

[0011] Handpiece 103 includes attachment 103a and grip 103b. Surgical burr 10 is detachably attached to attachment 103a at the tip of handpiece 103. A power source, such as an air motor or an electric motor (not shown), that rotates surgical burr 10 is provided at grip 103b of handpiece 103. The power source is rotated or stopped by foot switch 107 connected to control unit 101. Control unit 101 controls the driving of handpiece 103.

[0012] <Surgical Burr> FIG. 2 is a diagram of surgical burr 10. Surgical burr 10 has a rod-shaped shaft 13 along rotation axis L and a ball-shaped cutting portion 11 provided at one end of shaft 13. The term "ball-shaped" here means that when surgical burr 10 is rotated around rotation axis L, the shape of the curved surface that envelops the cutting edge formed on cutting portion 11 includes the surface shape of a sphere or spheroid centered on rotation axis L. This surgical burr 10 is made of a hard material such as stainless steel or cemented carbide (tungsten carbide). At the base end of shaft 13 opposite cutting portion 11, a connecting portion 15 is provided which is fixed to the rotating shaft of handpiece 103. Surgical burr 10 fixed to the rotating shaft is The handpiece 103 is driven to rotate, causing the cutting part 11 and the shaft part 13 to rotate about the rotation axis.

[0013] In this surgical system 100, the surgeon operates foot switch 107 while holding handpiece 103 to rotate surgical burr 10 at high speed. Then, when the surgeon moves handpiece 103 while pressing cutting part 11 of surgical burr 10 against the desired removal site, the rotating cutting part 11 can cut the desired removal site.

[0014] <Cutting section configuration> The configuration of the cutting unit 11 will be described below with reference to FIGS. FIG. 3 is a perspective view of cutting portion 11 of surgical burr 10. As shown in Figure 3, cutting part 11 provided at the tip of shaft 13 has multiple cutting edges formed by grinding and polishing various faces, grooves, etc., described in detail below, on the surface of a ball-shaped hard material. Cutting part 11 is equipped with multiple types of cutting blades with different cutting lengths. Of the multiple cutting blades, those with longer cutting lengths are called main blades, and those with shorter cutting lengths are called sub-blade.

[0015] The cutting section 11 of this configuration has a first cutting blade BL1 which is the first main blade, a third cutting blade BL3 which is the second main blade, a second cutting blade BL2 which is the first auxiliary blade, and a fourth cutting blade BL4 which is the second auxiliary blade.

[0016] In the following description, the cutting portion 11 of the surgical burr 10 has a connecting portion with the shank 13 at its axial rear end, This connecting portion side is referred to as the rear end side, and the end opposite to the shaft portion 13 is referred to as the tip or axial tip, and this end side is referred to as the tip side. The axial direction of the shaft portion 13 is referred to as the X direction, the direction perpendicular to the X direction is referred to as the Y direction, and the direction perpendicular to the X direction and the Y direction is referred to as the Z direction. The Y direction is the direction along the first cutting blade BL1 and the third cutting blade BL3, and the Z direction is the direction along the second cutting blade BL2 and the fourth cutting blade BL4. The same symbols are assigned to the same members or the same parts, The explanation will be omitted or simplified.

[0017] FIG. 4 is a front view of cutting portion 11 of surgical burr 10. As shown in Figure 4, when viewed from the front of the tip end of the surgical bar 10, the cutting portion 11 has a total of four cutting blades, namely a first cutting blade BL1 (main blade), a second cutting blade BL2 (minor blade), a third cutting blade BL3 (main blade), and a fourth cutting blade BL4 (minor blade), which are formed in this order clockwise around the rotation axis L, at different circumferential positions.

[0018] That is, the first cutting blade BL1 and the third cutting blade BL3 are disposed symmetrically at the axial tip of the cutting part 11 with respect to the rotation axis L (and the chisel CE described later) as the reference, and constitute a pair of main cutting edges. The second cutting blade BL2 and the fourth cutting blade BL4 are disposed between the main blades to form a pair of secondary blades. During cutting, the cutting portion 11 rotates counterclockwise in accordance with the rotation direction R when viewed from the distal end of the surgical burr 10, and the main blade and secondary blade alternately contribute to cutting.

[0019] FIG. 5 is a side view of cutting portion 11 of surgical burr 10. As shown in FIG. 5, the main cutting edge and the auxiliary cutting edge described above are centered on the rotation axis L and extend toward the shaft portion 13 along a twist toward the base end side of the cutting portion 11.

[0020] Table 1 shows the relationship between each of the cutting edges of the cutting portion 11 and the rake face, flank, etc. corresponding to each edge.

[0021] [Table 1]

[0022] Here, when expressing each surface of the cutting portion 11 by a symbol, each surface is defined as follows. That is, as shown in Fig. 4, when the cutting unit 11 is viewed from the tip side, four cutting blades are arranged at 90° intervals around the rotation axis L. Of the four cutting blades, with respect to the rotation direction R of the cutting unit 11, the surfaces arranged within the first quadrant between the cutting edge of the first cutting blade BL1 and the cutting edge of the second cutting blade BL2 are individually indicated by alphabets, and the number of the quadrant (here, "1" for the first quadrant) is added to each alphabet. Similarly, the section from the cutting edge of the second cutting blade BL2 to the cutting edge of the third cutting blade BL3 is defined as the second quadrant, the section from the cutting edge of the third cutting blade BL3 to the cutting edge of the fourth cutting blade BL4 is defined as the third quadrant, and the section from the cutting edge of the fourth cutting blade BL4 to the cutting edge of the first cutting blade BL1 is defined as the fourth quadrant.

[0023] The configurations of the main cutting edge and the sub cutting edge shown in Figs. 3, 4 and 5 are as follows, and the details of each surface will be described later. The first cutting edge BL1, which is the main cutting edge, has a first tip cutting edge BL1A and a first main peripheral cutting edge BL1B. The third cutting edge BL3, which is the main cutting edge, has a second tip cutting edge BL3A and a second main peripheral cutting edge BL3B. The second cutting edge BL2, which is a secondary edge, has a first secondary peripheral edge BL2B. The fourth cutting edge BL4, which is a secondary edge, has a second secondary peripheral edge BL4B. The first tip cutting edge BL1A is formed by a second flat gash J4, which is a cutting face, and a first tip cutting edge flank (flat face) A1. The second tip cutting edge BL3A is formed by a first flat gash J2, which is a cutting face, and a second tip cutting edge flank (flat face) A3. The first main peripheral cutting edge BL1B has a fourth lead gash B4 and a fourth main groove H4 as its rake face, and a first outer peripheral groove E1 as its relief face. The relief face of the first outer peripheral groove E1 is also connected to a first outer peripheral groove F1, a first outer peripheral groove G1, and a first back groove I1. The second main peripheral cutting edge BL3B has a second lead gash B2 and a second main groove H2 as its rake face, and a third outer peripheral groove E3 as its relief face.Furthermore, the relief face following the third outer peripheral groove E3 has a third outer peripheral groove F3, a third outer peripheral groove G3, and a third back groove I3.

[0024] The first auxiliary peripheral cutting edge BL2B has a rake face formed with a first lead gash B1 and a first main groove H1, and a second outer peripheral groove E2 as a relief face. The relief face following the second outer peripheral groove E2 is provided with a second outer peripheral groove F2, a second outer peripheral groove G2, and a second back groove I2. Furthermore, the first auxiliary cutting edge adjustment surface D2 is provided as a surface for adjusting the length of the first auxiliary peripheral cutting edge BL2B. The second auxiliary peripheral cutting edge BL4B has a third lead gash B3 and a third main groove H3 as its rake face, and a fourth outer peripheral groove E4 as its relief face. The relief face following the fourth outer peripheral groove E2 is a fourth outer peripheral groove F4, a fourth outer peripheral groove G4, and a fourth back groove I4. Furthermore, the second auxiliary cutting edge adjustment surface D4 is used to adjust the length of the second auxiliary peripheral cutting edge BL4B.

[0025] <Configuration of the chisel, first tip blade, and second tip blade> FIG. 6 is an enlarged view of the axial tip of the cutting part 11. As shown in FIG. A pair of tip surfaces, a first tip cutting edge flank A1 and a second tip cutting edge flank A3, are formed at the axial tip of the cutting portion 11. The first tip cutting edge flank A1 and the second tip cutting edge flank A3 are provided at an angle to each other with the rotation axis L in between, and intersect with each other to form a ridgeline between points P1 and P2. A chisel CE is formed along this ridgeline. In other words, the line (ridgeline) connecting points P1 and P2, where the first tip cutting edge flank A1 and the second tip cutting edge flank A3 are connected, becomes the chisel CE.

[0026] The first tip edge flank (tip surface) A1 is connected to the first cutting edge BL1, which is one of the main edges, and the second tip edge flank (tip surface) A3 is connected to the third cutting edge BL3, which is the other main edge.

[0027] Specifically, a first tip cutting edge BL1A is formed on the front edge of the first tip cutting edge flank A1 in the direction of rotation R. Similarly, a second tip cutting edge BL3A is formed on the front edge of the second tip cutting edge flank A3 in the direction of rotation R. The first main peripheral cutting edge BL1B is formed along a line connecting points P1 and P2 between points P1 and P3, and one end of the first main peripheral cutting edge BL1B is connected to the chisel CE at point P1. Similarly, the second main peripheral cutting edge BL3B is formed along a line connecting points P2 and P4 between points P2 and P4, and one end of the second main peripheral cutting edge BL3B is formed along a line connecting points P2 and P4 between points P2 and P4, and one end of the second main peripheral cutting edge BL3B is connected to the chisel CE at point P2.

[0028] Returning to FIG. 5, the side surface of the cutting portion 11 will be referred to. As shown in FIG. 5 , the first tip cutting edge BL1A and the second tip cutting edge BL3A are arranged in the same plane perpendicular to the rotation axis L across a width W sandwiched between the rotation axis L. In other words, the first tip cutting edge BL1A and the second tip cutting edge BL3A constituting a pair of tip cutting edges are formed so that the trajectory of the cutting edge when the cutting unit 11 rotates is a plane including a connecting line connecting points P3, P1, P2, and P4 in this order. Therefore, when the axial tip of the cutting unit 11 is brought into frontal contact with the workpiece, the chisel CE, the first tip cutting edge BL1A, and the second tip cutting edge BL3A come into line contact with the workpiece along the connecting line. Then, when the cutting unit 11 rotates, each of the first tip cutting edge BL1A and the second tip cutting edge BL3A moves in a plane whose normal is parallel to the rotation axis L. As a result, the cutting object is cut by the pair of tip blades, the first tip blade BL1A and the second tip blade BL3A.

[0029] In general, surgical burrs, known as round cutting burrs, have a roughly spherical outer periphery (the path traced by the cutting edge) when rotated around the rotation axis L. This results in point contact between the tip of the round cutting burr and the object being cut, making cutting difficult. At the axial tip of the cutting part 11 in this configuration, the chisel CE, the first tip edge BL1A, and the second tip edge BL3A come into line contact with the workpiece, and the first tip edge BL1A and the second tip edge BL3A function as cutting edges. Therefore, stable cutting is possible even when the axial tip of the cutting part 11 abuts against the workpiece from the front.

[0030] <Main cutting edge configuration> Next, the first cutting edge BL1, which is the first main cutting edge, and the third cutting edge BL3, which is the second main cutting edge, will be described in detail. 6, the first cutting edge BL1 includes the first tip edge BL1A and the first main peripheral cutting edge BL1B. The first tip edge BL1A is a linear cutting edge (straight edge) formed between point P1, which is one end of the chisel CE, and point P3. The first main peripheral cutting edge BL1B extends from the radially outer edge of the first tip edge flank A1, i.e., point P3, which is the radially outer end of the first tip edge BL1A, along the ball-shaped outer periphery of the cutting part 11, twisting toward the axial rear end.

[0031] The third cutting edge BL3 comprises the second tip edge BL3A and the second main peripheral cutting edge BL3B. The second tip edge BL3A is a straight edge formed between point P2, which is the other end of the chisel CE, and point P4. The second main peripheral cutting edge BL3B extends from the radially outer edge of the second tip edge flank A2, i.e., from point P4, which is the radially outer end of the second tip edge BL3A, along the ball-shaped outer periphery of the cutting part 11, twisting toward the axial rear end.

[0032] The first tip cutting edge BL1A and the second tip cutting edge BL3A are formed with 180° rotational symmetry around the rotation axis L. The first tip cutting edge BL1A is formed with the first tip cutting edge flank (one tip cutting edge) A1 as its flank face and the second flat gash J4 as its rake face. The second tip cutting edge BL3A is formed with the second tip cutting edge flank (the other tip cutting edge) A3 as its flank face and the first flat gash J2 as its rake face.

[0033] In this way, the second flat gash J4 acts as a cutting face for the first leading cutting edge BL1A (the cutting edge corresponding to the line connecting points P1 and P3). Similarly, the first flat gash J2 acts as a cutting face for the second main peripheral cutting edge BL3B.

[0034] The first tip cutting edge BL1A and the second tip cutting edge BL3A are also aligned at points P1 and P3, which are the ends of the first tip cutting edge BL1A, and points P2 and P4, which are the ends of the second tip cutting edge BL3A. It is preferable that the blade be formed into an evenly sharp edge. Therefore, the first flat gash J2 forming the cutting face of the second leading cutting edge BL3A is formed radially inward beyond point P2 up to the position of the second lead gash B2, and is also formed up to the position of the second main peripheral cutting edge BL3B radially outward of point P4. In other words, the first flat gash J2 is formed to a length that exceeds both ends of the line connecting point P2, which is the other end of the chisel CE, to point P4, which is the radial outer edge of the second leading cutting edge flank A2.

[0035] Similarly, the second flat gash J4 forming the cutting face of the first tip cutting edge BL1A is formed radially inward beyond point P1 to the position of the fourth lead gash B4, and is also formed radially outward from point P3 to the position of the first main peripheral cutting edge BL1B. In other words, the second flat gash J4 is formed to a length that exceeds both ends of the line connecting point P1, which is one end of the chisel CE, to point P3, which is the radial outer edge of the first tip cutting edge flank A1.

[0036] This ensures that the second flat gash J4, which forms the cutting face of the first tip cutting edge BL1A, and the first flat gash J2, which forms the cutting face of the second tip cutting edge BL3A, are formed, enabling the first tip cutting edge BL1A and the second tip cutting edge BL3A to have uniformly high sharpness throughout the entire cutting edge.In addition, this also enables the smooth discharge of chips (swarf) generated during cutting.

[0037] <Main cutting edge peripheral flank> Referring again to Figure 4, the first main peripheral cutting edge BL1B connected to the first leading edge BL1A is mainly formed by the fourth lead gash B4, the fourth main groove H4 which forms the cutting face, and the first outer peripheral groove E1 which forms the flank. The second main peripheral cutting edge BL3B connected to the second leading edge BL3A is mainly formed by the second lead gash B2, the second main groove H2 which forms the cutting face, and the third outer peripheral groove E3 which forms the flank.

[0038] Strictly speaking, the components of the first main peripheral cutting edge BL1B described above are the second flat gash J4, the fourth lead gash B4, the fourth main groove H4, and multiple outer flank surfaces described below. The components of the second main peripheral cutting edge BL3B are the first flat gash J2, the second lead gash B2, the second main groove H2, and multiple outer flank surfaces described below. The effects of the first flat gash J2 and the second flat gash J4 on the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B are small. Therefore, detailed descriptions of the first flat gash J2 and the second flat gash J4 will be omitted in the following descriptions of the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B.

[0039] Next, the rake face and the plurality of peripheral flanks will be described with reference to FIG. 4, which shows the front of the cutting portion 11. As shown in Figure 4, the cutting face of the first main peripheral cutting edge BL1B is the fourth lead gash B4 and the fourth main groove H4. The peripheral relief face of the first main peripheral cutting edge BL1B is the first peripheral groove 2 E1, the first peripheral groove 3 F1, and the first peripheral groove 4 G1. Similarly, the cutting face of the second main peripheral cutting edge BL3B is the second lead gash B2 and the second main groove H2. The peripheral relief face of the second main peripheral cutting edge BL3B is the third peripheral groove 2 E3, the third peripheral groove 3 F3, and the third peripheral groove 4 G3. In this way, the outer circumferential flanks of the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B are each configured to have a plurality of surfaces with different clearance angles.

[0040] Figure 7 is an enlarged perspective view of a portion of the axial tip of the cutting portion 11. As shown in Figure 7, the outer circumferential flank of the first main peripheral cutting edge BL1B comprises a first outer circumferential edge No. 2 E1 and a first outer circumferential edge No. 3 F1, and further comprises a first outer circumferential edge No. 4 G1 that cuts the corner of the first outer circumferential edge No. 3 F1 to complement the outer circumferential flank of the first main peripheral cutting edge BL1B.

[0041] Similarly, as shown in Figure 4, the peripheral flank of the second main peripheral cutting edge BL3B also has a third peripheral edge 2 E3 and a third peripheral edge 3 F3, and further has a peripheral edge 4 G3 that cuts the corner of the third peripheral edge 3 F3 to complement the peripheral flank of the second main peripheral cutting edge BL3B.

[0042] FIG. 8 is a cross-sectional view of the cutting portion 11 taken along the line VIII-VIII shown in FIG. As described above, the peripheral flank of the first main peripheral cutting edge BL1B is composed of the first peripheral edge 2 E1, the first peripheral edge 3 F1, and the complementary first peripheral edge 4 G1. These first peripheral edge 2 E1, first peripheral edge 3 F1, and the complementary first peripheral edge 4 G1 form a plurality of different clearance angles γa, γb, and γc, as shown in FIG.

[0043] The first main peripheral cutting edge BL1B has multiple peripheral flanks with different clearance angles, ensuring the appropriate thickness and improving the rigidity of the cutting edge.Similarly, the second main peripheral cutting edge BL3B also has multiple peripheral flanks, ensuring the appropriate thickness and improving the rigidity of the cutting edge.

[0044] <Configuration of the secondary cutting edge and the relationship between the main cutting edge and secondary cutting edge> Next, the second cutting edge BL2 and the fourth cutting edge BL4 that constitute the secondary cutting edge will be described in detail. Returning to Figure 4, let us refer to the front view of the cutting part 11. As shown in Figure 4, the second cutting blade BL2 and the fourth cutting blade BL4 are provided at circumferential positions different from the main blades (first cutting blade BL1, third cutting blade BL3) of the cutting part 11. The second cutting blade BL2, which is the first auxiliary blade, has a first auxiliary peripheral blade BL2B, and the fourth cutting blade BL4, which is the second auxiliary blade, has a second auxiliary peripheral blade BL4B.

[0045] The first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have rotationally symmetric shapes that overlap with each other when rotated around the rotation axis L. Similarly, the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B described above also have rotationally symmetric shapes that overlap with each other when rotated around the rotation axis L.

[0046] The first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B each extend twisted along the rotation axis L. When the cutting portion 11 is cut at a plane perpendicular to the rotation axis at the same axial position in the axial region in which they are formed, the shapes of the blade cross sections of the first main peripheral cutting edge BL1B, the second main peripheral cutting edge BL3B, the first auxiliary peripheral cutting edge BL2B, and the second auxiliary peripheral cutting edge BL4B are each a shape centered on the rotation axis L.

[0047] That is, when the cutting part 11 is rotated 90° around the rotation axis L along the rotation direction R, The first auxiliary peripheral cutting edge BL2B overlaps with the blade shape of the first main peripheral cutting edge BL1B at its position before rotation, with the same blade shape. Similarly, the second auxiliary peripheral cutting edge BL4B overlaps with the blade shape of the second main peripheral cutting edge BL3B at its position before rotation, with the same blade shape. In this way, the cutting edges of the outermost diameter portions of the first main peripheral cutting edge BL1B, the second main peripheral cutting edge BL3B, the first auxiliary peripheral cutting edge BL2B, and the second auxiliary peripheral cutting edge BL4B are each positioned at the same radial distance from the rotation axis L, and the shapes of their blade cross sections are all the same.

[0048] On the other hand, the first major peripheral cutting edge BL1B has overlapping and non-overlapping portions with the same blade shape as the second auxiliary peripheral cutting edge BL4B before rotation. Similarly, the second major peripheral cutting edge BL3B has overlapping and non-overlapping portions with the same blade shape as the first auxiliary peripheral cutting edge BL2B before rotation. This is because the second cutting edge BL2 and the fourth cutting edge BL4, which are auxiliary cutting edges, do not have blades corresponding to the first tip cutting edge BL1A or the second tip cutting edge BL3A, unlike the first cutting edge BL1 and the third cutting edge BL3, which are major cutting edges. Therefore, the axial lengths (blade lengths) of the first major peripheral cutting edge BL1B and the second major peripheral cutting edge BL3B are longer than the axial lengths of the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B.

[0049] <Cutting with main and sub cutting edges> Here, cutting by the main cutting edge and the sub cutting edge will be described. FIG. 9 is an explanatory diagram showing a schematic view of each cutting edge of the first cutting blade, the second cutting blade, the third cutting blade, and the fourth cutting blade when the cutting portion 11 is viewed from the axial tip. As shown in Figure 9, the first auxiliary peripheral cutting edge BL2B has its axial end point at point P5. Similarly, the second auxiliary peripheral cutting edge BL4B has its axial end point at point P6. The first tip cutting edge BL1A and the first main peripheral cutting edge BL1B are connected to each other at point P3, and the second tip cutting edge BL3A and the second main peripheral cutting edge BL3B are connected to each other at point P4.

[0050] Point P5 is located closer to the rear end in the axial direction than point P3 or point P4. Similarly, point P6 is located closer to the rear end in the axial direction than point P3 or point P4. The rear end in the axial direction here refers to the shank 13 side of the cutting portion 11, and is also the radially outer side in FIG. 9.

[0051] In other words, the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have shorter cutting lengths than the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B. The first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have an area at the axial tip of the cutting portion 11 where no cutting edge corresponding to the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B is formed.

[0052] This configuration means that the type and number of blades (the number of blades that rotate and contribute to cutting) of the cutting part 11 change sequentially from the rotation axis L, which is the axial center of the cutting part 11, along the outer circumferential surface of the cutting part 11. That is, the concentric tip region K1 centered on the rotation axis L, the annular region K2 outside the tip region K1, and the outer region K3 outside the annular region K2 each include the following elements.

[0053] Tip region K1: chisel CE, first tip cutting edge BL1A, second tip cutting edge BL3A Annular region K2: first main peripheral cutting edge BL1B, second main peripheral cutting edge BL3B Outer region K3: first main peripheral cutting edge BL1B, second main peripheral cutting edge BL3B, first auxiliary peripheral cutting edge BL2B, second auxiliary peripheral cutting edge BL4B

[0054] In the tip region K1 and annular region K2 shown in Figure 9, the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B do not have cutting edges corresponding to the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B, which are shown by dashed virtual lines.

[0055] In this way, in this configuration, the type and number of blades that actually contribute to cutting are gradually changed for each peripheral position along the axial direction of the cutting portion 11. There are three blades in the tip region K1 at the axial tip of the cutting portion 11, two main peripheral blades in the annular region K2, and a total of four blades, consisting of two main peripheral blades and two auxiliary peripheral blades in the outer region K3.

[0056] As a result, when the surgeon holds handpiece 103 and presses surgical burr 10 against a cutting target, the cutting ability of cutting portion 11 can be optimized according to the inclination angle of surgical burr 10. In other words, the cutting ability is suppressed at the axial tip of cutting portion 11 to reduce rebound, while the cutting ability is increased in the region near the maximum diameter position of cutting portion 11, achieving highly efficient cutting. Furthermore, since the cutting ability does not change significantly from a specific inclination angle and changes approximately continuously according to the inclination angle, there is no discomfort in operation. This allows for smooth and stable cutting.

[0057] The annular region K2 where the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B are not present is, as shown in FIG. 4, a second lead gash B2, a fourth lead gash B4, It is defined by the first minor cutting edge adjustment surface D2, the second minor cutting edge adjustment surface D4, the first lead gash B1, and the third lead gash B3. That is, the second lead gash B2 and the fourth lead gash B4 remove the first minor cutting edge BL2B and the second minor cutting edge BL4B from the rake face side over a predetermined area from the axial tip of the cutting portion 11. The first minor cutting edge adjustment surface D2 and the second minor cutting edge adjustment surface D4 are located radially outside the second lead gash B2 and the fourth lead gash B4, on the axial base end side of the cutting portion 11, and adjust the starting end points P5 and P6 (Figure 9) of the first minor cutting edge BL2B and the second minor cutting edge BL4B.

[0058] 9, point P5, which is the end point of the axial tip side of the first auxiliary peripheral cutting edge BL2B, is located axially rearward (radially outward) from the tip region K1. The first auxiliary peripheral cutting edge BL2B is not present in the annular region K2 on the axial tip side of the cutting portion 11. Similarly, point P6, which is the end point of the axial tip side of the second auxiliary peripheral cutting edge BL4B, is located axially rearward (radially outward) from the tip region K1. The second auxiliary peripheral cutting edge BL4B is not present in the annular region K2 on the axial tip side of the cutting portion 11.

[0059] Returning to Figure 4, let us refer to the front view of the cutting portion 11. As shown in Figure 4, the other components that make up the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B are the same as the components of the first main peripheral cutting edge BL1B or the second main peripheral cutting edge BL3B.

[0060] The gash surface of the first auxiliary peripheral cutting edge BL2B is the first lead gash B1, and the gash surface of the second auxiliary peripheral cutting edge BL4B is the third lead gash B3. The flank surface of the first auxiliary peripheral cutting edge BL2B is composed of multiple peripheral flank surfaces. The peripheral flank surface of the first auxiliary peripheral cutting edge BL2B is composed of the second peripheral edge 2 E2, the second peripheral edge 3 F2, and the second peripheral edge 4 G2. The flank surface of the second auxiliary peripheral cutting edge BL4B is composed of the fourth peripheral edge 2 E4, the fourth peripheral edge 3 F4, and the fourth peripheral edge 4 G4.

[0061] Each of the outer circumferential flanks E2, F2, G2 of the first auxiliary peripheral cutting edge BL2B forms a plurality of different clearance angles, similar to the first main peripheral cutting edge BL1B described using Figures 7 and 8. Similarly, each of the outer circumferential flanks E4, F4, G4 of the second auxiliary peripheral cutting edge BL4B forms a plurality of different clearance angles.

[0062] The first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have a plurality of peripheral flanks that form different clearance angles, so that, similar to the first main peripheral cutting edge BL1B shown in FIG. The three peripheral flanks are located radially inward of the cutting edge rotation orbits S of the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B, while ensuring an appropriate blade thickness. This maintains a balance between sharpness and blade strength.

[0063] 5, a first main groove (flute) H1 extending in the axial direction of the cutting portion 11 is formed between the first main peripheral cutting edge BL1B and the first auxiliary peripheral cutting edge BL2B adjacent to it in the rear of the rotational direction. Similarly, as shown in FIG. 4, a second main groove H2 is formed between the first auxiliary peripheral cutting edge BL2B and the second main peripheral cutting edge BL3B, a third main groove H3 is formed between the second main peripheral cutting edge BL3B and the second auxiliary peripheral cutting edge BL4B, and a fourth main groove H4 is formed between the second auxiliary peripheral cutting edge BL4B and the first main peripheral cutting edge BL1B.

[0064] The first main groove H1, second main groove H2, third main groove H3, and fourth main groove H4 each function to smoothly discharge cutting chips. Furthermore, as shown in Figure 5, a first back groove I1 is formed along the first main groove H1, and similarly, back grooves I2, I3, and I4 are formed corresponding to the other main grooves H2, H3, and H4, respectively. The first back groove I1, second back groove I2, third back groove I3, and fourth back groove I4 enable smoother discharge of cutting chips.

[0065] As described above, the four blades, consisting of the first main peripheral cutting edge BL1B, the second main peripheral cutting edge BL3B, and the first auxiliary peripheral cutting edge BL2B, and the second auxiliary peripheral cutting edge BL4B, each have a rotationally symmetrical shape with the same positional relationship (circumferential and radial) around the rotation axis L. Therefore, when the cutting part 11 rotates half a turn, the four blades are positioned in the same circumferential and radial positions before and after the rotation. Furthermore, because the four blades each have the same blade shape at the same axial position, the sharpness of each blade is uniform during continuous rotation of the cutting part 11, ensuring consistent sharpness in the circumferential direction and enabling smooth cutting. The same is true for the first tip cutting edge BL1A and the second tip cutting edge BL3A.

[0066] <Axial change in the cutting edge shape of the main cutting edge and the secondary cutting edge> Next, the blade shapes along the axial direction of the first major peripheral cutting edge BL1B and the second major peripheral cutting edge BL3B, and the first minor peripheral cutting edge BL2B and the second minor peripheral cutting edge BL4B will be described. FIG. 10 is a side view of cutting portion 11 of surgical burr 10. In the surgical bar 10 of this configuration, the first main peripheral blade BL1B, the second main peripheral blade BL3B, the first auxiliary peripheral blade BL2B, and the second auxiliary peripheral blade BL4B have rotationally symmetric shapes centered on the rotation axis L, and their respective blade shapes change along the rotation axis L. In other words, each of the above blades has a different blade shape depending on the axial position along the rotation axis L, and as described above, the same blade shape is obtained in the rotation direction at the same axial position.

[0067] The surgeon's pressing pressure against the cutting target tends to be higher at the axial tip side of the cutting portion 11 than at the maximum diameter position in the axial center. Therefore, it is preferable that the axial tip side of the cutting portion 11 has a shape that prioritizes reducing blade wear and extending its lifespan. On the other hand, at the axial rear end side of the maximum diameter position, the surgeon performs cutting by pulling back the surgical burr 10, so the pressing pressure against the cutting target is lower. Therefore, it is preferable that the axial rear end side of the cutting portion 11 has a shape that prioritizes sharpness. Therefore, in the surgical burr 10 of this configuration, the blade shape is changed depending on the performance required of the blade, which differs depending on the axial position of the cutting portion 11.

[0068] Figures 11, 12, 13, 14, and 15 are cross-sectional views of the cutting portion 11 taken along lines AA, BB, CC, DD, and EE, respectively, as shown in Figure 10. Figures 11 to 15 show the cross-sectional shapes of the cutting portion 11 at different axial positions, with the cutting portion being rotated in sequence relative to the first main peripheral cutting edge BL1B so that the first main peripheral cutting edge BL1B is positioned at a fixed vertex in each cross-sectional view. Line CC in Figure 10 indicates the axial center of the cutting portion 11, which is the maximum diameter position of the cutting portion 11.

[0069] As shown in Figures 11 and 12, at the axial tip end of the cutting portion 11, the first major peripheral cutting edge BL1B and the second major peripheral cutting edge BL3B, and the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B each have a cross-sectional shape with a negative rake angle, resulting in a relatively large cutting edge angle. Generally, ahead of the cutting edge in the direction of blade travel (direction of rotation), there is a rake face where chips are generated and scooped up. The rake angle is the angle between the rake face and a plane perpendicular to the surface of the workpiece, including the line where the cutting edge at the tip of the rake face intersects with the workpiece. A rake angle on the side of the perpendicular where the cutting edge angle becomes smaller is called positive, and a rake angle on the side where the cutting edge angle becomes larger is called negative.

[0070] As shown in Figure 13, in the axial center of the cutting portion 11, the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B, and the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have cross-sectional shapes in which each blade has a positive rake angle, and the cutting edge angle is relatively small.

[0071] As shown in Fig. 14, at the axial rear end side of the cutting portion 11, the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B, and the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B have cross-sectional shapes with negative rake angles and relatively large cutting edge angles.Then, as shown in Fig. 15, further at the axial rear end side of the cutting portion 11, the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B, and the first auxiliary peripheral cutting edge BL2B and the second auxiliary peripheral cutting edge BL4B maintain blade shapes capable of cutting.

[0072] 14 and 15, the cutting portion 11 has a rear cutting edge region formed in the range from the axial center to the axial rear end. The blade shape of this rear cutting edge region has sufficient cutting ability, and the entire region from line CC to line EE shown in Fig. 10 maintains cutting ability equivalent to that of the cutting edges near the axial center. In particular, in the region from line CC to line DD, it is preferable that each of the first main peripheral cutting edge BL1B and second main peripheral cutting edge BL3B and the first auxiliary peripheral cutting edge BL2B and second auxiliary peripheral cutting edge BL4B has a positive rake angle, in which case the cutting ability can be improved compared to other regions.

[0073] Here, the curved surface enveloping the cutting edges of the first main peripheral cutting edge BL1B, the second main peripheral cutting edge BL3B, the first auxiliary peripheral cutting edge BL2B, and the second auxiliary peripheral cutting edge BL4B (see FIG. 3) of the cutting portion 11 is The cutting part 11 has a substantially spherical shape (ball shape) with the rotation axis L as its central axis. The part where this spherical shape is connected to the outer circumferential surface of the shaft part 13 is defined as the rear end connecting part 23 of the cutting part 11. The axial length from line CC, which is the maximum diameter position of the cutting part 11 shown in FIG. 10, to the rear end connecting part 23 is defined as LT.

[0074] The rear cutting edge region is preferably formed over a length from the line CC at the maximum diameter position in the axial direction that is 50% or more of the axial length LT, preferably 60% or more of LT, and more preferably 70% or more of LT. By providing such a rear cutting edge region over a wide range on the axial rear end side of the cutting part 11, the degree of cutting freedom of the cutting part 11 is improved, and the cutting object can be cut in a variety of positions.

[0075] The change in blade shape along the axial direction described above is set because the main performance required of the blade differs depending on the axial position of the cutting portion 11. The main performance includes ensuring sharpness and ensuring life, and the balance of each required performance differs depending on the position of the cutting portion 11. As mentioned above, the first main peripheral cutting edge BL1B and the second main peripheral cutting edge BL3B in Fig. 11 have the same blade shape. Furthermore, the first main peripheral cutting edge BL1B, the second main peripheral cutting edge BL3B, the first auxiliary peripheral cutting edge BL2B, and the second auxiliary peripheral cutting edge BL4B in Figs. 12 to 15 each have the same blade shape at the same axial position. This ensures that the sharpness of each edge is uniform at any axial position, ensuring consistent sharpness in the circumferential direction.

[0076] <Cutting by the cutting part> FIG. 16 is an explanatory diagram showing a state in which the cutting part 11 is pressed perpendicularly against the cutting object 21. The cutting part 11 is often pressed against the cutting object 21 on the axial tip side of the maximum diameter position, so cutting resistance during cutting tends to increase. For this reason, it is sometimes preferred to have a sharp blade while suppressing blade wear as much as possible. When it is required to design a blade shape that prioritizes lifespan at the axial tip side of the maximum diameter position of the cutting portion 11, the blade shape may be set to a negative rake angle so that the cutting edge angle becomes large.

[0077] Furthermore, when the cutting part 11 of this configuration is pressed against the cutting object 21 in the vertical direction indicated by the arrow Da, The chisel CE, the first tip cutting edge BL1A, and the second tip cutting edge BL3A, which are arranged in the same plane, are in line contact with the cutting object 21 symmetrically from the center of rotation. When cutting unit 11 comes into contact with cutting object 21, rebound due to partial contact is suppressed, allowing cutting of cutting object 21 in a stable posture. In this way, sufficient cutting ability can be ensured even when cutting unit 11 is pressed perpendicularly against cutting object 21. Furthermore, even when surgical burr 10 is tilted appropriately and moved in the direction indicated by arrow Db, stable and smooth cutting can be performed regardless of the tilt angle.

[0078] FIG. 17 is an explanatory diagram showing a state in which cutting is performed while the rear end side in the axial direction of the inclined cutting part 11 is pressed against the cutting object 21. Because surgical burr 10 is often used by being pressed against cutting target 12 while being pulled in the direction of arrow Dc, the cutting resistance tends to be smaller at the rear axial end of cutting portion 11 than when cutting at the leading axial end. Therefore, sharpness takes priority over blade wear. Therefore, the blade shape at the rear axial end of cutting portion 11 is set to a positive rake angle to reduce the cutting edge angle.

[0079] Furthermore, the blade has little opportunity to contribute to cutting near the connection between the cutting portion 11 and the shank 13. Therefore, high sharpness is not required in this area, and in order to ensure the strength of the blade continuing to the tip of the shank and the connection strength with the shank 13, the blade shape is set to a negative rake angle, making the cutting edge angle larger. This allows good cutting on both the axial leading end side and the axial trailing end side of the cutting portion 11, allowing the surgeon to perform cutting with a high degree of freedom without having to worry about the orientation of the cutting portion 11.

[0080] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0081] In the above-described embodiment, the second cutting edge BL2 and the third cutting edge BL3 are provided as minor cutting edges between the first cutting edge BL1 and the third cutting edge BL3 provided as major cutting edges, but the number of minor cutting edges provided between the major cutting edges is not particularly limited. In addition, the number, positions, types, etc. of the rake faces, flank faces, etc. that form each cutting edge can also be changed.

[0082] As described above, the present specification discloses the following: (1) A surgical burr having a shaft portion that rotates about a rotation axis and a ball-shaped cutting portion provided at the tip of the shaft, The cutting portion is a first main cutting edge connected to one end of a ridge formed by the intersection of a pair of tip surfaces provided at an axial tip end portion at an angle to each other across the rotation axis, and extending toward an axial rear end connected to the shank of the cutting part; a second main cutting edge connected to the other end of the ridge line opposite to the one end and extending toward the axial rear end of the cutting portion so as to be rotationally symmetrical to the first main cutting edge with respect to the rotation axis; a first minor cutting edge extending from the axial leading end side of the cutting portion toward the axial rear end thereof between the first major cutting edge and the second major cutting edge along the circumferential direction of the cutting portion; a second auxiliary cutting edge extending toward the axial rear end of the cutting portion so as to be rotationally symmetrical with the first auxiliary cutting edge about the rotation axis; Equipped with the first main cutting edge has a first tip cutting edge formed from one end of the ridge line along an edge portion on the front side in the rotation direction of one of the pair of tip surfaces to a radially outer edge of the tip surface, the second main cutting edge has a second tip cutting edge formed from the other end of the ridge line along an edge portion on the front side in the rotation direction of the other of the pair of tip surfaces to a radially outer edge of the tip surface, The first tip cutting edge and the second tip cutting edge are arranged in the same plane perpendicular to the rotation axis of the cutting part. Surgical burr. With this surgical burr, the tip of the cutting part makes line contact with the cutting object via a pair of tip blades. This suppresses rebound and allows cutting in a stable position. In addition, because the main peripheral cutting edge and the sub-peripheral cutting edge have symmetrical shapes, consistent sharpness is ensured in the circumferential direction during rotation, allowing for smooth cutting.

[0083] (2) A surgical burr according to (1), 10. The surgical burr of claim 1, The first main cutting edge has a first main peripheral cutting edge connected to a radially outer end of the first tip cutting edge and extending in a twisted manner toward the axial rear end of the cutting portion, The second main cutting edge has a second main peripheral cutting edge connected to a radially outer end of the second tip cutting edge and extending in a twisted manner toward the axial rear end of the cutting portion. Surgical burr. According to this surgical bar, the cutting portion has a first main peripheral cutting edge and a second main peripheral cutting edge formed in a twisted manner, and a first auxiliary peripheral cutting edge and a second auxiliary peripheral cutting edge formed in a twisted manner so as to be rotationally symmetrical to the first and second main peripheral cutting edges.

[0084] (3) A surgical burr according to (2), In the axial region where the first minor cutting edge and the second minor cutting edge of the cutting portion are formed, When the cutting portion is cut along a plane perpendicular to the rotation axis at the same axial position, the shapes of the cross sections of the first main peripheral cutting edge, the second main peripheral cutting edge, the first auxiliary cutting edge, and the second auxiliary cutting edge are rotationally symmetrical about the rotation axis. Surgical burr. According to this surgical burr, the shapes of the cross sections of the first and second minor blades are as follows: The rotational symmetry around the rotation axis allows each cutting object to be cut with the same sharpness, which enables stable cutting.

[0085] (4) A surgical burr according to (2) or (3), The first major peripheral cutting edge, the second major peripheral cutting edge, the first minor cutting edge, and the second minor cutting edge have cutting edge shapes that change along the axial direction of the cutting portion. Surgical burr. This surgical burr can meet the performance requirements of the blade, which differ depending on the axial position of the cutting portion.

[0086] (5) A surgical burr according to (4), Each of the first major peripheral cutting edge, the second major peripheral cutting edge, the first minor cutting edge, and the second minor cutting edge has a rear cutting edge region, on the axial rear end side of the maximum diameter position of the cutting portion, with a cutting edge angle smaller than the cutting edge angle on the axial front end side of the maximum diameter position. Surgical burr. This surgical burr allows for good cutting even at the axial rear end of the cutting portion. When the surgical burr is pressed against the cutting object at an angle and moved along the inclined direction to perform cutting, the main and sub-circumferential cutting edges in the rear cutting edge region allow for smooth and efficient cutting.

[0087] (6) A surgical burr according to (5), The rear cutting edge region is formed from the maximum diameter position toward the shank portion over a length equal to or greater than half of the axial length from the maximum diameter position of the cutting portion to the axial rear end, Surgical burr. According to this surgical burr, a rear cutting edge region is provided over a predetermined length on the connecting side of the cutting portion with the shank, thereby improving operability.

[0088] (7) A surgical burr according to any one of (1) to (6), a second flat gash that forms a cutting face of the first tip cutting edge; a first flat gash that forms a cutting face of the second tip cutting edge, the second flat gash is formed from one end of the ridge line beyond a radially outer edge of one of the pair of tip surfaces, The first flat gash is formed from the other end of the ridge line beyond the radial outer edge of the other tip surface of the pair of tip surfaces, Surgical burr. According to this surgical burr, the first tip cutting edge and the second tip cutting edge are reliably formed from the end of the ridge line to the connection point with the main peripheral cutting edge.

[0089] (8) A surgical burr according to any one of (2) to (7), The end points on the axial tip side of the first minor cutting edge and the second minor cutting edge are: The cutting edge is disposed axially rearward of a connecting point between the first cutting edge and the first main cutting edge and a connecting point between the second cutting edge and the second main cutting edge. Surgical burr. This surgical burr allows the type and number of blades that actually contribute to cutting to be changed in stages along the axial direction of the cutting section, enabling smooth and stable cutting without causing discomfort to the surgeon.

[0090] (9) A surgical burr according to any one of (1) to (8), The first major cutting edge and the second major cutting edge, and the first minor cutting edge and the second minor cutting edge each have a main groove along a radial direction and an outer peripheral flank surface along a circumferential direction, Each of the outer peripheral flanks is composed of a plurality of surfaces that form different flank angles. Surgical burr. This surgical burr allows for smooth chip removal through the main grooves. It also ensures an appropriate blade thickness while keeping multiple peripheral flanks radially inward of the cutting edge rotation paths of the main and auxiliary cutting edges, thereby maintaining a balance between sharpness and blade strength.

[0091] <Additional Notes> The surgical burr of the present invention further has the following features: [1] A surgical burr configured to be detachable from a surgical handpiece held by a surgeon, The surgical burr comprises: a shaft portion that rotates about a rotation axis; a ball-shaped cutting portion provided at the tip of the shaft portion and rotating in conjunction with the rotation of the shaft portion; Equipped with The cutting portion is a front cutting portion; a rear cutting portion between the front cutting portion and the shank; Equipped with The rear cutting portion is A first main cutting edge; a second main cutting edge symmetrical to the first main cutting edge with respect to the rotation axis; a first minor blade; a second minor cutting edge symmetrical to the first minor cutting edge with respect to the rotation axis; Equipped with The front cutting portion is a first tip cutting edge continuous with the first main cutting edge; a second tip cutting edge that is continuous with the second main cutting edge and symmetrical to the first tip cutting edge with respect to the rotation axis; Equipped with When the cutting portion rotates, each of the first tip cutting edge and the second tip cutting edge moves in a plane having a normal line parallel to the rotation axis. Surgical burr. [2] The surgical burr according to [1], When the rear cutting portion of the cutting portion is cut at a predetermined position in a plane perpendicular to the rotation axis, A surgical burr, wherein the cross-sectional shape of the first major cutting edge, the cross-sectional shape of the second major cutting edge, the cross-sectional shape of the first minor cutting edge, and the cross-sectional shape of the second minor cutting edge are congruent. [3] The surgical burr according to [1] or [2], Each of the first major blade, the second major blade, the first minor blade, and the second minor blade is The boundary between the front cutting portion and the rear cutting portion is set as a starting point, and the vicinity of the area where the rear cutting portion and the shaft portion are connected is set as an end point. Surgical burr. [4] A ball-shaped surgical burr according to any one of [1] to [3], When cut perpendicular to the axial direction, all blades have the same cross section. [Explanation of symbols]

[0092] 10 Surgical Burs 11 Cutting part 13 Shaft 15 Connection 100 Surgical Systems 101 Control unit 103 Handpiece 103a Attachment 103b Grip part 105 Connection Cable 107 Footswitch A1 First cutting edge flank A3 Second cutting edge flank B1: First lead gash B2: Second lead gash B3: Third lead gash B4: 4th lead gash BL1 First cutting edge (first main cutting edge) BL2 Second cutting edge (second auxiliary edge) BL3 3rd cutting edge (3rd main cutting edge) BL4 4th cutting edge (4th minor edge) BL1A 1st cutting edge, BL3A Second cutting edge BL1B 1st main peripheral cutting edge BL3B Second main peripheral cutting edge BL2B 1st auxiliary peripheral cutting edge BL4B Second auxiliary peripheral cutting edge CE Chisel D2: First minor cutting edge adjustment surface D4: Second auxiliary cutting edge adjustment surface E1: 1st outer perimeter, no. 2 E2: 2nd outer perimeter no. 2 E3: 3rd outer perimeter no. 2 E4: 4th outer perimeter, no. 2 F1: 1st outer perimeter, no. 3 F2: 2nd outer perimeter, number 3 F3: 3rd outer perimeter, no. 3 F4: 4th outer perimeter, no. 3 G1: 1st outer perimeter, number 4 G2: 2nd outer perimeter, number 4 G3: 3rd outer perimeter, number 4 G4: 4th outer perimeter, number 4 H1: First main groove H2: Second main groove H3: Third main groove H4: 4th main groove I1: First dorsal groove I2: Second dorsal groove I3: Third dorsal groove I4: Fourth dorsal groove J2: First flat gash J4: Second Flat Gash K1:Tip area K2: Annular region K3: Outer area L: Return axis P1: Point P2: Point P3: Point P4: Point P5: Point P6: Point

Claims

1. A surgical burr having a shaft portion that rotates around a rotation axis line and a ball-shaped cutting portion provided at a tip of the shaft portion, The cutting portion is a ridgeline formed by the intersection of a pair of tip surfaces provided at the axial tip end portion at an angle to each other with the rotation axis therebetween; a first main cutting edge connected to one end of the ridge line and extending toward an axial rear end connected to the shank of the cutting portion; a second main cutting edge connected to the other end of the ridge line and extending toward the axial rear end of the cutting portion so as to be rotationally symmetrical to the first main cutting edge with respect to the rotation axis; Equipped with the first main cutting edge has a first tip cutting edge formed from one end of the ridge line in a tip region of the cutting portion, the second main cutting edge has a second tip cutting edge formed from the other end of the ridge line in a tip region of the cutting portion, the ridge line, the first tip cutting edge, and the second tip cutting edge are arranged rotationally symmetrically within the same plane perpendicular to the rotation axis of the cutting portion. Surgical burr.

2. 10. The surgical burr of claim 1, The first main cutting edge has a first main peripheral cutting edge connected to a radially outer end of the first tip cutting edge and extending in a twisted manner toward the axial rear end of the cutting portion, The second main cutting edge has a second main peripheral cutting edge connected to a radially outer end of the second tip cutting edge and extending in a twisted manner toward the axial rear end of the cutting portion. Surgical burr.

3. 3. The surgical burr of claim 2, The first main peripheral cutting edge and the second main peripheral cutting edge each have a blade shape that changes along the axial direction of the cutting portion. Surgical burr.

4. 4. The surgical burr of claim 3, Each of the first main peripheral cutting edge and the second main peripheral cutting edge has a rear cutting edge region, on the axial rear end side of the maximum diameter position of the cutting portion, with a cutting edge angle smaller than the cutting edge angle on the axial front end side of the maximum diameter position. Surgical burr.

5. 5. The surgical burr of claim 4, The rear cutting edge region is formed from the maximum diameter position toward the shank portion over a length equal to or greater than half of the axial length from the maximum diameter position of the cutting portion to the axial rear end, Surgical burr.

6. 6. The surgical burr of claim 1, a second flat gash that forms a rake face of the first tip cutting edge; a first flat gash that forms a cutting face of the second tip cutting edge, the second flat gash is formed from one end of the ridge line beyond a radially outer edge of one of a pair of tip surfaces that are provided at the axial tip end portion at an angle to each other across the rotation axis and form the ridge line, The first flat gash is formed from the other end of the ridge line beyond the radial outer edge of the other tip surface of the pair of tip surfaces. Surgical burr.

7. 7. The surgical burr of claim 1, The first main cutting edge and the second main cutting edge each have a main groove extending along a radial direction and an outer peripheral flank extending along a circumferential direction, Each of the outer peripheral flanks is composed of a plurality of surfaces that form different flank angles. Surgical burr.

Images