TWI667086B - Forming apparatus with back pressure - Google Patents

Abstract

A back pressure auxiliary forming device includes a lower die unit, an upper die unit, and a modulation unit. The lower die unit includes a lower die plate, an ejection plate located above the lower die plate, at least one first elastic member connecting the lower die plate and the ejection plate, a back pressure plate located above the ejection plate, and at least one connection The ejector plate and the second elastic member of the back pressure plate, and a die. When the upper mold unit is closed down with the lower mold unit, the at least one second elastic member is compressed to generate back pressure, and when compressed to a certain degree, the ejector plate is moved downward through the modulation unit The speed is higher than the downward movement speed of the upper mold unit, so that the compression of the at least one second elastic member is slowed down, and the back pressure is gradually reduced to achieve the effect of reducing the load and extending the service life.

Description

Back pressure auxiliary forming device

The invention relates to a mold for assisting forming through back pressure, in particular to a back pressure assisting forming device for forging cycloid gears.

With the rise of artificial intelligence, the robot industry, which has been highly developed due to the needs of automation, has once again produced a wave of revolution, which has brought a lot of demand to the market. The key components, which account for 36% of the cost of the robot, can understand its importance. The cycloid gear is the transmission element in the cycloid reducer. The high precision, low surface roughness, high rigidity and fatigue resistance of the cycloid gear are the goals pursued by major developers today.

If the general cycloid gear is processed by cutting, it will produce more scrap material due to subtraction processing, which not only reduces the utilization rate of raw materials, but also reduces the strength of the cycloid gear during the cutting process. Although the cycloid gear can be produced by forging, it can overcome the aforementioned shortcomings, but it is easy to control the size of the cycloid gear due to heating during the forging process, which reduces the accuracy of the product.

Referring to FIG. 1, a cold extrusion forming die 1 as shown in FIG. 1 currently appears, which is composed of an upper die 11 and a lower die 12. The lower die 12 is provided with a spring 13 and a pressing plate 14. When the die is compressed, a back pressure will be generated in the reverse direction due to the compression of the spring 13, so that the blank is subjected to both forging pressure and back pressure during the forming process. Under double extrusion, it can reduce dimensional errors and improve accuracy. However, as the upper die 11 is gradually depressed, the compression amount of the spring 13 will increase synchronously, which causes the elastic force generated by the spring 13 to gradually increase, causing the back pressure to gradually increase rather than be fixed during the forming process, resulting in The cold extrusion molding die 1 generates an excessive load due to excessive back pressure, and reduces the service life of the cold extrusion molding die 1.

Therefore, the object of the present invention is to provide a back pressure auxiliary forming device which can reduce the load of the mold.

Therefore, the back-pressure auxiliary forming device of the present invention includes a lower die unit, an upper die unit, and a modulation unit. The lower die unit includes a lower die plate, an ejector plate located above the lower die plate, at least one first end connected to the lower die plate and the ejector plate at both ends, and a back pressure plate located above the ejector plate, At least one second end respectively connecting the ejector plate and the back pressure plate with a second elastic member, and a die located above the ejector plate and defining a cavity around the back pressure plate, the back pressure plate can be attached to the mold Renai moves relative to the mold.

The upper die unit includes an upper die plate located above the die core, and an upper punch protruding from the upper die plate toward the lower die unit. The modulation unit is used to make the ejection plate of the lower mold unit move downward faster than the upper mold unit drives the back pressure plate to move downward.

The effect of the present invention is that when the upper mold unit is closed down with the lower mold unit, the at least one second elastic member is compressed to generate back pressure, and then when compressed to a certain degree, through the modulation unit The speed at which the ejector plate moves downward is greater than the speed at which the upper mold unit drives the back pressure plate to move downward, so that the compression of the at least one second elastic member is gradually slowed (or no longer compressed), and the back pressure is gradually increased Reduce to achieve the effect of reducing load and extending service life.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same number.

Referring to FIG. 2, it is a first embodiment of the back-pressure auxiliary forming device of the present invention, which includes a lower die unit 2, an upper die unit 3 that can mold with the lower die unit 2 from top to bottom, and a modulation unit 4 . The lower die unit 2 includes a lower die plate 21 placed on a plane, an ejector plate 22 spaced apart above the lower die plate 21, and a plurality of first ends connecting the lower die plate 21 and the ejector plate 22 with first elasticity Piece 23, a back pressure plate 24 spaced apart above the ejector plate 22, a second elastic member 25 connected to the ejection plate 22 and the back pressure plate 24 at both ends, and a piece above the ejector plate 22 and A mold cavity 26 of a mold cavity 260 is defined around the back pressure plate 24. The back pressure plate 24 can move relative to the mold core 26 in the mold core 26, and the second elastic member 25 penetrates the mold core 26 downward to connect the ejector plate 22. The upper die unit 3 includes an upper die plate 31 located above the die core 26 and an upper punch 32 protruding downward from the upper die plate 31 toward the die cavity 260 of the die core 26.

The modulation unit 4 includes a plurality of followers 41 extending upward from the ejector plate 22 of the lower mold unit 2, a plurality of drive members 42 extending downward from the upper template 31 of the upper mold unit 3, and a plurality of A speed change mechanism 43 between the follower 41 and the drive 42. Each follower 41 is generally plate-shaped, and has a driven rack 411 formed on the outer surface and facing one of the corresponding drive members 42, each drive member 42 is generally plate-shaped, and has a The driving rack 421 on the surface and toward the driven rack 411 is spaced apart from each other in the horizontal direction. Each shifting mechanism 43 is disposed between one of the followers 41 and a driving member 42 corresponding to the follower 41. The shifting mechanism 43 has a driven rack 411 engaged with the follower 41 A first gear 431, and a second gear 432 that meshes with the first gear 431 and the driving rack 421 of the driving member 42. In the first embodiment, the number of teeth of the first gear 431 is smaller than the number of teeth of the second gear 432. For example, the ratio of the number of teeth of the second gear 432 to the first gear 431 can be selected as 3/2, 4 / 3 or 5/4.

Referring to FIGS. 2, 3, and 4, the forming process of the first embodiment is described below. First, a blank A is placed in the cavity 260 of the die 26, and then the upper punch 32 is aligned with the After the mold cavity 260, the upper template 31 is driven to move downward as shown in FIG. Then the upper die plate 31 continues to move downward and the upper punch 32 protrudes into the die cavity 260 to squeeze the blank A, so that the blank A begins to fill the die cavity 260 and push the back pressure plate downward 24, after the back pressure plate 24 is pushed down, the second elastic member 25 is compressed as shown in FIG. 4, and the back pressure plate 24 is reversely given to push up against the embryo by the elastic force generated by the second elastic member 25 The back pressure at the bottom of the material A, so the blank A is simultaneously subjected to the downward pressing force of the upper punch 32 and the upward back pressure of the back pressure plate 24. The design of the bidirectional force can improve the blank A In the formability of the tooth-shaped features (not shown) flowing in the cavity 260, during the foregoing process, the ejector plate 22 is moved downward by the downward pressure of the second elastic member 25 and compressed downward The first elastic members 23 generate cushioning force.

Referring to FIG. 3, FIG. 4, and FIG. 5, then, while the back pressure plate 24 continues to move to the bottom dead center (from FIG. 4 to FIG. 5), the driving members 42 are respectively in phase with the second gears 432 Mesh, and drive the followers 41 to move downward through the first gears 431, so the ejector plate 22 is simultaneously driven by the second elastic member 25 and the followers 41 to move downwards, because The number of teeth of the first gear 431 is smaller than the number of teeth of the second gear 432, so the rotation speed of the first gear 431 is greater than that of the second gear 432, and the ejection plate 22 moves downward faster than the upper template 31 The moving speed is fast, which causes the back pressure plate 24 to be pushed down by the upper punch 32 at a slower speed than the ejecting plate 22 moves down, so that the compression of the second elastic member 25 is gradually slowed down, as the The distance between the back pressure plate 24 and the ejection plate 22 is changed from being close to each other and away from each other, and the second elastic member 25 is also changed from being compressed to being uncompressed, thereby making the back pressure provided by the second elastic member 25 Gradually decrease, so as to avoid the load on the auxiliary forming device of back pressure caused by the back pressure gradually increasing. Life, and simple structure of the first embodiment according to the present embodiment, without other auxiliary power, can reduce the manufacturing cost, and in completion of a step passes.

Referring to FIG. 6, it is a second embodiment of the back pressure auxiliary forming device of the present invention. The second embodiment is substantially the same as the first embodiment, except that each slave of the second embodiment The member 41 does not have a rack structure, but has a driven slope 412 facing upward. Each driving member 42 also does not have a rack structure, but has a driving slope 422 facing downward. Each shifting mechanism 43 has a wedge block 433 whose two ends extend horizontally toward a corresponding driven member 41 and a corresponding driving member 42, respectively. The wedge block 433 has a first sliding surface 434 that contacts the driven inclined surface 412 of the driven member 41 and a second sliding surface 435 that faces the driven inclined surface 422 of the driving member 42. For example, the angle between the driven inclined surface 412 and the first sliding surface 434 and the horizontal is 60 degrees, and the angle between the driving inclined surface 422 and the second sliding surface 435 and the horizontal is 45 degrees.

Referring to FIGS. 7, 8, and 9, when the second embodiment is closed, the blank A is first subjected to the downward pressing force of the upper punch 32 and the upward pressure of the back pressure plate 24 After the driving ramps 422 of the driving members 42 contact the second sliding surfaces 435 of the wedge-shaped blocks 433, each driving ramp 422 pushes the corresponding second sliding surface 435 to make the corresponding wedge-shaped blocks 433 moves outward in the horizontal direction, and then the first sliding surface 434 of the wedge-shaped block 433 pushes against the driven inclined surface 412 of the corresponding follower 41, and makes the follower 41 faster than the upper template 31 Move Downward.

In the second embodiment, the wedge block 433 having a sloped surface is used to interlock the ejection plate 22 so that the downward movement speed of the back pressure plate 24 is less than the downward movement speed of the ejection plate 22, so that the second elastic member The elastic force of 25 is gradually reduced, so that it can gradually reduce the back pressure to avoid excessive load. In summary, in the present invention, the speed of downward movement of the back pressure plate 24 through the speed change mechanisms 43 is less than the downward movement speed of the ejection plate 22, which can reduce the back pressure and facilitate the formation of tooth-shaped features, and The forging can be completed in a single pass, the structure is simple and the production cost can be reduced, so the purpose of cost invention can indeed be achieved.

However, the above are only examples of the present invention, and should not be used to limit the scope of implementation of the present invention, any simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the contents of the patent specification are still Within the scope of the invention patent.

2‧‧‧Lower die unit

21‧‧‧ Lower template

22‧‧‧Push out the board

23‧‧‧The first elastic piece

24‧‧‧Back pressure plate

25‧‧‧Second elastic piece

26‧‧‧ Mo Ren

260‧‧‧Cavities

3‧‧‧ Upper mold unit

31‧‧‧Up template

32‧‧‧Punch

4‧‧‧Modulation unit

41‧‧‧Follower

411‧‧‧ driven rack

412‧‧‧Following slope

42‧‧‧Drive parts

421‧‧‧Drive rack

422‧‧‧Drive ramp

43‧‧‧shift mechanism

431‧‧‧The first gear

432‧‧‧Second gear

433‧‧‧Wedge block

434‧‧‧The first sliding surface

435‧‧‧Second sliding surface

A‧‧‧Blend

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a side cross-sectional view illustrating a conventional cold extrusion molding die; FIG. 2 is a schematic diagram, A first embodiment of the back pressure auxiliary forming device of the present invention will be described. FIGS. 3 to 5 are schematic diagrams illustrating the forming process of the first embodiment. FIG. 6 is a schematic view illustrating one of the back pressure auxiliary forming devices of the present invention. The second embodiment; and FIGS. 7 to 9 are schematic diagrams illustrating the forming process of the second embodiment.

Claims (4)

A back pressure auxiliary forming device includes: a lower die unit, including a lower die plate, an ejection plate located above the lower die plate, at least one first end connected to the lower die plate and the ejection plate, and a The back pressure plate above the ejection plate, at least one two ends respectively connecting the ejection plate and the second elastic piece of the back pressure plate, and a mold located above the ejection plate and defining a cavity around the back pressure plate Ren, the back pressure plate can move relative to the die inside the die; an upper die unit includes an upper die plate located above the die die, and an upper punch protruding from the upper die plate toward the lower die unit; And a modulation unit for moving the ejection plate of the lower mold unit downwards at a speed greater than the speed at which the upper mold unit drives the back pressure plate downward. The back pressure auxiliary forming device according to claim 1, wherein the modulation unit includes a plurality of followers provided on the ejection plate of the lower mold unit, and a plurality of drives provided on the template on the upper mold unit Components, and a plurality of speed-changing mechanisms, each speed-changing mechanism is disposed between one of the driven members and the corresponding one of the driving members, and the downward moving speed of the driven member is greater than the downward moving speed of the driving member. The back pressure auxiliary forming device according to claim 2, wherein each driven member of the modulation unit has a driven rack formed on the outer surface, and each driving member has a formed on the outer surface and faces the opposite The driving rack of the driven rack that should be the follower, each speed change mechanism has a first gear that meshes with the driven rack of the corresponding follower, and a drive that is driven by the first gear and the corresponding drive member For the second gear meshed with the rack, the number of teeth of the first gear is smaller than the number of teeth of the second gear. The back pressure auxiliary forming device according to claim 2, wherein each follower of the modulation unit has a follower slope facing upward, each drive member has a drive slope facing downward, and each speed change mechanism A wedge-shaped block having a lateral extension and two ends respectively facing the corresponding driven member and the corresponding driving member, the wedge-shaped block has a first sliding surface that contacts the driven inclined surface of the driven member, and a toward the driving member Drive the second sliding surface of the inclined plane.