A double straight edge milling cutter assembly and medical milling cutter

Abstract

The utility model relates to medical instrument technical field especially, it is a kind of double straight edge milling cutter assembly and medical milling cutter, including cutter shaft and cutting part, cutting part and cutter shaft fixed connection. One end of cutter shaft is integrally formed with cutting part, another end has connecting part, and connecting part is used to be connected with driving handle or power mechanism, to drive cutter shaft and cutting part synchronous rotation and carry out milling. Cutting part includes cutting shaft body fixedly connected with cutter shaft, and double straight edge fixed on the periphery of cutting shaft body, and double straight edge includes two identical straight blade structures, for cutting bone tissue. Two straight blade structures are in central symmetry with the center line of cutting shaft body, two straight blade structures are connected head to tail, and two straight blade structures have chip flute between them. The utility model solves the problem that the milling cutter with existing helical edge has big machining difficulty, machining consistency is difficult to guarantee, and burr is prone to appear in the process of machining.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a double straight-edge milling cutter assembly and a medical milling cutter. Background Technology

[0002] Medical end mills are common surgical tools widely used in orthopedic, neurosurgical, and oral and maxillofacial surgeries. Their primary function is to cut, reduce, and shape bone or soft tissue, allowing surgeons to perform procedures with greater precision. Due to their high efficiency and precision, medical end mills have become indispensable tools in modern orthopedic and oral and maxillofacial surgeries.

[0003] Current medical end mills are typically rod-shaped, with multiple cutting edges circumferentially arranged at their distal end (the end in contact with bone or soft tissue), and a drive connection at their proximal end (the end furthest from the distal end). These end mills are generally three-flute helical end mills. The rake and clearance angles of the helical edges are difficult to machine, and consistent machining is challenging. Burrs are easily generated during machining, making them difficult to remove and potentially damaging the cutting edges. To effectively remove bone fragments generated during the end mill's action on bone or soft tissue, chip evacuation grooves are usually designed into the end mill. However, with helical end mills, bone fragments can easily become trapped in these grooves, reducing surgical efficiency and causing tool runout. Utility Model Content

[0004] In view of this, the purpose of this utility model is to provide a double straight-edge milling cutter assembly and a medical milling cutter, so as to at least solve the problems of high machining difficulty, difficulty in ensuring machining consistency, and easy occurrence of burrs during the machining process of existing spiral-edge milling cutters.

[0005] This utility model solves the above-mentioned technical problems through the following technical means: The first aspect of this utility model provides a double straight-edge end mill assembly, comprising: The cutter shaft; and, The cutting part is fixedly connected to the tool shaft. The cutting part includes a cutting shaft body fixedly connected to the tool shaft, and a double straight cutting edge fixed to the outer periphery of the cutting shaft body. The double straight cutting edge includes two straight cutting edge structures with identical structures. The two straight cutting edge structures are centrally symmetrical about the center line of the cutting shaft body. The two straight cutting edge structures are connected end to end, and there is a chip removal groove between the two straight cutting edge structures.

[0006] In conjunction with the first aspect, in some embodiments, the straight cutting edge structure includes a cutting straight edge and a clearance surface, and on any cross-section along the axial direction of the cutting shaft, the height difference between the circumference of the clearance surface and the cutting straight edge is the same. The straight cutting edge structure also includes a front cutting face and a rear cutting face, the intersection line between the rear cutting face and the front cutting face forms a cutting straight edge, and the rear cutting face is connected to the avoidance surface.

[0007] In conjunction with the first aspect, in some embodiments, on any cross-section along the axial direction of the cutting shaft, the line connecting the tip of the cutting straight edge and the axial center of the cutting shaft has a first included angle with the rake face, the first included angle being greater than 0°.

[0008] In conjunction with the first aspect, in some embodiments, the second included angle between the flank face and the rake face is an acute angle or a right angle, and the third included angle between the flank face and the connected clearance face is an obtuse angle.

[0009] In conjunction with the first aspect, in some embodiments, the avoidance surface is formed by splicing together multiple planes of the same size and shape, or the avoidance surface is a smooth arc-shaped surface.

[0010] In conjunction with the first aspect, in some embodiments, the straight cutting edge structure has multiple chip breaker grooves, which are distributed at equal intervals along the length direction of the straight cutting edge structure.

[0011] In conjunction with the first aspect, in some embodiments, the plurality of chip breaker grooves are evenly distributed on the cutting straight edge, the chip breaker grooves on two cutting straight edges are staggered, and the vertical projection profiles of the plurality of chip breaker grooves on the longitudinal section including the center line of the cutting shaft are completely staggered. In conjunction with the first aspect, in some embodiments, the bottom of the chip breaker groove has a smooth transition arc.

[0012] The second aspect of this utility model provides a medical milling cutter, including the double straight-edged milling cutter assembly described in the first aspect above, and a drive handle, wherein the cutter shaft is connected to the drive handle.

[0013] The double straight-edge end mill assembly of this utility model adopts a double straight-edge structure, which is not only sharper but also easier to process. It is less likely to produce burrs during processing, and the processing consistency is easily guaranteed. The chip removal groove allows bone chips to be smoothly discharged from the chip removal groove, resulting in better overall chip removal performance and stability.

[0014] This utility model's double straight-edge end mill assembly has several advantages. First, it employs a straight-edge structure with an acute or right angle between the flank and rake faces, resulting in a clear and sharp cutting edge. Second, the clearance surface is formed by splicing multiple planes of uniform size and shape, making it easy to machine and producing almost no burrs, simplifying and stabilizing the machining process. Third, the circumference of the clearance surface and the cutting edge share a consistent height difference across any cross-section along the axial direction of the cutting axis, ensuring a smoother bone-cutting process. Fourth, the chip breaker groove design breaks bone chips, facilitating their removal and improving overall chip removal performance, further enhancing the stability of the double straight-edge end mill assembly. Finally, the smooth transition arc at the bottom of the chip breaker groove further facilitates chip removal and reduces chip blockage. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a structure of an embodiment of a double straight-edge end mill assembly; Figure 2 yes Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of another embodiment of the double straight-edge end mill assembly; Figure 4 yes Figure 2 Enlarged view of point B in the middle; Figure 5 This is a schematic diagram of the structure of a medical end mill; The components include: a cutter shaft 100, a cutting section 200, a cutting shaft body 210, a cutting straight edge 221, a clearance surface 222, a rake face 223, a flank face 224, a connecting section 300, a chip removal groove 400, a transition arc 410, a chip breaking groove 500, a drive handle 600, and a protective sheath 700. Detailed Implementation

[0016] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can understand the advantages and effects of this utility model from the content disclosed in this specification. It should be noted that the illustrations provided in the following embodiments are for illustrative purposes only and represent schematic diagrams, not actual pictures. They should not be construed as limiting the utility model. To better illustrate the embodiments of this utility model, some components in the figures may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable that some well-known structures and their descriptions may be omitted in the figures for those skilled in the art.

[0017] In the figures of this utility model embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the figure, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe the positional relationship in the figure are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above-mentioned terms can be understood according to the specific circumstances.

[0018] Please refer to Figure 1-5 : This application discloses a double straight-edged milling cutter assembly, comprising a cutter shaft 100 and a cutting section 200, the cutting section 200 being fixedly connected to the cutter shaft 100. One end of the cutter shaft 100 is integrally formed with the cutting section 200, and the other end has a connecting section 300 for connecting to a drive handle or power mechanism to drive the cutter shaft 100 and the cutting section 200 to rotate synchronously for milling. The cutting section 200 includes a cutting shaft body 210 fixedly connected to the cutter shaft 100, and double straight cutting edges fixed to the outer periphery of the cutting shaft body 210. The double straight cutting edges include two identical straight cutting edge structures for cutting bone tissue. The two straight cutting edge structures are centrally symmetrical about the centerline of the cutting shaft body 210, the two straight cutting edge structures are connected end to end, and a chip removal groove 400 is provided between the two straight cutting edge structures.

[0019] In one embodiment, the straight cutting edge structure includes a cutting straight edge 221 and a clearance surface 222. On any cross-section along the axial direction of the cutting shaft 210, the height difference between the circumference of the clearance surface 222 and the cutting straight edge 221 is the same, thus achieving a consistent height difference between the clearance surface 222 and the cutting straight edge 221 on any cross-section, making the double straight cutting edge end mill assembly more stable during bone cutting. Here, the cross-section refers to a surface perpendicular to the axial direction of the cutting shaft 210, and the circumference of the clearance surface 222 is centered on the centerline of the cutting shaft 210. The straight cutting edge structure also includes a rake face 223 and a flank face 224. The intersection line between the flank face 224 and the rake face 223 forms the cutting straight edge 221, and the flank face 224 is connected to the clearance surface 222.

[0020] In one embodiment, on any cross section along the axial direction of the cutting shaft 210, the line connecting the tip of the cutting straight edge 221 and the axis center of the cutting shaft 210 has a first included angle with the rake face 223. The first included angle is greater than 0° and the angle of the first included angle is 5 to 15°, which is beneficial for chip removal.

[0021] In one embodiment, the second included angle between the flank face 224 and the front face 223 is an acute angle or a right angle, and the third included angle between the flank face 224 and the connected clearance face 222 is an obtuse angle.

[0022] In one embodiment, the clearance surface 222 is formed by splicing together multiple planes of the same size and shape, that is, the cutting part 200 has a polygonal prism structure, which makes the entire processing technology simpler and more stable, such as Figure 1 As shown. In another embodiment, the clearance surface 222 can also be a smooth arc-shaped surface. In this case, the clearance surface 222 and the flank face 224 are smoothly connected, that is, the cutting part 200 has a cylindrical structure as a whole, such as... Figure 2 As shown.

[0023] To improve the chip-breaking capability of the double straight-edge end mill assembly of this application and to better remove bone chips, in one embodiment, the straight-edge structure has multiple chip-breaking grooves 500. These grooves 500 are evenly spaced along the length of the straight-edge structure to create multiple chip-breaking locations, thereby reducing the volume of bone chips and facilitating their removal. The chip-breaking grooves 500 are arranged on the cutting straight edge 221, dividing the continuous cutting straight edge 221 into multiple segments to achieve chip fragmentation.

[0024] In one embodiment, the chip breaker grooves 500 on the two cutting straight edges 221 are staggered, and the vertical projection profiles of all the chip breaker grooves on the longitudinal section including the center line of the cutting shaft 210 are completely staggered, with no overlap. That is, the vertical projections of the outer edge profiles of all the chip breaker grooves 500 on the center line of the cutting shaft 210 do not overlap. This achieves complementary cutting at more chip breaker locations, further improving the chip breaking effect and promoting the removal of bone chips.

[0025] The overall shape of the chip breaker groove 500 includes, but is not limited to, a triangular, trapezoidal, or rectangular shape, as well as other irregular shapes, as long as they are conducive to chip breaking. For example, in one embodiment, the overall shape of the chip breaker groove 500 is trapezoidal, such as... Figure 1 and Figure 2 As shown. In another embodiment, the chip breaker groove 500 has an overall triangular shape, as shown. Figure 3 and Figure 4 As shown.

[0026] In one embodiment, to reduce chip clogging, the bottom of the chip discharge groove 400 has a smooth transition arc 410.

[0027] In one embodiment, the cutting portion 200 is a uniform cylindrical structure, meaning that the radial dimension of the circumscribed circle of any cross-section of the cutting portion 200 is the same. In other embodiments, the cutting portion 200 may also be tapered, with the radial dimension formed by the double straight cutting edges on the outer periphery of the cutting shaft 210 gradually decreasing from the end near the tool shaft 100 to the end away from the tool shaft 100, forming a structure that is smaller at the far end and larger at the near end, so that the cutting portion 200 is sloped. However, the cutting portion 200 still has a consistent rake face 223, flank face 224, clearance surface 222, and chip breaker groove 500.

[0028] A rake face 223 and a chip groove 400 are vertically ground on a grinding machine. Then, the cutting spindle 210 is rotated 180°, and another rake face 223 and chip groove 400 are ground in the same manner. Next, the flank face 224 is machined. The cutting spindle 210 is clamped and rotated back and forth 120°-160°, and the flank face 224 and the tool clearance surface 222 are ground on a grinding machine to achieve consistency in the clearance surface 222. During machining, the rotation angle of the cutting spindle 210 is limited to prevent damage to the cutting edge 221. Using the above machining method, the rake face 223, flank face 224, and clearance surface 222 can be stably machined, ensuring a relatively sharp cutting edge 221 with almost no burrs. The difference in cutting edge length between the two cutting edges 221 can be kept below 0.02mm, and the clearance surface 222 and the cutting edge 221 have a consistent height difference across any cross-section.

[0029] The aforementioned double straight-edge end mill assembly has several advantages. First, it employs a straight-edge structure, with an acute or right angle formed between the flank face 224 and the rake face 223, resulting in a clear and sharp cutting edge 221. Second, the clearance surface 222 is formed by splicing multiple planes of consistent size and shape, making it easy to machine and producing almost no burrs during processing, simplifying and stabilizing the machining process. Third, the circumference of the clearance surface 222 and the cutting edge 221 have a consistent height difference on any cross-section along the axial direction of the cutting shaft 210, making the entire bone-cutting process smoother during use. Fourth, the chip breaker groove 500 breaks bone chips, facilitating their removal and improving overall chip removal performance, further enhancing the stability of the double straight-edge end mill assembly. Finally, the smooth transition arc 410 at the bottom of the chip breaker groove 400 further facilitates chip removal and alleviates chip blockage.

[0030] like Figure 5As shown, an embodiment of this application also provides a medical end mill, including the above-mentioned double straight-edge end mill assembly and a drive handle 600. The cutter shaft 100 is connected to the drive handle 600, and a sheath 700 is also provided on the drive handle 600. The cutting part 200 of the double straight-edge end mill assembly is located inside the sheath 700.

[0031] The above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

Claims

1. A double straight-edge end mill assembly, characterized in that, include: Cutter shaft; as well as, The cutting part is fixedly connected to the tool shaft. The cutting part includes a cutting shaft body fixedly connected to the tool shaft, and a double straight cutting edge fixed to the outer periphery of the cutting shaft body. The double straight cutting edge includes two straight cutting edge structures with identical structures. The two straight cutting edge structures are centrally symmetrical about the center line of the cutting shaft body. The two straight cutting edge structures are connected end to end, and there is a chip removal groove between the two straight cutting edge structures.

2. The double straight-edge end mill assembly according to claim 1, characterized in that, The straight cutting edge structure includes a cutting straight edge and a clearance surface. On any cross-section along the axial direction of the cutting shaft, the height difference between the circumference of the clearance surface and the cutting straight edge is the same. The straight cutting edge structure also includes a front cutting face and a rear cutting face, the intersection line between the rear cutting face and the front cutting face forms a cutting straight edge, and the rear cutting face is connected to the avoidance surface.

3. A double straight-edge end mill assembly according to claim 2, characterized in that, On any cross section along the axial direction of the cutting shaft, the line connecting the tip of the cutting straight edge and the axial center of the cutting shaft has a first included angle with the rake face, the first included angle being greater than 0°.

4. A double straight-edge end mill assembly according to claim 3, characterized in that, The second included angle between the back face and the front face is an acute angle or a right angle, and the third included angle between the back face and the connected clearance face is an obtuse angle.

5. A double straight-edge end mill assembly according to claim 2, characterized in that, The avoidance surface is formed by splicing together multiple planes of the same size and shape, or the avoidance surface is a smooth arc surface.

6. A double straight-edge end mill assembly according to claim 2, characterized in that, The straight cutting edge structure has multiple chip breaking grooves, which are evenly spaced along the length of the straight cutting edge structure.

7. A double straight-edge end mill assembly according to claim 6, characterized in that, Multiple chip breaker grooves are evenly distributed on the cutting straight edge, and the chip breaker grooves on two cutting straight edges are staggered. Furthermore, the vertical projection contours of the multiple chip breaker grooves on the longitudinal section containing the center line of the cutting shaft are completely staggered.

8. A double straight-edge end mill assembly according to claim 1, characterized in that, The bottom of the chip removal groove has a smooth transition arc.

9. A medical end mill, characterized in that, It includes a double straight-edge end mill assembly as described in any one of claims 1-8, and a drive handle, wherein the cutter shaft is connected to the drive handle.

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