Medical hip joint femoral stem pre-forging die

Abstract

According to the medical hip joint femoral stem pre-forging die, the service life of the die can be prolonged, a pre-forged piece obtained through machining of the die can play a limiting role in a final forged piece, and the defects of folding, material gnawing and the like in the forming process are overcome. The die comprises an upper die and a lower die, the upper die and the lower die are respectively provided with a cavity, the cavities comprise a head cavity, a neck cavity and a stem body cavity which respectively correspond to the head, the neck and the stem body of the medical hip joint femoral stem, the upper end face of the upper die and the lower end face of the lower die are respectively provided with a bridge part protruding out of the end faces, and the middles of the bridge parts are concaved inwards to form the cavities. The lower end face of the bridge part of the upper die and the upper end face of the bridge part of the lower die are bridge part die surfaces, and transfer fillets are arranged at the transfer positions of the cavities and the bridge part die surfaces; the depth of the head cavity is half of the head thickness of the medical hip joint femoral stem final forge piece plus (0.3-0.8) mm, and the width of the head cavity is minus (0.1-0.3) mm of the head width of the medical hip joint femoral stem final forge piece.

Description

Technical Field

[0001] The utility model relates to the technical field of pre-forging dies, in particular to a pre-forging die for a medical hip joint femoral stem. Background Art

[0002] The hip femoral stem and acetabular cup are used together as hip prostheses, and are suitable for artificial hip replacement for patients with hip joint diseases. Hip femoral stem forgings are obtained by forging, which is the mainstream production method of hip stem blanks. Since the precision forging of medical hip femoral stems is generally formed by three fires: blank making, pre-forging, and final forging, the conventional design of the pre-forging die generally includes an upper die and a lower die, and the upper and lower dies are concave to form a cavity. During use, the connection between the cavity and the parting surface of the die is prone to wear, which affects the service life of the die. At the same time, the pre-forgings obtained by the pre-forging die will also affect the processing of the final forgings. Utility Model Content

[0003] In view of the problems that the existing molds are prone to wear and affect the service life of the molds, and how to reduce the adverse effects on the forging of the final forgings, the utility model provides a medical hip joint femoral stem pre-forging mold, which can not only improve the life of the mold, but the pre-forgings obtained by the processing can also play a limiting role in the final forgings, avoiding defects such as folding and gnawing during the forming process.

[0004] The technical solution is as follows: a pre-forging die for a medical hip joint femoral stem, comprising an upper die and a lower die, wherein the upper die and the lower die are respectively provided with cavities, wherein the cavities include a head cavity, a neck cavity and a stem body cavity corresponding to the head, neck and stem body of the medical hip joint femoral stem respectively, and characterized in that: the upper end face of the upper die and the lower end face of the lower die are respectively provided with a bridge portion protruding from the end face, the middle of the bridge portion is concave to form the cavity, the lower end face of the bridge portion of the upper die and the upper end face of the bridge portion of the lower die are the bridge portion die surface, and a transition fillet is provided at the transition between the cavity and the bridge portion die surface; the depth of the head cavity is half the thickness of the head of the final forging of the medical hip joint femoral stem + (0.3~0.8) mm, and the width of the head cavity is the width of the head of the final forging of the medical hip joint femoral stem - (0.1~0.3) mm.

[0005] It is further characterized by:

[0006] The radius of the transition fillet is 0.5 mm to 1.8 mm;

[0007] The clamping gap between the upper die and the lower die in the pre-forging die is 1.2 to 2.0 mm;

[0008] The depth of the neck cavity / the stem cavity is half the thickness of the neck / stem of the final forging of the medical hip joint femoral stem + (0.4-1.0) mm, and the width of the neck cavity / the stem cavity is the width of the neck / stem of the final forging of the medical hip joint femoral stem - (0.2-1.5) mm;

[0009] The lower die is also provided with a limit stopper protruding from the upper end surface, the height of the limit stopper is greater than the height of the bridge portion, and the upper die is provided with an avoidance groove at a position corresponding to the limit stopper;

[0010] The limit stopper has a height of 3 to 7 mm, a width of 10 to 20 mm, and a draft of 3 to 10°.

[0011] Beneficial effects: By setting the cavity in the bridge part and providing a transition radius at the transition between the cavity and the die surface of the bridge part, the most easily worn position of the die has sufficient margin to cope with wear, thereby improving the service life of the die; the head cavity size is related to the head size of the final forging, so that the processed pre-forging can play a limiting role in the final forging die, avoiding defects such as folding and gnawing during the forming process. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the pre-forging die clamping;

[0013] Figure 2 It is a schematic diagram of the upper die of the pre-forging die;

[0014] Figure 3 It is a schematic diagram of the lower die of the pre-forging die;

[0015] Figure 4 This is a schematic diagram of the transfer fillet of the lower model of the pre-forging die. DETAILED DESCRIPTION

[0016] like Figure 1-Figure 4A medical hip joint femoral stem pre-forging mold shown includes an upper mold 1 and a lower mold 2, and a cavity is respectively provided on the upper mold 1 and the lower mold 2. The cavity includes a head cavity 4, a neck cavity 5 and a stem body cavity 6, which respectively correspond to the head, neck and stem body of the medical hip joint femoral stem. The upper end face of the upper mold 1 and the lower end face of the lower mold 2 are respectively provided with a bridge portion 3 protruding from the end face. The setting of the bridge portion 3 is helpful for the processing of flash. The middle of the bridge portion 3 is concave to form a cavity. The lower end face of the bridge portion 3 of the upper mold 1 and the upper end face of the bridge portion 3 of the lower mold 2 are the bridge portion mold surface. A transition fillet 7 is provided at the transition between the cavity and the bridge portion mold surface. By setting the fillet to resist wear, the service life of the mold can be increased. At the same time, preferably, the radius of the transition fillet is 0.5mm~1.8mm. Compared with the common fillet radius of 2.5mm on the mold, the smaller transition fillet radius increases the margin of the mold at the most wear-prone position, thereby improving the mold life. In addition, the die clearance between the upper die 1 and the lower die 2 in the pre-forging die, that is, the flash thickness of the pre-forging part is 1.2 to 2.0 mm. The flash thickness of the pre-forging part is reduced, which facilitates the filling of the metal in the mold cavity during the forging process, and the reduction in the flash removal thickness also reduces the wear of the trimming die.

[0017] The depth of the head cavity 4 is half the thickness of the head of the final forging of the medical hip joint femoral stem + (0.3-0.8) mm, and the width of the head cavity 4 is the width of the head of the final forging of the medical hip joint femoral stem - (0.1-0.3) mm. This design is to ensure that the gap between the head and the final forging mold cavity is small during the forging process, and the pre-forging can play a limiting role in the final forging die to avoid defects such as folding and gnawing during the final forging process.

[0018] In addition, the depth of the neck cavity 5 / stem body cavity 6 is half the thickness of the neck / stem body of the medical hip joint femoral stem final forging + (0.4~1.0) mm, and the width of the neck cavity 5 / stem body cavity 6 is the width of the neck / stem body of the medical hip joint femoral stem final forging - (0.2~1.5) mm; the advantage of such a design is that it ensures that the discharged excess material of each cross section during the forging process is similar, makes the flash of the final forging uniform, ensures that the deformation degree of the final forging is small, the contour meets the requirements, and can also improve the surface quality.

[0019] Compared with the original design, the pre-forging cavity depth is unified as half of the thickness of the femoral stem final forging + about 1.5mm, and the pre-forging model cavity width is unified as about -0.5mm of the femoral stem final forging width. The excess material discharged from each section varies greatly, resulting in uneven flash of the final forging, making the thickness profile fail to meet the requirements of the drawing, requiring later shape correction, etc., and the pre-forging is not well limited in the final forging model cavity, which can easily cause defects such as folding and gnawing.

[0020] The lower die 2 is also provided with a limit stopper 9 protruding from the upper end surface, the height of the limit stopper 9 is greater than the height of the bridge portion 3, and the upper die 1 is provided with an avoidance groove 8 at the position corresponding to the limit stopper 9; the limit stopper 9 has a height of 3 to 7 mm, a width of 10 to 20 mm, and a draft of 3 to 10°. The advantage of such a design is that the limit stopper 9 acts as a limiter during pre-forging, preventing the pre-forging from folding defects caused by the deviation of the discharge position.

[0021] The above are only preferred specific implementations of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by anyone familiar with the technology within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A pre-forging die for a medical hip joint femoral stem, comprising an upper die and a lower die, wherein the upper die and the lower die are respectively provided with a cavity, wherein the cavity comprises a head cavity, a neck cavity and a stem body cavity, which respectively correspond to the head, neck and stem body of the medical hip joint femoral stem, and wherein: The upper end face of the upper die and the lower end face of the lower die are respectively provided with a bridge portion protruding from the end face, the middle of the bridge portion is concave to form the cavity, the lower end face of the bridge portion of the upper die and the upper end face of the bridge portion of the lower die are the bridge portion mold surface, and a transition fillet is provided at the transition between the cavity and the bridge portion mold surface; the depth of the head cavity is half the thickness of the head of the final forging of the medical hip joint femoral stem + (0.3~0.8) mm, and the width of the head cavity is the width of the head of the final forging of the medical hip joint femoral stem - (0.1~0.3) mm.

2. A medical hip joint femoral stem pre-forging die according to claim 1, characterized in that: The radius of the transition fillet is 0.5 mm to 1.8 mm.

3. A medical hip joint femoral stem pre-forging die according to claim 1, characterized in that: The clamping gap between the upper die and the lower die in the pre-forging die is 1.2-2.0 mm.

4. A medical hip joint femoral stem pre-forging die according to claim 1, characterized in that: The depth of the neck cavity / the stem cavity is half the thickness of the neck / stem body of the final forging of the medical hip joint femoral stem + (0.4~1.0) mm, and the width of the neck cavity / the stem cavity is the width of the neck / stem body of the final forging of the medical hip joint femoral stem - (0.2~1.5) mm.

5. The medical hip joint femoral stem pre-forging die according to claim 1, characterized in that: The lower die is also provided with a limit stopper protruding from the upper end surface, the height of the limit stopper is greater than the height of the bridge portion, and the upper die is provided with an avoidance groove at a position corresponding to the limit stopper.

6. A medical hip joint femoral stem pre-forging die according to claim 5, characterized in that: The limit stopper has a height of 3 to 7 mm, a width of 10 to 20 mm, and a draft of 3 to 10 degrees.

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