Overcapacity With the gradual entry into China of all types of excavator parts manufacturers in recent years, Chinese excavator companies are catching up with foreign companies quickly. Currently, in addition to Doosan Heavy Industries, Caterpillar, Hitachi Construction Machinery, Kobelco, Volvo and other overseas investors, there are Xiagong, Sany Heavy Machinery, Liugong, XCMG, Zoomlion, and Shandong Lingong. excavator.
If you look at the sales figures, the rapid growth of the entire excavator industry can be described as a “scrap of flowersâ€.
In the first quarter of this year, domestic excavators sold a total of 74.214 million units, a year-on-year increase of 59%. In March alone, 24 excavator manufacturers sold about 43,000 units.
However, another senior executive of Zoomlion told this reporter that the domestic production capacity of excavators in the first quarter of this year has exceeded 300,000 units. Last year, the sales volume of excavators in China was about 160,000 units, which means that this year in each Under the premise that companies do not expand their production capacity, sales will double and it will be possible to digest these excess production capacity.
Industry insiders believe that it is unlikely that the excavator market will achieve sales of 300,000 units this year. According to the forecasts of the excavator branch of the China Construction Machinery Association, the total sales volume of excavators this year is about 190,000 units, between 2012 and 2014 between 218,500 units and 302,000 units.
Future or there will be a price war, "the future phenomenon of excess capacity will be more serious." The aforementioned Zoomlion senior pointed out that there are currently a total of 12 companies in the mid-to-long-term planning, such as Caterpillar completed the Jiangsu Wujiang, Xuzhou After the expansion of the production base, the total production capacity will reach 34,000 units; Sany Heavy Machinery will have 80,000 mid- and long-term plans, and Rongsheng Heavy Industries & Construction Co., Ltd., which invests in shipbuilding, is expected to build 30,000 hydraulic excavator production bases in the next few years. .
Chen Peiliang told this reporter that the reason why the excavator industry was generally optimistic, based on the following aspects: As 4 trillion investment projects have been launched one after another, whether it is construction sites or manufacturing companies, airports, railways, etc. Demand; Many manufacturers and distributors use various promotion methods. Buyers can use their own products on the one hand, and they can also lease excavators to third parties and repay them with rent. Excavators, unlike pumping machinery, have relatively high selling prices. It's very cheap, with less than 1 million yuan to buy several units, and pumping machinery costs as much as a few million; excavator key components such as castings, speed reducers, etc. are also expanding, so state-owned mining Machine companies can quickly mass production to meet market demand.
"In the short term, the production capacity of excavators may be passively reduced due to the impact of the earthquake in Japan." A fund company researcher told reporters that the current supply situation of hydraulic parts companies such as KYB and Kawasaki Heavy Industries is not stable, and their own accessories are also There is a shortage, so the capacity expansion of excavators in China will slow down in recent months. However, many companies have invested a lot of manpower and material resources, so they will not easily give up this part of the market.
The aforementioned senior executives of Zoomlion also pointed out that the excavator market will face an overall price war and a sharp drop in profitability. “This situation occurred five years ago in the loader market. At that time, there were 50 companies in the country with a production capacity of 300,000 units per year, but the demand was only about 100,000 units per year, resulting in some enterprises having only 300,000 yuan worth of products left. Less than 10,000 yuan in profits."
â‘ Single acting cylinder: only one end of the cylinder has a piston rod. Air is supplied from one side of the piston to generate air pressure. The air pressure pushes the piston to produce thrust to extend and return by spring or self weight.
â‘¡ Double acting cylinder: supply air alternately from both sides of piston, output force in one or two directions.
â‘¢ Rodless cylinder: general term for cylinders without piston rod. There are magnetic cylinder and cable cylinder.
The reciprocating cylinder is called swing cylinder. The inner cavity is divided into two parts by the blade, and the air is supplied to the two cavities alternately. The output shaft swings, and the swing angle is less than 280 °. In addition, there are rotary cylinder, gas-liquid damping cylinder and stepping cylinder.
Compared with the electric actuator, the cylinder can work reliably under harsh conditions, and the operation is simple, and the basic maintenance free can be realized. Cylinder is good at reciprocating linear motion, especially suitable for industrial automation in the most transmission requirements - workpiece linear handling. Moreover, only adjusting the one-way throttle valve installed on both sides of the cylinder can simply achieve stable speed control, which has become the biggest feature and advantage of the cylinder drive system. Therefore, for users without multi-point positioning requirements, most of them prefer to use cylinder from the perspective of convenience. At present, most of the applications of electric actuators in the industrial field require high-precision multi-point positioning, which is the result that it is difficult to achieve with the air cylinder.
The electric actuator is mainly used for rotating and swinging conditions. Its advantage lies in the fast response time and the precise control of speed, position and torque through the feedback system. But when it needs to complete the linear motion, it needs to be transformed by mechanical devices such as toothed belt or screw rod, so the structure is relatively complex, and there are high requirements for the working environment and the professional knowledge of the operation and maintenance personnel.
advantage
(1) The requirement for users is low. The principle and structure of the cylinder are simple, easy to install and maintain, and the requirements for users are not high. Electric cylinder is different, engineering personnel must have certain electrical knowledge, otherwise it is likely to be damaged due to misoperation.
(2) The output force is large. The output force of the cylinder is proportional to the square of the cylinder diameter; The output force of the electric cylinder is related to three factors: cylinder diameter, motor power and screw pitch. The larger the cylinder diameter and power, the smaller the screw pitch, the greater the output force. The theoretical output force of a cylinder with a diameter of 50 mm can reach 2000 n. for the electric cylinder with the same diameter, although the products of different companies are different, they are basically no more than 1000 n. Obviously, the cylinder has more advantages in terms of output force.
(3) Strong adaptability. The cylinder can work normally in high and low temperature environment, and has the ability of dustproof and waterproof, which can adapt to all kinds of harsh environment. Because of a large number of electrical components, the electric cylinder has high requirements for the environment and poor adaptability.
Air Cylinder, Pneumatic Cylinder, double acting cylinder, single acting cylinder, rodless cylinder
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