A powder metallurgy external helical gear forming mold

Abstract

This invention discloses a powder metallurgy external helical gear workpiece forming die, comprising a forming base with a forming cavity; a first punch; a second punch with a first forming end and a first connecting end, and a first through-channel within the second punch; a third punch with a second forming end and a second connecting end, and a second through-channel within the third punch; forming helical teeth on the inner surface of the second forming end; at least two clearance through holes on the second connecting end, extending circumferentially along the second connecting end; a fourth punch with a third forming end and a third connecting end; guiding helical teeth on the outer surface of the third forming end, the guiding helical teeth engaging with the forming helical teeth; and a mandrel assembly including a mounting base and at least two mandrels spaced apart axially from the mounting base. This invention can form helical teeth and holes on the helical teeth in a single die-casting operation.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy technology, and in particular to a powder metallurgy external helical tooth workpiece forming mold. Background Technology

[0002] Powder metallurgy is a process technology that uses metal powders (or mixtures of metal and non-metal powders) as raw materials, and manufactures metallic materials, composite materials, and various types of products through forming and sintering. Powder metallurgy shares similarities with ceramic production, both belonging to powder sintering technology; therefore, a range of new powder metallurgy technologies can also be applied to the preparation of ceramic materials.

[0003] Existing powder workpieces are generally formed by die stamping, using pressure to press scattered powder into a whole. When processing helical tooth structures, and needing to process hole structures on the helical teeth, the product will be damaged if the helical teeth are demolded directly after forming. Therefore, selective demolding is performed. If the hole is processed directly after forming, the hole is easily damaged during demolding. Therefore, the conventional practice is to take out the product after the helical teeth are powder metallurgically formed and then process the hole separately. Summary of the Invention

[0004] In order to overcome at least one of the defects of the prior art, the present invention provides a powder metallurgy external helical gear workpiece forming mold, which can form helical teeth and holes on the helical teeth in one punch.

[0005] The technical solution adopted by this invention to solve its problem is:

[0006] A powder metallurgy external helical gear workpiece forming mold, comprising,

[0007] A molding base, wherein the molding base is provided with a molding cavity, the molding cavity having a first end and a second end that are opposite to each other;

[0008] A first punch, which can move closer to or away from the first end, so that the first punch can extend into or retract from the first end;

[0009] The second punch has a first forming end and a first connecting end. The second punch has a first through-channel that extends from the first connecting end to the first forming end. The first forming end extends into the second end.

[0010] The third punch has a second forming end and a second connecting end. The third punch has a second through channel that extends from the second connecting end to the second forming end. The second forming end can rotatably extend into the first through channel and into the first forming end. The inner surface of the second forming end has forming oblique teeth. The second connecting end has at least two clearance through holes that extend circumferentially along the second connecting end.

[0011] The fourth punch has a third forming end and a third connecting end. The fourth punch can move closer to or further away from the second end. The third forming end passes through the second through-channel and can move along the axial direction of the second through-channel. The outer surface of the third forming end is provided with guide helical teeth. The guide helical teeth mesh with the forming helical teeth and guide the third punch to rotate when the fourth punch moves along the axial direction of the second through-channel.

[0012] The mandrel assembly includes a mounting base and at least two mandrels, which are spaced apart axially from the mounting base. Each mandrel passes sequentially through the third connecting end, the clearance through hole, and the second punch and extends into the molding cavity.

[0013] Furthermore, the second punch also includes a first connecting seat, the first connecting end is mounted on the first connecting seat, the first connecting end is provided with at least two first positioning holes in the circumferential direction, the first connecting seat is provided with at least two first positioning pins, and the at least two first positioning pins are inserted into the at least two first positioning holes in a one-to-one correspondence to prevent the second punch from rotating.

[0014] Furthermore, the first connecting seat is provided with a first pressure cap, and the first connecting end is provided with a first limiting seat; the first pressure cap is sealed to the first connecting seat through a first connecting member, and the first limiting seat is pressed to the first connecting seat; the first positioning hole is provided in the first limiting seat.

[0015] Furthermore, the third punch also includes a second connecting seat, on which a first mounting cavity is provided, and the second connecting end is rotatably mounted in the first mounting cavity; the second connecting end rotates and engages with the first mounting cavity through a friction element.

[0016] Furthermore, the second connecting end is provided with a second limiting seat, the top end of the second limiting seat is provided with the friction element on the top wall of the first mounting cavity, and the bottom end of the second limiting seat is provided with the friction element on the bottom wall of the first mounting cavity.

[0017] Furthermore, the friction element includes at least two friction plates.

[0018] Furthermore, the fourth punch also includes a third connecting seat, the third connecting end is installed on the third connecting seat, the third connecting end is provided with at least two second positioning holes in the circumferential direction, the third connecting seat is provided with at least two second positioning pins, and the at least two second positioning pins are inserted into the at least two second positioning holes in a one-to-one correspondence to prevent the fourth punch from rotating.

[0019] Furthermore, the third connecting seat is provided with a second pressure cover, and the third connecting end is provided with a third limiting seat; the second pressure cover is sealed to the third connecting seat through a second connecting member, and the third limiting seat is pressed to the third connecting seat; the second positioning hole is provided in the third limiting seat.

[0020] Furthermore, the mandrel assembly also includes a first mandrel, and at least two mandrels include three second mandrels, the three second mandrels surrounding the outer periphery of the first mandrel and spaced apart; the second mandrels pass through the third connecting end, the clearance through hole, and the second punch and extend into the molding cavity; the first mandrel is connected to the third molding end by the third connecting end.

[0021] Furthermore, there are three clearance through holes, and the three core rods are connected to the three clearance through holes one by one and slide in cooperation with the clearance through holes.

[0022] In summary, the present invention has the following technical effects:

[0023] The external helical teeth and eccentric holes of the workpiece can be formed in one stamping process, simplifying the forming steps of the external helical teeth, reducing the processing technology, and improving the forming efficiency of the workpiece; during the demolding process, since the third punch is equipped with a clearance hole, the clearance hole avoids the mandrel when the third punch rotates to demold, preventing the mandrel from being pulled and causing damage to the workpiece during rotation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] Figure 2 This is an exploded structural diagram of the present invention;

[0026] Figure 3 This is a cross-sectional view of the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of the third punch of the present invention.

[0028] The meanings of the reference numerals in the attached drawings are as follows: 10, first punch; 20, second punch; 21, first connecting seat; 211, first forming end; 22, first pressure cap; 23, first limiting seat; 231, first positioning hole; 24, first positioning post; 30, third punch; 31, second connecting seat; 32, second limiting seat; 33, friction plate; 34, second forming end; 341, forming oblique tooth; 35, clearance hole; 40, fourth punch; 41, third connecting seat; 42, second pressure cap; 43, third limiting seat; 431, second positioning hole; 44, second positioning post; 45, third forming end; 451, guide oblique tooth; 50, mandrel seat; 51, first mandrel; 52, second mandrel; 60, forming seat; 61, forming cavity. Detailed Implementation

[0029] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0030] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0032] See Figures 1-4 This invention discloses a powder metallurgy external helical gear workpiece forming mold, including a forming base 60, a first punch 10, a second punch 20, a third punch 30, a fourth punch 40, and a mandrel assembly. The forming base 60 is provided with a forming cavity 61, which has a first end and a second end that are opposite to each other. The first punch 10 is located at the first end of the forming base 60. Specifically, the first punch 10 can move closer to or away from the first end. After moving closer to the first end, the first punch 10 can extend into the first end of the forming cavity 61. After moving away from the first end, the first punch 10 can retract from the second end of the forming cavity 61.

[0033] The second punch 20 is provided with a first forming end 211 and a first connecting end, and a first through-channel is provided inside the second punch 20. The first through-channel extends from the first connecting end to the first forming end 211. During assembly, the first forming end 211 of the second punch 20 can extend into the second end of the forming cavity 61. The third punch 30 is provided with a second forming end 34 and a second connecting end, and a second through-channel is provided inside the third punch 30. The second through-channel extends from the second connecting end to the second forming end 34. The second forming end 34 can rotatably extend into the first through-channel and into the first forming end 211. The inner surface of the second forming end 34 is provided with forming oblique teeth 341. When the second forming end 34 extends into the first forming end 211 through the first through-channel, the end face of the second forming end 34 can be flush with the end face of the first forming end 211, or the end face of the second forming end 34 can be lower than the end face of the first forming end 211. At least two clearance through holes are provided on the second connecting end, and the clearance through holes extend circumferentially along the second connecting end.

[0034] In addition, the fourth punch 40 is provided with a third forming end 45 and a third connecting end. The fourth punch 40 can move closer to or further away from the second end. The third forming end 45 passes through the second through channel and can move along the axial direction of the second through channel. A guide helical tooth 451 is provided on the outer surface of the third forming end 45, and the guide helical tooth 451 meshes with the forming helical tooth 341. The guide helical tooth 451 can guide the third punch 30 to rotate when the fourth punch 40 moves along the axial direction of the second through channel.

[0035] The mandrel assembly includes a mounting base and at least two mandrels, which are spaced apart axially from the mounting base. Each mandrel passes through a third connecting end, a clearance through hole, and a second punch 20 in sequence and extends into the forming cavity 61.

[0036] Based on the above structure, when using the powder metallurgy external helical tooth workpiece forming mold of the present invention, during forming, the first forming end 211 of the second punch 20 can extend into the forming cavity 61 through the second end of the forming cavity 61, and the second forming end 34 of the third punch 30 can penetrate into the interior of the first forming end 211 through the first through-channel of the second punch 20. When the formed external helical tooth workpiece has a stepped structure, the end face of the second forming end 34 can be lower than the end face of the first forming end 211. When the formed external helical tooth does not have a stepped structure, the end face of the second forming end 34 can be flush with the end face of the first forming end 211, together forming the forming surface. Meanwhile, the third forming end 45 of the fourth punch 40 can penetrate into the interior of the second forming end 34 through the second through-channel, and the end face of the third forming end 45 of the fourth punch 40 is lower than the end face of the second forming end 34. In this way, the inner wall of the forming cavity 61, the end face of the first forming end 211, the end face of the second forming end 34, the oblique teeth on the outer periphery of the second forming end 34, and the end face of the third forming end 45 together form a cavity for metallurgical powder to be placed. At the same time, each mandrel of the mandrel assembly can extend into the forming cavity 61 through the third connecting end, the clearance through hole, and the end face of the first forming end 211 of the second punch 20.

[0037] After the metallurgical powder is placed in, it can move close to the first end of the forming seat 60 through the first punch 10. The first punch 10 extends into one end of the forming cavity 61, so that the metallurgical powder can be stamped and formed. Under the action of the first punch 10, the metallurgical powder enters the space enclosed by the inner wall of the second forming end 34 and the end face of the third forming end 45 and is compacted. At this time, the oblique teeth of the second forming end 34 can form the external oblique tooth structure of the workpiece, while the mandrel can form a hole structure in the metallurgical powder on the end face of the first forming end 211.

[0038] After the workpiece is formed, when the demolding action begins, the first punch 10 can exit the first end of the forming cavity 61, while the third forming end 45 of the fourth punch 40 and the mandrel assembly can be flush with the first end of the forming cavity 61, pushing the product out from the second punch 20 and the third punch 30. When the third forming end 45 of the fourth punch 40 is pushed out, it can only move up and down and cannot rotate because of the anti-rotation structure (the anti-rotation structure in this embodiment is the second positioning post). At the same time, the guide helical tooth 451 can guide the second forming end 34 of the third punch 30 to rotate. The helical tooth structure on the inner wall of the second forming end 34 cooperates with the helical tooth structure on the workpiece. When the second forming end 34 rotates, the helical tooth workpiece can be pushed out, completing the demolding.

[0039] In this way, the external oblique teeth and eccentric holes of the workpiece can be formed in one stamping process, simplifying the forming steps of the external oblique teeth, reducing the processing technology, and improving the forming efficiency of the workpiece. During the demolding process, since the third punch 30 is provided with a clearance through hole 35, when the third punch 30 rotates to demold, the clearance through hole 35 avoids the mandrel, preventing the mandrel from being pulled and causing damage to the workpiece during rotation.

[0040] Of course, the linear motion of the fourth punch 40 and the linear motion of the mandrel assembly can be achieved by existing linear motion output structures such as cylinders or hydraulic cylinders. In this embodiment, the same drive structure drives the mandrel assembly and the fourth punch to move up and down simultaneously.

[0041] Furthermore, specifically, the aforementioned second punch 20 also includes a first connecting seat 21, on which the first connecting end is installed, and at least two first positioning holes 231 are provided in the circumferential direction of the first connecting end. Correspondingly, at least two first positioning pins 24 are provided on the first connecting seat 21, and at least two first positioning pins 24 are inserted into at least two first positioning holes 231 in a one-to-one correspondence to prevent the second punch 20 from rotating.

[0042] Since the second forming end 34 of the third punch 30 is inserted into the first through channel of the second punch 20, when the third punch 30 rotates to demold, in order to prevent the second punch 20 from rotating as well, a first connecting seat 21 can be set. The first connecting seat 21 can be installed on the mold body, and the first positioning pin 24 on the first connecting seat 21 can be inserted into the first positioning hole 231 of the first connecting end of the second punch 20. Multiple first positioning pins 24 in the circumferential direction cooperate with multiple first positioning holes 231 to achieve anti-rotation.

[0043] Of course, positioning and anti-rotation can also be achieved by setting a positioning hole on the first connecting seat 21 and setting a positioning post structure on the first connecting end of the second punch 20.

[0044] To further improve the assembly structure of the second punch 20, a first pressure cap 22 can be provided on the first connecting seat 21, and a first limiting seat 23 can be provided on the first connecting end. When assembling the second punch 20 and the first connecting seat 21, the first limiting seat 23 of the second punch 20 can be inserted into the gap between the first pressure cap 22 and the first connecting seat 21. Then, the first pressure cap 22 is sealed to the first connecting seat 21 through the first connector, and the first limiting seat 23 is pressed to the first connecting seat 21. The first positioning hole 231 is provided in the first limiting seat 23. That is, the axial positioning of the second punch 20 is limited by the pressing of the first limiting seat 23 and the first pressure cap 22, and the circumferential positioning is limited by the first positioning post 24 and the first positioning hole 231, which makes the stamping process more stable.

[0045] Of course, the first connecting member mentioned above can be implemented using existing technologies such as bolts or pins.

[0046] Furthermore, the third punch 30 also includes a second connecting seat 31, on which a first mounting cavity may be provided. The second connecting end is rotatably mounted in the first mounting cavity. The second connecting end rotates with the first mounting cavity through a friction element. Thus, when the third punch 30 rotates, the friction element reduces the friction between the third punch 30 and the first mounting cavity of the second connecting seat 31, thereby reducing the rotational resistance of the third punch 30, making the rotation smoother, and reducing mutual wear and tear, thus improving the service life of the mold.

[0047] More specifically, the second connecting end is provided with a second limiting seat 32, and the top end of the second limiting seat 32 is provided with a friction element with the top wall of the first mounting cavity, and the bottom end of the second limiting seat 32 is provided with a friction element with the bottom wall of the first mounting cavity. In this way, the third punch 30 can cooperate with the top and bottom walls of the first mounting cavity through the friction element by the protruding second limiting seat 32, so that the rotation contact surface is larger and the rotation is smoother.

[0048] Furthermore, the friction component includes at least two friction plates 33. Specifically, the friction component has a plate-like or plate-like structure, and oil reservoirs are provided on the top surface of the friction plates 33 and the bottom surface of the first friction component. Therefore, simply adding lubricating oil to the oil reservoirs can greatly improve the lubrication effect and thus reduce friction. Of course, the above-mentioned friction component is a plane bearing, thereby utilizing the inherent characteristics of the plane bearing to achieve the effect of reducing friction.

[0049] Furthermore, the fourth punch 40 also includes a third connecting seat 41, a third connecting end is mounted on the third connecting seat 41, the third connecting end is provided with at least two second positioning holes 431 in the circumferential direction, the third connecting seat 41 is provided with at least two second positioning pins 44, the at least two second positioning pins 44 are inserted into the at least two second positioning holes 431 in a one-to-one correspondence to prevent the fourth punch 40 from rotating.

[0050] Since the third forming end 45 of the fourth punch 40 is inserted into the second through channel of the third punch 30, when the third punch 30 rotates to demold, in order to prevent the fourth punch 40 from rotating as well, a third connecting seat 41 can be set. The third connecting seat 41 can be installed on the mold body, and the second positioning pin 44 on the third connecting seat 41 can be inserted into the second positioning hole 431 of the third connecting end of the fourth punch 40. Multiple second positioning pins 44 and multiple second positioning holes 431 in the circumferential direction cooperate to achieve anti-rotation.

[0051] Of course, positioning holes can also be set on the third connecting seat 41, and a positioning post structure can be set on the third connecting end of the fourth punch 40 to achieve positioning and anti-rotation.

[0052] Furthermore, the third connecting seat 41 is provided with a second pressure cover 42, and the third connecting end is provided with a third limiting seat 43 protruding outward; the second pressure cover 42 is sealed to the third connecting seat 41 through the second connecting member, and the third limiting seat 43 is pressed to the third connecting seat 41; the second positioning hole 431 is provided in the third limiting seat 43.

[0053] To further stabilize the assembly structure of the fourth punch 40, a second pressure cap 42 can be provided on the third connecting seat 41, and a second limiting seat 32 is provided on the third connecting end. When assembling the fourth punch 40 and the third connecting seat 41, the second limiting seat 32 of the fourth punch 40 can be inserted into the gap between the second pressure cap 42 and the third connecting seat 41. Then, the second pressure cap 42 is sealed to the third connecting seat 41 through the second connector, and the second limiting seat 32 is pressed to the third connecting seat 41. The second positioning hole 431 is provided in the second limiting seat 32. That is, the axial positioning of the fourth punch 40 is limited by the pressing of the second limiting seat 32 and the second pressure cap 42, and the circumferential positioning is limited by the second positioning post 44 and the second positioning hole 431, which makes the stamping process more stable.

[0054] Of course, the second connecting member mentioned above can be implemented using existing technologies such as bolts or pins.

[0055] Furthermore, the aforementioned mandrel assembly also includes a first mandrel 51, and at least two mandrels include three second mandrels 52. The three second mandrels 52 are arranged around the outer periphery of the first mandrel 51 and are spaced apart. The second mandrels 52 pass through the third connecting end, the through hole, and the second punch 20 and extend into the forming cavity 61. The first mandrel 51 is connected from the third connecting end to the third forming end 45. Thus, the first mandrel 51 and the three second mandrels 52 can be mounted on the mandrel seat 50 and driven by a cylinder or hydraulic cylinder and extended into the forming cavity 61. The three second mandrels 52 can extend from the end face of the first forming end 211 to form three holes in the circumference of the workpiece, while the first mandrel 51 can extend from the end face of the third forming end 45 and form holes in the middle of the workpiece.

[0056] Furthermore, the aforementioned clearance through-holes are provided three times, with the three second mandrels correspondingly passing through and slidingly engaging with the clearance through-holes. This allows the three mandrels to slide through the three clearance holes 35 during rotational demolding, achieving mandrel clearance and preventing damage. Alternatively, the third punch 30 can have continuous clearance annular holes opening upwards, also allowing the three second mandrels to pass through and clear the mandrels during rotational demolding.

[0057] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A powder metallurgy external helical gear workpiece forming mold, characterized in that, include, A molding base, wherein the molding base is provided with a molding cavity, the molding cavity having a first end and a second end that are opposite to each other; A first punch, which can move closer to or away from the first end, so that the first punch can extend into or retract from the first end; The second punch has a first forming end and a first connecting end. The second punch has a first through-channel that extends from the first connecting end to the first forming end. The first forming end extends into the second end. The third punch has a second forming end and a second connecting end. The third punch has a second through channel that extends from the second connecting end to the second forming end. The second forming end can rotatably extend into the first through channel and into the first forming end. The inner surface of the second forming end has forming oblique teeth. The second connecting end has at least two clearance through holes that extend circumferentially along the second connecting end. The fourth punch has a third forming end and a third connecting end. The fourth punch can move closer to or further away from the second end. The third forming end passes through the second through-channel and can move along the axial direction of the second through-channel. The outer surface of the third forming end is provided with guide helical teeth. The guide helical teeth mesh with the forming helical teeth and guide the third punch to rotate when the fourth punch moves along the axial direction of the second through-channel. The mandrel assembly includes a mounting base and at least two mandrels, which are spaced apart axially from the mounting base. Each mandrel passes sequentially through the third connecting end, the clearance through hole, and the second punch and extends into the forming cavity. The mandrels are circumferentially slidingly engaged with the clearance through hole.

2. The powder metallurgy external helical gear workpiece forming mold according to claim 1, characterized in that, The second punch also includes a first connecting seat, the first connecting end is mounted on the first connecting seat, the first connecting end is provided with at least two first positioning holes in the circumferential direction, the first connecting seat is provided with at least two first positioning pins, and the at least two first positioning pins are inserted into the at least two first positioning holes in a one-to-one correspondence to prevent the second punch from rotating.

3. The powder metallurgy external helical gear workpiece forming mold according to claim 2, characterized in that, The first connecting seat is provided with a first pressure cover, and the first connecting end is provided with a first limiting seat; the first pressure cover is sealed to the first connecting seat through a first connecting member, and the first limiting seat is pressed to the first connecting seat; the first positioning hole is provided in the first limiting seat.

4. The powder metallurgy external helical gear workpiece forming mold according to claim 1, characterized in that, The third punch further includes a second connecting seat, on which a first mounting cavity is provided, and the second connecting end is rotatably mounted in the first mounting cavity; the second connecting end rotates with the first mounting cavity through a friction element.

5. The powder metallurgy external helical gear workpiece forming mold according to claim 4, characterized in that, The second connecting end is provided with a second limiting seat, the top end of the second limiting seat and the top wall of the first mounting cavity are provided with the friction element, and the bottom end of the second limiting seat and the bottom wall of the first mounting cavity are provided with the friction element.

6. The powder metallurgy external helical gear workpiece forming mold according to claim 4, characterized in that, The friction element includes at least two friction plates.

7. The powder metallurgy external helical gear workpiece forming mold according to claim 1, characterized in that, The fourth punch also includes a third connecting seat. The third connecting end is installed on the third connecting seat. The third connecting end has at least two second positioning holes in its circumferential direction. The third connecting seat has at least two second positioning pins. The at least two second positioning pins are inserted into the at least two second positioning holes one-to-one to prevent the fourth punch from rotating.

8. The powder metallurgy external helical gear workpiece forming mold according to claim 7, characterized in that, The third connecting seat is provided with a second pressure cover, and the third connecting end is provided with a third limiting seat; the second pressure cover is sealed to the third connecting seat through a second connecting member, and the third limiting seat is pressed to the third connecting seat; the second positioning hole is provided in the third limiting seat.

9. The powder metallurgy external helical gear workpiece forming mold according to any one of claims 1-8, characterized in that, The mandrel assembly further includes a first mandrel, and at least two mandrels include three second mandrels, the three second mandrels surrounding the outer periphery of the first mandrel and spaced apart; the second mandrels pass through the third connecting end, the clearance through hole, and the second punch and extend into the molding cavity; the first mandrel is connected to the third molding end by the third connecting end.

10. The powder metallurgy external helical gear workpiece forming mold according to claim 9, characterized in that, The avoidance through hole is provided in three parts, and the three second core rods are respectively inserted into the three avoidance through holes and slide in cooperation with the avoidance through holes.

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