Universal joint how does it work

From the required speed in RPM, operating angle in degrees, and service condition intermittent or continuous , find the corresponding use factor from Table 2. Multiply the required torque, which is to be transmitted by the input shaft, by the use factor. If the application involves a significant amount of shock loading, multiply by an additional dynamic factor of 2. The result must be less than the static breaking torque of the joint.

Refer to the torque capacity column in the SOP catalogue and select a suitable joint having a torque capacity not less than the figure computed in ii , above. Select a suitable joint. From Table 2 for continuous operation, the use factor is given as Note that there are blank spaces in the table. If the combination of operating angle and speed results in a blank entry in the table, this combination should be avoided. There is no shock load and the dynamic factor of 2 does not apply in this case.

From the catalogue, it is seen that there are two joints meeting this specification: and , both with a torque capacity of in-lbs. The first has a solid-shaft construction and the second a bored construction. The choice depends on the application.

Select a suitable joint for Intermittent operation with shock loading. Due to shock loading there should be an additional dynamic factor of 2. Thus the same joints found in the previous example are usable in this case.

The polar mass moment of inertia, I, of the disc is given by Hence, if the inertia torque is not to exceed its limit, the max.

For joints made with thermoplastic material, consult the catalogue, which contain design charts for the torque rating of such joints. These are rocking couples in the planes of the yokes, which tend to bend the two shafts and rock them about their bearings.

The bearings are thus cyclically loaded at the rate of two cycles per shaft revolution. The bearing force induced by these couples is equal to the magnitude of the rocking couple divided by the distance between shaft bearings. For example if the input torque, T in , is in-Ibs. The bearings should be selected accordingly. The exact percentage is a complex function of system design and operating conditions.

Figure 2 shows a schematic of such an arrangement. If shafts 1 and 3 intersect, yokes 1 and 2 are coplanar. When the above phasing has been realized, torsional and inertial excitation is reduced to a minimum. Bearing Cap 5. Needle Bearings. Most over-the-counter u-joints are sealed and no greaseable and require little maintenance. They are not the best choice for harsh off-road conditions. Greaseable u-joints will last far longer when properly maintained.

When performing general maintenance on your vehicle, it is not a bad idea to visually and manually check your u-joints for unusual wear, play, and missing clips. Place the transmission in Neutral, crawl underneath and rotate the driveshaft back and forth, stopping quickly. Also, try to move the driveshaft forward and rearward.

If the u-joints are worn you will be able to feel movement in the joint. A bad drive shaft u-joint can also be indicated by a clunk when accelerating or decelerating, especially while backing up. Depending on the use of the vehicle. The shares the same cap size as the but with a larger cross.

Note the cross is the same size as to its left but the bearing caps, and therefore the trunnions that they pivot on are larger, i. The bearing caps of the u-joint are pressed into the yoke and held in place with a c-clip, an internal snap ring, or a full circle snap ring.

Vehicles that see heavy off-road use should use an internal or full circle snap ring. If c-clip style u-joints are only available for your application, you can have them modified to accept full circle clips. The u-joint trunnion then rips apart the axle yokes, causing a catastrophic failure. The concept of the universal joint is based on the design of gimbals, which have been in use since antiquity.

One anticipation of the universal joint was its use by the Ancient Greeks on ballistae. The first person known to have suggested its use for transmitting motive power was Gerolamo Cardano , an Italian mathematician, in , although it is unclear whether he produced a working model.

In Europe, the device is often called the Cardan joint or Cardan shaft. The input shaft will turn the cross, and the cross will turn the output shaft. It is clear that both the input and output shafts will turn at the same speed. Assume that the input shaft is moving at a constant speed.

When the shafts are at an angle the motion is quite different. To understand why, just note the behavior of the red and green ends of the cross. You can see that the green ends, which are connected to the input shaft, turn along a vertical plane, while the red ends, which are connected to the output shaft, have to move along a different plane. To make the red ends move along the inclined plane, the cross has to spin along the axis connecting the green ends. If you observe the mark on the cross, you can see this phenomenon.

To make the cross spin concept clearer, just imagine what happens when the spin of the green axis is halted.

Such a hypothetical motion is depicted in the following figure. It is clear that, such a situation is impossible. This means without this spin, the motion of the inclined hook joint is impossible.

The spin of the cross makes a huge difference in the speed of the output shaft. The cross has 2 kinds of motion: rotation and spin. It is clear that, when the cross is spinning as well as rotating, the velocity of the output shaft will have an added effect.

You can see here that, for the first 90 degrees of the input shaft rotation, the green axis spins to its maximum angle.

The forward spin aids and changes the output shaft rotation as shown in the graph. The output angle will get an added effect during this period. But for the next 90 degrees, it should spin back to the initial zero position.

The reverse spin will have an opposite effect on the output shaft rotation. So the motion of the output shaft will look as shown in the Fig.