The Modular Heart of Mechanical Weeding
In the intensive agricultural systems of Brazil, mechanical weed control is experiencing a renaissance. The rise of herbicide-resistant weeds and the demand for organic produce are driving farmers back to mechanical cultivation. The machine at the forefront of this shift is the Inter-row Cultivator (Cultivador Rotativo). Unlike old fixed-frame tillers, modern cultivators are modular. They consist of a main frame and multiple independent Row Units (Unidades de Linha) that float over the terrain contour.
Each of these row units requires its own power source. This is the job of the Row Unit Gearbox (Caixa de Transmissão da Unidade). It sits directly on the floating linkage of each row, receiving power from a common hexagonal drive shaft that spans the width of the machine. The gearbox turns this horizontal power 90 degrees to drive a small rotor equipped with C-blades or hoeing knives, churning the soil between the crop rows to uproot weeds and break the capillary crust.
The engineering challenge here is compactness and adjustability. The gearbox must be narrow enough to fit between tight crop rows (like 45cm soy spacing) without damaging the plants. It must also slide along the hex drive shaft to allow the farmer to change row width easily. EVER-POWER’s Série RU (Unité de rangée) gearboxes are designed with a slim-profile cast iron housing and a precision-broached hex input hub, creating the perfect balance of strength and versatility for the tropical fields of Mato Grosso and São Paulo.
Technical Specifications: RU-Series (Row Unit Drive)
| Paramètre | Spécification | Paramètre | Spécification |
|---|---|---|---|
| Puissance d'entrée | 10 HP – 25 HP (per row unit) | Taux de réduction | 1:1 / 1:1.25 / 1.5:1 |
| Vitesse d'entrée | 300 – 600 RPM (Variable) | Vitesse de sortie | 300 – 500 RPM |
| Matériau du boîtier | Ductile Iron QT450 (Slim) | Couple maximal | 450 Nm |
| Interface d'entrée | Hexagonal Bore (41mm / 50mm) | Arbre de sortie | Flanged / Splined 35mm |
| Type d'engrenage | Spiral Bevel (Gleason Cut) | Matériel d'équipement | 20CrMnTiH (Trempe superficiellement) |
| Type de roulement | Deep Groove Ball / Tapered | Montage | Top Flange / Side Bosses |
| Système d'étanchéité | Mechanical Face Seal / Cassette | Lubrification | Oil Bath (SAE 90) / Grease |
| Capacité pétrolière | 0.5 Liters – 1.2 Liters | Width (Profile) | Ultra-Narrow (< 150mm) |
| Input Design | Through-Bore (Sliding fit) | Locking Mechanism | Set Screw / Clamp Collar |
| Poids | 12 kg – 25 kg | Respiration | Low-Profile Filtered |
| Peinture | Abrasion Resistant Epoxy | Garantie | 18 mois |
| Compatibilité | Maschio / Kuhn / Baldan | Application | Inter-row Tillage / Ridging |
Engineering the “Sliding Drive”
1. The Hexagonal Through-Bore
The defining feature of the RU-Series is the input shaft. Instead of a solid shaft, it features a Broached Hexagonal Through-Bore (typically 41mm or 50mm). This allows the gearbox to be threaded onto the main drive line shaft like a bead on a string. The hexagonal shape provides positive drive engagement without the need for keys or set screws that can strip under load. This “Floating” design allows the gearbox to slide laterally for easy row width adjustment, a crucial feature for contractors working on multiple crop types.
2. Narrow Profile Design
In a sugarcane ratoon or a dense corn field, space is premium. A bulky gearbox would damage the crop roots or leaves. EVER-POWER engineers created a Slim-Line Housing that minimizes width while maximizing vertical clearance. The internal bevel gears are arranged to keep the profile sleek, ensuring the gearbox stays strictly within the inter-row zone (entrelinha), protecting valuable cash crops from mechanical damage.
3. Duo-Cone Seal Protection
The output shaft of a row unit works inches from the soil, often buried in loose dirt thrown up by the tines. Standard rubber lip seals fail quickly in this abrasive environment. For our premium RU-Series, we utilize Mechanical Face Seals (Duo-Cone). These metal-to-metal floating seals are impenetrable to sand, wire, and plastic mulch, extending the maintenance interval from daily to seasonal.
4. Overload Resilience
While the central gearbox has a slip clutch, the individual row unit often relies on the ruggedness of its gears. When a single row hits a large rock, the shock load is instant. We use Engrenages coniques à spirale with a high contact ratio and case-hardened teeth. The spiral geometry allows for gradual tooth engagement, which distributes the shock load better than straight bevel gears, preventing catastrophic tooth shear.
Comparative Analysis: Gearbox vs. Chain Drop Box
| Fonctionnalité | Row Unit Gearbox (RU Series) | Chain & Sprocket Drop Box |
|---|---|---|
| Entretien | Basse (bain d'huile scellé) | High (Chain Tensioning/Grease) |
| Profil de largeur | Very Narrow | Wide (Bulky chain case) |
| Efficacité | Haut (96-98%) | Moyen (90-95%) |
| Durabilité | High (Forged Gears) | Low (Chain Stretch/Wear) |
| Coût | Initial plus élevé | Initial inférieur |
*Analysis based on 8-row sugarcane cultivator field tests in Ribeirão Preto.
Application localisée : Agro-industrie brésilienne
Sugarcane (São Paulo)
Sugarcane cultivation requires deep tillage between rows to break compacted ratoon soil. The row units carry heavy rotors (80cm diameter). Our RU-Series gearboxes are reinforced with Ductile Iron (QT500) housings to prevent cracking under the severe vibration and impact loads typical of cane fields.
Vegetables (Cinturão Verde)
For vegetable crops like carrots and onions, precision is key. The gearboxes must drive smaller, faster-spinning rotors for fine tilth. We offer High-Ratio Models (1:1.92) that increase rotor speed, pulverizing the soil into a perfect seedbed while the slim profile ensures no damage to the delicate vegetable foliage.
📒 Field Engineer’s Log: The “Wobbly” Box
“November 2025, Araçatuba, SP. A cultivator manufacturer contacted us. Their customers were reporting oil leaks from the row unit input seals. We visited a farm.”
“The 6-meter hex drive shaft had a slight bow (bend) in the middle. As it rotated, it forced the row unit gearboxes to wobble on their mounts. This eccentric motion was destroying the rigid input seals.
Solution: We introduced our ‘Floating Hub’ Input Design. The hex bore is machined with a slight crown and clearance, allowing the gearbox to self-align on the shaft even if it’s not perfectly straight. We also switched to a dual-lip seal with a flexible outer case. The result? The boxes could ‘float’ on the shaft without stressing the seals, eliminating leaks entirely.”
Foire aux questions (OEM/B2B)
1. Can I use this gearbox for a fertilizer spreader?
Yes, smaller versions of the RU-Series are perfect for driving row-specific fertilizer hoppers. The hex shaft drive ensures all hoppers are synchronized with ground speed or the main drive, providing consistent application rates.
2. What grease should I use?
Most of our row unit gearboxes are oil-filled (SAE 90) for better heat dissipation. However, for low-speed applications, we offer Semi-Fluid Grease (NLGI 00) filled units. Grease eliminates the risk of leaks dripping onto crops but runs hotter at high speeds.
3. Are parts interchangeable with Maschio/Kuhn?
Our gearboxes are designed to be dimensionally compatible with the industry-standard “Italian Style” gearboxes used by major European OEMs. The mounting bolt pattern and hex bore dimensions (41mm/50mm) are standard ISO sizes.
4. How do I lock the gearbox on the shaft?
The gearbox is typically held in lateral position by the row unit frame itself. However, the input hub includes two Set Screws or a split-collar clamp to lock it onto the hex shaft, preventing it from walking during operation.
Complétez la transmission de votre cultivateur.
Boîtes de vitesses centrales
High-power T-Boxes to split PTO power to the hex shafts.
Arbres de transmission hexagonaux
Precision ground 41mm/50mm hex shafts in custom lengths.
Boron Steel Blades
Wear-resistant C-blades and hoes designed for our rotor hubs.
Reliability in Every Row
Eliminate downtime and improve weed control with EVER-POWER Row Unit Gearboxes.
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