Catalog – Components - Allied Automation, Inc.

Design ConsiderationsAll individual bearing force equations below pertainto a four bearing carriage which is at constant uniformvelocity or with the carriage at rest. During accelerationand deceleration intervals of a positioning system,the force exerted upon an individual bearing changesas the acceleration or deceleration rate varies. In mostcases, the extra force acting upon an individual bearingduring the acceleration interval is offset by a reducedforce during the deceleration interval. Therefore, usingjust the constant uniform velocity equations willadequately determine the life of an individual bearingfor a particular application.d 1d 2d 3d 4F BXF BYF BZW- distance between center lines of shafts or rails (in)Load Capacities- distance between center lines of linear bearing blocks (in)- distance between carriage center and load center of gravity (in)- distance between carriage center and load center of gravity (in)d r - distance between carriage surface and linear bearings (in)- force acting upon bearing in X-axis direction (lbs)- force acting upon bearing in Y-axis direction (lbs)- force acting upon bearing in Z-axis direction (lbs)- load weight (lbs)AHorizontal ApplicationsW Example #1d 4d 31 2WExample #2d 41W2d 3d 1 d 13 4 3 4d 2d 2WF 1Z F 3Z F 2Z F 4ZF 2Z F 4ZF 1Z=W4+F 2Z=W4-F 3Z=W4+W2W2W2xxxd 4d 2d 4d 2d 4d 2++-W2W2W2xxxd 3d 1d 3d 1d 3d 1F 4Z=W4W d 4- x -2d 2W2xd 3d 1Side Mounted ApplicationsVertical ApplicationsWd 4 W d 3F 1 ZF 2Zd rWd 4d rd 11 23F 3ZF 4Zd 14d 2F 1Y F 2YF 3Y F 4YF 3Yd 2 F 3Xd 3F 4YF 4XW W d 4F 1Z= F 3Z= + x4 2F 2Z=F 4ZW W= - x4 2d 2d 4d 2F 1Y F 3Y=W2xd 3d 1+ d rW d 4 + d rF 1X F 3X= x2F 1X+ F 3X F 2X+ F 4Xd 2F 1XF 1Y F 3Y F 2Y F 4YF 1Y F 3Y=+W2x+d 3d 2Mean Bearing Load CalculationWhen the force acting upon an individual bearing varies,as is the case with the bottom axis bearings of a multiaxespositioning system, a mean bearing load calculationdetermines the life of that bearing.F avg ( F min + 2 x F ) max=13F max - maximum force acting upon bearing (lbs)F avg - average force acting upon bearing (lbs)F min - minimum force acting upon bearing (lbs)LINTECH ®Positioning ComponentsA-15