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Torsional Damping Coupling

IP.com Disclosure Number: IPCOM000086515D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 26K

Publishing Venue

IBM

Related People

Baumeister, HK: AUTHOR [+5]

Abstract

In an inertial system which is intermittently driven, excess rotational energy is required to accelerate a driven mass and the excess energy must be dissipated by the system. The nonequilibrium dissipation of the excess energy may cause cyclic speed variations in the output drive which are undesirable and unacceptable under certain circumstances. The use of a viscoelastic damping coupling material reduces or eliminates the cyclic variations within the constraints of the geometry and system parameters of a driving system. Elastic deformation in torsion and viscous hysteresis losses results in a critical amount of damping for the output member.

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Torsional Damping Coupling

In an inertial system which is intermittently driven, excess rotational energy is required to accelerate a driven mass and the excess energy must be dissipated by the system. The nonequilibrium dissipation of the excess energy may cause cyclic speed variations in the output drive which are undesirable and unacceptable under certain circumstances. The use of a viscoelastic damping coupling material reduces or eliminates the cyclic variations within the constraints of the geometry and system parameters of a driving system. Elastic deformation in torsion and viscous hysteresis losses results in a critical amount of damping for the output member.

In the figure drive motor 1 supplies a continuous rotational output on shaft 2 which is connected to coupling 3 by a rigid connection (not shown). Driving output flange 4 is also connected to coupling 3 and has bonded or vulcanized to it the elastomeric damping disc 5 which is also bonded to the input flange 6 rigidly connected with input couple 7. Input couple 7 drives a clutch (not shown) to intermittently connect the output of motor 1 to the input of a driven member, e.g., mass 8 and beveled gear 9. It is desired to accelerate the mass 8 and beveled gear 9 in a smooth manner with a critical amount of damping in the drive system, such that unwanted oscillations in the output velocity of beveled gear 9 do not occur.

The relative motion of the axial shafts or coupling members 3, 7 and 8, under nonequilibrium loading conditions, may be modified by the torsional deformation of the coupling medium 5. This has the effect of reducing the instantaneous torque of the output shaft, and results in a more nearly equilibrium transfer of energy from the motor to the driven member. This characteristic must be balanced against transmitting a sufficient amount of nonequilibrium energy in order to overcome the inertia of the output elements 8 and 9 as well as the output coupling members 6 and 7. This characteristic is dependent upon the shear modulus of the coupling medium 5 and is reflected in the hardness of the elastomeric compound of disc 5. Hardness of the elastomeric compound 5 is tailored to suit the specific requirements of a given example which will follow, by suitable compounding practices, in making the elastomeric material. In addition, the time to reach an equilibrium output velocity may be reduced by increasing the torque capacity of the system and dissipating the excess energy or work through hysteresis losses in a viscous damping medium. This is provided in the compound of the damping disc 5. However, the effect of compounding is less noticeable than for the overall modulus of shear, noted above. Through a proper combination of viscous response characteristics and shear modulus in the compound of disc 5, excessive torque amplitudes of instantaneous loadings may be avoided, and an adequate approach to equilibrium energy transfer may be established within an allowable...