www.jbj.co.uk/couplings.html #DriveLineHarmony Series “P” - “E” - “H” (DIN 808) SIT Universal Joints 1 With Plain or Needle Roller Bearings P series joints are precision products made by 4 forks and solid pins machined from one piece, to have an extremely compact central block. Types E are with sliding bushes while type H has needle roller bearings. It’s produced in one only version: » P series according with DIN 808. Joints with plain bearings are available in 2 versions: » E series according with DIN 808. » EB series according with DIN 808/7551. Joints with roller bearings are available in 2 versions: » H series according with DIN 808. » HB series according with DIN 808/7551. Every model is made by 2 hubs with forks and a central block. Between pins and bores there are: » P series: 4 bearings with solid pins. » E series: with sliding bushes. » H series: with needle roller bearings. In the central blocks of P and E series there are the holes for lubrication. For the H series (for high speed applications) no lubrication is needed, because the roller bearing are maintenance free. P series joints is designed for high precision and lifetime applications. E series joint with sliding bushes are used for low-medium speed and when some shock load can occur. For high speed and medium torque, we suggest the type H with roller bearings. The maximum working angle is 45° for single joints, 90° for double joints. The maximum speed is 1000 rpm for P and E series, 4000 rpm for H series. Every execution can be supplied with extendable shaft. Selecting criteria Matching one single joint with two shafts (of which the driving one is rotating at a constant speed), it forms an angle which causes a periodic variation of the driven shaft, exactly four fluctuations per revolution. The difference between the maximum and the minimum speed of the driven shaft depends on the angle formed by the two shafts. The difference grows when increasing of the angle α. To have a homokinetic transmission, you have to fit either two opposite single joints (paying attention that the two central yokes lie on the same plain and the angles are equal) or a double joint. The irregularity caused by the former articulation is cancelled by the latter. The overall length resulting from the coupling of the two single joints is even more reduced using a double joint. In other words, the double joint is to be considered the shortest homokinetic transmission. For low speed applications (max 1.000 rpm) joint with plain bearings (rubbing bearings) are suggested: types E/EB. They are able to support shock loads, drive reserves, irregular running and relatively high torques. The working angles must be reduced in operation between 500 and 1.000 rpm. For high rotation speeds, relatively low torques or wide angles, joints with needle roller bearings (type V - H) are preferred. They can reach 5.000 rpm always relating to the angle. How to read diagrams The joint capacity to transmit a regular torque at a constant load with no shocks for a more or less long period, mainly depends on the number of revolutions per minute and the inclination angle α of the two axes. The following diagrams are based upon the criteria below. Each curve corresponds to the joint size (outside diameter D) and represents the torque that the joint can transmit depending upon speed and working angle α. The diagrams can be directly read if angle α is 10°; for wider angles, torques are reduced, therefore the values are to be corrected using correction factors (F) relating to the angle shown in the table. Note: Values shown in the diagrams are indicative only. Each application has its own particular motion characteristics, eg. shock loads, motion reversals, connected masses, type of starting, presence of elastic joints, stops and starts, etc. Call jbj Techniques Limited technical office, telephone: +44 (0)1737 767493 or email: info@jbj.co.uk for assistance.
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