js中配置amcarts，Y轴最大值最小值用maximun和minimum限定不了

如题，用amcharts做一个曲线图，Y轴配置参数如下：         var valueAxis1 = new AmCharts.ValueAxis();
         valueAxis1.axisColor = "#F20C00";
         valueAxis1.title = "温度";
         valueAxis1.axisThickness = 2;
         valueAxis1.minimum = 0;
         valueAxis1.maximum = 100;
         valueAxis1.strictMinMax = true;
可是画出来Y轴范围总是自动变，拖动zoom块也是一直变