Development and Innovation of Modern Forging Hammer Technology (1)

Overview

By discussing the different principles and structural forms of forging hammer developed by modern electro-hydraulic hammer technology, the innovation of electro-hydraulic hammer technology is embodied, and the development direction of electro-hydraulic hammer technology in the future is demonstrated.

The traditional steam-air dual-purpose forging hammer is the leading product in the forging industry in the middle and early stages of the last century. With the rapid development of modern hydraulic technology and electronic control technology, electro-hydraulic hammers have gradually developed, especially in the 1980s. Among them, the liquid-gas electro-hydraulic hammer has been continuously innovated and the technology has become increasingly mature. This technology is suitable for both free forging and die forging. Therefore, this technology has been promoted very quickly and has been recognized by the majority of users. At present, more than 95% of the electro-hydraulic hammers produced in China are liquid-liquid electro-hydraulic hammers. According to the level of maturity of the technology, the electro-hydraulic hammers with different structural principles are arranged in order:

1) Liquid-gas electro-hydraulic hammer; 2) Full-hydraulic electro-hydraulic hammer: 3) Programmable full hydraulic die forging hammer, 4) Manual full hydraulic die forging hammer.

1. Liquid-gas electro-hydraulic hammer

1, the principle

The basic principle of liquid-gas electro-hydraulic hammer is: the upper chamber of the working cylinder is closed high-pressure nitrogen, the lower chamber is hydraulic oil, and the middle is separated by the hammer piston. The system controls the lower chamber separately, the lower chamber enters the oil, and the hammer head lifts. The high-pressure nitrogen gas is compressed, the energy is stored, the lower chamber is drained, and the high-pressure nitrogen gas drives the piston to strike the hammer head, referred to as "pneumatic drive, hydraulic energy storage".

Electro-hydraulic power head, its main body is a tank, as a fuel tank for short-term oil storage during operation (when not working, the oil in the oil tank enters the oil tank of the hydraulic station placed on the ground through the oil return pipe), and there are eight bolts passing through. The cushion pad and the pre-pressure spring are fixed at the position of the original cylinder. The oil tank is also called a cylinder beam, and a master cylinder is arranged in the middle thereof. The top of the master cylinder is provided with a buffer cylinder, and a buffer piston is arranged therein. The upper part of the piston is filled with nitrogen gas with a certain pressure. The pressure is the same as the pressure at the top of the accumulator.

There are two holes in the lower part of the master cylinder which are respectively connected with the quick drain valve and the safety valve. The hydraulic station comes through the pipeline and enters the main control valve and accumulator installed on the upper right side of the tank. The oil chamber in the lower part of the accumulator is directly connected with the main control valve, and the upper part is connected to the gas cylinder group through the pipeline. The main cylinder is provided with a hammer piston, which separates the lower oil from the upper nitrogen, and the upper part of the piston is filled with a certain pressure of nitrogen and communicates with the auxiliary gas tank. The lower part of the hammer rod and the hammer head are rigidly connected, and the wedge iron is pressed tightly, and the operation part is basically unchanged. The hydraulic system adopts the combined transmission constant pressure liquid source composed of pump-accumulator-unloading valve, which not only ensures the stability and reliability of the system but also greatly reduces the installed capacity. The basic actions of the electro-hydraulic hammer are lifting hammer and striking.

When lifting the hammer, it is only necessary to operate the main valve so that the high-pressure oil in the accumulator of the oil pump can communicate with the lower chamber of the piston of the master cylinder. The hammer piston quickly completes the return stroke of the hammer head under the action of high pressure oil.

When striking, the main valve is operated to make the lower chamber of the piston communicate with the fuel tank, the quick release valve is opened, the oil in the lower part of the piston flows back to the hydraulic tank through the large aperture passage, and the upper part of the piston is under the action of the gas pressure and the weight of the hammer system to make the hammer Accelerate the downward movement until a blow is formed.

The acquisition of the energy can be realized by the handle to control the stroke, and the manipulation part can complete various actions such as lifting the hammer, striking, returning, slow rising, slow descending, emergency stopping, and hammer.

2, structure and composition

(1). The fuselage part includes: left and right fuselage, left and right rails, base (free forging), etc.; (2). Anvil part includes: anvil, anvil pad, lower anvil (free forging) and related parts; (3). Power head Some include: continuous cylinder beam, hammer head, hammer rod, cylinder, buffer cylinder, connecting plate, upper anvil (free forging), etc.; (4). Hydraulic station part includes: fuel tank, motor - oil pump set, electronically controlled unloading valve , valve seat, electronically controlled temperature gauge, heat exchange motor pump set, heat exchanger, oil filter, etc.; (5). Special valve, safety valve part includes: main control valve, quick discharge valve, safety valve, Hall switch (6). Pipeline and lubrication parts include: pipeline support, oil and gas pipe, lubrication pump, etc.; (7). Manipulating part: composed of operating handle assembly; (8). Gas cylinder part: nitrogen bottle, gas cylinder frame and gas cylinder , high-pressure ball valve, etc.; (9). The electronic control part includes: main motor, cooling motor, electric control box, button station, etc.; (10). Water cooling part includes: cooling water tower, pool, water pump, motor, water pipe, valve (the above user-owned (11). The basic part includes: anchor bolt assembly and so on.

3. Technological innovation

Anyang Forging Machinery Industry Co., Ltd., in the process of promoting the industrialization of electro-hydraulic hammer, relies on its own technical strength, closely links with user processes and requirements, and has the courage to tackle problems and solve a series of technical problems. A number of innovative designs have been made on the electro-hydraulic hammer to create an electro-hydraulic hammer product with “an forging characteristics”, which is described as follows: (1). The “X”-shaped rail structure is designed:

The comb-shaped guide rails of domestic steam-air forging hammers have the disadvantages of short arm, over-position and no temperature compensation. In order not to cause the hammer head to be stuck due to the temperature rise and expansion to reduce the gap of the guide rail, it is only necessary to increase the cold gap of the guide rail. When hitting, the hammer rod is subject to additional bending moment and is easy to break. When used for multi-cavity forging, the guide rail wears seriously.

In order to overcome this weakness, we have made an innovative design for the electro-hydraulic hammer mainframe, using an "X"-shaped rail structure. Since the X-shaped guide rail has a long force arm, the thermal expansion direction of the hammer head is substantially the same as the direction of the guide rail surface, and the thermal expansion has little effect on the guide rail clearance, and the guide rail clearance can be adjusted very small (about 0.2 mm), thus making the forging process The biasing force in the whole is borne by the hammer guide rail, which greatly improves the life of the hammer.

(2). Extend the sealing life and avoid oil and gas exchange:

a. The upper chamber of the liquid-air hammer working cylinder is high-pressure nitrogen, and the lower chamber is high-pressure oil, so the early electro-hydraulic hammer is easy to occur b. The wear-resistant and high-temperature resistant guide ring and the Ky ring with strong compensation ability are adopted. c. According to the difference between the sealing oil and the sealing medium, Ky rings with different Shore hardness are selected. d. Strengthen the positioning of the power head.

(3). Solve the problem of hammer breakage in abnormal life:

a. Improve the connection method of the hammer rod and the hammer head. According to the tribological principle, the 3 sets (pressing parts, taper sleeves and hammer rods) are designed to be tightened, so that the hammer rod is changed from the original "double cone structure" to "single The conical structure greatly avoids the generation of stress concentration, thereby achieving the advantages of reliable coupling and easy disassembly. The life of the hammer is doubled. b. The surface of the hammer rod is rolled to improve the surface hardened layer, thereby improving the service life of the hammer rod.

(4). Solving the problem of valve flexibility;

The poor flexibility of the early electro-hydraulic hammer operation and the slow down action have always been a problem for users. In the past, "free forging electro-hydraulic hammer is not free". In response to this problem, we have taken the following measures:

a. Improve the design of the secondary valve and increase the area of ​​the orifice to increase the flow rate and flow rate during the slow drop. b. Shorten the distance between the main valve and the secondary valve to achieve a "zero distance" connection, thereby shortening the reaction speed of the secondary valve and eliminating the effect of the volume effect.

(5). The theory of the rough hammer is used for the transformation of the power head;

The theory of electro-hydraulic hammer flexible thin hammer is very famous. It was invented by Lasco Company of Germany. The theory of flexible liquid hammer of electro-hydraulic hammer completely changed the "rail-hammer-hammer" system of the original steam-empty hammer. The rigid condition makes the biasing force in the forging process mostly carried by the hammer guide rail. For the free forging hammer, due to the characteristics of the forging process, the biasing force is not large, and the flexible thin hammer rod plays just right. Its unique superiority.

However, for the multi-cavity forging die forging hammer to implement the "head change" transformation, the "flexible thin hammer rod theory" is obviously not applicable. Due to the large biasing force of the multi-cavity forging, coupled with the serious cold-shock phenomenon during the final forging, the early damage of the guide rail is serious, and even the phenomenon of "card hammer" occurs. Therefore, when we carry out the “replacement” transformation, the “rigid rough hammer theory” of the steam-air forging hammer is still used for the die forging hammer with multi-cavity forging and large eccentric force, and satisfactory results are obtained.