A two-way plate-type wedge-type cross-rolling die and forming method for ball parts without idle stroke

Abstract

The present invention relates to the technical field of metal plastic forming technology, and provides a bidirectional plate-type wedge-type cross-rolling die and forming method for ball parts with no idle stroke. The die is provided with two mold cavities arranged symmetrically in opposite directions in parallel, and the die is installed on a plate-type wedge-type cross-rolling mill, and a metal round bar material is fed into the wedge-type cross-rolling mill. The two plate-type dies with oppositely symmetrical cavities on their surfaces move linearly in opposite directions, and the metal blank is rotated and formed under the action of the mold cavities, achieving continuous radial compression and axial extension deformation to obtain the desired ball parts. The plate-type die forms a group of ball parts by one-way motion, discharges the material, and feeds the material again. The two dies make reverse retreat movements in opposite directions, and the metal blank is formed again under the action of the mold cavity to obtain a group of ball parts. The present invention realizes the plate-type wedge-type cross-rolling forming of ball parts without idle stroke, significantly improves production efficiency, greatly reduces costs, and has fewer processes. It can be used for mass production of ball parts and has broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of metal plastic forming technology, in particular to a bidirectional plate-type wedge cross-rolling die with no idle stroke for ball parts and a forming method. Background Art

[0002] Ball parts are important and indispensable products for applications in mining, building materials, coal and other industrial sectors, as well as bearing manufacturing. The current production methods are mainly concentrated on casting, forging, cold heading, and the oblique rolling that has emerged in recent years. Traditional casting, forging, cold heading and other processes have low production efficiency, poor working environment, and high requirements for equipment. Although the oblique rolling forming of ball parts has the advantage of high production efficiency, the formed ball parts have poor dimensional accuracy, serious surface defects, and low mechanical properties, and cannot be used in bearing manufacturing and other production and manufacturing processes that require high mechanical properties. Therefore, it is urgent to develop new ball parts forming methods to meet the needs of large-scale, high-efficiency production, good mechanical performance, high dimensional accuracy, and metal ball parts that can be used for bearing manufacturing.

[0003] As an efficient metal plastic forming process, wedge cross rolling is recognized as an important part of today's advanced manufacturing technology. Plate wedge cross rolling has low forming technology difficulty, and the rolling mill equipment is simple and easy to manufacture. Since it uses a flat mold, only a general planer or milling machine is needed to complete the mold processing, and the mold manufacturing cost is greatly reduced. It has been highly praised in recent years. However, due to the problem of retracting empty stroke during reciprocating motion, the production efficiency of traditional plate wedge cross rolling is lower than that of roller and arc wedge cross rolling, generally 4 to 10 (pairs) per minute, which affects its large-scale promotion and use. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a bidirectional, non-idle plate-type wedge cross-rolling die and a forming method for ball parts. The die can form two groups of ball parts in one reciprocating motion, and the production efficiency is greatly improved.

[0005] The present invention adopts the following technical solution:

[0006] On the one hand, the present invention provides a two-way plate-type wedge cross-rolling die for ball parts without idle stroke, comprising an upper die and a lower die;

[0007] The upper mold and the lower mold are both integral plate structures; the lower bottom surface of the upper mold is provided with a first half forming area and a second half forming area, and the upper surface of the lower mold is correspondingly provided with a third half forming area and a fourth half forming area; the first half forming area and the third half forming area form a forward stage forming area, and the second half forming area and the fourth half forming area form a backward stage forming area;

[0008] The forward stage forming area is used to wedge-roll the metal round bar material in the forward stage of the mold to obtain a batch of multiple ball parts, and the retreat stage forming area is used to wedge-roll the metal round bar material in the retreat stage of the mold to obtain another batch of multiple ball parts.

[0009] According to any possible implementation manner described above, there is further provided an implementation manner, wherein the first semi-forming area, the second semi-forming area, the third semi-forming area and the fourth semi-forming area each include semi-forming cavities of multiple passes arranged side by side, and adjacent semi-forming cavities are separated from each other by convex ridges; and the length of the semi-forming cavities decreases from the middle pass to the passes on both sides;

[0010] The multiple-pass semi-forming cavities arranged in the first semi-forming zone and the multiple-pass semi-forming cavities correspondingly arranged in the third semi-forming zone form a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material in one step to obtain multiple ball parts during the die forward stage;

[0011] The multiple-pass semi-forming cavities arranged in the second semi-forming zone and the multiple-pass semi-forming cavities correspondingly arranged in the fourth semi-forming zone constitute a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material at one time during the mold retraction stage to obtain multiple spherical parts.

[0012] Any possible implementation as described above further provides an implementation, wherein the first half forming zone and the second half forming zone are arranged side by side and are inversely symmetrical; the third half forming zone and the fourth half forming zone are arranged side by side and are inversely symmetrical.

[0013] As described above, any possible implementation method further provides an implementation method, in which, during the forming process, the first half-forming zone and the third half-forming zone are always symmetrical about the metal round bar stock; the second half-forming zone and the fourth half-forming zone are always symmetrical about the metal round bar stock.

[0014] According to any possible implementation described above, there is further provided an implementation, wherein the first semi-forming zone, the second semi-forming zone, the third semi-forming zone and the fourth semi-forming zone all include a wedging section, a forming section and a finishing section which are arranged in sequence;

[0015] The wedging section is used for the mold wedge tip to wedge into the metal round bar material, the ridge of the forming section gradually rises to a set height, the ridge of the finishing section is maintained at the set height, the rear section of the finishing section is provided with a cutting section, and the cutting section is provided with a cutting ridge for cutting off the connecting necks between adjacent ball parts.

[0016] As described above in any possible implementation, there is further provided an implementation, wherein the convex edge is rounded at the top, and the wedge tip of the wedging section is trapezoidal or triangular.

[0017] The wedge tip can usually be triangular, and a more optimized form is trapezoidal. The reason for using a trapezoidal wedge tip: The wedge tip in the prior art is usually triangular, and is mainly used to form shaft parts. The inventor found in actual tests and simulations that when using the wedge cross-rolling technology to form ball parts, using a trapezoidal wedge tip has higher efficiency and better technical effects.

[0018] According to any possible implementation described above, a further implementation is provided, in the finishing stage, a gap is left between the ridges of the upper mold and the lower mold, and a connecting neck is formed during the forming process. The size of the connecting neck has a certain proportional relationship with the diameter of the formed ball. For example, a ball with a larger formed diameter has a larger corresponding connecting neck, and vice versa. The diameter of the connecting neck (i.e., the gap between the ridges of the upper and lower molds) is defined as follows:

[0019] 25%*D <d<35%*D;

[0020] Wherein, d is the diameter of the connecting neck, and D is the diameter of the ball part formed corresponding to the corresponding cavity.

[0021] If the diameter of the connecting neck is too small, it is easy to be cut off prematurely, resulting in the connecting neck being broken before the finishing stage is fully effective; if the diameter of the connecting neck is too large, it is difficult to cut, and after rolling it will appear in the shape of a candied haws and cannot be completely cut off; both cannot meet the actual process requirements, so the above parameters need to be limited.

[0022] Any possible implementation as described above further provides an implementation in which a rounded corner is provided on the upper portion of the wedge tip of the wedging section, which can reduce stress concentration during the rolling process and increase the life of the mold.

[0023] Any possible implementation described above further provides an implementation, wherein the length range of the cut ridge is:

[0024] L / 4 <l<L / 2;

[0025] Where l is the length of the cut ridge and L is the total length of the finishing section.

[0026] Any possible implementation as described above further provides an implementation, wherein the upper mold and the lower mold are both arranged horizontally; or the upper mold and the lower mold are both arranged vertically.

[0027] On the other hand, the present invention also provides a method for forming a ball part by bidirectional plate-type wedge cross-rolling without idle stroke, using the above-mentioned ball part bidirectional plate-type wedge cross-rolling die without idle stroke, the forming method comprising:

[0028] S1, die forwarding stage: the first metal round bar is fed into the wedge starting position between the first half forming area of ​​the upper die and the third half forming area of ​​the lower die in advance, and the upper die and the lower die move forward in opposite directions at a constant speed. The first metal round bar is radially compressed and axially extended under the action of the die wedging section, the forming section and the finishing section to form a plurality of ball parts of set sizes. After forming, the ball parts are separated from the die for recovery;

[0029] S2, mold retraction stage: the second metal round bar material is pre-fed into the wedging position between the second half forming area of ​​the upper mold and the fourth half forming area of ​​the lower mold, and the upper mold and the lower mold retract linearly at the same speed and in opposite directions. The second metal round bar material is radially compressed and axially extended under the action of the mold wedging section, forming section and finishing section to form a plurality of ball parts of set sizes. After forming, the ball parts are separated from the mold for recovery.

[0030] As described above in any possible implementation manner, there is further provided an implementation manner in which the first metal bar and the second metal bar are of the same size.

[0031] Any possible implementation method as described above further provides an implementation method, in which the axial symmetry plane of the first metal round bar material coincides with the central symmetry plane of the plate type wedge cross rolling die in the forward stage; the axial symmetry plane of the second metal round bar material coincides with the central symmetry plane of the plate type wedge cross rolling die in the retracting stage.

[0032] According to any possible implementation described above, a further implementation is provided, in step S1 and step S2, the metal round bar material is processed in the die wedging section, the forming section and the finishing section as follows:

[0033] The wedging section of the mold wedges into the middle of the metal round bar material; as the ridge of the mold forming section rises, the metal round bar material is gradually formed into a plurality of metal balls with connecting necks by the complete forming cavity; the metal balls with connecting necks are refined into spherical contours in the mold finishing section; at the end of the mold finishing section, the connecting necks between adjacent metal balls are cut off by the cutting ridges and separated into a plurality of complete ball parts.

[0034] As any possible implementation described above, a further implementation is provided, wherein the forming method is used for hot forming, warm forming, and cold forming processes, and the rolling diameter range of the ball parts is φ3-φ100.

[0035] The beneficial effects of the present invention are as follows: the present invention innovates the mold design and adopts a multi-hole plate-type wedge cross-rolling mold with a forming cavity arranged symmetrically in reverse, thereby ensuring that there is no empty stroke during the reciprocating motion of the plate-type wedge cross-rolling forming process, and two groups of ball parts can be formed in one reciprocating motion; it has the advantages of significantly improving production efficiency, being easy to implement, and having low manufacturing cost, and can be used for mass production of plate-type wedge cross-rolling forming of ball parts, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Shown is a schematic structural diagram of a bidirectional, zero-idle-stroke plate-type wedge cross-rolling die for ball parts according to an embodiment of the present invention.

[0037] Figure 2 Shown is a side view of the upper mold and the lower mold in the embodiment.

[0038] Figure 3 Shown is a schematic diagram of a semi-forming cavity of a mold in an embodiment.

[0039] Figure 4 Shown is a schematic diagram of the end surface of the lower mold in the embodiment.

[0040] Figure 5 The diagram shown is a schematic diagram of an embodiment in which the wedge tip of the wedging section is a triangle.

[0041] Figure 6 The diagram shown is a schematic diagram of an embodiment in which the wedge tip of the wedging section is trapezoidal.

[0042] Figure 7 Shown is a schematic diagram of multiple ball parts with connecting necks in an embodiment.

[0043] In the figure: 1-upper mold; 2-metal round bar material; 3-lower mold; 4-first half forming area; 5-second half forming area; 6-third half forming area; 7-fourth half forming area. DETAILED DESCRIPTION

[0044] The specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects. In the drawings of the following embodiments, the same reference numerals appearing in each drawing represent the same features or components, which can be applied to different embodiments.

[0045] like Figure 1 , Figure 2As shown, an embodiment of the present invention is a bidirectional, non-idle-stroke plate-type wedge-type cross-rolling die for ball parts, comprising an upper die 1 and a lower die 3; both the upper die 1 and the lower die 3 are integral plate structures; the lower bottom surface of the upper die 1 is provided with a first semi-forming area 4 and a second semi-forming area 5, and the upper surface of the lower die 3 is correspondingly provided with a third semi-forming area 6 and a fourth semi-forming area 7; the first semi-forming area 4 and the third semi-forming area 6 form a forward stage forming area, and the second semi-forming area 5 and the fourth semi-forming area 7 form a retreat stage forming area; the forward stage forming area is used for wedge-rolling the metal round bar material 2 in the forward stage of the die to obtain a batch of multiple ball parts, and the retreat stage forming area is used for wedge-rolling the metal round bar material 2 in the retreat stage of the die to obtain another batch of multiple ball parts.

[0046] In a specific embodiment, Figure 1 , Figure 3 As shown, the first semi-forming zone 4, the second semi-forming zone 5, the third semi-forming zone 6 and the fourth semi-forming zone 7 all include multiple semi-forming cavities arranged side by side, and the adjacent semi-forming cavities are separated from each other by convex ridges; the length of the semi-forming cavities decreases from the middle pass to the two side passes; the semi-forming cavities of multiple passes arranged in the first semi-forming zone 4, together with the semi-forming cavities of multiple passes correspondingly arranged in the third semi-forming zone 6, form a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material 2 at one time during the mold forward stage to obtain multiple ball parts; the semi-forming cavities of multiple passes arranged in the second semi-forming zone 5, together with the semi-forming cavities of multiple passes correspondingly arranged in the fourth semi-forming zone 7, form a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material 2 at one time during the mold retracting stage to obtain multiple ball parts.

[0047] In a specific embodiment, the first half forming zone 4 and the second half forming zone 5 are arranged side by side and inversely symmetrical; the third half forming zone 6 and the fourth half forming zone 7 are arranged side by side and inversely symmetrical.

[0048] In another specific embodiment, the first semi-forming zone 4 and the second semi-forming zone 5 are arranged side by side, but do not need to be inversely symmetrical; the number of passes of the semi-forming chambers of the first semi-forming zone 4 and the second semi-forming zone 5 can be different, resulting in different numbers of ball parts formed in the mold forward stage and the mold retracting stage.

[0049] In a specific embodiment, during the forming process, the first half forming zone 4 and the third half forming zone 6 are always symmetrical about the metal round bar material 2; the second half forming zone 5 and the fourth half forming zone 7 are always symmetrical about the metal round bar material 2.

[0050] In a specific embodiment, the first semi-forming zone 4, the second semi-forming zone 5, the third semi-forming zone 6, and the fourth semi-forming zone 7 each include a wedging section, a forming section, and a finishing section; the wedging section is used for the die wedge tip to wedge into the metal round bar 2, the convex rib of the forming section gradually rises to a set height, the convex rib of the finishing section remains at the set height, a cutting section is provided at the rear section of the finishing section, and a cutting convex rib is provided on the cutting section for cutting the connecting neck between adjacent spherical parts.

[0051] In a specific embodiment, the convex rib is rounded at the top, and the wedge tip of the wedging section is trapezoidal or triangular; the triangular wedge tip is shown in Figure 5 , and the trapezoidal wedge tip is shown in Figure 6 . The trapezoidal wedge tip can make the spherical parts have higher quality after wedging and cutting the connecting neck.

[0052] In a specific embodiment, the relationship between the diameter of the connecting neck (i.e., the gap between the upper and lower die convex ribs) is as follows: 25%*D < d < 35%*D; where d is the diameter of the connecting neck and D is the diameter of the formed spherical part corresponding to the corresponding cavity.

[0053] In a specific embodiment, a fillet is provided at the upper part of the wedge tip of the wedging section, which can reduce the stress concentration during the rolling process and increase the die life.

[0054] In a specific embodiment, the length range of the cutting convex rib is: L / 4 < l < L / 2; where l is the length of the cutting convex rib and L is the total length of the finishing section.

[0055] In a specific embodiment, the upper die 1 and the lower die 3 are both horizontally arranged; or the upper die 1 and the lower die 3 are both vertically arranged, and the object of the present invention can be achieved.

[0056] An embodiment of the present invention provides a two-way non-idle-stroke plate-type cross wedge rolling forming method for spherical parts, which uses the above-mentioned two-way non-idle-stroke plate-type cross wedge rolling die for spherical parts. The forming method includes:

[0057] S1. Die forward movement stage: The first metal round bar 2 is pre-fed into the wedging position between the first semi-forming zone 4 of the upper die 1 and the third semi-forming zone 6 of the lower die 3. The upper die 1 and the lower die 3 move forward in a straight line at the same speed and in opposite directions. Under the action of the die wedging section, forming section, and finishing section, the first metal round bar 2 is radially compressed and axially extended to form a plurality of spherical parts with set dimensions. After forming, the spherical parts are separated from the die and recycled;

[0058] S2, die retraction stage: the second metal round bar material 2 is pre-sent to the wedging position between the second half forming area 5 of the upper die 1 and the fourth half forming area 7 of the lower die 3. The upper die 1 and the lower die 3 retract linearly at the same speed in opposite directions. The second metal round bar material 2 is radially compressed and axially extended under the action of the die wedging section, forming section and finishing section to form a plurality of ball parts of set size. After forming, the ball parts are separated from the die for recovery. The die end structure is as follows: Figure 4 shown.

[0059] In a specific embodiment, the first metal bar 2 and the second metal bar 2 have the same size.

[0060] In a specific embodiment, the axial symmetry plane of the first metal round bar material 2 coincides with the central symmetry plane of the plate type wedge cross rolling die in the forward stage; the axial symmetry plane of the second metal round bar material 2 coincides with the central symmetry plane of the plate type wedge cross rolling die in the retracting stage.

[0061] In a specific embodiment, in step S1 and step S2, the processing process of the metal round bar material 2 in the die wedging section, the forming section and the finishing section is as follows:

[0062] The die wedging section wedges into the middle of the metal round bar 2; as the ridge of the die forming section rises, the metal round bar 2 is gradually formed into a plurality of metal balls with connecting necks by the complete forming cavity, such as Figure 7 As shown; the metal ball with a connecting neck is refined into a spherical contour in the mold finishing section; at the end of the mold finishing section, the connecting necks between adjacent metal balls are cut off by cutting ridges and separated into multiple complete ball parts.

[0063] The forming method of the invention can be used for hot forming, warm forming and cold forming processes, and the rolling diameter range of the ball parts is φ3-φ100.

[0064] The present invention has innovative mold design, and adopts two parallel and counter-symmetrically arranged forming cavity plate-type wedge cross-rolling molds, which greatly reduces the mold manufacturing cost. At the same time, it ensures that the two forming cavities act alternately during the reciprocating motion of the plate-type wedge cross-rolling to ensure that there is no empty stroke. Two groups of ball parts can be formed in one reciprocating motion, which doubles the production efficiency and greatly reduces the production cost.

[0065] Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments of the present invention may be modified without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as a limitation on the scope of the present invention.

Claims

1. A two-way plate-type wedge cross-rolling die for ball parts without idle stroke, characterized in that: The mold comprises an upper mold and a lower mold; The upper mold and the lower mold are both integral plate structures; the lower bottom surface of the upper mold is provided with a first half forming area and a second half forming area, and the upper surface of the lower mold is correspondingly provided with a third half forming area and a fourth half forming area; the first half forming area and the third half forming area form a forward stage forming area, and the second half forming area and the fourth half forming area form a backward stage forming area; The forward stage forming area is used to wedge-roll the metal round bar material in the forward stage of the die to obtain a batch of multiple ball parts, and the retracting stage forming area is used to wedge-roll the metal round bar material in the retracting stage of the die to obtain another batch of multiple ball parts; The first semi-forming area, the second semi-forming area, the third semi-forming area and the fourth semi-forming area all include a plurality of semi-forming cavities arranged side by side, and the adjacent semi-forming cavities are separated from each other by convex ridges; the length of the semi-forming cavities decreases from the middle pass to the passes on both sides; The multiple-pass semi-forming cavities arranged in the first semi-forming zone and the multiple-pass semi-forming cavities correspondingly arranged in the third semi-forming zone form a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material in one step to obtain multiple ball parts during the die forward stage; The multiple-pass semi-forming cavities arranged in the second semi-forming zone and the multiple-pass semi-forming cavities correspondingly arranged in the fourth semi-forming zone form a complete multi-pass forming cavity, which is used to wedge-roll the metal round bar material in one step to obtain multiple ball parts during the mold retraction stage; The first half forming area and the second half forming area are arranged side by side and inversely symmetrical; the third half forming area and the fourth half forming area are arranged side by side and inversely symmetrical; The first half forming area, the second half forming area, the third half forming area and the fourth half forming area all include a wedging section, a forming section and a finishing section which are arranged in sequence; The wedging section is used for the tip of the die wedge to wedge into the metal round bar material, the ridge of the forming section gradually rises to a set height, the ridge of the finishing section is maintained at the set height, the rear section of the finishing section is provided with a cutting section, and the cutting section is provided with a cutting ridge for cutting off the connection necks between adjacent ball parts; The convex edge is rounded at the top, and the wedge tip of the wedging section is trapezoidal or triangular.

2. The two-way plate-type wedge-type cross-rolling die for ball parts according to claim 1, characterized in that: The length range of the cutting ridge is: L / 4 <l<L / 2; Where l is the length of the cut ridge and L is the total length of the finishing section.

3. The two-way plate-type wedge-type cross-rolling die for ball parts according to claim 1, characterized in that: The upper mold and the lower mold are both arranged horizontally; or the upper mold and the lower mold are both arranged vertically.

4. A bidirectional plate-type wedge cross-rolling forming method for ball parts without idle stroke, characterized in that: The forming method uses the bidirectional plate-type wedge cross-rolling die for ball parts without idle stroke as described in any one of claims 1 to 3, and the forming method comprises: S1, die forwarding stage: the first metal round bar is fed into the wedge starting position between the first half forming area of ​​the upper die and the third half forming area of ​​the lower die in advance, and the upper die and the lower die move forward in opposite directions at a constant speed. The first metal round bar is radially compressed and axially extended under the action of the die wedging section, the forming section and the finishing section to form a plurality of ball parts of set sizes. After forming, the ball parts are separated from the die for recovery; S2, mold retraction stage: the second metal round bar material is pre-fed into the wedging position between the second half forming area of ​​the upper mold and the fourth half forming area of ​​the lower mold, and the upper mold and the lower mold retract linearly at the same speed and in opposite directions. The second metal round bar material is radially compressed and axially extended under the action of the mold wedging section, forming section and finishing section to form a plurality of ball parts of set sizes. After forming, the ball parts are separated from the mold for recovery.

5. The method for forming ball parts by bidirectional plate-type wedge cross-rolling without idle stroke as claimed in claim 4, characterized in that: In step S1 and step S2, the processing process of the metal round bar material in the die wedging section, forming section and finishing section is as follows: The wedging section of the mold wedges into the middle of the metal round bar material; as the ridge of the mold forming section rises, the metal round bar material is gradually formed into a plurality of metal balls with connecting necks by the complete forming cavity; the metal balls with connecting necks are refined into spherical contours in the mold finishing section; at the end of the mold finishing section, the connecting necks between adjacent metal balls are cut off by the cutting ridges and separated into a plurality of complete ball parts.

6. The method for forming ball parts by bidirectional plate-type wedge cross-rolling without idle stroke as claimed in claim 4, characterized in that: The forming method is used for hot forming, warm forming and cold forming processes, and the rolling diameter range of the ball parts is φ3-φ100mm.

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