Nacházíte se zde: Úvodní stránka > Cylinders > Double acting cylinders > Rodless series S1 > Rodless series S1 - technical data

Double acting pneumatic cylinders

rodless, series S1

The rodless cylinders of the S1 series are particularly useful where there is no space for a standard cylinder. The piston rod does not extend from the cylinder. Thanks to their maximum stroke of up to 6 meters, they can also be used in applications where the use of a conventional cylinder would be impossible. This series uses the proven two-strip principle.

Technical information

Technical data

Working pressure	0,6 MPa
Min. pressure	0,3 MPa
Max. pressure	1,0 MPa
Temp. range	-20^oC to +80^oC
Working medium	modified compressed air
Carriage speed	min. 20 mm.s^-1 max. 3 m.s^-1

Piston dia.	16	25	32	40	50
Force at 0,6 MPa [N]	125	250	420	640	1050
Connection	M5	G1/8"	G1/4"	G3/8"	G3/8"
Length of adjustable cushioning [mm]	16,5	25	32,5	41,5	52
Max. stroke [mm]	5000	6000	6000	6000	6000
Stroke tolerance [mm]	+2,5	+2,5	+3,2	+3,2	+3,2

For long-term and trouble-free operation, we recommend:
1) speed maximum 1 m.s^-1
2) use a hydraulic shock absorber if the efficiency of the internal cushioning approaches the limit value
3) if the cylinder is used vertically, the cushioning capacity is reduced by 40%
4) maintain a correct and constant lubrication

The pneumatic sealing is achieved through an axial elastomer stripseal reinforced with Kevlar. This system guarantees dimensional stability even with high speeds. The external protection seal consists of a thermoplastic stripseal reinforced with Kevlar.

Weights

Piston dia.	16	25	32	40	50
Base weight (0mm) with standard carriage [kg]	0,31	0,75	1,31	2,60	4,79
Base weight (0mm) with medium carriage [kg]	-	0,84	1,48	2,91	5,55
Base weight (0mm) with long carriage [kg]	-	1,05	1,93	3,80	7,33
Weight of 100 mm of stroke [kg]	0,104	0,210	0,325	0,555	0,955

Construction / materials

caps: ø16: zamak ø25-50: die-cast aluminium
tube: anodized aluminium
piston: aluminium
piston guide slide: acetalic resin
sealings: NBR
magnet: neodymium

Permissible static load and stress

Cylinder force F	Static load			Static moment
Cylinder force F	P1	P2	P3	M1	M2	M3

Piston dia.	F [N] at 0,6 MPa	P1 [N]	P2 [N]	P3 [N]	Standard carriage [Nm]			Medium carriage [Nm]			Long carriage [Nm]
Piston dia.	F [N] at 0,6 MPa	P1 [N]	P2 [N]	P3 [N]	M1	M2	M3	M1	M2	M3	M1	M2	M3
16	125	100	100	25	5	0,2	0,8	-	-	-	-	-	-
25	250	200	200	50	8	2	3	14	3	5	15	6	9
32	420	250	250	65	9	3	4	15	4	7	28	8	12
40	640	350	350	90	11	9	14	16	14	20	31	27	39
50	1050	500	500	125	19	13	19	29	20	30	52	36	53

A moment is the product of the load (N) and the arm (m), i.e the distance between the centre of gravity of the load and the longitudinal axis of the piston. Please note that in dynamic conditions, the load must be reduced due to effects associated with the speed. Calculation of permissible dynamic stress and verification of internal damping efficiency can be found below.

Examination and verification of internal cushioning

In a system with moving masses, as in the case of rodless cylinders, it is essential to control the dissipation of the system’s kinetc energy as it is brought to a stop. First of all, it is necessary to establish and verify the most suitable method for cushioning the system, in order to avoid the moving mass (carriage with load) striking against the end-caps and compromising the life of the cylinder.

If the point corresponding to a given load and speed lies beneath the appropriate curve, the cushioning is able to absorb the kinetic energy of the system. Vice versa if the point lies above the curve, the cushioning is not able to absorbe the kinetic energy. In that case you must:
a) decrease the load and mantain the translation speed
b) decrease the speed and mantain the load
c) select a cylinder with a bigger bore or with twin chambers
d) use external hydtŕaulic shock absorber

Attention: if the cylinder is mounted vertically, the damping efficiency is reduced by 40%.

Dynamic load capacity

Procedure for determining the permissible values for dynamic stress:

determine the KRV coefficient according to the speed

multiply the permissible values for static stress by the KRV coefficient and the value calculated in this way is the maximum permissible value for dynamic stress

Example - verification of the suitability of the cylinder with a load directly on the carriage

As previously discussed, it is necessary to produce (for a correct use of the cylinder) a gradual deceleration of the moving mass. Let us consider the case of a S1 series cylinder with a load of 50 N placed on the carriage, at the max. translation speed of 1 m/s, as shown in the picture. Verify the cushioning capacity and calculate the capacity of the dinamic load and of the torque and bending moments.

P = 50 N
V = 1 m.s^-1
b1 = 110 mm

Verification of the cushioning capacity
According to the graph shown above a 50 bore size cylinder is able to absorb the developed kinetic energy developed by the application in the picture above, since the intersection point corresponding to the speed and load lies beneath the cushioning curve.

Calculation and verification of the dynamic load capacity
From the graph for the permissible dynamic load, we determine the value of the coefficient KRV. For a speed of 1 m.s^-1 and the series S1, the value of KRV = 0,26. The value of the permissible dynamic stress CD is the product of the coefficient KRV and the permissible static load CM (P1 value).
CD = CM · KRV = 500 · 0.26 = 130 N
Since the load P (50 N) is less than the calculated value of CD (130 N), the selected cylinder is suitable for use.

Calculation of dynamic torque
Different load applications have different moments M1 - M2 - M3, which directly influence the life of the cylinder. By selecting a cylinder that can support off -set loads, we can avoid compomising the cylinder life. Load must be applied, if possible, so that it acts through the centre point B.

In order to calculate the various moments, which act on the carriage, we must calculate the force, generated by the load, when it is subjected to accelerations and decelerations. We will therefore determine the deceleration „a“ at speed V and cushioning length L.

Ø	L [mm]
16	16,5
25	25
32	32,5
40	41,5
50	52

a = v²/(2 * L * 10^-3) = 1²/(2 * 52 * 10^-3) = 9,6 m.s^-2

The dynamic force F will then be

F = (P * a)/9,81 = (50 * 9,6)/9,81 = 49 N

The toquue is then given by the relation

MD1 = F * b1 = 49 * 110 = 5390 Nmm = 5,4 Nm

Since the permissible value of the torque M1 (19 Nm) is greater than the calculated value of MD1 (5.4 Nm), the selected cylinder is suitable for use. However, if, for example, the speed V = 2 m.s^-1, the cylinder would not meet the requirements in terms of internal damping efficiency or torque stress.

See also other examples given for the S5 series and VL1 series rodless cylinders.