A cold extrusion precision forming die for a universal joint sleeve

Abstract

The present invention relates to a cold extrusion precision forming die for a universal joint shaft sleeve, which is composed of an upper die assembly, a first ejector rod, a concave die assembly, an upper cap, a lower die assembly, a punch, a blank positioning plate, and an elastic assembly. The concave die assembly is located in the upper die assembly, the top of the concave die assembly is concavely provided with a third center hole, and the bottom is concavely provided with a fourth center hole connected to each other, the first ejector rod has a guide part movably arranged in the third center hole, and a crimping part moving in the fourth center hole; the bottom of the punch is fixed to the lower die assembly, one end of the elastic assembly is fixed to the blank positioning plate, and the other end is fixed to the lower die assembly, the blank positioning plate is provided with an accommodating hole, the top of the punch is located in the accommodating hole, and is surrounded with the accommodating hole to form an accommodating groove; when the upper die assembly is moved downward, the upper cap contacts the blank positioning plate and continues to move downward, the top of the punch extends into the fourth center hole, and squeezes the blank with the crimping part. In this way, the potential quality problem caused by the small iron piece easily falling into the die to participate in the forming is solved.

Description

Technical Field

[0001] The invention relates to the technical field of extrusion molding dies, and in particular to a cold extrusion precision molding die for a universal joint shaft sleeve. Background Art

[0002] The cross shaft is a joint component of the universal transmission device in the automobile drive system. Its function is to achieve variable-angle power transmission and is used in positions where the direction of the transmission axis needs to be changed. The existing cross shafts are composed of a center body and journals radially distributed around the center body. The cross shaft assembly is formed by installing bearings on the journals. Among them, the cross shaft and the inner bottom of the sleeve are flat and tight, so the processing quality of the sleeve will directly affect the operating efficiency of the cross shaft assembly.

[0003] In the existing technical scheme, the processing of the sleeve adopts two processing methods. First, the die is at the bottom, the sleeve is inside the die, and the opening is upward (reverse extrusion). During the forming process, the punch presses from top to bottom, and the equipment needs to have a lower ejection device; second, the die is at the top, the sleeve is inside the die, and the opening is upward (reverse extrusion). During the forming process, the punch and the die press from top to bottom together, and the material is removed with a punching sheet. In the above processing method, there is a possibility that foreign objects such as small iron sheets will fall during the production process and fall into the die, participating in the forming process, resulting in poor surface quality of the product being scrapped. Because it is an automated operation, it is impossible to identify abnormal parts, and 100% manual sorting and sorting is required, resulting in a large workload; at the same time, the contact area between the ejection sheet and the product is small, which is easy to damage the sleeve; furthermore, the outer bottom fillet of the sleeve cannot be squeezed out, and an additional lathe process is required, resulting in an increase in processing costs. Summary of the invention

[0004] In order to solve the potential quality problem caused by small iron pieces easily falling into the mold and participating in the molding in the existing molding method, the present invention provides a cold extrusion precision molding mold for a universal joint sleeve.

[0005] In a first aspect, the present invention provides a cold extrusion precision forming die for a universal joint sleeve, comprising:

[0006] An upper mold, the upper mold is composed of an upper mold assembly, a push rod assembly, a die assembly and an upper cap, the bottom of the upper mold assembly is inwardly concavely provided with a first center hole, the upper cap is sleeved on the bottom of the upper mold assembly, so that the die assembly is fixed in the first center hole, the middle of the upper cap is penetrated with a second center hole, and the bottom part of the die assembly is convexly provided in the second center hole, the top of the die assembly is inwardly concavely provided with a third center hole, the bottom of the die assembly is inwardly concavely provided with a fourth center hole connected with the third center hole, and the inner diameter of the third center hole is greater than the inner diameter of the fourth center hole, the push rod assembly has a first push rod, the first push rod has a guide part and a crimping part located at the bottom of the guide part, the guide part is movably provided in the third center hole, and drives the crimping part to move in the fourth center hole;

[0007] The lower mold is located below the upper mold, and the lower mold is composed of a lower mold assembly, a punch, a blank positioning plate, an elastic assembly and a lower cap. The top of the lower mold assembly is recessed with a fifth center hole, and the lower cap is sleeved on the top of the lower mold assembly so that the bottom of the punch is fixed in the fifth center hole. The middle of the lower cap is penetrated with a sixth center hole, and the top of the punch passes through the sixth center hole and is arranged in alignment with the fourth center hole. One end of the elastic assembly is fixed to the blank positioning plate, and the other end of the elastic assembly is fixed to the lower mold assembly. The middle of the blank positioning plate is penetrated with a receiving hole in the up-and-down direction, and the top of the punch is located in the receiving hole. The top of the punch and the receiving hole are surrounded by a receiving groove to place the blank.

[0008] The upper mold assembly plate is also fixed with a guide column, the other end of which is arranged toward the lower mold, and the lower mold assembly is fixed with a guide sleeve, and the guide column extends into the guide sleeve to form a clearance fit;

[0009] When the upper die assembly is moved downward, the bottom of the upper cap contacts the blank positioning plate and continues to move downward, the top of the punch extends into the fourth center hole, and squeezes the blank in the fourth center hole together with the crimping portion of the first push rod.

[0010] In some embodiments, the guide portion of the first push rod reciprocates between the first position and the second position in the third center hole, driving the crimping portion of the first push rod to reciprocate between the third position and the fourth position in the fourth center hole, wherein the first position is located above the second position;

[0011] The fourth center hole is formed with a first step portion at a third position, the step surface of the first step portion is arranged toward the side where the punch is located, the fourth center hole is located above the first step portion and is a first guide hole, and the fourth center hole is located below the first step portion and is an operating hole;

[0012] The connection between the step surface of the first step portion and the inner wall surface of the working hole is an arc surface.

[0013] In some embodiments, the punch has a fixing portion at the bottom, an extending portion at the middle, and a working portion at the top, and the diameter of the extending portion is larger than the diameter of the working portion;

[0014] When the top of the punch drives the blank to force the crimping portion of the first push rod to move to the third position, the outer surface of the working portion of the punch, the bottom surface of the crimping portion of the first push rod, the step surface of the first step portion, the inner wall surface of the working hole, and the top surface of the extending portion of the punch together form an extrusion working space;

[0015] There is a first gap between the extending portion of the punch and the working hole, and the first gap is 0.01 mm to 0.03 mm.

[0016] In some embodiments, there is a second gap between the crimping portion of the first push rod and the first guide hole, and the second gap is 0.02 mm~0.05 mm.

[0017] In some embodiments, the roughness value of the outer surface of the working portion of the punch is smaller than the roughness value of the inner wall surface of the working hole.

[0018] In some embodiments, the die assembly comprises a push rod sleeve and a die piece, the push rod sleeve is formed with the third center hole in the middle part, the die piece is formed with the fourth center hole in the middle part, the die piece is formed with a second step portion at the bottom, the die piece is abutted against the upper cap through the second step surface of the second step portion, so that part of the die piece protrudes in the second center hole, thereby realizing that the opposite end surfaces of the push rod sleeve are respectively abutted against the bottom of the first center hole and the top of the die piece.

[0019] In some embodiments, it further comprises a device fixing block, wherein the device fixing block is located above the upper mold;

[0020] The upper mold assembly comprises an upper mold plate and an upper mold base, the upper mold plate is fixedly connected to the upper mold base, the bottom of the upper mold base is recessed with the first center hole, the upper cap is sleeved on the bottom of the upper mold base, the middle of the upper mold plate and the upper mold base are penetrated by a second guide hole, the two second guide holes are connected in the vertical direction, the ejector assembly comprises a striker, one end of the striker abuts against the guide portion of the first ejector, the other end of the striker passes through the two second guide holes and is exposed outside the upper mold assembly, and the other end of the striker is located at the bottom of the equipment fixing block;

[0021] The guide column is fixed on the upper template.

[0022] In some embodiments, the lower mold assembly has a lower mold plate and a lower mold base, the lower mold plate is fixedly connected to the lower mold base, the top of the lower mold base is recessed with the fifth center hole, the lower cap is sleeved on the top of the lower mold base, the other end of the elastic component is fixed to the lower mold plate, and the guide sleeve is fixed on the lower mold plate.

[0023] In some embodiments, there are two elastic components, and the two elastic components are symmetrically arranged along the axial direction of the punch.

[0024] In some embodiments, there are two guide sleeves, and the two guide sleeves are symmetrically arranged along the axial direction of the punch.

[0025] In order to solve the problem that in the existing molding method, small iron pieces are easy to fall into the mold and participate in the molding, thus causing potential quality problems, the present invention has the following advantages:

[0026] Through the technical solution of the present invention, the blank can be extruded in the fourth center hole in the die assembly, thereby avoiding potential quality problems caused by small iron pieces falling into the die and participating in the molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic structural diagram of a cold extrusion precision forming die for a universal joint sleeve is shown;

[0028] Figure 2 Shows Figure 1 The schematic diagram of the structure of the universal joint sleeve cold extrusion precision forming die for extrusion molding shown in FIG;

[0029] Figure 3 Shows Figure 2 A partial enlarged schematic diagram of the dotted circle A shown in FIG.

[0030] Figure markings: 1-upper template; 2-upper die base; 3-upper cap; 4-blank; 5-blank positioning plate; 6-punch; 61-working part; 62-extension part; 7-lower die base; 8-spring; 9-bolt; 10-lower template; 11-guide column; 12-guide sleeve; 13-striker; 15-thrower sleeve; 16-first pusher; 161-guide part; 162-crimping part; 17-sleeve; 18-die part; 181-first guide hole; 182-working hole; 183-first step part; 19-equipment fixing block. DETAILED DESCRIPTION

[0031] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, rather than implying any limitation on the scope of the present disclosure.

[0032] As used herein, the term "including" and its variants are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "based at least in part on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like is based on the orientation or position relationship shown in the accompanying drawings. These terms are mainly for better describing the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or position relationship, some of the above terms may also be used to indicate other meanings, such as the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to the specific circumstances. In addition, the terms "install", "set", "provided with", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0033] This embodiment discloses a cold extrusion precision forming die for a universal joint sleeve, such as Figure 1 and Figure 2As shown, the cold extrusion precision forming mold of the universal joint shaft sleeve includes an upper mold, and the upper mold is composed of an upper mold assembly, a push rod assembly, a die assembly and an upper cap 3. The bottom of the upper mold assembly is inwardly concave with a first center hole, and the upper cap 3 is sleeved on the bottom of the upper mold assembly so that the die assembly is fixed in the first center hole. The middle of the upper cap 3 is penetrated with a second center hole, and the bottom part of the die assembly is convexly arranged in the second center hole. The top of the die assembly is inwardly concave with a third center hole, and the bottom of the die assembly is inwardly concave with a fourth center hole connected with the third center hole, and the inner diameter of the third center hole is greater than the inner diameter of the fourth center hole. The push rod assembly has a first push rod 16, and the first push rod 16 has a guide portion 161 and a crimping portion 162 located at the bottom of the guide portion 161. The guide portion 161 is movably arranged in the third center hole to drive the crimping portion 162 to move in the fourth center hole.

[0034] The lower mold is located below the upper mold, and the lower mold is composed of a lower mold assembly, a punch 6, a blank 4 positioning plate, an elastic assembly and a lower cap. The top of the lower mold assembly is recessed with a fifth center hole, and the lower cap is sleeved on the top of the lower mold assembly so that the bottom of the punch 6 is fixed in the fifth center hole. The middle of the lower cap is penetrated with a sixth center hole, and the top of the punch 6 passes through the sixth center hole and is arranged in alignment with the fourth center hole. One end of the elastic assembly is fixed to the blank 4 positioning plate, and the other end of the elastic assembly is fixed to the lower mold assembly. A receiving hole is penetrated in the middle of the blank 4 positioning plate along the up and down directions, and the top of the punch 6 is located in the receiving hole. The top of the punch 6 and the receiving hole are surrounded by a receiving groove, and the receiving groove is used to place the blank 4;

[0035] The upper mold assembly plate is also fixed with a guide post 11, the other end of which is arranged toward the lower mold, and a guide sleeve 12 is fixed on the lower mold assembly, and the guide post 11 extends into the guide sleeve 12 to form a clearance fit;

[0036] When the upper die assembly is moved downward, the bottom of the upper cap 3 contacts the blank 4 positioning plate and continues to move downward, and the top of the punch 6 extends into the fourth center hole and squeezes the blank 4 in the fourth center hole together with the crimping portion 162 of the first push rod 16.

[0037] In the present embodiment, a precision cold extrusion forming die for a universal joint sleeve is provided, in which the bottom of the punch 6 is placed in the fifth center hole recessed inwardly at the top of the lower die assembly, and the lower cap and the top of the lower die assembly are threadedly connected to realize that the lower cap is sleeved on the top of the lower die assembly, so as to fix the punch 6 at the top position of the lower die assembly, so that the top of the punch 6 passes through the sixth center hole of the lower cap and is aligned with the fourth center hole of the die assembly.

[0038] Furthermore, a receiving hole is provided in the middle of the positioning plate of the blank 4 in the up-down direction, the top of the punch 6 is located in the receiving hole, and a receiving groove is formed between the top of the punch 6 and the inner peripheral side wall of the receiving hole, and the receiving groove is used to place the blank 4. The opposite ends of the elastic component are respectively abutted and fixed to the positioning plate of the blank 4 and the lower die assembly, so that the positioning plate of the blank 4 can move in the vertical direction relative to the lower die assembly, so that the top of the punch 6 can push the blank 4 placed in the receiving groove out of the receiving hole.

[0039] Furthermore, the bottom of the upper die assembly is provided with a first center hole inwardly, the die assembly is placed in the first center hole, and the upper cap 3 is connected to the bottom of the upper die assembly by a threaded connection to realize that the upper cap 3 is sleeved on the bottom of the upper die assembly, thereby realizing that the bottom part of the die assembly is convexly provided in the second center hole of the upper cap 3, so that the fourth center hole inwardly provided at the bottom of the die assembly is directly opposite to the accommodating hole provided on the blank 4 positioning plate through the second center hole. Among them, the guide portion 161 of the first push rod 16 is movably provided in the third center hole, and the crimping portion 162 of the first push rod 16 is located in the fourth center hole, and the guide portion 161 of the first push rod 16 is in a clearance fit with the third center hole. When the guide portion 161 of the first push rod 16 moves in the third center hole, the crimping portion 162 is driven to move in the fourth center hole.

[0040] Furthermore, a guide post 11 is fixed on the upper die assembly, and the other end of the guide post 11 is arranged toward the lower die, and a guide sleeve 12 is fixed on the die assembly. The guide post 11 extends into the guide sleeve 12 to form a clearance fit, so that when the upper die assembly is moved downward, the bottom of the upper cap 3 sleeved on the bottom of the upper die assembly contacts the blank 4 positioning plate and continues to move downward, and the blank 4 positioning plate moves downward to crimp the elastic component, so that the top of the punch 6 moves relative to the blank 4 positioning plate, so that the top of the punch 6 extends into the fourth center hole, and the top of the punch 6 drives the blank 4 to force the crimping portion 162 of the first push rod 16 to move upward. When the guide portion 161 of the first push rod 16 moves to the bottom of the first center hole and contacts the upper die assembly, the crimping portion 162 of the first push rod 16 cannot continue to move upward, so that the crimping portion 162 of the first push rod 16 and the top of the punch 6 are forced to extrude the blank 4 in the fourth center hole to extrude into a sleeve 17.

[0041] Through the technical solution of the present invention, the blank 4 can be extruded in the fourth center hole in the die assembly. When the extrusion molding starts, the opposite ends of the blank 4 located in the fourth center hole are abutted by the crimping portion 162 of the first push rod 16 and the top of the punch 6, thereby avoiding the potential quality problem of small iron pieces falling into the mold and participating in the molding.

[0042] In some embodiments, Figure 3 As shown, the guide portion 161 of the first push rod 16 reciprocates between the first position and the second position in the third center hole, driving the crimping portion 162 of the first push rod 16 to reciprocate between the third position and the fourth position in the fourth center hole, wherein the first position is located above the second position;

[0043] The fourth center hole is formed with a first step portion 183 at the third position, the step surface of the first step portion 183 is arranged toward the side where the punch 6 is located, the fourth center hole located above the first step portion 183 is a first guide hole 181, and the fourth center hole located below the first step portion 183 is an operation hole 182;

[0044] The connection between the step surface of the first step portion 183 and the inner wall surface of the working hole 182 is an arc surface.

[0045] Furthermore, the punch 6 has a fixing portion at the bottom, an extending portion 62 at the middle, and a working portion 61 at the top, and the diameter of the extending portion 62 is larger than the diameter of the working portion 61;

[0046] When the top of the punch 6 drives the blank 4 to force the crimping portion 162 of the first push rod 16 to move to the third position, the outer surface of the working portion 61 of the punch 6, the bottom surface of the crimping portion 162 of the first push rod 16, the step surface of the first step portion 183, the inner wall surface of the working hole 182, and the top surface of the extending portion 62 of the punch 6 together form an extrusion working space;

[0047] There is a first gap between the extending portion 62 of the punch 6 and the working hole 182 , and the first gap is 0.01 mm to 0.03 mm.

[0048] In this embodiment, when the guide portion 161 of the first push rod 16 moves to the first position of the third center hole, the crimping portion 162 of the first push rod 16 cannot continue to move upward, and the crimping portion 162 of the first push rod 16 is located at the third position of the fourth center hole, so that the blank 4 is pushed into the extrusion working space formed by the outer surface of the working portion 61 of the punch 6, the bottom surface of the crimping portion 162 of the first push rod 16, the step surface of the first step portion 183, the inner wall surface of the working hole 182, and the top surface of the extension portion 62 of the punch 6, thereby forcing the crimping portion 162 of the first push rod 16 and the top of the punch 6 to extrude the blank 4 at the third position in the fourth center hole. Since the connection between the step surface of the first step portion 183 and the inner wall surface of the working hole 182 is set as an arc surface, the bottom of the sleeve 17 has an extruded fillet, thereby solving the problem of less cutting or no cutting of the outer bottom surface of the sleeve 17 forging design and production. In the present application, the connection between the step surface of the first step portion 183 and the inner wall surface of the working hole 182 can also be set as a curved surface, an angular surface, or other irregular surfaces, and can be designed according to the specific use requirements of the sleeve 17. The present application is not limited to this.

[0049] Furthermore, since there is a first gap between the extension portion 62 of the punch 6 and the working hole 182, the first gap is preferably between 0.01 mm and 0.03 mm, the working portion 61 of the punch 6 can be more accurately axially aligned with the fourth center hole of the die assembly, and it is convenient to ensure that the coaxiality of the inner and outer diameters of the sleeve 17 during molding meets the design requirements.

[0050] In some embodiments, a second gap is provided between the crimping portion 162 of the first push rod 16 and the first guide hole 181 , and the second gap is 0.02 mm to 0.05 mm.

[0051] In this embodiment, through the above-mentioned structural arrangement, when the blank 4 is extruded into the sleeve 17 in the extrusion working space, the design of the second gap can increase the friction between the sleeve 17 and the die assembly.

[0052] In some embodiments, the roughness value of the outer surface of the working portion 61 of the punch 6 is smaller than the roughness value of the inner wall surface of the working hole 182 .

[0053] In this embodiment, through the above-mentioned arrangement, the surface roughness requirement of the working part 61 of the punch 6 is relatively high, while the surface roughness requirement of the working hole 182 in the die assembly is relatively low, thereby achieving that the sleeve 17 can remain in the inner cavity of the die assembly, that is, in the working hole 182 of the fourth center hole when the mold is opened, instead of sticking to the working part 61 of the punch 6, so as to facilitate the subsequent removal of the sleeve 17.

[0054] In some embodiments, the die assembly comprises a push rod sleeve 15 and a die piece 18, the third center hole is formed in the middle of the push rod sleeve 15, the fourth center hole is formed in the middle of the die piece 18, a second step portion is formed at the bottom of the die piece 18, and the die piece 18 abuts against the upper cap 3 through the second step surface of the second step portion, so that part of the die piece 18 protrudes in the second center hole, so that the opposite end faces of the push rod sleeve 15 respectively abut against the bottom of the first center hole and the top of the die piece 18.

[0055] In this embodiment, through the above-mentioned arrangement, the ejector sleeve 15 and the die member 18 of the die assembly can be quickly opened, thereby reducing the manufacturing cost of the die assembly. It is also convenient for installing the die assembly and the first ejector 16 in the upper die assembly to improve the assembly efficiency of the cold extrusion precision forming die for the universal joint sleeve.

[0056] In some embodiments, it further comprises a device fixing block 19, wherein the device fixing block 19 is located above the upper mold;

[0057] The upper mold assembly comprises an upper mold plate 1 and an upper mold base 2, the upper mold plate 1 is fixedly connected to the upper mold base 2, the bottom of the upper mold base 2 is recessed with the first center hole, the upper cap 3 is sleeved on the bottom of the upper mold base 2, the middle of the upper mold plate 1 and the upper mold base 2 are penetrated with a second guide hole, the two second guide holes are connected in the vertical direction, the ejector assembly comprises a striker 13, one end of the striker 13 abuts against the guide portion 161 of the first ejector 16, the other end of the striker 13 passes through the two second guide holes and is exposed outside the upper mold assembly, and the other end of the striker 13 is located at the bottom of the equipment fixing block 19;

[0058] The guide pillar 11 is fixed on the upper template 1 .

[0059] Furthermore, the lower mold assembly has a lower mold plate 10 and a lower mold base 7, the lower mold plate 10 is fixedly connected to the lower mold base 7, the top of the lower mold base 7 is recessed with the fifth center hole, the lower cap is sleeved on the top of the lower mold base 7, the other end of the elastic component is fixed to the lower mold plate 10, and the guide sleeve 12 is fixed to the lower mold plate 10.

[0060] In this embodiment, the upper mold plate 1 and the upper mold base 2 can be fixed by means of screw locking connection, and the lower mold plate 10 and the lower mold base 7 can also be fixed by means of screw locking connection.

[0061] In the present application, when the blank 4 needs to be extruded, the upper template 1 can be moved downward, thereby driving the upper die base 2 to move downward, and the bottom of the upper cap 3 contacts the blank 4 positioning plate and continues to move downward, thereby forcing the blank 4 to enter the extrusion operation space. After the blank 4 is extruded into the sleeve 17, the upper template 1 can be moved upward, thereby driving the upper die base 2 to move upward, and the bottom of the upper cap 3 is separated from the blank 4 positioning plate and continues to move upward. Since an elastic component is provided between the blank 4 positioning plate and the lower template 10, when the blank 4 positioning plate moves downward, the elastic component is in a compressed state, and then when the bottom of the upper cap 3 is separated from the blank 4 positioning plate, the elastic component restores the elastic deformation and releases the pressure to push the blank 4 positioning plate to move upward, thereby causing the top of the punch 6 to move relative to the blank 4 positioning plate, so as to achieve the top of the punch 6 to separate from the fourth center hole and return to the receiving hole of the blank 4 positioning plate. Since the outer area of ​​the sleeve 17 is larger than the inner area during extrusion molding, and the first gap between the extension portion 62 of the punch 6 and the working hole 182 is preferably between 0.01 mm and 0.03 mm, and the roughness value of the outer surface of the working portion 61 of the punch 6 is smaller than the roughness value of the inner wall surface of the working hole 182, when the top of the punch 6 is separated from the fourth center hole, the extruded sleeve 17 is located in the working hole 182 of the fourth center hole.

[0062] Furthermore, since the bottom of the upper cap 3 detaches from the blank 4 positioning plate and continues to move upward, when the striker 13 hits the bottom of the equipment fixing block 19, one end of the striker 13 will push the guide portion 161 of the first push rod 16 to move downward, forcing the guide portion 161 of the first push rod 16 to move from the first position to the second position, thereby causing the crimping portion 162 of the first push rod 16 to move from the third position to the fourth position, so that the crimping portion 162 of the first push rod 16 can push the extruded sleeve 17 to detach from the fourth center hole.

[0063] Furthermore, the elastic component includes a bolt 9, a nut and a compression spring 8. The upper template 1 and the lower template 10 are both provided with mounting holes, the bolt 9 passes through the mounting hole of the lower template 10 and then sleeves the compression spring 8, and passes through the mounting hole of the upper template 1 and then sleeves the nut, thereby achieving that the opposite ends of the compression spring 8 are respectively abutted against the end surfaces of the upper template 1 and the lower template 10. In the present application, the elastic component can also be composed of an elastic ball or other implementable elastic components, and the present application is not limited thereto.

[0064] In some embodiments, there are two elastic components, and the two elastic components are symmetrically arranged along the axial direction of the punch 6.

[0065] Furthermore, there are two guide sleeves 12 , and the two guide sleeves 12 are symmetrically arranged along the axial direction of the punch 6 .

[0066] In this embodiment, through the above-mentioned arrangement, when the upper template 1 is moved downward, the bottom of the upper cap 3 contacts the blank 4 positioning plate and continues to press the blank 4 positioning plate downward, so that the forces on each part are the same when the blank 4 positioning plate moves downward and presses the elastic element, thereby improving the precise positioning of the fourth center hole of the upper mold and the receiving groove of the lower mold, further improving the accuracy of extrusion molding, and improving the processing efficiency of extrusion molding of the sleeve 17.

[0067] In summary, through the above-mentioned structural setting, the blank can be extruded and formed in the fourth center hole in the die assembly, thereby avoiding potential quality problems caused by small iron pieces falling into the die and participating in the forming.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0069] In addition, it should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that those skilled in the art can understand.

Claims

1. A cold extrusion precision forming die for a universal joint sleeve, characterized in that: include: An upper mold, the upper mold is composed of an upper mold assembly, a push rod assembly, a die assembly and an upper cap, the bottom of the upper mold assembly is inwardly concavely provided with a first center hole, the upper cap is sleeved on the bottom of the upper mold assembly, so that the die assembly is fixed in the first center hole, the middle of the upper cap is penetrated with a second center hole, and the bottom part of the die assembly is convexly provided in the second center hole, the top of the die assembly is inwardly concavely provided with a third center hole, the bottom of the die assembly is inwardly concavely provided with a fourth center hole connected with the third center hole, and the inner diameter of the third center hole is greater than the inner diameter of the fourth center hole, the push rod assembly has a first push rod, the first push rod has a guide part and a crimping part located at the bottom of the guide part, the guide part is movably provided in the third center hole, and drives the crimping part to move in the fourth center hole; The lower mold is located below the upper mold, and the lower mold is composed of a lower mold assembly, a punch, a blank positioning plate, an elastic assembly and a lower cap. The top of the lower mold assembly is recessed with a fifth center hole, and the lower cap is sleeved on the top of the lower mold assembly so that the bottom of the punch is fixed in the fifth center hole. The middle of the lower cap is penetrated with a sixth center hole, and the top of the punch passes through the sixth center hole and is arranged in alignment with the fourth center hole. One end of the elastic assembly is fixed to the blank positioning plate, and the other end of the elastic assembly is fixed to the lower mold assembly. The middle of the blank positioning plate is penetrated with a receiving hole in the up-and-down direction, and the top of the punch is located in the receiving hole. The top of the punch and the receiving hole are surrounded by a receiving groove to place the blank. The upper mold assembly plate is also fixed with a guide column, the other end of which is arranged toward the lower mold, and the lower mold assembly is fixed with a guide sleeve, and the guide column extends into the guide sleeve to form a clearance fit; When the upper die assembly is moved downward, the bottom of the upper cap contacts the blank positioning plate and continues to move downward, and the top of the punch extends into the fourth center hole and squeezes the blank in the fourth center hole with the crimping portion of the first ejector rod; The guide portion of the first push rod reciprocates between the first position and the second position in the third center hole, driving the crimping portion of the first push rod to reciprocate between the third position and the fourth position in the fourth center hole, wherein the first position is located above the second position; The fourth center hole is formed with a first step portion at a third position, the step surface of the first step portion is arranged toward the side where the punch is located, the fourth center hole is located above the first step portion and is a first guide hole, and the fourth center hole is located below the first step portion and is an operating hole; The connection between the step surface of the first step portion and the inner wall surface of the working hole is a curved surface; The punch has a fixing portion at the bottom, an extending portion at the middle, and a working portion at the top, wherein the diameter of the extending portion is larger than the diameter of the working portion; When the top of the punch drives the blank to force the crimping portion of the first push rod to move to the third position, the outer surface of the working portion of the punch, the bottom surface of the crimping portion of the first push rod, the step surface of the first step portion, the inner wall surface of the working hole, and the top surface of the extending portion of the punch together form an extrusion working space; There is a first gap between the extension portion of the punch and the working hole, and the first gap is 0.01 mm to 0.03 mm; A second gap is provided between the crimping portion of the first push rod and the first guide hole, and the second gap is 0.02 mm to 0.05 mm.

2. The cold extrusion precision forming die for the universal joint sleeve according to claim 1, characterized in that: The roughness value of the outer surface of the working portion of the punch is smaller than the roughness value of the inner wall surface of the working hole.

3. The cold extrusion precision forming die for the universal joint sleeve according to claim 1, characterized in that: The die assembly comprises a push rod sleeve and a die piece, the push rod sleeve is formed with the third center hole in the middle, the die piece is formed with the fourth center hole in the middle, the die piece is formed with a second step portion at the bottom, the die piece is abutted against the upper cap via the second step surface of the second step portion, so that part of the die piece protrudes in the second center hole, so that the opposite end surfaces of the push rod sleeve are respectively abutted against the bottom of the first center hole and the top of the die piece.

4. The cold extrusion precision forming die for a universal joint sleeve according to claim 1, characterized in that: Also included is a device fixing block, the device fixing block being located above the upper mold; The upper mold assembly comprises an upper mold plate and an upper mold base, the upper mold plate is fixedly connected to the upper mold base, the bottom of the upper mold base is recessed with the first center hole, the upper cap is sleeved on the bottom of the upper mold base, the middle of the upper mold plate and the upper mold base are penetrated by a second guide hole, the two second guide holes are connected in the vertical direction, the ejector assembly comprises a striker, one end of the striker abuts against the guide portion of the first ejector, the other end of the striker passes through the two second guide holes and is exposed outside the upper mold assembly, and the other end of the striker is located at the bottom of the equipment fixing block; The guide column is fixed on the upper template.

5. The cold extrusion precision forming die for the universal joint sleeve according to claim 4, characterized in that: The lower mold assembly comprises a lower mold plate and a lower mold base, the lower mold plate is fixedly connected to the lower mold base, the top of the lower mold base is recessed with the fifth center hole, the lower cap is sleeved on the top of the lower mold base, the other end of the elastic component is fixed to the lower mold plate, and the guide sleeve is fixed on the lower mold plate.

6. The cold extrusion precision forming die for the universal joint sleeve according to claim 5, characterized in that: There are two elastic components, and the two elastic components are symmetrically arranged along the axial direction of the punch.

7. The cold extrusion precision forming die for the universal joint sleeve according to claim 5, characterized in that: There are two guide sleeves, and the two guide sleeves are symmetrically arranged along the axial direction of the punch.

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