ahp informiert. 1 Basic information about hydraulic cylinders In this chapter the cylinder types, physical details and special applications are explained. This chapter gives important explanation about the general assembly and the quality differences of hydraulic cylinders. 3 Switches and sensor systems In this chapter the correct application and implementation of hydraulic cylinders with switching and position measuring systems is explained. 4 Operating and maintenance instructions In this chapter the basics about how to service hydraulic cylinders is explained. E.g. a detailed explanation of how to change seals. A clear overview ot the large product range from AHP Merkle. A fast selection giving the perfect product is possible through the required product properties.

Basic information about hydraulic cylinders 1.1 Descriptions of the various types of cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 General calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Conversions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Force / piston diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

Switches and sensor systems 3.1 3.2 Magnetic field sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Inductive proximity switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Linear position transducers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Operating and maintenance instructions 4.1 4.2 Procedure for assembly and maintenance work . . . . . . . . . . . . . . . . . . . . . . . . ....

Basic information about hydraulic cylinders 1 Basic information about hydraulic cylinders 1.1 Descriptions of the various types of cylinders Differential cylinders For hydraulic cylinders, a distinction is made between differential cylinders and double rod cylinders based on their methods of operation. Differential cylinders generally have only one piston rod. This means that there are differences in the size of the surfaces that determine the force generated and the speed of the piston. Under the same pressure and flow conditions both the force generation and the speed of the forwards and return...

Circular block cylinder (RZ) Circular block cylinders are a variant of the block cylinder product line. Their structural design is the same as that of the block cylinder. Their externally visible difference from them is their cylindrical housing, which has proven to be advantageous in some installation situations where little space is available. Flanged cylinder (FZ) Flanged cylinders are round hydraulic cylinders with flanges. Thanks to their small dimensions they are often used in fixture and mold construction. The pressure ports are located in the screw-on flange, and thus at one end of the...

Basic information about hydraulic cylinders Stamping cylinder (STZ) The stamping cylinders are a further development of the block cylinder. A characteristic feature of stamping cylinders is that thanks to the special design and arrangement of their seals and guides they can absorb the large dynamic loads that are generated during stamping. Screw-in cylinder (EZ) The most space-saving option among AHP Merkle hydraulic cylinders are the screw in cylinders. Because these cylinders are screwed directly into the tool, the tool functions as a housing. The customer / user only has to create the mounting...

1.3 General calculations Conversions N Force / piston diameter effective piston surface [mm2] force [N] pressure [bar] piston diameter [mm] rod diameter [mm] efficiency of the hydraulic cylinder The efficiency [η], which is for the most part the result of the frictional losses (seals, guides), can be approximated as 0.8. The larger the cylinder, the smaller the effect of friction on the overall force. At speeds of less than 0.05 m/s (0.164 feet/s), the friction is practically independent of the pressure. For piston diameters of 100 mm (3.94 inches) and larger the percentage loss is not more than...

Basic information about hydraulic cylinders Especially for pushing loads, in addition to the dimensioning of the hydraulic cylinder it is also necessary to calculate the buckling strength of the piston rod. For easy calculation of hydraulic cylinders you can use the cylinder calculator available on the Internet at www.ahp.de, which will recommend to you the suitable cylinder for your application. Piston speed from flow rate / pump capacity v: Q: A: P: p: η: piston speed [m/s] flow rate [l/min] piston surface [mm2] required pump capacity [KW] system pressure [bar] efficiency of the hydraulic system...

Buckling strength Proper dimensioning of hydraulic cylinders with pushing load makes use of the four so-called Euler buckling modes. Because the following calculations already include a quintuple safety margin, the results can be used directly. d: F: L: Piston rod diameter [mm] Axial force [N] Mounting distance [mm] First Euler buckling mode: piston rod is neither guided nor fastened – cylinder fixed Second Euler buckling mode: piston rod and cylinder with rotating bearing Third Euler buckling mode: piston rod with rotating bearing – cylinder fixed Fourth Euler buckling mode: piston rod guided...

Basic information about hydraulic cylinders 1.4 Pressures in hydraulic cylinders Pressure spikes In the operation of hydraulic cylinders, it is a basic rule that the permitted pressure values must not be exceeded, even for a short time. It must be ensured that no pressure spikes occur in the system, either caused by the pump, nor due to external mechanical influences. Otherwise damage may result in the seals or the cylinder. Pressure spikes due to highly dynamic motions must always be absorbed by means of separate cushioning measures in the cylinder (cushioning) or outside of the cylinder (shock...