BARREL COUPLINGS FOR DRUMS

Transcription

1 BARREL COUPLINGS FOR DRUMS MVX SERIES MECHANICAL AND TRANSMISSIONS

2 4. APPLICATION 6. DESIGN AND CHARACTERISTICS 9. ADVANTAGES BETWEEN HOIST GEAR AND BARREL COUPLINGS 10. COUPLINGS SIZE SELECTION 14. DIMENSIONS AND PARAMETERS MVX 16. SHAFT CONNECTION TYPES 17. WEAR INDICATOR 19. MANUFACTURING PROGRAM

3 COMPANY PROFILE Meccanica Vimercati was founded in 1972 as a mechanical engineering workshop specialized in the production of high precision mechanical parts on behalf of third parties. Over the last twenty years, we have specialized in the production of a wide range of mechanical couplings and transmissions for an increasingly demanding clientele worldwide. In Italy, we design and produce Barrel Couplings for hoisting equipments, Gear Couplings, Special Bearing Cages. Continuous research into cutting-edge technology is one of the strengths of Meccanica Vimercati. In fact the production department can rely on the latest generation CNC machinery and tooling. Production technology follows strict rules in the pursuit of total product quality and customer satisfaction. 3

4 APPLICATION MVX Barrel Couplings are recommended to connect the output shaft of a gearbox with the rope drum of cranes and hoisting equipment. The MVX coupling allows to remedy the problems deriving from a rigid connection between the gearbox shaft and rope drum, eliminating the need of a third support and compensating for substantial misalignments. Thus it eliminates the difficulty of alignment during component assembly, stress concentration mainly on the gearbox shaft; high bending moments due to misalignments and subsequent damage to bearings and gears, long shut-down times due to long installation times and subsequently increasing general costs. 4

5 RIGID CONNECTION WITHOUT MVX BARREL COUPLINGS Fig. 1 CONNECTION WITH MVX BARREL COUPLINGS Barrel Coupling Fixed bearing Fig. 2 5

6 DESIGN DESIGN AND DESIGN AND CHARACTERISTICS MVX Barrel Couplings are built with special high quality steel and the perfect dimensions are guaranteed by the latest generation CNC technology. In order to guarantee easy assembly and maintenance, MVX Barrel Couplings comprise only a small number of components (Fig. 3-4) 6

7 Fig. 3 1 External Sleeve 2 Hub 3 Barrel rollers 4 Cover 5 Wear indicator 6 Cover screws 7 Grease connection 8 Seal 7

8 Fig. 4 MVX Barrel Couplings can compensate misalignments of the hub and the external sleeve thanks to hardened steel barrel rollers, positioned in the holes formed by the machining of hub and external sleeve, with high precision internal tolerance. The described design allows to achieve high torque and radial load ratings, to compensate unpredictable axial displacements and misalignments between gearbox and rope drum. 8 MVX Barrel Couplings is provided ready assembled and without lubricant. They are supplied with a corrosion protection adequate for normal storage conditions. According to Meccanica Vimercati s warranty policy the coupling hub and the external sleeve cannot be supplied separately. The coupling should be considered as a complete spare part.

9 ADVANTAGES BETWEEN HOIST GEAR AND BARREL COUPLINGS The first advantage of the use of a MVX Barrel Coupling instead of a gear coupling is a significant decrease in needed room. The barrel coupling is partly positioned inside the drum and it is quite narrower than the corresponding gear coupling. Barrel couplings are subjected to much lower bending stress compared to gear couplings. As barrel couplings have increased contact area, the radial load is better distributed and hence the life of the coupling is increased. The radial load is also better distributed with coupling wear. b1 b2 9

10 COUPLINGS SIZE SELECTION Max. torque T max [Nm] The determined torque T max to be transmitted on the basis of the installed or used capacity of the coupling must be smaller than the max. permissible torque TN max of the Barrel Coupling in accordance with Table 1. N = max. motor power [kw] n = speed of the rope drum [rpm] fs = necessary service factor for drive groups Drive group according to DIN15020 F.E.M fs 1Bm / 1 Am M3 / M4 1,25 T max = N 9550 n fs 2 m M 5 1,40 3 m M 6 1,60 4 m M 7 1,80 5 m M8 2,00 MAX. RADIAL LOAD F max [N] The radial load is the portion of the load that must be covered by the barrel coupling due to the payload and the weight of the cable hoist. Since the Barrel Coupling forms one of the drum bearings, it must bear part of the total load. The static load P [N] on the rope drum must be determined first before calculating the radial load F max Q = max payload under hook [N] G = load of tackle and ropes[n] z = transmission ratio of tackle ƞ = efficiency of the rope drum and tackle Efficiency η P = (Q + G) z ƞ z Slide bearing Roller bearing 2 0,92 0,97 3 0,90 0,96 4 0,88 0,95 5 0,86 0,94 6 0,84 0,93 7 0,83 0,92 8 0,81 0,91 10

11 Calculation of the radial load F max with multiple rope lines to the drum P = static load on the rope drum [N] W = dead weight of the rope drum [N] F max = P + W 2 2 Multiple rope lines Calculation of the radial load F max with a single rope line to the drum P = static load on the rope drum [N] W = dead weight of the rope drum [N] b = smallest distance from the rope to the middle of the barrel roller [mm] I = distance between the bearings [mm] The determined radial load F max must be smaller than the max permissible radial load Fr max of the Barrel Coupling in accordance with Table 1. ( F max = P 1- ) [ ] b + W l 2 Single rope line 11

12 Option for corrected radial load Fr agg [N] If the max torque TN max is smaller than the max. permissible torque TN max of the preselected barrel coupling, the max permissible radial load Fr max can be corrected or increased. The unused torque can be converted for the purporse of increasing the max permissible radial load Fr max as follows: T max = max torque. [Nm] TN max = max permissibile torque [Nm] according to Table 1 fs = necessary service factor for drive groups according to DIN15020 or F.E.M Fr max = max permissibile radial force [N] according to Table 1 The reverse procedure to increase the max. permissible torque if the radial load is not fully exploited, is not allowed. Fr agg = (TN max - T max ) fs + Fr max Check the geometric dimensions of the hub-shaft connection It must also be checked whether or not the diameter of the gear shaft is smaller than the max. permissible bore diameter in the barrel coupling according to Table 1. In addition, the transmitted torque related to the hub/shaft connection must be checked for all types of connection. 12

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14 DIMENSIONS AND PARAMETERS MVX TABLE 1 MVX TN max (Nm) Fr (N) d max [mm] d min [mm] D [mm] L [mm] L min. [mm] M [mm] B [mm] C [mm] E [mm] 2, , size

15 F [mm] K [mm] G [mm] R [mm] e [mm] I [mm] d2 [mm] d1 i [mm] d3 [mm] Max.axial displacement [+\-mm] weight [kg] , M , M , M , M , M , M , M M , M M , M M , M M , M M , M M , M M M M M M M M M M M M M M M M size size size

16 SHAFT CONNECTION TYPES 0.0 PILOT 0.1 CYLINDRICAL 1.1 ONE KEYWAY 1.2 TWO KEYWAYS AT 180º 1.3 TWO KEYWAYS AT 120º 1.4 TWO KEYWAYS AT 90º 2.1 CONICAL BORE ONE STRAIGTH KEYWAY 2.2 CONICAL BORE TWO STRAIGTH KEYWAYS 3.1 CONICAL BORE ONE TAPERED KEYWAY 3.2 CONICAL BORE TWO TAPERED KEYWAYS For any special requests please do not hesitate to contact our Technical Assistance Office 16

17 INDICATOR WEAR INDICATOR MVX Barrel Couplings are provided with a wear indicator which allows to perform preventative maintenance operations. The amount of wear in the barrel coupling can be inspected using the wear indicator by comparing the location of the center marker to the wear mark. The recommended wear limits are shown in Table 2. MVX Barrel Couplings must be replaced whenever the mark exceeds the recommended limits. The recommended wear limits shown in Table 2 are for applications in which the load is applied in only one direction (e.g. crane hoists). In the case where the coupling is loaded in both directions (e.g. travelling cranes), then the recommended wear limits (u/2) must be halved. Unless otherwise specified in the customer s order, the wear indicator marks on the coupling will be equal to the values shown in Table 2. Tab. 2 Coupling size 2,5 5 7, Max. wear u/2 [mm] Coupling size Max. wear u/2 [mm] INDICATOR u/2 u 17

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19 MANUFACTURING PROGRAM PROGRAM Gear Couplings Barrel Roller Couplings Barrel Couplings for drums 19

20 MECCANICA VIMERCATI S.R.L. Via W.Tobagi, , Cernusco sul Naviglio (MI) Italy C.F./P.Iva T F info@meccanicavimercati.com