CN105414427B - A kind of manufacturing process of contact base and the closed molds for being exclusively used in the manufacturing process - Google Patents

Abstract

The invention discloses a forming method of a contact seat and a closed mold specially used for the forming method. A method for forming a contact seat, comprising the following steps: Step 1, placing a bar-shaped pre-forging between the punch and the die pad of the die, the top of the outer peripheral surface of the pre-forging faces the bottom surface of the punch, and the bottom is at the bottom of the die pad On the top surface, the bottom surface of the punch is used to match and complement the top surface of the final forging, and the top surface of the die pad is used to coincide and complement the bottom surface of the final forging; step 2, the punch and the die pad are forged against each other along the radial direction of the pre-forging , until the pre-forging is forged into the final forging. When carrying out the design of the flat-type red copper contact seat closed-type overmold forming process, according to the structural characteristics of the contact seat whose length is much greater than the height, the method of forging the rod-shaped pre-forging along the radial direction is adopted, thereby shortening the The forming cycle of the contact seat improves the forming efficiency of the free forging process of the contact seat.

Description

A method of forming a contact seat and a closed mold specially used for the forming method

technical field

The invention relates to a forming method of a contact seat and a closed mold specially used in the forming method.

Background technique

At present, a flat contact seat made of pure copper used in a vacuum circuit breaker belongs to a special-shaped non-rotating body structure, and the upper and lower sides of the flat plate have flanges of different heights. As shown in Figure 1-2, the standard contact seat 8 includes an annular flange 81, a plate body 82 and a cylinder 83 arranged in sequence from top to bottom, wherein the annular flange 81 and the cylinder body 83 are rotary structures, and the plate body 82 is a non-revolving body structure. The plate body 82 is a horizontal plate with a plate thickness of h2, and a circular groove 84 is provided at the center of the top of the plate body 82; the annular flange 81 is located at the edge of the upper end of the circular groove, and the height of the annular flange is h1; the cylinder 83 It is convexly arranged on the lower side of the board body 82 , the height of the board cylinder 83 is h3 , and h1+h2+h3 is much smaller than the length of the board body 82 . In the traditional processing method, the contact seat 8 is directly processed by bar material, and the material utilization rate is very low, less than 17%. If the contact seat is produced by the ordinary free forging process, Material utilization has improved, but still not above 31%.

Chinese patent document CN 104139146 A discloses a "closed mold for contact seat", which includes a mold sleeve and a punch and a die pad that are relatively assembled along the axial direction in the mold sleeve, wherein the inner cavity of the mold sleeve is divided into two parts: Arranged from top to bottom, the upper cavity for inserting the punch, the middle cavity for accommodating the edge of the final forging of the contact seat, and the lower cavity for inserting the die pad; the die pad is an annular cylindrical structure, The die pad has an inner cavity for forming a cylinder of a standard contact seat and an outer wall for matching with the lower cavity, and the die pad has an upper end face for forming a lower end face of a plate body of a standard contact seat; the punch includes a die The lower part of the center of the mold base is provided with a convex part for forming the groove of the standard contact base. The mold base has a lower end surface for forming the upper end surface of the standard contact base. The upper cavity has a The inner wall of the side surface of the board body of the contact seat. When forging, the bar is put into the inner cavity of the die pad, and then the punch is forged along the axial direction of the die pad to form the required contact seat with the gradual upsetting of the bar. In this forging process of axial upsetting forging, the metal structure on the top of the bar needs to be formed by radial flow, and the flow stroke of the metal structure is relatively large, resulting in a large deformation stroke of the bar during forging and pressing of the contact seat. , prolong the cycle of forging and pressing, and reduce work efficiency.

Contents of the invention

The object of the present invention is to provide a method for forming a contact seat which improves the forming efficiency of the free forging process of the contact seat, and also provides a closed die specially used for implementing the method.

In order to achieve the above object, the technical scheme of the forming method of the contact seat in the present invention is as follows:

A method for forming a contact seat, comprising the steps of:

Step 1, place the bar-shaped pre-forging between the punch and the die cushion of the die, the top of the outer peripheral surface of the pre-forging faces the bottom surface of the punch, and the bottom is on the top surface of the die pad, and the bottom surface of the punch is used for contact with the die pad. The top surface of the final forging is matched and complementary, and the top surface of the die pad is used to match and complement the bottom surface of the final forging;

In step 2, the punch and the die pad are forged against each other along the radial direction of the pre-forging until the pre-forging is forged into a final forging.

In step 1, before the pre-forging is put into the punch and the die pad, the cylindrical elongated bar is pre-forged into a pre-forging in the radial direction, and the opposite sides of the outer periphery of the pre-forging have plane segments parallel to each other .

Pre-forging of slender bars is carried out on flat anvils.

The slender bar is heated before pre-forging, and no further heating is required during the pre-forging process and during the forging and pressing process of the pre-forging.

The technical scheme of closed mold in the present invention is as follows:

Closed mold, including the mold sleeve and the punch and die pad inserted in the upper and lower sides, the punch is above the die pad, and the bottom surface of the punch is protruded with a forming convex part for forming the circular groove of the contact seat. There is a forming cavity for forming the cylinder of the contact seat on the die pad, and the forming cavity and the forming convex part are coaxially arranged with the die sleeve, and the bottom surface of the punch is provided with an annular ring for forming the annular flange of the contact seat. The groove, the annular groove is transitionally connected between the bottom surface of the punch and the outer peripheral surface of the forming convex part, and the annular groove surrounds the outer peripheral surface of the forming convex part.

The forming die cavity is a circular forming groove provided on the top surface of the mold pad, and the groove bottom of the forming groove is a closed groove bottom for forming the lower end surface of the cylinder.

The die pad is also provided with a vent hole, one end of the vent hole is connected to the forming groove, and the other end of the vent is on the bottom surface of the die pad.

The air vent extends up and down, the upper end of the air vent is on the bottom surface of the forming groove and communicates with the forming groove, and the lower end of the air vent is on the bottom surface of the die pad.

From top to bottom, the inner cavity of the mold sleeve is divided into the upper cavity that cooperates with the punch to guide and move in the up and down direction, the middle cavity that cooperates with the die pad to guide and move in the up and down direction, and the lower cavity that is narrow at the top and wide at the bottom. The upper port of the cavity is integrated with the lower port of the middle cavity.

The inner wall surface of the lower cavity is an inner cone surface gradually expanding outward from top to bottom.

According to the structural feature that the length of the contact seat is much greater than the height, the present invention adopts the method of forging the rod-shaped pre-forging along the radial direction when designing the forming process of the flat copper contact seat. Compared with the process method of forging along the axial direction in the prior art, the flow stroke of the metal structure of the pre-forging can be reduced during forging, thereby shortening the cycle of contact seat forming and improving the free forging process of contact seat. efficiency.

Description of drawings

Fig. 1 is a structural schematic diagram of an existing contact seat;

Fig. 2 is the top view of Fig. 1;

Fig. 3 is the front view of the pre-forging in the embodiment of the forming method of the contact seat in the present invention;

Fig. 4 is the left view of Fig. 3;

Fig. 5 is a schematic structural view of the final forging preparation stage in the embodiment of the forming method of the contact seat in the present invention;

Fig. 6 is a schematic view of the structure after the final forging in the embodiment of the forming method of the contact seat in the present invention;

Fig. 7 is the left view of Fig. 6;

Fig. 8 is a schematic structural view of the punch in the embodiment of the forming method of the contact seat in the present invention;

Figure 9 is a top view of Figure 8;

Fig. 10 is a schematic structural view of the mold cover in the embodiment of the forming method of the contact seat in the present invention;

Figure 11 is a top view of Figure 10;

Fig. 12 is a schematic structural view of the mold pad in the embodiment of the method for forming the contact base in the present invention.

Detailed ways

Embodiment of the forming method of the contact seat in the present invention: the forming method is suitable for the closed forming process of the flat contact seat, comprising the following steps:

1) Prepare the material, prepare a slender bar with a circular cross section, and heat the slender bar;

2) Pre-forging, place the slender bar material flat on the flat anvil, and pre-forge the pre-forging 1 along the radial direction, as shown in Figure 3 and Figure 4, the pre-forging 1 is in the shape of a rod, and the top and bottom surfaces of the pre-forging 1 are uniform. is a plane segment, and the plane segments at the top and bottom of pre-forging 1 are parallel to each other;

3) For final forging preparation, put the pre-forging 1 flat in the closed mold, as shown in Figure 5, the closed mold is composed of the mold sleeve 3 and the punch 2 and the mold pad 4 inserted in the upper and lower sides of the mold;

4) Final forging, under the condition of keeping the die sleeve 3 and the die pad 4 still, the punch 2 is forged downward to forge the pre-forging 1 into the final forging 9 through the bottom surface of the punch 2, as shown in Fig. 6 and Fig. 7.

As shown in Figure 10 and Figure 11, in step 2), the inner cavity of the die sleeve 3 is divided from top to bottom into an upper cavity 31 that cooperates with the punch 2 to guide and move in the up and down direction, and an upper cavity 31 that cooperates with the die pad 4 along the vertical direction. The middle cavity 32 that guides and moves in the up and down direction and the lower cavity 33 that is narrow at the top and wide at the bottom. The shape of the upper cavity 31 is the same as the shape of the plate body of the contact seat. 33 has a height of h5. The purpose of designing the lower cavity 33 is to reduce the difficulty of demolding the mold pad 4 . The upper port of the lower cavity 33 is integrally arranged with the lower port of the middle cavity 32, and the inner wall of the lower cavity 33 is an inner tapered surface that gradually expands outwards from top to bottom, so that the inner wall of the lower cavity 33 and the mold An annular draft angle 5 is formed between the outer peripheral surfaces of the pads.

As shown in Figures 8 and 9, in step 2), the punch 2 includes a mold base 21 for guiding and moving in the upper and lower directions and inserted in the upper mold cavity 31 of the mold sleeve 3, and the shape of the mold base 21 is the same as The upper mold cavity 31 is a non-revolving structure with complementary shapes, and its cross section is the same shape as the cross section of the plate body of the flat contact base, and its lower end surface is used to shape the upper side plate surface of the plate body of the contact base. The bottom surface of the mold base 21 is coaxially provided with an inverted conical forming protrusion 22, and the lower end surface of the forming protrusion 22 is used to form a circular groove in the middle of the upper end of the flat contact base. The bottom surface of the mold base 21 is provided with an annular groove 23 surrounding the forming convex portion 22. The annular groove 23 is transitionally connected between the bottom surface of the punch 2 and the outer peripheral surface of the forming convex portion 22. The annular groove 23 is used for An annular flange on the upper end face of the shaped contact seat.

As shown in Figure 12, in step 2), the mold pad 4 is a cylindrical body structure, and the outer peripheral surface of the mold pad 4 is guided and matched with the cavity wall of the middle cavity 32 of the mold sleeve 3 in the vertical direction. The height is h6. The top surface of the mold pad 4 is provided with a forming cavity for forming a cylinder of a flat contact seat, and the forming cavity is a circular forming groove 41 coaxial with the die cover 3, and the groove of the forming groove 41 The bottom surface is a closed groove bottom for forming the lower end surface of the cylinder. The upper end surface of the die pad 4 is used to form the lower end surface of the plate body of the flat contact base. In order to make the upper end surface of the mold cushion 4 closely fit the lower end surface of the upper mold cavity 31 of the mold sleeve 3 and effectively reduce the generation of burrs and even flash, when designing the mold, set the value of h6 to be slightly greater than h4+h5. In order to ensure that the inner cavity of the mold pad 4 will not hold air when the cylinder of the flat contact seat is formed, resulting in insufficient filling and waste products, the vent holes extending up and down coaxially arranged under the forming groove 41 are designed. 6. The upper opening of the exhaust hole 6 is on the bottom surface of the forming groove 41 and communicates with the forming groove 41 , and the lower opening of the exhaust hole 6 is on the bottom surface of the mold pad 4 .

In order to facilitate the clamping of the mold, when designing the mold, a jaw 7 is provided on at least one of the outer peripheral surfaces of the punch 2 , the mold sleeve 3 and the mold pad 4 . However, in this embodiment, the jaws 7 are all provided on the outer circular surfaces of the punch 2 , the die sleeve 3 and the die pad 4 .

In step 2), first put the die pad 4 into the middle cavity 32 of the die sleeve 3, then put the pre-forging 1 into the upper end surface of the die pad 4, and then put the punch 2 into the upper mold of the die sleeve 3 In the cavity, start the hammer to hit the punch 2 to realize the final forging of the contact seat. In step 3), after the final forging process is completed, continue to hit the punch 2 downwards, so that the final forging 9 of the contact seat and the die pad 4 can be released from the die sleeve 3 at the same time, and a parting of the die can be realized; then the contact The seat final forging 9 is clamped out from the die pad 4 to realize secondary parting. Because the mold adopts two-way parting mode, it is convenient to realize the demoulding of forgings. The flat non-rotating body contact seat can be forged successfully by using the forming process and the closed die designed in the invention. Compared with the existing technology, the production process of this technology is simple. Except for the outer circular surface parts at both ends of the contact seat plate body, the rest of the outer wall is no longer machined, so that the material utilization rate is increased from the original nearly 31% to 65.8%. , the subsequent mechanical processing efficiency is significantly improved, the processing cost is reduced by 55.3%, and the economic benefit is remarkable.

In the above-mentioned embodiments, the pre-forging is forged with a flat anvil before final forging. In other embodiments, the pre-forging can also be directly made of cylindrical bar or block base material, so that the pre-forging process can be omitted.

Embodiment of the closed mold in the present invention: the structure of the closed mold in this embodiment is the same as that of the closed mold in the above embodiment, so it will not be repeated.

Claims (9)

1. The forming method of contact seat is characterized in that, comprises the following steps: Step 1, place the bar-shaped pre-forging between the punch and the die cushion of the die, the top of the outer peripheral surface of the pre-forging faces the bottom surface of the punch, and the bottom is on the top surface of the die pad, and the bottom surface of the punch is used for contact with the die pad. The top surface of the final forging is matched and complementary, and the top surface of the die cushion is used to match and complement the bottom surface of the final forging. Pre-forging, the top and bottom of the pre-forging are flat and parallel to each other. The pre-forging is flat. After being placed in the mold, the top of the pre-forging faces the bottom of the punch, and the bottom of the pre-forging is in contact with the top surface of the die pad. ; In step 2, the punch and the die pad are forged against each other along the radial direction of the pre-forging until the pre-forging is forged into a final forging. 2. The forming method of the contact base according to claim 1, characterized in that the pre-forging of the elongated bar is carried out on a flat anvil. 3. The method for forming a contact seat according to claim 1, wherein the elongated bar is heated before pre-forging, and no further heating is required during the pre-forging process and during the forging process of the pre-forging. heating. 4. Closed mold, including the mold sleeve and the punch and die pad inserted in the upper and lower sides of the die sleeve, the punch is above the die pad, and the bottom surface of the punch is provided with a circular groove for forming the contact seat part, the mold pad is provided with a forming cavity for forming the cylinder of the contact seat, the forming cavity and the forming convex part are coaxially arranged with the die sleeve, and the characteristic is that the bottom surface of the punch is provided with a forming cavity for forming the contact seat The annular groove of the annular flange, the annular groove is transitionally connected between the bottom surface of the punch and the outer peripheral surface of the forming convex part, and the annular groove surrounds the outer periphery of the forming convex part, and the bottom surface of the punch is used to face the top The top surface and the bottom surface of the pre-forging are flat and parallel to each other, and the top surface of the die pad is used to contact the bottom surface of the pre-forging. 5. The closed mold according to claim 4, wherein the forming die cavity is a circular forming groove provided on the top surface of the die pad, and the groove bottom surface of the forming groove is used for forming the cylinder. The bottom of the closed groove on the lower end face. 6. The closed mold according to claim 5, characterized in that, the mold pad is also provided with a vent hole, one end of the vent hole is connected to the forming groove, and the other end of the vent is on the bottom surface of the mold pad. 7. The closed mold according to claim 6, wherein the vent hole extends up and down, the upper end of the vent hole is on the groove bottom surface of the forming groove and communicates with the forming groove, the lower end of the vent hole The orifice is on the bottom surface of the die pad. 8. The closed mold according to any one of claims 4 to 7, characterized in that the inner cavity of the mold sleeve is divided into an upper mold cavity that cooperates with the punch to guide and move in the up and down direction from top to bottom, and a mold cavity that cooperates with the mold The pad guides and moves in the up and down direction the middle cavity and the lower cavity which is narrow at the top and wide at the bottom, and the upper port of the lower cavity is integrated with the lower port of the middle cavity. 9. The closed mold according to claim 8, characterized in that, the inner wall surface of the lower cavity is an inner tapered surface gradually expanding outward from top to bottom.