Principle of The Propshaft/Driveshaft
The propshaft is the shaft that can transmit power in the propshaft of a universal drive, and for front engine rear wheel drive cars it is the shaft that transmits the rotation of the transmission to the main reduction gear, it can be several sections, and the sections can be connected to each other by universal joints, the universal joints are the key components on the propshaft of the automobile, which are responsible for both the drive and the steering of the front axle between the half-shafts and the wheels.
The traditional structure of the propshaft expansion sleeve is the spline sleeve and flange fork welded together, the spline shaft welded to the propshaft tube.
As an important part of automobile transmission system to transmit power, automobile prop shaft can be used with transmission, drive axle together with the engine power to the wheels, so that the automobile generates driving force.
Usually the special automobile prop shaft is mainly used in tanker trucks, gasoline trucks, sprinkler trucks, sewage trucks, suction trucks, septic tankers, fire trucks, high-pressure cleaning trucks, road clearance trucks, aerial work trucks, garbage trucks and other models.
Observe the fault phenomenon
- When the car starts or driving in the gearshift transmission shaft are impact sound, especially in the high-speed gear for low-speed driving sound is more obvious.
- When the car starts the drive shaft has no abnormal sound, while the car is traveling the drive shaft has impact sound.
- There is no abnormal noise of the drive shaft when the car starts, but there is abnormal noise of the drive shaft when the car is coasting.
- The sound is constant during the whole driving process.
Reasons for Automobile Drive Shaft Rattling
When the technical condition of the automobile prop shaft becomes bad, the amplitude of the bending vibration increases, the vibration is intense, and even causes the body to vibrate and shake, and emits obvious periodic sound, which is called vibration and rattling. Automobile drive shaft with the increase in speed and aggravation, the prop shaft produces
The main reasons for vibration and rattling are as follows.
- The transmission shaft flange connections (or connection bolts) loose, causing abnormal noise.
- The grease nipple (commonly known as grease nipple), the cross shaft oil channel blockage and injection of grease, not according to the regular injection of grease, cross shaft oil seal damage and oil leakage, etc., resulting in the cross shaft needle roller bearings in the long-term lack of lubricating oil under the conditions of work, so that the cross shaft neck, needle and sleeve wear and tear, the formation of the looseness of the noise.
- The universal cross shaft assembly is too tight.
- Sleeve and universal joint fork hole with loose, support piece bolt loosening lead to sleeve rotation, so that the universal joint fork hole wear excessive, loose and cause noise.
- The transmission second shaft spline and the flange spline wear is too large, the formation of loose and cause noise.
- The propshaft intermediate support bracket bolts loose, intermediate support and intermediate propshaft journal with loose, intermediate propshaft rear end spline and flange keyway with loose and rear end nut loose.
- Propshaft intermediate support bearing loose, bearing raceway damage, bearing lubrication is poor, wear and excessive loosening.
- The propshaft intermediate support bracket installation position skewed, bearing preload adjustment is not appropriate, the rubber gasket ring spacer damage, intermediate support bracket fixing bolt tightening torque is too large or too small and caused by the bracket position of the skew and other reasons, and caused by the noise.
- The universal joint fork at both ends of the propshaft is not in the same plane, so that the equal speed arrangement has been damaged and caused by the noise.
Diagnosis and troubleshooting
- The car driving suddenly change speed, the drive shaft appear a metal knocking sound, it can be explained individual flange or universal joint cross shaft bearing wear and tear is too large and loose, caused by the propshaft rattling.
- When the car starts, the propshaft will make a “Dang-dang” sound or a chaotic sound. When the car is reversing backward on a gentle slope, the intermittent sound of “Geba” will indicate that the needle roller is broken or shattered, and the needle roller bearings should be replaced.
- The car start or gear shift, the propshaft has obvious metal impact sound, and low-speed gear than high-speed gear is more obvious, mostly for the middle bearing inner ring and shaft interference with the reduction of loose caused by the noise.
- The car starts or driving, the propshaft has always been obvious “kala” noise, and accompanied by vibration, the middle support bracket fixed bolt loosening and cause noise.
- Auto low-speed driving when the propshaft appears crisp and rhythmic metal impact sound, the car out of gear when there is a clear sound. Most of the universal joint bearing shell compression force is too large, so that the bearing can not rotate flexibly.
- The car driving propshaft sound increases with the increase in speed, the middle support bearing issued a dull and continuous turbid sound, then the middle support bearing due to excessive wear and tear and fall apart.
Automobile driving transmission shaft issued a continuous “woo ……” sound, first check the middle bearing bearing bracket rubber gasket ring spacer fastening bolts are too tight or too loose (not in accordance with the requirements of the specified torque requirements), so that the bearing bracket position skewed.
Can adjust the tightness of the bearing cover bolts to exclude rattling failure, if the adjustment of the bearing pre-tightness is still ringing, you should check the lubrication status of the bearing, if the bearing lubrication is poor, should be dismantled to clean the bearings, and add grease to reassemble the bearings and brackets.
- When the car is running, the sound of the drive shaft is disorderly and irregular, and sometimes there is a metal impact sound, it means that the universal joint forks at both ends of the drive shaft are not in the same plane, so that the equal-speed arrangement is damaged.
- The car driving at high speeds when the drive shaft has a strange sound, out of gear when the prop shaft noise still exists, more intermediate bearing raceway damage, or intermediate bearing bearing bracket mounting position has been shifted.
- In order to further verify the correctness of the above diagnosis, can be examined in the parking and hand shaking drive shafts, see whether the installation position is correct, the surface of the parts are not scarred, fastening connections are loose, with clearance is too loose or too tight.
a. After parking, release the parking brake and push the universal joints up and down by hand. If there is any looseness, it means that the needle bearings of the cross shaft are loose.
b. Shake the parking brake disk back and forth with your hand, if it is loose, then the second shaft spline of the transmission is loose.
c. Tighten the parking brake, and shake the rear flange of the intermediate drive shaft back and forth by hand, if it is loose, it means the intermediate drive shaft spline shaft key tooth is loose.
d. Pull the intermediate drive shaft flange back and forth by hand, if it is loose, it means the nut at the rear end of the intermediate drive shaft is loose.
- The car is moving, if the brake deceleration drive shaft appears heavy metal knocking sound, it means that the rear plate spring jockey nut is loose.