Low-vibration cylinder

Abstract

The invention relates to a cylinder (10) which is set up for application of at least one hollow cylinder, the cylinder (10) having a layer structure which comprises in this order, from inside to outside, a base layer (12) or a cylinder core, a first compressible layer (14), a filling layer (16), an interlayer (18), a second compressible layer (20) and an outer layer (22), the outer layer forming a lateral surface of the cylinder. The invention further relates to arrangements comprising at least one such cylinder (10) and further cylinders.

Claims

1. A hollow cylinder, the cylinder having a layer structure which comprises in this order, from inside to outside, a base layer or a cylinder core, a first compressible layer of an elastic material, a filling layer, a first interlayer, a second compressible layer of an elastic material, a second interlayer and an outer layer, the outer layer forming a lateral surface of the cylinder, wherein the hardness of the first compressible layer and the hardness of the second compressible layer are less than the hardness of the base layer, the filing layer, the interlayers and the outer layer.

2. The cylinder according to claim 1, wherein the cylinder has at least one further interlayer, the at least one further interlayer being disposed between the first compressible layer and the filling layer.

3. The cylinder according to claim 2, wherein the elastic material of the first compressible layer is an ethylene-propylene-diene rubber, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a polyether-amide, a silicone rubber or combinations thereof and the elastic material of the second compressible layer is an ethylene-propylene-diene rubber, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a polyether-amide, a silicone rubber or combinations thereof.

4. The cylinder according to claim 1, wherein the cylinder comprises at least one channel which is disposed in its interior and which communicates with openings on the lateral surface of the cylinder and/or with openings or connections on an end face of the cylinder and/or, if the cylinder is designed as a hollow cylinder having a base layer, with openings on an inside or on an end face of the hollow cylinder.

5. The cylinder according to claim 1, wherein the material of the base layer and/or of the first interlayer is a fibre-reinforced plastic.

6. The cylinder according to claim 1, wherein the first compressible layer and/or the second compressible layer has a thickness in the range from 0.1 mm to 10 mm.

7. The cylinder according to claim 1, wherein the ratio between the sum of the thicknesses of the base layer, the first interlayer and the second interlayer and the outer layer to the sum of the thicknesses of the compressible layers is in the range from 0.01 to 400.

8. The cylinder according to claim 1, wherein the ratio of the thickness of the first compressible layer (14) to the thickness of the second compressible layer (20) is in the range from 0.1 to 10.

9. The cylinder according to claim 1, wherein the outer layer has a thickness in the range from 0.1 mm to 50 mm.

10. The cylinder according to claim 1, wherein on excitation with a testing hammer having a mass of 390 g, a length to the fulcrum of 245 mm and a deflection of 30, resonant vibrations of the cylinder have at most an acceleration value of 3 m/s.sup.2.

11. The cylinder according to claim 1, wherein vibrations of the cylinder decay exponentially, with a decay constant d having a value of 0.15<d<0.95.

12. The cylinder according to claim 1, wherein the cylinder is a printing forme cylinder.

13. An arrangement comprising the cylinder according to claim 12 and a printing sleeve disposed on a lateral surface of the cylinder.

14. The cylinder according to claim 1, wherein the cylinder is a hollow cylinder forming an adaptor sleeve or a printing sleeve.

15. An arrangement comprising a first cylinder according to claim 14 and a second cylinder according to claim 14 which is disposed in the interior of the first cylinder.

16. The arrangement according to claim 15, further comprising a printing sleeve disposed on a lateral surface of the first cylinder.

17. The cylinder according to claim 1, wherein the material of the second interlayer is a fibre-reinforced plastic.

18. The cylinder according to claim 1, wherein the material of the first compressible layer and the material of the second compressible layer have a Shore A hardness in the range from 1.5 to 80.

19. A hollow cylinder, the cylinder having a layer structure which comprises in this order, from inside to outside, a base layer or a cylinder core, a first compressible layer, a filling layer, a first interlayer made of a fibre-reinforced plastic, a second compressible layer, a second interlayer made of a fibre-reinforced plastic, and an outer layer for accommodating further cylinders, the outer layer forming a lateral surface of the cylinder, the outer layer being dimensionally stable, wherein the first and the second compressible layer have an elasticity modulus lower than the elasticity modulus of any of the other layers of the cylinder.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a hollow cylinder having a layer structure in a sectional view,

(2) FIG. 2 shows a schematic representation of a measuring arrangement for ascertaining the vibration behaviour of a (hollow) cylinder,

(3) FIG. 3 shows a spectrum of the vibrations of a (hollow) cylinder,

(4) FIG. 4 shows a diagram of the decay behaviour of a first (hollow) cylinder, and

(5) FIG. 5 shows a diagram of the decay behaviour of a second (hollow) cylinder.

(6) FIG. 1 shows a cylinder 10 implemented as a hollow cylinder. The cylinder 10 has a layer structure which has, in this order from inside to outside, a base layer 12, a first compressible layer 14, a filling layer 16, an interlayer 18, a second compressible layer 20 and an outer layer 22.

(7) In other embodiments, the cylinder 10 may also be configured as a solid cylinder, in which case a cylinder core is used instead of the base layer 12. Furthermore, there may optionally be further interlayers disposed in each case between the first compressible layer and the filling layer and between the second compressible layer and the outer layer.

(8) FIG. 2 shows a measuring arrangement 100 for studying the vibration behaviour of a cylinder 10. The vibration behaviour of the cylinder 10 here is determined in particular by the frequencies at which resonances occur. Moreover, the respective extent of a resonance is important for the properties of the cylinder.

(9) To determine the item, in other words the frequency of a resonance, and the extent thereof, the cylinder 10 being studied is inserted into the measuring arrangement 100. A measuring sensor 102 is secured on the cylinder 10. The measuring arrangement 100 further comprises a hammer 104 for the controlled stimulation of the cylinder 10 with a defined jolt.

(10) The measuring sensor 102 is configured, for example, as an acceleration sensor and is set up to measure vibrations stimulated in the cylinder 10 after a jolt. For this purpose, the measurement data of the measuring sensor 102 are transmitted to a measuring unit 106, where they are stored and analysed.

EXAMPLES

(11) Pendulum Impact Tests

(12) For a measurement using the measuring arrangement 100 described with reference to FIG. 2, a hollow cylinder configured as an adaptor sleeve is engaged over a fitting steel cylinder. The measuring sensor 102 is secured at of the length of the adaptor at 12 o'clock, i.e. on the top side. At 3 o'clock, i.e. at an offset of 90 to the measuring sensor 102, a strike is made with the hammer 104 at the same length position. This strike would influence the measurement. The hammer 104 has a mass of 390 g and a length to the fulcrum of 245 mm. For a defined jolt on the cylinder 10, the hammer 104 is deflected by 30 degrees and then released. The head of the hammer 104 consists of rigid plastic, so that the cylinder 10 under measurement is not damaged.

(13) The following trials were performed using the VIBXpertII instrument with the Omnitrend software version 2.91 (DB Prftechnik) and the fitting measuring sensor IPC100 mV/g (DB Prftechnik), the measuring sensor being secured with wax on the cylinder being studied.

(14) The resonance frequencies are measured by capture of the time profile of the acceleration due to the hammer blow, measured by the measuring sensor 102. The time signal is subsequently subjected to a frequency analysis by the measuring unit 106, by means of Fourier transformation or numerical transformations, for example.

(15) The resonances of the cylinder are measured via a five-fold measurement in the frequency range from 2 Hz to 6400 Hz with a resolution of 0.25 Hz by way of a strike test. The time profile or the decay of the vibrations is measured with a single measurement over the entire frequency range from 1 Hz to 10 000 Hz with a sampling rate of 65.5 kHz and over a time of 450 ms via the acceleration measurement.

(16) The time profile looks at how quickly the vibration decays. The measured values of the time profile are analysed for this purpose.

(17) The enveloping exponential function
A(t)=A.sub.0e.sup.dt
is fitted to the measurement values themselves by curve fitting. In this case the amplitude A.sub.0 is the maximum acceleration at the time t=0. The decay constant d determines how quickly the exponential function falls, with the exponential function falling more quickly as d becomes greater. The smaller A.sub.0 is and the quicker the exponential function falls, the greater the damping in the cylinder.

(18) FIGS. 4 and 5 show examples of acceleration measurements in the time range. Plotted on the Y axis in each case is the acceleration A in m/s.sup.2, and on the X axis the time tin ms.

(19) FIG. 4 shows a first example of an acceleration measurement on a first cylinder configured as an adaptor sleeve. The first adaptor sleeve has a high decay constant d of 0.9, and the measured acceleration at the starting time of the measurement was 850 m/s.sup.2.

(20) FIG. 5 shows a second example of an acceleration measurement on a second cylinder configured as an adaptor sleeve. The second adaptor sleeve has a high decay constant d of 0.1, and the measured acceleration at the starting time of the measurement was 1350 m/s.sup.2.

(21) As can be seen from the representation in FIGS. 4 and 5, the vibration of the first adaptor sleeve decays more rapidly than in the case of the second adaptor sleeve, owing to the greater decay constant d.

(22) Printing Tests

(23) In addition the cylinders produced were trialled on a printing machine and the printed image obtained evaluated. For these trials, the printing machine used was a Soma Optima 2 equipped with corona treatment (Soma spol. s r.o.), Flexcell NX printing plates with a thickness of 1.12 mm (Kodak) and FlexPrint MV magenta ink (Flint Group), BOPP with 20 m thickness and 1300 mm width. The printing result was assessed at printing speeds of 375 m/min and 500 m/min. Here, the printing result ought to be good overall and additionally there ought to be only slight differences occurring between web centre and web edges. In the case of highly vibrating cylinders, large differences have been observed between middle and edge. Results are assessed as + if good (little vibration), as if poor, and as 0 for results in between.

(24) For the measurements listed below in Table 2, various cylinders of the invention and comparative examples with different layer sequences were produced and were studied in accordance with the above-described measurement and evaluation. Table 1 describes their construction.

(25) Here, the abbreviation PEUR denotes a polyester-urethane rubber having a density of around 400 kg/m3, a tensile strength of >3.5 N/mm.sup.2 and an elongation at break of >330%. The abbreviation GRP denotes a glass fibre-reinforced polyester resin and CRP denotes a carbon fibre-reinforced polyester resin.

(26) TABLE-US-00001 TABLE 1 1.sup.st 2.sup.nd 2.sup.nd Base compressible 1.sup.st further Filling compressible further Outer Adaptor No. Hollow layer layer interlayer layer Interlayer layer interlayer layer Inventive 1 no 1 mm GRP 2 mm PEUR 1.2 mm GRP 13 mm 0.4 mm GRP 3 mm PEUR 4.8 mm CRP 1 mm PU PU foam Inventive 2 no 1 mm GRP 2 mm PEUR 1.2 mm GRP 16 mm 1.2 mm GRP 3 mm PEUR 1.2 mm GRP 1.5 mm PU PU foam Inventive 3 yes 1 mm GRP 2 mm PEUR 1.2 mm GRP 16 mm 1.2 mm GRP 1 mm PEUR 4.8 mm CRP 2 mm PU PU foam Inventive 4 yes 1 mm GRP 2 mm PEUR 1.2 mm GRP 15 mm 1.2 mm GRP 2 mm PEUR 4.8 mm CRP 2 mm PU PU foam Inventive 5 no 1 mm GRP 2 mm PEUR 16 mm 1.2 mm GRP 3 mm PEUR 1.5 mm PU PU foam Inventive 6 no 1 mm GRP 2 mm PEUR 1.2 mm GRP 16 mm 1.2 mm GRP 3 mm PEUR 1.5 mm PU PU foam Comparative no 1 mm GRP 3 mm PEUR 1.2 mm GRP 12 mm 0.4 mm GRP 4.8 mm CRP 1 mm 1 PU PU foam Comparative yes 1 mm GRP 3 mm PEUR 1.2 mm GRP 12 mm 4.8 mm CRP 1 mm 2 PU PU foam Comparative no 1 mm GRP 1 mm PEUR 1.5 mm GRP 16 mm 0.4 mm GRP 4.8 mm CRP 1 mm 3 PU PU foam Comparative no 1 mm GRP 2 mm PEUR 1.2 mm GRP 15 mm 0.4 mm GRP 4.8 mm CRP 1 mm 4 PU PU foam

(27) TABLE-US-00002 TABLE 2 Time profile acceleration at of the length Printing results Cylinder No. d A 375 m/min 500 m/min Inventive 1 0.9 850 + + Inventive 2 0.65 600 + + Inventive 3 0.2 1100 + + Inventive 4 0.16 1050 Inventive 5 0.92 400 Inventive 6 0.58 250 Comparative 1 1.05 750 Comparative 2 0.07 1100 Comparative 3 1.8 550 Comparative 4 1.9 800

LIST OF REFERENCE NUMERALS

(28) 10 cylinder 12 base layer 14 first compressible layer 16 filling layer 18 interlayer 20 second compressible layer 22 outer layer 100 measuring arrangement 102 measuring sensor 104 hammer 106 measuring unit