Ogura clutch used to deliver the proper amount of tension for tightening screws.
Ogura hysteresis clutch series.
Description of Operation
The motor is turned on and off by the controller. The motor is connected to a series of gears which in turn drive the hysteresis clutch input shafts. The hysteresis input shafts are connected through the clutch to the output shaft which in turn drives the screw (HO 1,2,3,4). Once the predetermined tightening torque is reached on each screw the clutch simply slips. While it is slipping it is delivering its predetermined tightening torque.
Reason for Selection of the Ogura Hysteresis Clutch
Since this is a vertical application the use of a hysteresis clutch is preferred over a magnetic particle clutch. In vertical applications magnetic particle clutches tend to have powder packing problems. A hysteresis clutch is also more accurate in its torque transmittal than a magnetic particle clutch. Since voltage to torque is almost a linear relationship once the voltage is preset the clutch will deliver its predetermined torque regardless of its slip speed. (see position A on the torque chart). Since the torque that is being transmitted through the clutch is done strictly by a magnetic (hysteresis) field there is no wearing parts, accept for the bearings. Life is therefore extremely long in hysteresis clutch applications.
Besides an automatic fastening machine, hysteresis clutches could be used in capping equipment in the pharmaceutical industry. Other applications for hysteresis clutches are in motor torque testing equipment where accurate torque control is required. Since the hysteresis clutch offers a wider range of torque than a magnetic particle unit it is also very well suited for controlling tension when the material itself is extremely expensive such as gold or platinum wire.