Ensemble d'arbre central supérieur droit FAW de la boîte principale: Une ventilation complète de 16 Pièces réparables

Bienvenue dans ce guide technique complet sur le Ensemble d'arbre central supérieur droit FAW de la boîte principale. This is a complete, load-bearing gear and shaft set for the main gearbox of the FAW Jiefang CA4251P66K24T1A3E5 6×4 tracteur semi-remorque diesel.

Le Ensemble d'arbre central supérieur droit FAW de la boîte principale, également connu sous le nom de “counter-shaft,” is one of the most critical components in a heavy-duty transmission. It is part of a “twin-countershaft” conception, working in tandem with a second (lower left) shaft to split the engine’s torque, thereby doubling the gearbox’s strength.

Ce guide détaillé est une ressource essentielle pour les techniciens professionnels de transmission et les spécialistes des pièces.. Nous déconstruirons l'ensemble Ensemble d'arbre central supérieur droit FAW de la boîte principale dans son 16 composants réparables, including the main ‘Countershaft’ (1701211-A9P), all of its drive gears, the critical bearings, and all associated locking hardware.

Le “Twin-Shaft” Logic Explained

The main gearbox of this FAW tractor uses a **twin-countershaft** (ou “twin-shaft”) conception. This is the gold standard for heavy-duty applications. Instead of one large countershaft handling 100% of the engine’s torque, the load is “split” 50/50 between two smaller, identical countershafts.

Cet assemblage, le Ensemble d'arbre central supérieur droit FAW de la boîte principale, is one of those two critical shafts. By splitting the torque, le “separating forces” (the forces of the gear teeth trying to push each other apart) are balanced. This dramatically reduces the stress on the transmission housing and the bearings, allowing the gearbox to be lighter, more compact, and significantly more durable.

Le “logique” of this system requires that both the Ensemble d'arbre central supérieur droit FAW de la boîte principale et son “Lower Left” twin are perfectly “timed” so that their helical gear teeth engage the main shaft gears at the exact same instant. If the timing is off by a single tooth, one shaft will take the entire load, leading to its rapid and catastrophic failure.

Composant principal: The Countershaft (1701211-A9P)

L'épine dorsale du Ensemble d'arbre central supérieur droit FAW de la boîte principale is the ‘Countershaft’ (1701211-A9P) lui-même. C'est un seul, massif, forged component made from high-carbon, acier cémenté. It is designed to be the primary torque-bearing component in the main box.

Its function is to “counter” the rotation of the input shaft. The input shaft’s gear (voir montage 143) is in permanent, constant mesh with the “input drive gear” on this Ensemble d'arbre central supérieur droit FAW de la boîte principale. This means that any time the clutch is engaged and the engine is spinning, this countershaft is also spinning.

The shaft itself is precision-machined with multiple “steps,” splines, and bearing journals. The splines are used to mount the various drive gears, while the journals provide a mirror-smooth, ultra-hard surface for the main roller bearings to ride on. A bent or twisted countershaft is a catastrophic failure that requires a full transmission rebuild, making the integrity of this core Ensemble d'arbre central supérieur droit FAW de la boîte principale absolutely critical.

The Main Drive Gears (3rd, 4ème, 5ème, Réduction)

Le “logique” de la Ensemble d'arbre central supérieur droit FAW de la boîte principale is embodied in its set of fixed, constant-mesh drive gears. This parts list details the following:

• ‘3rd gear-countershaft’ (1701212-A9K)
• ‘4th gear-countershaft’ (1701213-A9K)
• ‘5th gear-countershaft’ (1701214-A9K)
• ‘Reduction gear-countershaft’ (1701217-A7G)

Ce sont les “conduire” engrenages. They are fixed (splined or press-fit) to the ‘Countershaft’ and are *always* spinning at the same speed as the shaft. They are in permanent, constant mesh with their corresponding “conduit” engrenages, which spin freely on the main shaft (le “deuxième arbre”).

Lorsque le conducteur sélectionne “3rd gear,” they are actually engaging a clutch (un “synchronizer”) that locks the *freewheeling 3rd gear* to the main shaft. The power flow is then from the input gear, au Ensemble d'arbre central supérieur droit FAW de la boîte principale, through this ‘3rd gear-countershaft’, to the main shaft, and out to the wheels. These helically-cut gears are designed for quiet, high-torque operation.

Bearing and Alignment System

L'ensemble Ensemble d'arbre central supérieur droit FAW de la boîte principale is supported at both ends by heavy-duty bearings.

• **Front Bearing (1701205-A2V-C00):** This ‘Cylindrical roller bearing with stop ring’ supports the front of the countershaft. C'est un “roller” palier, designed for extreme radial loads. Le “stop ring” (a circlip) est critique, as it locks the bearing’s outer race into the front transmission housing, setting the shaft’s position.
• **Rear Bearing (1701215-A2V-C00):** This ‘Cylindrical roller bearing’ supports the rear of the shaft inside the main housing.

These bearings are protected by “baffles,” which are oil slingers. The ‘Baffle-countershaft front bearing’ (1701233-A7G) and ‘Baffle-countershaft rear bearing’ (1701233-A9P) are secured by ‘Hex head bolts’ (CQ1511235S, CQ1511645S). These discs spin with the shaft, flinging oil *away* from the bearing seals, preventing leaks and ensuring a long service life for the Ensemble d'arbre central supérieur droit FAW de la boîte principale.

Enfin, the ‘Circlip-reduction gear’ (1701229-A7G) and ‘Spacer’ (1701247-A7K) are used to lock the ‘Reduction gear’ in its precise location on the shaft. The ‘Woodruff Key’ (1701226-A7G), ‘Flat Key’ (1701228-A7G), and ‘Spring dowel pin’ (Q5280510) are all used to physically lock the various gears to the shaft, ensuring they cannot spin freely and that 100% of the torque from the Ensemble d'arbre central supérieur droit FAW de la boîte principale is transferred.

FAW Upper Right Centre Shaft Assembly Of The Main Box Parts List

Le tableau suivant fournit l'intégralité, ventilation détaillée de tous 16 components identified in the ‘Main Box Upper Right Centre Shaft Assembly’ schéma du tracteur FAW CA4251P66K24T1A3E5. Ce Ensemble d'arbre central supérieur droit FAW de la boîte principale is a key to the transmission’s torque capacity.

Spécifications techniques et contexte d'assemblage

Les spécifications pour le Ensemble d'arbre central supérieur droit FAW de la boîte principale are defined by its function as the core, torque-handling gear cluster of the transmission. L'ensemble Ensemble d'arbre central supérieur droit FAW de la boîte principale is a precision-balanced and matched set.