def __init__(self, pairdata):
        """
        Initialization of GearPair-object
        Should be overwritten in derived classes

        :rtype : object
        INPUT parameters:
        pairdata   : data of gear wheel pair (dictionary)
        Pinion     : pinion (GearWheel-instance)
        Gear       : gear   (GearWheel-instance)
        """

        self.data = deepcopy(pairdata)
        gear = {'z': self.data['z'], 'x': self.data['x'], 'alpha_n': self.data['alpha_n'], 'beta': self.data['beta'],
                'm_n': self.data['m_n'], 'rho_f': self.data['rho_f'], 'd_s': self.data['d_s'], 'c': self.data['c'],
                'b': self.data['b']}

        self.gear = self.__set_gear(gear)