Application of the principle of the hottest floati

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Application of floating cup principle in quantitative pump and variable displacement pump

the water in Dutch "hydraulic kitchen" is boiling. A few years ago, the innas bv Design Institute in Breda introduced a new and improved axial piston pump concept: the floating cup principle. After the successful development of a floating cup quantitative pump, the prototype of batch production has been manufactured (Fig. 1), which makes the Dutch interested in continuing the development. Subsequently, a variable type of the pump variable floating cup pump was developed

advantages of floating cup principle

innas Design Institute established its goal four years ago to develop a low-cost universal principle of hydraulic pump and put forward a scheme combining the advantages of existing pump principles. Therefore, an axial piston pump has been developed, which has the following advantages: on the one hand, the noise radiation is low, the efficiency is high (up to 95%), and the pressure fluctuation is low; On the other hand, the cost is greatly reduced. At present, the floating cup principle is further developed for adjustable pumps, which means that manufacturers of axial piston pumps and engines will face greater competition (Figure 2). The floating cup principle means that the relevant supporting documents of various ministries and commissions in the production technology of the hydraulic industry are followed by another evolutionary leap - a leap that automobile manufacturers have completed many years ago: chip free production, automatic measurement and classification can produce high-precision parts, and the single piece price is lower than the limit value in Europe

Figure 1 quantitative pump with floating cup device. The prototype of this new axial piston pump has been suitable for batch production

different from the traditional axial piston pump, this new type of piston pump has a total of 24 pistons firmly connected to the drive shaft through the rotor. Sealing and articulation functions are formed on the limiting surface between the single piston and the piston cylinder (hole). The traditional roller hole (floating cup) is designed as a "loose" part, which floats on two rotating roller plates. These plates are directly driven by the shaft to avoid large contact forces between the piston and the floating cup. The oil drainage is carried out through the tilt of the rotary disc that determines the position of the roller plate. In order to reduce the friction loss as much as possible, hydraulic pressure is used to compensate the force on the contact surface where large sliding force acts

Fig. 2 in the variable floating cup principle, the cylinder seems to float on two rotating roller plates

therefore, the application in variable displacement pump becomes possible.

a - adjusting piston B - roller plate C - control disc D - rotary disc e - counter piston

the design of quantitative pump has shown that a large number of pistons can reduce the pressure fluctuation by 80%. In addition, a large number of pistons have a positive impact on the shell noise and fluctuation noise. Compared with swash shaft and swash plate pumps, the noise level of floating cup quantitative pump can be reduced by 10dB at most

the combination of small friction and small fluctuation improves the adjustment quality in the system application. The low pressure fluctuation reduces the system noise, which is often transmitted to the application cylinder through the load sensing device. In addition, high efficiency has a beneficial effect on the required cooling capacity. In this way, for the system builder, the floating cup principle may become the basis of a new group of pump products with more compact structure

large scale production produces economic benefits

at first glance, compared with traditional pumps, it seems that the increase in the number of parts of floating cup pumps will lead to higher costs. However, the development of the floating cup principle is based on the typical production process methods in the automotive industry: sintering, precision stamping, deep drawing, forging, automatic measurement and grading as an excellent supplier of spray free materials. In the development, we not only pay attention to the simplicity of parts, but also avoid a series of complex tolerances

as for classification, this is an unconventional production strategy for hydraulic equipment manufacturers. The doubts often expressed by interested parties about the manufacturing cost of pistons and floating cups (1) it is understandable to collect data. As we all know, the size of leakage crack has a great impact on the efficiency and power density of axial piston pump. In the hydraulic industry, it is said that the cost of strict tolerance is very high

the trick of grading is to make full use of large quantities. Mass production with lower tolerances, followed by inspection and measurement in the micron range and the allocation of parts according to the size grade. The required fitting accuracy can be achieved through the fitting of the correct size. Combined with the chip free machining, which is mostly used in piston and floating cup manufacturing, high cost efficiency can be achieved

in the past two years, innas Design Institute has conducted research on key aspects of variable floating cup technology. Because the flow regulation should be doubled, a technically simple and cost-effective structure is of great significance. In addition, due to the mirror like structure, it is very important to supply oil for drainage through two rotating discs. It is confirmed that the deformation of the two control boards and the rotary disc under high pressure may lead to the formation of large leakage cracks, which will have disastrous consequences for the efficiency of the machine

the solution to the deformation problem is simple and inexpensive: the rotating disc is supported by the piston and floating cup with the same structure, just as it is contained in the rotating parts. On the adjusting mechanism of the rotary disc, it should also be noted that the larger force should be balanced as much as possible to minimize the deformation. Each rotary disc is driven by two reaction pistons to form a simple torque regulating rotary disc. The contact friction between the housing and the disc is reduced. Since the regulating force is distributed to multiple cylinders, the overall size of the pump can be kept small

actively test and strengthen market promotion

at the beginning of 2007, the preliminary test of variable models was started. During the year, variable displacement pumps will be provided to interested parties for manual control button boxes! The operation is more user-friendly. Since the quantitative floating cup pump has achieved excellent test results, it can be expected that in both mobile and fixed hydraulic technologies, variable displacement pump will be more important to users: for example, in load sensing system or injection molding machine. In fact, as for the floating cup principle, it is not a question of when to enter the market, but a question of which application this principle is first adopted. (end)

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