Hydraulic edge pressing device

Abstract

The present invention belongs to the field of stamping dies, and in particular discloses a hydraulic edge pressing device, which adopts the following technical scheme: it comprises an upper die seat and a lower die seat which are arranged relatively, a guide column and a guide sleeve are installed between the upper die seat and the lower die seat, and the upper die seat can make up and down reciprocating motion along the guide column and the guide sleeve under the action of a press, a punch is fixedly arranged in the middle of the upper die seat, a concave die matching with the punch is arranged on the lower die seat below the punch, a edge pressing ring is a structure of multiple component splicing, a hydraulic cylinder is fixedly arranged on each component of the edge pressing ring, a piston rod of the hydraulic cylinder is connected to a component of the edge pressing ring, and its cylinder body is fixedly arranged on the upper die seat, the oil inlets of the multiple hydraulic cylinders are connected through a flow pipe, overflow valves are connected in parallel at both ends of the oil inlet and the oil outlet of the hydraulic cylinder, a gear is installed on the valve stem of the overflow valve, and the gear is meshed with a rack fixed on the lower die seat.

Description

Technical Field

[0001] The invention belongs to the field of stamping dies, and in particular relates to a hydraulic edge pressing device. Background Art

[0002] The types of traditional blank holders usually include rubber blank holders, spring blank holders, and air cushion blank holders. This type of blank holder is mostly used on ordinary single-action presses, while rigid blank holders are mainly used on double-action presses.

[0003] In 2005, the Institute of Metal Forming Technology (IFU) at the University of Stuttgart in Germany successfully developed an elastic partitioned blank holder. The main body of this blank holder is composed of multiple cone-shaped stumps. Each cone constitutes a partition. Each partition is provided with pressure by a separate hydraulic cylinder. The pressure is applied at the small end of the cone. A metal plate connects the large end together, and the small end is connected together by another metal plate to increase strength and prevent the cones from bending or deflecting when subjected to force.

[0004] The nylon ring combined blank holder uses eight hydraulic cylinders to provide pressure and can be used on a small hydraulic press. The blank holder generally uses four hydraulic cylinders to provide pressure, but the four hydraulic cylinders cannot be completely synchronized, that is, the pressing surfaces of the four blank holders during the blanking process cannot form an absolute plane, and there will be a height difference between two adjacent blank holders. In order to solve the problem of serious scratches on the surface of the drawn parts, the designer added a whole ring made of nylon under the partitioned blank holder, so that the whole surface of the nylon ring is in contact with the blank, and a smooth transition between the surfaces of the blank holders is achieved.

[0005] Chen Gongzhen from the School of Mechanical Engineering at Fuzhou University has developed a conical blank holder. While other drawing equipment remains unchanged, the minimum limit drawing coefficient can be reduced by simply replacing the original blank holder with a conical blank holder. For example, the drawing coefficient of 08 steel plate with a relative thickness of 1.5 can reach 0.22, which is 54.16% lower than the ideal minimum limit drawing coefficient. In some practical applications, such a drawing coefficient may be too large and cannot meet the drawing requirements, so the minimum limit drawing coefficient needs to be further reduced.

[0006] The blank holding devices described above all have different problems. Either the blank holding force cannot always reach the optimal value, or the structure is relatively complex. Whether it is possible to design a blank holding device with a relatively simple structure and a blank holding force that can always be close to the optimal value is the key problem to be solved by the present invention. Summary of the invention

[0007] The present invention overcomes the deficiencies of the prior art and aims to provide a hydraulic edge holding device which has a simple structure, is easy to operate, and can dynamically adjust the edge holding force according to the drawing depth so that the edge holding force is always maintained at a close to optimal value, thereby ensuring the drawing effect.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a hydraulic edge pressing device, comprising an upper die seat and a lower die seat arranged opposite to each other, a guide pin and a guide sleeve are installed between the upper die seat and the lower die seat, and the upper die seat can reciprocate up and down along the guide pin and the guide sleeve under the action of a press;

[0009] A punch is fixedly arranged in the middle of the upper die seat, and a matching die is arranged on the lower die seat below the punch. The blank holder is a structure of multiple components spliced ​​together. A hydraulic cylinder is fixedly arranged on each component of the blank holder. The piston rod of the hydraulic cylinder is connected to the component of the blank holder, and its cylinder body is fixed to the upper die seat. The oil inlets of the multiple hydraulic cylinders are connected by flow pipes, and overflow valves are connected in parallel at both ends of the oil inlet and outlet of the hydraulic cylinder. A gear is installed on the valve stem of the overflow valve, and the gear is meshed with a rack fixed on the lower die seat.

[0010] Furthermore, the blank holder is composed of four components, and the four components are divided by an S-shaped dividing line. By adopting the S-shaped dividing line, no convex marks are generated along the dividing line during the drawing process.

[0011] Furthermore, the relief valve is installed on the upper die seat through the relief valve fixing plate.

[0012] Furthermore, a pressure gauge is installed at the overflow valve to detect the pressure value at the overflow valve.

[0013] Compared with the prior art, the present invention has the following beneficial effects: the present invention derives the relationship between the blank holding force and the drawing depth based on the empirical calculation formula of the drawing force and the blank holding force, and designs a gear rack structure using the relationship to rotate the pressure relief valve, thereby achieving the purpose of changing the blank holding force. In addition, the joints of the block blank holding rings are S-shaped, avoiding the convex mark defect caused by the lack of blank holding force in the joint part. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0015] Figure 1 It is a schematic diagram of the hydraulic edge pressing device of the present invention.

[0016] Figure 2 It is a schematic diagram of the structure of the pressure ring.

[0017] In the figure: 1 is the upper die base, 2 is the lower die base, 3 is the guide pin and guide sleeve, 4 is the punch, 5 is the pressure ring, 6 is the hydraulic cylinder, 7 is the piston rod, 8 is the flow pipe, 9 is the overflow valve, 10 is the gear, 11 is the rack, 12 is the pressure gauge, and 13 is the die. DETAILED DESCRIPTION

[0018] like Figure 1 , Figure 2 As shown, the hydraulic edge pressing device includes an upper die base 1 and a lower die base 2 which are arranged opposite to each other, a guide pin and a guide sleeve 3 are installed between the upper die base 1 and the lower die base 2, and the upper die base 1 can reciprocate up and down along the guide pin and the guide sleeve 3 under the action of the press.

[0019] A punch 4 is fixedly arranged in the middle of the upper die base 1, and a matching die 13 is arranged on the lower die base 2 below the punch 4. The blank holder 5 is a structure of multiple components spliced ​​together, and a hydraulic cylinder 6 is fixedly arranged on each component of the blank holder 5. The piston rod 7 of the hydraulic cylinder 6 is connected to the component of the blank holder 5, and its cylinder body is fixedly arranged on the upper die base 1. The oil inlets of the multiple hydraulic cylinders 6 are connected through the flow pipe 8. The oil inlet and the oil outlet of the hydraulic cylinder 6 are connected in parallel with the overflow valve 9, and the overflow valve 9 is installed on the upper die base 1 through the overflow valve 9 fixing plate. A gear 10 is installed on the valve stem of the overflow valve 9, and the gear 10 is meshed with the rack 11 fixed on the lower die base 2.

[0020] Working principle of the present invention: When the hydraulic pressure device is working, the oil pump first provides pressure oil to the oil circuit through the one-way valve and the relief valve 9 to enter the hydraulic cylinder 6. The punch 4 moves downward and approaches the die 13 under the action of the press. When the punch 4 contacts the blank, the pressure ring 5 also contacts the blank, causing the piston rod 7 of the hydraulic cylinder 6 to start to return to the top. Because it was in a deadweight state before, the pressure value of the upper chamber of the hydraulic cylinder is greater than the set value. The set discharge value is the pressure force provided by the pressure ring 5. As the punch 4 moves downward, the space in the upper chamber of the hydraulic cylinder decreases, resulting in an increase in oil pressure. Returning to the relief valve 9 will cause the relief valve 9 to open and discharge. At the same time, as the punch 4 moves downward, the rack 11 drives the gear 10 to move, the relief valve 9 rotates, the overflow value becomes smaller, and the pressure force continues to decrease, so that the pressure is always kept close to the optimal value. After the deep drawing is completed, the hydraulic cylinder 6 moves up with the punch 4, the overflow valve 9 rotates, the overflow value becomes larger, and the oil enters the upper chamber of the hydraulic cylinder again. When the oil fills the upper chamber of the hydraulic cylinder again, the punch 4 completely leaves, the component is taken out, and the edge pressing process is completed.

[0021] In order to ensure the blank holding effect at the dividing line, the blank holding ring 5 is composed of four components, and the four components are divided by an S-shaped dividing line. By adopting the S-shaped dividing line, no convex marks are generated along the dividing line during the drawing process.

[0022] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. Hydraulic edge pressing device, characterized by: The invention comprises an upper die base (1) and a lower die base (2) which are arranged opposite to each other, a guide column and a guide sleeve (3) being installed between the upper die base (1) and the lower die base (2), and the upper die base (1) can make up and down reciprocating motion along the guide column and the guide sleeve (3) under the action of a press, a punch (4) being fixedly arranged in the middle of the upper die base (1), and a matching die (13) being arranged on the lower die base (2) below the punch (4); The blank holding ring (5) is a structure composed of multiple components. A hydraulic cylinder (6) is fixedly arranged on each component of the blank holding ring (5). The piston rod (7) of the hydraulic cylinder (6) is connected to the component of the blank holding ring (5). The cylinder body of the hydraulic cylinder (6) is fixedly arranged on the upper die base (1). The oil inlets of the multiple hydraulic cylinders (6) are connected through a flow pipe (8). The oil inlets and the oil outlets of the hydraulic cylinder (6) are connected in parallel with overflow valves (9). A gear (10) is installed on the valve stem of the overflow valve (9). The gear (10) is meshed with a rack (11) fixed on the lower die base (2).

2. The hydraulic edge pressing device according to claim 1 is characterized in that: The blank holder (5) is composed of four components, and the four components are divided by an S-shaped dividing line.

3. The hydraulic edge pressing device according to claim 1 is characterized in that: The relief valve (9) is mounted on the upper die base (1) via a relief valve fixing plate.

4. The hydraulic edge pressing device according to claim 1, characterized in that: A pressure gauge (12) is installed at the overflow valve (9).

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