Rear drilling forming device for boat plate nut

Abstract

The utility model discloses a back drilling forming device of a boat plate nut, which relates to the field of cold heading processing of the boat plate nut and comprises a forming die for processing the boat plate nut, the forming die comprises a first die, a second die and a third die which are sequentially arranged, the first die upsets a blank into a first pre-upset part, and the second die upsets a second pre-upset part into a second pre-upset part; the edge of one end of the first pre-upsetting piece is upset into a first round corner, the second die upsets the first pre-upsetting piece into a second pre-upsetting piece, the first round corner is reduced and upset into a second round corner, the third die upsets the second pre-upsetting piece into a to-be-drilled piece, the second round corner is upset into a right angle, and a second conical groove used for positioning a threaded hole is upset at one end of the to-be-drilled piece. And a nut head is formed through repeated step-by-step cold heading, a conical hole is accurately positioned and upset in the plane center of the nut head, and a through hole is machined through subsequent drilling. And flow and deformation of materials can be accurately controlled, the deformation amount of the nut head and the nut rod is controlled, it is guaranteed that the nut head and the nut rod meet the forming precision requirement, and the situation that the surface size of a product does not meet the form and location tolerance is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of boat plate nut cold heading processing, in particular to a kind of rear drilling forming device of boat plate nut. BACKGROUND

[0002] Cold heading is a kind of forging method that uses die to upset (usually local upset) metal bar at room temperature. It is usually used to manufacture the head of screws, bolts, rivets, etc. It can reduce or replace cutting processing.

[0003] As shown in the boat plate nut in the Figure 11 The boat plate nut includes nut head and nut rod, the nut head is provided with rectangular plane and circular arc surface at both ends respectively, the nut rod is integrally formed at the center position of circular arc surface, the nut rod and circular arc surface are filleted, and the nut rod is a cylinder. The nut head is boat-shaped, and the end faces of the upper and lower ends of the nut head are quadrilateral plane and circular arc surface respectively. The center position of the rectangular plane is provided with a threaded hole coaxially arranged with the nut rod, and the threaded hole penetrates the nut head and the nut rod in sequence.

[0004] A threaded hole needs to be processed inside the nut rod of the boat plate nut. Since the diameter of the nut rod is small, the wall thickness of the nut rod after processing the threaded hole is only 0.75 mm. Since the diameter of the nut rod is small and a threaded hole needs to be processed, the boat plate nut has high requirements for the precision of the nut head and the threaded hole, and also has high requirements for the structural strength of the nut rod. When a complete through hole (a threaded hole without tapping) is directly cold headed by using a ejector rod or a punch rod, the thin wall of the nut rod may be deformed due to the impact force, which may result in high thread error, and even cause cracking and breaking of the nut rod wall.

[0005] Therefore, the purpose of the utility model is to provide a rear drilling forming device of boat plate nut to solve the problem of deformation control out of place that may occur during one-time cold heading, avoid cracking and breaking of the nut rod, and ensure that the dimensional accuracy of the nut head meets the requirements. UTILITY MODEL CONTENTS

[0006] To achieve the above purpose, the utility model adopts the following technical scheme: a rear drilling forming device of boat plate nut, comprising a forming die for processing boat plate nut, the boat plate nut includes nut head and nut rod, the nut head is provided with rectangular plane and circular arc surface at both ends respectively, the nut rod is integrally formed at the center position of circular arc surface, the nut rod is a cylinder, the center position of the rectangular plane is provided with a threaded hole coaxially arranged with the nut rod, the threaded hole penetrates the nut head and the nut rod in sequence, and the forming die includes one die, two die and three die arranged in sequence.

[0007] The first mold forms a first pre-upset head at one end of the blank, forms a first pre-upset rod at the other end of the blank, forms a first flat surface at the other end of the first pre-upset head away from the first pre-upset rod, and forms a first rounded corner at the edge of the first flat surface by strong bundle extrusion, thereby forming a first pre-upset part;

[0008] The second mold forms a second pre-upset rod by expanding the diameter of the first pre-upset rod, forms a second pre-upset head by upsetting the first pre-upset head, forms a second flat surface by expanding the first flat surface, forms a circular arc surface by upsetting the surface of the first pre-upset head away from the first flat surface, forms a second rounded corner by strong bundle extrusion of the first rounded corner, and forms a first conical groove coaxial with the second pre-upset rod at the center of the second flat surface, thereby forming a second pre-upset part.

[0009] The third mold forms a nut rod by expanding the diameter of the second pre-upset rod, forms a nut head by upsetting the second pre-upset head, forms a rectangular flat surface by expanding the second flat surface, forms a right angle by strong bundle extrusion of the second rounded corner, and forms a second conical groove by deepening the first conical groove, wherein the second conical groove is coaxially arranged with the nut rod, thereby forming a part to be drilled.

[0010] Preferably, the axial section of the nut head is a curved trapezoid, the radial section of the nut head is a quadrilateral composed of two straight lines and two circular arcs, and the straight lines and the circular arcs are sequentially connected end to end.

[0011] Preferably, 120°≤a≤150°, b=90°, wherein a is the angle of the vertex angle of the first conical groove, and b is the angle of the vertex angle of the second conical groove.

[0012] Preferably, the first mold includes a first main mold and a first punch mold, the first punch mold includes a first punch and a first punch rod, the first punch rod is arranged in the first punch, one end of the first punch is provided with a first punch groove for forming one end of the first pre-upset head, the first punch groove is a spherical cap-shaped groove, and the edge of the end face of the first punch rod close to the first main mold abuts against the inner wall of the first punch groove.

[0013] Preferably, the first main mold includes a first mold core and a first ejector rod, the first ejector rod is arranged in the first mold core, one end of the first mold core is provided with a first cavity, the first cavity includes a first groove for forming the other end of the first pre-upset head and a second groove for forming the first pre-upset rod, the first groove is a circular truncated cone, and the second groove is a circular cylinder.

[0014] Preferably, the second mold includes a second main mold and a second punch mold, the second punch mold includes a second punch and a second punch rod, the second punch rod is arranged in the second punch, one end of the second punch is provided with a second punch groove for forming one end of the second pre-upset head, the second flat surface and the second rounded corner are arranged inside the second punch groove, and the second punch rod is provided with a first upper cone for forming the first conical groove on the end face close to the second main mold.

[0015] Preferably, the second main mold comprises a second mold core and a second ejector rod, the second ejector rod is arranged in the second mold core, the second mold core is provided with a second cavity at one end for forming the second upset table and the second upset rod, an outer fillet is arranged between the arc surface and the cap rod, and a first inner fillet for forming the outer fillet is arranged on the inner wall of the second cavity.

[0016] Preferably, the three molds comprise a third main mold and a third punch, the third punch comprises a third punch head and a third punch rod, the third punch head is provided with a forming hole at one end, the forming hole is the same as the radial section of the cap head, the third punch rod is arranged in the forming hole at one end, and the end face of the third punch rod close to the third main mold divides the forming hole into a containing groove and a third punch groove, the third punch rod is arranged in the containing groove, and the end of the cap head away from the cap rod is formed in the third punch groove.

[0017] Preferably, the third main mold comprises a third mold core and a third ejector rod, the third ejector rod is arranged in the third mold core, and the third mold core is provided with a third cavity at one end for forming the arc surface and the cap rod.

[0018] The third punch rod comprises a sleeve and a punch rod, the punch rod is arranged in the sleeve, and the end face of the punch rod close to the third main mold is provided with a second upper cone for forming a second conical groove.

[0019] Preferably, the inner wall of the third cavity is provided with a second inner fillet for forming an outer fillet, the radius of the second inner fillet is equal to the radius of the outer fillet, and the radius of the first inner fillet is greater than the radius of the second inner fillet.

[0020] The beneficial effects of the utility model are as follows: the cap head is formed through multiple step cold upsetting, the conical hole is accurately positioned and upset in the planar center of the cap head, and the through hole is processed through subsequent drilling. The material flow and deformation can be accurately controlled, the deformation amount of the cap head and the cap rod can be controlled, the cap head and the cap rod meet the forming precision requirements, the situation that the product surface size does not meet the shape tolerance is avoided. The chamfering process of the thread hole can be performed at the same time as the conical hole is processed, and the process of chamfering the thread hole can be saved. BRIEF DESCRIPTION OF DRAWINGS

[0021] The drawings further illustrate the utility model, but the embodiments in the drawings do not constitute any limitation on the utility model.

[0022] Figure 1 The structure schematic view of the forming mold provided by one embodiment of the utility model is shown in the figure;

[0023] Figure 2 The forming schematic view of the boat plate cap provided by one embodiment of the utility model is shown in the figure;

[0024] Figure 3 The structural schematic view of a die provided by the utility model for an embodiment;

[0025] Figure 4 The structural schematic view of a die provided by the utility model for an embodiment;

[0026] Figure 5 The structural schematic view of a die provided by the utility model for an embodiment;

[0027] Figure 6 The Figure 3 enlarged view of the A area in the

[0028] Figure 7 The Figure 4 enlarged view of the B area in the

[0029] Figure 8 The Figure 5 enlarged view of the C area in the

[0030] Figure 9 The front view of the third main die provided by the utility model for an embodiment;

[0031] Figure 10 The front view of the third die provided by the utility model for an embodiment;

[0032] Figure 11 The structural schematic view of the boat plate nut provided by the utility model for an embodiment;

[0033] Figure 12 The partial enlarged view of the third die provided by the utility model for an embodiment.

[0034] Reference signs: 1: first pre-header; 11: first pre-header table; 12: first pre-header rod; 13: first plane; 14: first round corner; 2: second pre-header; 21: second pre-header table; 22: second pre-header rod; 23: second plane; 24: second round corner; 3: to-be-drilled part; 31: nut head; 32: nut rod; 33: rectangular plane; 34: right angle; 35: second conical groove; 36: circular arc surface; 41: first punch; 42: first punch rod; 43: first punch groove; 51: first die core; 52: first ejector rod; 53: first cavity; 61: second punch; 62: second punch rod; 63: second punch groove; 64: first upper cone; 71: second die core; 72: second ejector rod; 73: second cavity; 81: third punch; 82: third punch rod; 83: third punch groove; 84: second upper cone; 91: third die core; 92: third ejector rod; 93: third cavity. DETAILED DESCRIPTION

[0035] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0036] It should be noted that in the present application, when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element. The orientation words such as "upper, lower, left, right" generally refer to the up and down, left and right as shown in the drawings. "Inner, outer" refers to the inner and outer of the specific contour. "Far, near" refers to the far and near relative to a certain component. Figure 1

[0037] Figures 1-11 As shown in the figure, the present application provides a rear drilling forming device for a boat plate nut, which comprises a forming die for processing a boat plate nut. The boat plate nut comprises a nut head 31 and a nut rod 32. The two ends of the nut head 31 are respectively provided with a rectangular plane 33 and a circular arc surface 36. The nut rod 32 is integrally formed at the center position of the circular arc surface 36. The nut rod 32 is a cylinder. A threaded hole coaxial with the nut rod 32 is provided at the center position of the rectangular plane 33. The threaded hole penetrates the nut head 31 and the nut rod 32 in turn. The forming die comprises a first die, a second die and a third die arranged in turn.

[0038] The first die forms a first pre-upset table 11 by upsetting one end of the blank. The first die forms a first pre-upset rod 12 by reducing the diameter of the other end of the blank. The first die forms a first flat surface 13 by upsetting the end of the first pre-upset table 11 away from the first pre-upset rod 12. The first die forms a first fillet 14 by strongly extruding the edge position of the first flat surface 13. The first die forms a first pre-upset part 1.

[0039] The second die forms a second pre-upset rod 22 by expanding the diameter of the first pre-upset rod 12. The second die forms a second pre-upset table 21 by upsetting the first pre-upset table 11. The second die forms a second flat surface 23 by expanding the first flat surface 13. The second die forms a circular arc surface 36 by upsetting the surface of the first pre-upset table 11 away from the first flat surface 13. The second die forms a second fillet 24 by strongly extruding and reducing the first fillet 14. The second die forms a first conical groove coaxial with the second pre-upset rod 22 at the center position of the second flat surface 23. The second die forms a second pre-upset part 2.

[0040] The third die forms a nut rod 32 by expanding the diameter of the second pre-upset rod 22. The third die forms a nut head 31 by upsetting the second pre-upset table 21. The third die forms a rectangular plane 33 by expanding the second flat surface 23. The third die forms a right angle 34 by strongly extruding the second fillet 24. The third die forms a second conical groove 35 by deepening the first conical groove. The second conical groove 35 is coaxial with the nut rod 32. The third die forms a drilling part 3.​​

[0041] The axial section of the nut head 31 is trapezoidal, and the radial section of the nut head 31 is quadrilateral, which is composed of two straight lines and two circular arcs, and the straight lines and the circular arcs are connected in sequence.

[0042] 120°≤a≤150°, b=90°, wherein a is the angle of the first conical groove, and b is the angle of the second conical groove 35.

[0043] As shown in Figure 3 With Figure 6 As shown, the mold includes a first main mold and a first punch mold, the first punch mold includes a first punch 41 and a first punch rod 42, the first punch rod 42 is provided through the first punch 41, one end of the first punch 41 is provided with a first punch groove 43 for forming one end of the first pre-header 11, the first punch groove 43 is a spherical cap-shaped groove, and the edge of the end face of the first punch rod 42 close to the first main mold is in abutment with the inner wall of the first punch groove 43.

[0044] The first main mold includes a first mold core 51 and a first ejector pin 52, the first ejector pin 52 is provided through the first mold core 51, one end of the first mold core 51 is provided with a first cavity 53, the first cavity 53 includes a first groove for forming the other end of the first pre-header 11 and a second groove for forming the first pre-header 12, the first groove is a circular truncated cone, and the second groove is a circular cylinder.

[0045] As shown in Figure 4 With Figure 7 As shown, the second mold includes a second main mold and a second punch mold, the second punch mold includes a second punch 61 and a second punch rod 62, the second punch rod 62 is provided through the second punch 61, one end of the second punch 61 is provided with a second punch groove 63 for forming one end of the second pre-header 21, the second flat surface 23 and the second round corner 24 are both arranged inside the second punch groove 63, and the second punch rod 62 is provided with a first upper conical surface 64 for forming the first conical groove close to the end face of the second main mold.

[0046] The second main mold includes a second mold core 71 and a second ejector pin 72, the second ejector pin 72 is provided through the second mold core 71, one end of the second mold core 71 is provided with a second cavity 73 for forming the other end of the second pre-header 21 and the second pre-header 22, an outer round corner is arranged between the circular arc surface 36 and the nut rod 32, and the inner wall of the second cavity 73 is provided with a first inner round corner for forming the outer round corner.

[0047] As shown in Figure 5 With Figure 8 As shown, the third mold includes a third main mold and a third punch mold. As shown in Figure 5 , Figure 8 ,Figure 10 As shown in the figure, the third die includes a third punch 81 and a third punch rod 82. The third punch 81 has a forming hole at one end, and the forming hole has the same radial section as the cap head 31. The third punch rod 82 is arranged inside the forming hole, and the third punch rod 82 is separated into a receiving groove and a third punch groove 83 by the end face of the third main die. The third punch rod 82 is arranged inside the receiving groove, and the cap head 31 is formed inside the third punch groove 83 at the end away from the cap rod 32.

[0048] As shown in the figure, Figure 5 , Figure 8 , Figure 9 As shown in the figure, the third main die includes a third die core 91 and a third ejector rod 92. The third ejector rod 92 is arranged in the third die core 91. The third die core 91 has a third cavity 93 at one end for forming the arc surface 36 and the cap rod 32.

[0049] As shown in the figure, Figure 5 and Figure 8 As shown in the figure, the inner wall of the third cavity 93 is provided with a second fillet for forming an outer fillet. The radius of the second fillet is equal to the radius of the outer fillet, and the radius of the first fillet is greater than the radius of the second fillet.

[0050] As shown in the figure, Figure 12 In an embodiment, compared with the above-mentioned embodiments, the forming die of the embodiment includes a third main die and a third die. The third die includes a third punch 81 and a third punch rod 82. The third punch 81 has a forming hole at one end, and the forming hole has the same radial section as the cap head 31. The third punch rod 82 is arranged inside the forming hole, and the third punch rod 82 is separated into a receiving groove and a third punch groove 83 by the end face of the third main die. The third punch rod 82 is arranged inside the receiving groove, and the cap head 31 is formed inside the third punch groove 83 at the end away from the cap rod 32. The third punch rod 82 includes a sleeve and a punch rod. The punch rod is arranged in the sleeve, and the punch rod has a second upper cone 84 for forming the second conical groove 35 at the end face close to the third main die. The sleeve and the punch rod are coplanar at the end face close to the third main die.

[0051] The technical features of the above-mentioned embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these should be considered within the scope of the present application.

Claims

1. A post-drilling forming device for a boat plate nut, characterized in that: The mold includes a forming die for processing a boat plate nut. The boat plate nut includes a nut head and a nut rod. The nut head has a rectangular plane and an arc surface at its two ends, respectively. The nut rod is integrally formed and located at the center of the arc surface. The nut rod is cylindrical. A threaded hole coaxial with the nut rod is opened at the center of the rectangular plane. The threaded hole passes through the nut head and the nut rod in sequence. The forming die includes a first die, a second die, and a third die arranged in sequence. The first mold upsets one end of the blank to form a first pre-upsetting platform, and the other end of the blank is reduced in diameter and upset to form a first pre-upsetting rod. The first mold upsets the end of the first pre-upsetting platform away from the first pre-upsetting rod to form a first plane, and the edge of the first plane is strongly compressed to form a first rounded corner, thus forming a first pre-upset part. The two molds expand the diameter of the first pre-upsetting rod to upset the second pre-upsetting rod, upset the first pre-upsetting platform to form the second pre-upsetting platform, expand the first plane to form the second plane, upset the surface of the first pre-upsetting platform away from the first plane into an arc surface, and then squeeze the first rounded corner to shrink it into the second rounded corner. At the center position of the second plane, upset the first conical groove coaxial with the second pre-upsetting rod to form the second pre-upsetting part. The three molds expand the diameter of the second pre-upsetting rod and upset it into a nut rod. The three molds upset the second pre-upsetting platform into a nut head, expand the second plane to form a rectangular plane, squeeze the second rounded corner to form a right angle, and upset the first conical groove to form a second conical groove. The second conical groove is coaxially arranged with the nut rod to form a part to be drilled.

2. The post-drilling forming device for the boat plate nut according to claim 1, characterized in that: The axial section of the nut head is a curved trapezoid, and the radial section of the nut head is a quadrilateral. The quadrilateral is composed of two straight sides and two circular arc sides, and the straight sides and circular arc sides are connected end to end in sequence.

3. The post-drilling forming device for the boat plate nut according to claim 2, characterized in that: 120°≤a≤150°, b=90°, where a is the angle of the apex of the first conical groove and b is the angle of the apex of the second conical groove.

4. The post-drilling forming device for the boat plate nut according to claim 2, characterized in that: The first die includes a first main die and a first punch. The first punch includes a first punch and a first punch bar. The first punch bar passes through the first punch. One end of the first punch has a first groove for forming one end of the first pre-upsetting table. The first groove is a spherical crown-shaped groove. The edge of the end face of the first punch bar near the first main die abuts against the inner wall of the first groove.

5. The post-drilling forming device for the boat plate nut according to claim 4, characterized in that: The first main mold includes a first mold core and a first ejector pin. The first ejector pin passes through the first mold core. A first cavity is formed at one end of the first mold core. The first cavity includes a first groove for forming the other end of the first pre-upsetting platform and a second groove for forming the first pre-upsetting rod. The first groove is frustum-shaped and the second groove is cylindrical.

6. The post-drilling forming device for the boat plate nut according to claim 2, characterized in that: The two molds include a second main mold and a second punch. The second punch includes a second punch and a second punch bar. The second punch bar passes through the second punch. One end of the second punch has a second groove for forming one end of the second pre-upsetting table. The second plane and the second rounded corner are both set inside the second groove. The end face of the second punch bar near the second main mold has a first upper cone for forming the first conical groove.

7. The post-drilling forming device for the boat plate nut according to claim 6, characterized in that: The second main mold includes a second mold core and a second ejector rod. The second ejector rod passes through the second mold core. One end of the second mold core has a second cavity for forming the second pre-upsetting platform and the other end of the second pre-upsetting rod. An outer rounded corner is provided between the arc surface and the nut rod. The inner wall of the second cavity has a first inner rounded corner for forming the outer rounded corner.

8. The post-drilling forming device for the boat plate nut according to claim 2, characterized in that: The three molds include a third main mold and a third punch. The third punch includes a third punch head and a third punch bar. One end of the third punch head has a forming hole, which has the same radial cross-section as the nut head. One end of the third punch bar is located inside the forming hole. The end face of the third punch bar near the third main mold divides the forming hole into a receiving groove and a third punch groove. The third punch bar is located inside the receiving groove. The end of the nut head away from the nut rod is formed inside the third punch groove.

9. The post-drilling forming device for the boat plate nut according to claim 8, characterized in that: The third main mold includes a third mold core and a third ejector rod. The third ejector rod passes through the third mold core, and one end of the third mold core has a third cavity for forming an arc surface and a nut rod.

10. The post-drilling forming device for the boat plate nut according to claim 8, characterized in that: The third punch includes a sleeve and a punch rod. The punch rod passes through the sleeve. The end face of the punch rod near the third main mold has a second upper cone for forming the second conical groove. The end faces of the sleeve and the punch rod near the third main mold are coplanar.

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