Views:308 Author:Cardan Shaft Manufacturer Publish Time: 2015-06-08 Origin:Sitong Cardan Shaft Co.,Ltd
Gewes cardan shaft is of high quality, low maintenance, long service life, and reliable, they can meet the specific needs of nearly any industrial applications. Compared with other types of the same cardan shaft, Gewes cardan shaft delivers more torque, the complete range is more advantageous.
Gewes cardan shaft through a wide range of power and speed meet the application requirements of most modern machinery: truck, bus, special vehicle, car, pickup, SUV, minivan, small truck, minibus, crane, car construction, agricultural tractor, forestry tractor, lifting equipment, technical industrial transport, locomotive, railway construction, shipbuilding, heavy engineering industry, mining, and metallurgical industry.
A cardan shaft is a device to smoothly transmit rotation torque by connect-ing a driving shaft and a driven shaft that is not aligned on the same axis. Since it has two universal joints on one shaft, it can connect the driving shaft and the driven shaft flexibly. In addition, one universal joint has four rolling bearings (cross & bearing) that can minimize torque loss with low friction.
1) Cross & bearing
The cross & bearings are the most critical components of Cardan shafts. A cross & bearing has a cross-shaped shaft and four rolling bearings that individually support each end of the shaft.
2) Bearing set bolt
The bearing set bolt is used to connect the cross & bearing and its mating part (a retaining ring is used for mixed type).
3) Spline sleeve/shaft
The splined sleeve has a spline bore and shaft, which realize a variable cardan shafts insaling length.
1. Long-interval greasing cross & bearing
(1) Oil seal lip from double to triple, and the optimization of shape and position.
(2) Reduction of roller contact stress with torque load by length up and crowning optimization
(3) Abrasion resistance improved by adding glass fiber to thrust washer
(4) Bearing cup shape reviewed and cost reduced by abolishing the roller washer
2. Spline seal structure of muddy water resistance improvement
Since the cover tube type spline seal has a structure that seals the sleeve (female spline) outer diameter part,
(1) It is not necessary to surpass the male spline major diameter by deforming the seal lip at the time of assembly,
so a urethane rubber seal with high rigidity can be used.
(2) The distance from the seal to the spline is long, so muddy water does not reach the spline easily.
(3) A double cover has been added to protect the seal part, improving endurance further.
Gewes cardan shaft series features safe and secure torque transmission by a parallel key and high torque capacity. The following are the handling method and caution points to ensure that the driveshaft delivers its expected performance.
1) Do not hit the cross & bearing part with hard metal so that a shock should be avoided. If it is necessary at the time of assembling, hit it lightly with a non-ferrous metal (copper, etc.) or plastic hammer.
2) Tighten the fixing bolts of the bearing cups by setting the bearing cups in the proper positions in the yoke to form an X shape. If you fit the bearing cups with the tightening force of bolts or fx only one bearing cup with the bolt and then set the other, it may cause troubles such as scars on the spigot joint part and attaching surface, and attachment of bearing cups at a slant.
3) Never conduct welding between the bolts and the bearing cups and between the yoke and the bearing cups.
4) Do not disassemble the Cross & bearings unless absolutely necessary.
1) Greasing interval
It is recommended to apply grease every 2000 - 4000 hours, though it depends on the usage environment.
2) Grease to be used
Lithium grease with extreme-pressure additive
3) Greasing of cross & bearings
Applies grease until it overflows from all of the four shafts of the cross. Wipe off the overflowing grease because dirt may adhere to it.
4) Greasing of spline part
To apply to grease an onboard cardan shaft, move the vehicle body so that the spline should compress to the minimum. When grease leaks out of the center of the plug attached to the sleeve yoke, The greasing is complete. If the driveshaft is removed from the vehicle because of the overhaul, etc, apply grease with the spline compressed to the minimum.
Use the attached bolt or part for repair specified by
2) Torque wrench
Use a calibrated torque wrench.
3) Specified tightening torque
Tighten with the specified torque.
1. Flaking has occurred in the raceway surface of rolling contact surface of the cross and cup.
Compare the calculated life and the required life and increase the size as necessary
2. Breakage is caused from the flt radius part of the neck of the cross and the fracture surface has no beach mark
Brittle fracture due to excessive load
Check the usage conditions
Increase the size as necessary
3. The bearing set bolts are broken near the yoke interface
Bolt fatigue fracture caused by looseness of the bolts
Check that the tightening torque has the specified value
4. Bending near the center of the driveshaft
Brittle fracture caused by using around the dangerous rotational speed
Decrease the maximum rotational speed. If it is impossible, reduce the length or increase the tube size
The driving shaft and driven shaft intermediated by a universal joint This means that, even if the rotational speed and torque of the driving shaft are constant, the driven shaft is subject to fluctuation in rotational speed and torque.
Advantages of the Single cardan shafts
1）Easy to install: Need no special installation tools.
2）Lightweight and powerful: have a good weight advantage over other design solutions while transmitting greater power loads
Cardan shafts are usually installed in pairs.
1) With equal operating angles in both joints
2) Yokes connected to the same shaft inline
3) Central lines of all three shafts (driving shaft, intermediate shaft, and driven shaft) in the same plane, the driven shaft rotates exactly in the same way as the driving shaft. Therefore, they should be attached as shown in the figure on the right as far as possible.
This configuration known as a double Cardan joint cardan shafts partially overcomes the problem of jerky rotation. This configuration uses two U_joints joined by an intermediate shaft, with the second U-joint phased in relation to the first U-joint to cancel the changing angular velocity.
This assembly is commonly employed in rear-wheel drive vehicles, where it is known as a cardan shaft or propeller shaft. Even when the driving and driven shafts are at equal angles with respect to the intermediate shaft, if these angles are greater than zero, oscillating moments are applied to the three shafts as they rotate. These tend to bend them in a direction perpendicular to the common plane of the shifts. This applies forces to the support bearings and can cause "launch shudder" in rear-wheel drive vehicles.
It is often necessary to consider the secondary couples imposed by universal joints operating at an angle; especially under high angle or large torque. These couples must be taken into account in designing the shafts and supporting bearings. The secondary couples in the universal joints are in the planes of the yoke. These couples are about the intersection of the shaft axis. They impose a load on the bearings and bending stress in the shaft connecting the joints, and they fluctuate from maximum to zero every 90° of shaft revolution.
Advantages of the Secondary couple.
1). Eliminate alignment problems: Have no need for the tight tolerances that solid shafts required.
2). Have higher efficiency: Have 85% -95% efficient. Gears, UJoints Belts and Pulleys give much lower performance due to greater frictional losses.
A cardan shaft should be selected so as to satisfty the required strength, service life, operating angle and dimensions necessitated by its purpose. Especially, a cardan shafts can be selected if it meets conditions of both strength and life of the universal joint, except for special cases. A cardan shafts should be selected by considering the type of the machine, peripheral equipment, particular operating conditions, and other factors.
The first step in selecting a Cardan shaft is determining the maximum torque to be transmitted. The maximum torque should take into account the maximum prime mover torque including inertial effects from the prime mover when decelerating during overloads. To decide the size of the cardan shafts, it is necessary to grasp the load torque first. and maximum torque including an impact torque and a mean torque should be known, and it is essential for selecting an appropriate cardan shaft to understand the correct maximum torque and mean torque.
Maximum torque: Value to determine if the strength of each part is sufficient.
Mean torque: Value necessary to calculate the service life
A cardan shaft should be selected so that the normal maximum torque shall not exceed the“Tb torque." However, it is difficult to determine the true maximum torque, and the engine capacity or motor capacity is used as the maximum torque in many cases, so the safety factor (fs) of no less than 1.0 should be considered as the most desirable.
There is no worldwide standard for service life calculation of universal joint bearings (cross & bearings) and the service life is calculated according to the unique method developed by each manufacturer. The service life Lh is defined as the expected number of operating hours before flaking occurs on the rolling contact surface of the bearing. The use of the bearings over the service life Lh may be practical on a low-speed machine.
For each application, the strength and life must meet the specifications, while the weight and price must be kept as low as possible. The useful life of a driveshaft is determined mainly by the joints. For this reason, they can, in any case, be designed using the general principles of strength of materials. With good lubrication and sealing life is limited to the material after millions of reversals. With bad sealing, life is limited by corrosion and, if there is contamination, by the resultant increase in wear.
If a rotating cardan shaft is unbalanced, it may adversely influence the equipment and ambient conditions, thus posing a problem.
corrects the unbalance of cardan shafts to the optimal value by the two plane balancing method, using the latest balance system. To correct the balance of cardan shafts, it is critical to correct the balance between two planes each near the two individual universal joints, instead of by the one plane balancing as used to balance car wheels. Especially in the case of long cardan shafts, this two-plane balancing method is the only way to acquire good results.
Gewes cardan shaft is rugged assemblies that withstand the requirements of today‘s more powerful engines and transmissions. Precision balancing assures smooth, vibration-free operation. A wide range of cardan shafts is backed by years of proven performance in some of the most extreme applications.