Orthopaedics implant spherical surface precision machining assembly
Technical Field
The invention relates to the field of precision manufacturing of medical instruments, in particular to a precision machining assembly for spherical surfaces of orthopedic implants.
Background
The skeleton is the most important tissue for supporting the human body and is the basis for human to realize all motor functions, the joint is an important mechanism for connecting the skeleton, the joint system is damaged to cause joint diseases, the normal functions of the joint can be affected, and great inconvenience is brought to the life and work of a patient; the artificial hip joint becomes an artificial organ for replacing a hip joint without functions in an orthopedic surgery, the artificial hip joint imitates the structure of a human hip joint, the stem part of a prosthesis is inserted into a marrow cavity, and the head part and a joint mortar or a metal cup of the prosthesis are rotated to realize the flexion and extension and the movement of thighbones; the surface roughness of the ball joint as a moving part determines the abrasion loss and the service life of the ball joint, the lower the surface roughness of the ball joint is, the better the surface quality is, the longer the service life is, and the stronger the corrosion resistance and the fatigue strength of the spherical moving surface are.
The traditional ball joint mostly adopts precision forging turning and manual step-by-step polishing of a ball part, the polishing process is manually completed, and the polishing quality hardly meets the clinical requirement; the existing magnetorheological polishing technology utilizes the characteristic that solid-liquid phase of magnetorheological polishing liquid in a magnetic field is converted mutually, real-time control is carried out by controlling the shear yield stress and local shape of the magnetorheological polishing liquid through an external magnetic field, a flexible polishing die which can be matched with the surface to be processed is created, and grinding, polishing and finishing of workpieces are realized; although this technique has the advantages of less surface damage and high polishing precision, it still has a disadvantage that striated polishing marks are generated in the polishing contact area, resulting in an increase in surface roughness.
The invention patent with application publication number CN110340744A discloses an orthopedic implant spherical surface precision machining assembly, magnetorheological polishing liquid is converted into a solid-like form through a magnetic field, a horizontal moving mechanism and a rotating mechanism are started simultaneously, the polishing piece rotates and moves relatively in the horizontal direction at the same time, all-dimensional polishing is carried out, automatic polishing is realized, and the magnetorheological polishing liquid is liquid when not subjected to the magnetic field, can be well filled between the side wall of a polishing groove and the polishing piece, and can be polished aiming at each tiny position of the polished piece after being converted into the solid-like form by the change of the magnetic field, the polishing precision is greatly improved, and automatic polishing is realized; however, in the invention, the output shaft of the motor is connected with the polishing element through the rotating shaft, the flaring device and the holder, the motor drives the polishing element to rotate, the motor is fixed above the polishing groove of the polishing body, and the polishing element is positioned in the polishing groove, so that the motor, the polishing element and the polishing body cannot move horizontally, the horizontal moving mechanism cannot push the polishing body to reciprocate through the fixed block to realize horizontal polishing, and the problem of increased surface roughness caused by the generation of stripe-shaped polishing traces in a polishing contact area still cannot be solved only by driving the polishing element to rotate and polish through the motor.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, an object of the present invention is to provide a precision machining assembly for spherical surfaces of orthopedic implants, which can effectively avoid the generation of stripe-shaped polishing marks, has a smaller surface roughness and a better finish machining effect, and can achieve a vertical cross grinding track to the whole spherical surface by the combined motion of a first driving motor and a second driving motor (or a machine tool spindle).
The invention is realized by the following technical scheme.
An orthopedic implant spherical surface precision machining assembly comprises an upper fixing plate and a magnetorheological polishing device arranged below the upper fixing plate; the magnetorheological polishing device comprises a left polishing body and a right polishing body; the central holes of the left polishing body and the right polishing body are respectively connected with the left rotating shaft and the right rotating shaft in a key way; one end of the left rotating shaft is rotatably connected with the sliding support through a first bearing, one end of the right rotating shaft is rotatably connected with the fixed support through a second bearing, and the other ends of the left rotating shaft and the right rotating shaft are mutually matched and connected; the sliding bracket is connected with the upper fixing plate through a fixing bracket, and the fixing bracket is fixed on the upper fixing plate;
the left polishing body and the right polishing body are of symmetrical structures and respectively comprise a first boss, a second boss and a third boss, the first boss, the second boss and the third boss are concentric and integrally formed, a through shaft hole is formed in the center of the first boss, the center of the second boss and the center of the third boss, which are concentric and integrally formed, an annular hemispherical cavity is formed at the joint of the first boss and the second boss, and a semi-cylindrical groove communicated with the hemispherical cavity is formed in one side, adjacent to the first boss, of the second boss; when the left polishing body and the right polishing body are connected, the second bosses of the left polishing body and the right polishing body are tightly attached, the shaft holes of the left polishing body and the right polishing body are concentric, a gap with a certain width is kept between the first bosses of the left polishing body and the right polishing body, the hemispherical cavities of the left polishing body and the right polishing body are connected to form a spherical cavity, and the spherical cavity is communicated with the gap between the first bosses of the left polishing body and the right polishing body.
Furthermore, a left annular electromagnet and a right annular electromagnet are respectively sleeved on third bosses of the left polishing body and the right polishing body.
Further, when the left polishing body and the right polishing body are connected, a gap between the first bosses of the left polishing body and the right polishing body is sealed by a check ring; the retainer ring comprises an outer ring and an inner ring which are integrally formed; the outer loop of retaining ring cup joints on the first boss outer wall of the left side polishing body and the right side polishing body, the inner ring block of retaining ring is in the gap between the first boss of the left side polishing body and the right side polishing body, the retaining ring can rotate along the gap between the first boss of the left side polishing body and the right side polishing body.
Furthermore, a fourth boss coaxial with the right rotating shaft is arranged at one end of the right rotating shaft, the fourth boss is a cylindrical boss, and a small plane is cut at one side of the cylindrical boss along the axis; the one end that left side pivot and right side pivot are connected is equipped with the spacing hole with fourth boss sliding fit, the degree of depth in spacing hole slightly is greater than the height of fourth boss.
Furthermore, the bottom of the sliding support is connected with a fixed support in a sliding manner, and the fixed support is fixed at the bottom of the upper fixed plate; one side and the left side pivot rotatable coupling of sliding bracket, the opposite side of sliding bracket is connected with the telescopic shaft of cylinder, the cylinder passes through the cylinder support to be fixed on the fixed bolster, the telescopic shaft both sides of cylinder still parallel arrangement have the guide bar, the one end of guide bar is fixed in the one side that the telescopic shaft of sliding bracket and cylinder is connected, the other end of guide bar respectively with cylinder support sliding connection.
Furthermore, the right side pivot is worn out by the fixed bolster after being connected with the fixed bolster rotation, wears out the back and is connected with first driving motor's output shaft, first driving motor fixes on the fixed bolster.
The device further comprises an orthopedic implant and an expansion shaft connected with the orthopedic implant, wherein one end of the expansion shaft is connected with the orthopedic implant, and the other end of the expansion shaft is connected with a second driving motor positioned on an upper fixing plate through the upper fixing plate; the orthopedic implant is positioned in the hemispherical cavities of the first bosses of the left polishing body and the right polishing body which are connected into a spherical cavity.
Furthermore, the expansion shaft penetrates through an expansion shaft hole in the retainer ring, magnetorheological polishing liquid inlets are further formed in two sides of the expansion shaft hole, magnetorheological polishing liquid outlets are formed in the other side, opposite to the magnetorheological polishing liquid inlets, of the retainer ring, the magnetorheological polishing liquid inlets and the magnetorheological polishing liquid outlets are respectively connected with a magnetorheological polishing liquid storage box through pipelines, valves are respectively arranged on the pipelines, the magnetorheological polishing liquid inlets and the magnetorheological polishing liquid outlets are controlled to enter and exit through the valves, and the magnetorheological polishing liquid storage box is fixed at the bottom of the upper fixing plate.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention utilizes the characteristic of solid-liquid phase mutual conversion of magnetorheological polishing solution in a magnetic field, the magnetorheological polishing solution enters a spherical cavity of a polishing body along with the spherical outer surface of the orthopedic implant by controlling the external magnetic field and then generates rheology to form a solid grinding layer under the action of the external magnetic field, and the solid grinding layer and the spherical outer surface of the orthopedic implant have rapid relative motion along with the relative rotation of the polishing body and the orthopedic implant, so that the spherical outer surface of the orthopedic implant is subjected to great shearing force, the grinding, polishing and trimming processing of the orthopedic implant are realized, and compared with the traditional processing technologies of precision forging turning, manual step-by-step ball polishing and the like, the polishing effect of the invention is better, and the polishing precision is higher.
2. According to the invention, the vertical cross grinding track of the whole spherical surface can be realized through the compound motion of the first driving motor and the second driving motor (or the main shaft of the machine tool), so that the generation of stripe-shaped polishing marks can be effectively avoided, the surface roughness is smaller, and the finish machining effect is better.
Drawings
FIG. 1 is a schematic view of a spherical precision machining assembly for orthopedic implants according to the present invention;
FIG. 2 is a left side view of FIG. 1;
FIG. 3 is a schematic cross-sectional view of a left side polishing body and a right side polishing body of an orthopedic implant spherical precision machining assembly according to the present invention;
FIG. 4 is a view taken along line A of FIG. 3;
FIG. 5 is a schematic perspective view of a left side polishing body or a right side polishing body in an orthopedic implant spherical precision machining assembly according to the present invention;
FIG. 6 is a schematic cross-sectional view of a retainer ring in the precision spherical machining assembly for orthopedic implants according to the present invention;
FIG. 7 is a top view of FIG. 6;
FIG. 8 is a schematic view of the structure of the left rotating shaft in the precision spherical machining assembly for orthopedic implants according to the present invention;
FIG. 9 is a schematic view of the right side shaft of the precision spherical machining assembly for orthopedic implants according to the present invention;
FIG. 10 is a schematic structural diagram of a spherical precision machining assembly for an orthopedic implant according to another embodiment of the present invention.
In the figure: 1. a fixing plate; 2. a magnetorheological polishing device; 201. a left polishing body; 202. a right polishing body; 203. a left rotating shaft; 204. a right rotating shaft; 205. a first bearing; 206. a second bearing; 207. a sliding support; 208. fixing a bracket; 209. a first boss; 210. a second boss; 211. a third boss; 212. a shaft hole; 213. a hemispherical cavity; 214. a semi-cylindrical trough; 215. a left annular electromagnet; 216. a right annular electromagnet; 217. a fourth boss; 218. a cylinder; 219. a cylinder support; 220. a guide bar; 221. a first drive motor; 222. a retainer ring; 2221. an outer ring; 2222. an inner ring; 2223. expanding the shaft hole; 2224. a magnetorheological polishing solution inlet; 2225. a magnetorheological polishing solution outlet; 3. an orthopedic implant; 4. expanding and tightening the shaft; 5. a second drive motor; 6. a magnetorheological polishing solution storage box; 7. magnetorheological polishing solution; 8. a machine tool spindle; 9. a support; 10. a machine tool workbench.
Detailed Description
The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.
The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.
Example 1
Referring to fig. 1, the orthopedic implant spherical surface precision machining assembly of the present invention comprises an upper fixing plate 1 and a magnetorheological polishing device 2 installed below the upper fixing plate 1; the magnetorheological polishing device 2 comprises a left polishing body 201 and a right polishing body 202; the central holes of the left polishing body 201 and the right polishing body 202 are respectively connected with a left rotating shaft 203 and a right rotating shaft 204 in a key mode; one end of the left rotating shaft 203 is rotatably connected with the sliding bracket 207 through a first bearing 205, one end of the right rotating shaft 204 is rotatably connected with the fixed bracket 208 through a second bearing 206, and the other ends of the left rotating shaft 203 and the right rotating shaft 204 are mutually matched and connected; the sliding bracket 207 is connected with the upper fixing plate 1 through a fixing bracket 208, and the fixing bracket 208 is fixed on the upper fixing plate 1.
Referring to fig. 3, 4 and 5, the left polishing body 201 and the right polishing body 202 are symmetrical structures, and each of the left polishing body 201 and the right polishing body 202 includes a first boss 209, a second boss 210 and a third boss 211, the first boss 209, the second boss 210 and the third boss 211 are concentrically and integrally formed, a through shaft hole 212 is formed in the center of the first boss 209, the second boss 210 and the third boss 211, the joint of the first boss 209 and the second boss 210 is provided with an annular hemispherical cavity 213, and one side of the second boss 210 adjacent to the first boss 209 is provided with a semi-cylindrical groove 214 communicated with the hemispherical cavity 213.
Referring to fig. 1, the third bosses 211 of the left polishing body 201 and the right polishing body 202 are respectively sleeved with a left annular electromagnet 215 and a right annular electromagnet 216.
Referring to fig. 1, when the left polishing body 201 and the right polishing body 202 are connected, the second bosses 210 of the left polishing body 201 and the right polishing body 202 are tightly attached, the shaft holes 212 of the left polishing body and the right polishing body 202 are concentric, a gap with a certain width is maintained between the first bosses 209 of the left polishing body 201 and the right polishing body 202, and the hemispherical cavities 213 of the left polishing body and the right polishing body 202 are connected to form a spherical cavity, which is in gap communication with the first bosses 209 of the left polishing body 201 and the right polishing body 202.
Referring to fig. 1, when the left polishing body 201 and the right polishing body 202 are connected, a gap between the first bosses 209 of the left polishing body 201 and the right polishing body 202 is sealed by the retainer ring 222; referring to fig. 6, the retainer ring 222 includes an outer ring 2221 and an inner ring 2222, and the outer ring 2221 and the inner ring 2222 are integrally formed; referring to fig. 1, the outer ring 2221 of the retainer ring 222 is sleeved on the outer walls of the first bosses 209 of the left polishing body 201 and the right polishing body 202, the inner ring 2222 of the retainer ring 222 is clamped in the gap between the first bosses 209 of the left polishing body 201 and the right polishing body 202, and the retainer ring 222 can rotate along the gap between the first bosses 209 of the left polishing body 201 and the right polishing body 202.
Referring to fig. 9, one end of the right rotating shaft 204 is provided with a fourth boss 217 coaxial with the right rotating shaft 204, the fourth boss 217 is a cylindrical boss, and a small plane is cut at one side of the cylindrical boss along an axis; referring to fig. 8, a limiting hole in sliding fit with the fourth boss 217 is formed at one end of the left rotating shaft 203 connected with the right rotating shaft 204, and the depth of the limiting hole is slightly greater than the height of the fourth boss 217.
Referring to fig. 1, the bottom of the sliding bracket 207 is slidably connected to a fixed bracket 208, and the fixed bracket 208 is fixed to the bottom of the upper fixed plate 1; one side and the left side pivot 203 rotatable coupling of sliding bracket 207, the opposite side of sliding bracket 207 is connected with the telescopic shaft of cylinder 218, cylinder 218 passes through cylinder support 219 and fixes on fixed bolster 208, the telescopic shaft both sides of cylinder 218 still parallel arrangement have guide bar 220, the one end of guide bar 220 is fixed in the one side that sliding bracket 207 and the telescopic shaft of cylinder 218 are connected, the other end of guide bar 220 respectively with cylinder support 219 sliding connection.
Referring to fig. 1, the right rotating shaft 204 is rotatably connected with the fixed bracket 208 and then penetrates out of the fixed bracket 208, and then penetrates out of the fixed bracket 208 and is connected with an output shaft of a first driving motor 221, and the first driving motor 221 is fixed on the fixed bracket 208.
Referring to fig. 1, the precision machining assembly for the spherical surface of the orthopedic implant further comprises an orthopedic implant 3 and an expansion shaft 4 connected with the orthopedic implant 3, wherein one end of the expansion shaft 4 is connected with the orthopedic implant 3, and the other end of the expansion shaft is connected with a second driving motor 5 positioned on an upper fixing plate 1 through the upper fixing plate 1; the orthopedic implant 3 is located in the hemispherical cavities 213 of the first bosses 209 of the left polishing body 201 and the right polishing body 202 connected into a spherical cavity.
Referring to fig. 7, the expansion shaft 4 penetrates through an expansion shaft hole 2223 of the retainer ring 222, magnetorheological polishing solution inlets 2224 are further disposed at two sides of the expansion shaft hole 2223, a magnetorheological polishing solution outlet 2225 is disposed at the other side of the retainer ring 222, which is opposite to the magnetorheological polishing solution inlet 2224, the magnetorheological polishing solution inlets 2224 and the magnetorheological polishing solution outlets 2225 are respectively connected with a magnetorheological polishing solution storage box 6 through pipes, valves (not shown in the figure) are respectively disposed on the pipes, the magnetorheological polishing solution 7 is controlled to flow in and out through the valves, and the magnetorheological polishing solution storage box 6 is fixed at the bottom of the upper fixing plate 1.
Example 2
As shown in fig. 10, the present embodiment is similar to the structural principle of embodiment 1, and is different from embodiment 1 in that in the present embodiment, the second driving motor 5 is removed, the tightening shaft 4 connected with the second driving motor 5 is directly connected with the machine tool spindle 8, and both sides of the upper fixing plate 1 are fixed on the machine tool table 10 through the brackets 9; the expansion shaft 4 is driven to rotate by the machine tool main shaft 8, so that the orthopedic implant 3 is driven to rotate to realize polishing.
Before the orthopedic implant spherical surface precision machining component starts to work, firstly, the air cylinder 218 is started, the telescopic shaft of the air cylinder 218 is contracted to drive the sliding support 207 connected with the air cylinder to move leftwards, the left polishing body 201 is moved leftwards, the left polishing body 201 and the right polishing body 202 are separated to a certain distance, then the orthopedic implant 3 is installed on the expansion shaft 4 and is positioned in the hemispherical cavity 213 of the right polishing body 202, then the air cylinder 218 is started, the telescopic shaft of the air cylinder 218 is contracted to drive the sliding support 207 connected with the air cylinder 218 to move rightwards, the left polishing body 201 is moved rightwards, the left polishing body 201 is connected with the right polishing body 202, and the orthopedic implant 3 is positioned in the spherical cavity formed by connecting the hemispherical cavities 213 of the left polishing body 201 and the right polishing body 202.
In operation, the first driving motor 221 and the second driving motor 5 (or the machine tool spindle 8) are simultaneously started, the left polishing body 201 and the right polishing body 202 start to rotate along with the left rotating shaft 203 and the right rotating shaft 204, simultaneously, the valve on the pipeline connecting the magnetorheological polishing solution storage box 6 and the magnetorheological polishing solution inlet 2224 is opened, the magnetorheological polishing solution 7 enters the gap between the spherical cavity and the spherical outer surface of the orthopedic implant 3, at this time, the left annular electromagnet 215 and the right annular electromagnet 216 are electrified, under the action of the magnetic field force, the magnetorheological polishing solution 7 is subjected to rheological deformation to form a solid grinding layer, along with the relative rotation of the polishing bodies and the orthopedic implant, a solid grinding layer is formed in the spherical cavity formed by the connection of the left polishing body 201 and the right polishing body 202 and is attached to the surface of the spherical cavity, and during the movement, the grinding layer and the spherical outer surface of the orthopedic implant 3 have rapid relative movement, the spherical outer surface of the orthopedic implant 3 is subjected to a large shearing force, grinding, polishing and finishing of the orthopedic implant 3 are realized, and compared with the traditional processing technologies of precision forging turning, manual step-by-step ball polishing and the like, the spherical surface polishing device has the advantages that the polishing effect is better, and the polishing precision is higher; due to the fact that the vertical cross grinding track of the whole spherical surface can be obtained through the compound motion of the first driving motor 221 and the second driving motor 5 (or the machine tool spindle 8), the generation of stripe-shaped polishing marks can be effectively avoided, the surface roughness is smaller, and the finish machining effect is better.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention.