Electrohydraulic hammer transformation of the most

Electrohydraulic hammer transformation of steam empty single arm hammer

Abstract: the technology of changing steam empty hammer into electrohydraulic hammer has been widely used in 1 ~ 3T arch and Bridge hammers. Practice has proved that it can be used for stable production. However, the transformation of electro-hydraulic hammer of steam empty single arm hammer is still in the stage of trial production. This paper puts forward a new transformation scheme for the transformation of 750KG single arm hammer

key words: single arm hammer; Electrohydraulic hammer; Transformation

I. raising problems

the steam air hammers in active service, whether arch, bridge or single arm, are mostly products from the 1950s and 1960s. At present, they are facing the situation of aging products and waiting for overhaul. And the energy utilization rate of the old steam hammer is less than 2%; The contradiction between supply and demand often occurs between the boiler room (or air compression station) and the forging plant, affecting production; In addition, environmental pollution and other problems have restricted the benefits of the steam hammer. Alternative products must be developed to overcome the above shortcomings

China began to study the technology of changing the head of the steam hammer into an electro-hydraulic hammer since the 1980s. Over the past ten years, through the unremitting efforts of domestic peers, now the technology of 1 ~ 3T hammer is basically mature, and there are also successful examples of 5t die forging hammer

a large number of practices have proved that changing the head of the steam hammer into an electro-hydraulic hammer can fully meet the needs of production. At the same time, it also has obvious effects on energy conservation, environmental protection, reducing the labor intensity of workers, improving the working environment, reducing the amount of maintenance, etc. it is a cause of great merit for the country and the people. However, there are still two dead zones in this technology. One is that the transformation of large tonnage 10t and 16t die forging hammers has not been practiced; The other is that there are still some technical problems in the transformation of single arm hammer. The number of large tonnage hammers is small, and they are all double armed, so their structure will not change greatly. The main problem is how to select and participate in its repair, which is more difficult than other environmental experimental facilities. However, the single arm hammer is not the case. It has a large number and is estimated to account for 1/4 ~ 1/5 of the total number of hammers. In particular, the system of the Ministry of Railways is more than 2/3. Coupled with the particularity of the single arm hammer structure, it brings great inconvenience to the transformation. In short, if the two dead zones of large tonnage hammer and single arm hammer are not conquered, the technology of changing steam hammer into electro-hydraulic hammer cannot be comprehensively promoted

II. About the transformation of single arm hammer

at present, domestic single arm hammer has roughly two structures. One is that it has its own guide rail and hammer head similar to double arm hammer. This kind of hammer transformation is relatively simple. Like double arm hammer, it can use the original guide rail and hammer head and replace it with electrohydraulic power head. The other is no guide rail, which flattens both sides of the piston rod to prevent rotation and guide. At present, there are three plans to transform this hammer. One is to remove the flattened guide on both sides of the original round rod, add a closed guide frame, fix it on the hammer arm with four studs, lengthen the rear part of the power head base plate, and then connect it with the base with a column. A counterweight (3T hammer counterweight 10t) is placed on the base. The problem with this structure is that the new guiding structure is complex, the processing difficulty is increased, and the vision is not as wide as the original hammer. Moreover, the base plate is enlarged, the weight is increased, and the center of gravity is increased, which is easy to cause shaking, and a heavy counterweight is added, so that the structure is complex and the cost is increased. The second one is to feed oil and hit a single arm hammer. This structure keeps the original round rod flattening and guiding unchanged, and the lower chamber is filled with air. Fix an oil inlet pipe (plunger type) on the shock absorption cylinder head, and insert the lower end of the oil inlet pipe into the empty hammer rod. When the pipe enters the oil, the oil pressure pushes the hammer head downward to strike. The problem of this scheme is that the flattened round rod has poor sealing performance, and the air source is supplemented to solve the problem of air leakage, resulting in complex structure and increased cost. In addition, when the plunger type oil inlet pipe is inserted into the empty hammer rod, a sealing bushing is added to the upper end of the hammer rod. The liner is worn out, and the sleeve is equivalent to being added to the hammer head, which cannot be fixed at all, and it is still in the cylinder. Problems are not easy to find and repair

to sum up, these two structures have their own characteristics and advantages and disadvantages. Based on years of experience in reforming double arm hammers; Based on BASF's new material solution, which makes driving and riding more comfortable, and the understanding of the original single arm hammer guidance mode, with its guidance, regardless of its sealing, the hydraulic system of the double arm hammer is organically combined with the guidance mode of the single arm hammer, and a new type of structural single arm hammer is designed and implemented on the 750KG single arm hammer in Qishuyan Locomotive and rolling stock factory. The structure diagram is shown in Figure 1

Figure 1 this structure mainly solves the two problems of guidance and hammer body shaking

(1) guidance problem the original steam empty single arm hammer is guided by machining two planes symmetrically on the cylindrical rod, and the rotation of the hammer head is limited by these two planes. A lot of practice has proved that this structure is simple, easy to process, and can meet the use requirements. In order to organically combine the hydraulic system of double arm hammer with the guiding system of single arm hammer, we designed the connector. The connection method between the connector and the hammer arm is the same as that of the original steam empty single arm hammer. The upper platform of the connector is equipped with a power head - a hydraulic system similar to a double arm hammer; The lower part of the hammer is equipped with a guiding system, which is consistent with the method of flattening and anti rotation on both sides of the original hammer cylinder, that is, the guiding system of the original single arm hammer is retained. For the convenience of disassembly and assembly, the guide system is designed into a two-part open and close structure, and only guides without sealing

(2) shaking problem from the perspective of the structure of the single arm hammer body, shaking is its inherent defect and cannot be overcome. However, from years of practice, this shaking within the allowable limit does not affect production. In order to reduce the shaking, we have done two things: one is to reduce the system mass as much as possible, reduce the cylinder connecting beam, and reasonably set the system components; the other is to reduce the center of gravity as much as possible. After the center of gravity is reduced, the rigidity is improved, and the shaking torque is reduced, so as to reduce the shaking. After solving the two problems of anti rotation and shaking, the transformation of single arm hammer can be realized

this new structure single arm hammer has the following characteristics:

(1) simple structure, convenient processing and low cost

(2) adopting the original single arm hammer guiding mode and the double arm hammer electro-hydraulic driving principle, the structure is reasonable and the performance is reliable

(3) the flat hammer rod is only guided and not sealed, which is safe and reliable

(4) low center of gravity, light weight and small shaking

(5) the operating space is exactly the same as that of the original single arm hammer

(6) the guiding system is made into a two half open and close structure, which is convenient for maintenance

III. conclusion

after changing 750KG single arm hammer to electro-hydraulic hammer in Qishuyan Locomotive and rolling stock factory, after more than 4 months of assessment, it can fully meet the production requirements. In the first four months, more than 100 tons of forgings have been produced, with a maximum of 34kg forgings. The thump frequency is 90 times/min, and the tap frequency is 150 times/min. When working, your eyes can't see obvious shaking. (end)