Axis2D = function (dim, scale, coordExtent, axisType, position) {
	        Axis.call(this, dim, scale, coordExtent);
	        /**
	         * Axis type
	         *  - 'category'
	         *  - 'value'
	         *  - 'time'
	         *  - 'log'
	         * @type {string}
	         */
	        this.type = axisType || 'value';

	        /**
	         * Axis position
	         *  - 'top'
	         *  - 'bottom'
	         *  - 'left'
	         *  - 'right'
	         */
	        this.position = position || 'bottom';
	    }
Generate sub axis model class
@param {string} axisName 'x' 'y' 'radius' 'angle' 'parallel'
@param {module:echarts/model/Component} BaseAxisModelClass
@param {Function} axisTypeDefaulter
@param {Object} [extraDefaultOption]