Reasons and Solutions for Gear Jumping and Misalignment of the Transmission of Truck-Mounted Cranes Tow Crane

Truck-Mounted Cranes are a type of vehicle commonly utilized in engineering construction and have gained significant popularity within the realm of special vehicles. Have you been acquainted with the gear jumping fault that might occur in the transmission of truck-mounted cranes? Gear jumping refers to the phenomenon where the gear lever spontaneously reverts to the neutral position while the truck-mounted crane is in motion, resulting in the sliding gears disengaging from their normal meshing positions. Misalignment, on the other hand, pertains to the situation where the gear lever is unable to engage the intended gear. Or, even after engagement, it shifts into a different gear rather than the desired one, rendering the vehicle uncontrollable and potentially leading to accidents. Both misalignment and gear jumping of the transmission are prevalent faults, and there exists a certain interrelationship between the two. They are typically caused by wear, looseness, damage to the relevant components of the transmission, or improper adjustment of the fit clearance.

Cause analysis:

The positioning pin of the gear lever is subject to wear, looseness, breakage, or loss, leading to its unregulated and random swinging. The positioning pin plays a crucial role in maintaining the stability and accuracy of the gear lever’s position. Any deterioration in its condition can result in an inability to precisely control the gear selection.
The interlock device of the shift fork shaft is worn and loses its effectiveness; the ball joint of the gear lever is excessively worn and becomes loose. The interlock device ensures that only one gear is engaged at a time, preventing multiple gears from being selected simultaneously. Its wear can cause gear shifting confusion and instability. The ball joint connects the gear lever to the shift fork shaft and excessive wear can lead to imprecise movement and gear engagement issues.
Gears, gear rings, or gear sleeves exhibit wear in the longitudinal direction of the teeth. During operation, the axial force generated causes them to disengage. The prolonged use and stress placed on these components can lead to gradual wear, affecting their ability to maintain a secure meshing position.
Components such as the shift fork shaft chute and lock pin are excessively worn. The shift fork is bent and deformed, or the working surface and the gear ring groove are worn and loose. The excessive wear of the chute and lock pin can compromise the smooth movement and positioning of the shift fork. A bent or deformed shift fork fails to accurately engage the gears, while worn working surfaces and loose gear ring grooves contribute to unstable gear engagement.
The fixed at the rear end of the second shaft is loose, allowing the second shaft to undergo axial movement. The proper positioning and stability of the second shaft are crucial for accurate gear engagement. A loose disrupts this alignment and can lead to gear jumping and misalignment.
The synchronizer lock pin is loose or disintegrated, and the conical surface fails to function as intended. The synchronizer and its components are essential for smooth and synchronized gear changes. Any malfunction in these parts can cause difficulties in gear shifting and increase the likelihood of gear jumping and misalignment.

Solution: When a gear jumping is detected, initially, push the gear lever firmly back into that gear. Subsequently, remove the transmission cover to inspect the gear meshing. If the gear meshing appears satisfactory, the issue likely lies within the shifting mechanism. Manually push the shifting fork of the jumping gear to test the positioning device. If the positioning is inadequate, it becomes necessary to remove the shift fork shaft and closely examine the positioning ball and spring. If the gears are not fully meshed, but the jumping gears or gear sleeves can be properly meshed by hand, it is essential to inspect whether the shift fork is bent or worn, whether the fixing screws of the shift fork are loose, and whether the gap between the fork end and the gear groove is overly large. If the shifting feels smooth and the gears or gear sleeves can be fully meshed, it is then necessary to check for wear on the gears, looseness in the bearings, and any forward or backward movement of the transmission shaft. Based on the problems identified during the above inspections, repairs should be carried out in accordance with the prescribed standards. If necessary, replacing new components can completely eliminate the faults of misalignment and gear jumping of the transmission.

In conclusion, understanding the causes of gear jumping and misalignment in the transmission of truck-mounted cranes and implementing appropriate solutions is essential for ensuring the smooth and safe operation of these vehicles. Regular inspections and maintenance can help detect and address potential issues before they escalate into significant problems, enhancing the reliability and performance of the transmission system. By promptly addressing these faults and adhering to proper maintenance practices, the operational efficiency and longevity of the truck-mounted cranes can be significantly improved.