Cushion When a load that is operated by a cylinder must be stopped at the end of the stroke, the piston in the cylinder will collide with the cover unless an external stopper is provided. A built-in function that cushions the impact and the sound that are generated at this time is the cushion mechanism. There are two types in the cushion mechanism as below. Rubber bumper: Dampens the impact sound and prevents the installation area from becoming loosened or damaged by the impact. Air cushion: Similar to a rubber bumper, but achieves a higher level of effectiveness. It cushions the vibrations that are generated by collision. Note) Depending on the model of the cylinder, it might not be possible to have either of the above two cushions built into the cylinder. Even if the one of the cushion mechanisms described above is used for stopping a load, it might not be possible to completely absorb the impact if the kinetic energy of he load is too large. Therefore, be careful of overloading or excessive speed. The kinetic energy of a load can be expressed by the formula given below. Kinetic energy absorbable by the cushion mechanism is the table at right. When the values are exceeded, following countermeasures are required like using a bigger bore size cylinder or mounting an external stopper, etc. Formula E: Kinetic energy [J] m: Load mass [kg] V: Max. piston speed [m/s] Bore size (mm) Standard type 0.022 0.038 0.055 0.09 0.15 0.26 0.46 0.77 1.36 2.27 With rubber bumper 0.043 0.075 0.11 0.18 0.29 0.52 0.91 1.54 2.71 4.54 12 16 20 25 32 40 50 63 80 100 Series CQ2 Allowable kinetic energy (J) Bore size (mm) 5.8 6.1 6.6 6.6 7.1 7.0 7.5 8.0 0.40 0.63 1.00 1.60 2.50 4.00 6.40 10.00 20 25 32 40 50 63 80 100 Series RQ Effective cushion length (mm) Kinetic energy absorbable (J) Kinetic Energy Absorbable by the Cushion Mechanism R: Rod side, H: Head side Bore size (mm) Effective cushion length (mm) 15.0 15.0 15.0 24.0 29.0 21.0 21.0 21.0 22.5 22.5 28.5 28.5 Kinetic energy absorbable (J) 2.8 4.6 7.8 16 29 32.3 44.6 58.8 78.4 98.0 147 265 40 50 63 80 100 125 140 160 180 200 250 300 Bore size (mm) Rubber bumper Allowable kinetic energy (J) 0.012 0.035 0.090 Effective cushion length (mm) . 9.4 9.4 Kinetic energy absorbable (J) . 0.07 0.18 Air cushion 6 10 16 Series CJ2 Bore size (mm) Rubber bumper Allowable kinetic energy (J) 0.27 0.4 0.65 1.2 Effective cushion length (mm) 11.0 11.0 11.0 11.8 Kinetic energy absorbable (J) 0.54 0.78 1.27 2.35 Air cushion 20 25 32 40 Series CM2 Bore size (mm) Rubber bumper Allowable kinetic energy (J) 0.28 0.41 0.66 1.2 2.0 3.4 5.9 9.9 Effective cushion length (mm) R: 7.0, H: 7.5 R: 7.0, H: 7.5 7.5 8.7 11.8 11.8 17.3 15.8 Kinetic energy absorbable (J) R: 0.35, H: 0.42 R: 0.56, H: 0.65 0.91 1.8 3.4 4.9 11.8 16.7 Air cushion 20 25 32 40 50 63 80 100 R: Rod side, H: Head side Series CG1 Series CA2, CS1, CS2 Bore size (mm) Effective cushion length (mm) 18.8 18.8 21.3 21.3 30.3 29.3 R: 31.4 H: 29.4 Kinetic energy absorbable (J) 2.2 3.4 5.9 11 20 29 45 32 40 50 63 80 100 125 Series MB Series CG1 Series CA2 Series MB Series CS1 Series CS2 E = 2 x V2 ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・(7) m Bore Size Selection 1823 Technical data