The Central Nervous System of the Transplanter
In the highly mechanized rice cultivation zones of Southern Brazil, particularly in the Várzea regions of Rio Grande do Sul and Santa Catarina, the Rice Transplanter Main Transmission (Caixa de Transmissão Principal) is the single most critical component. It is the powerhouse that dictates both the machine’s traction in deep mud and the precision of the planting rhythm.
Unlike a standard tractor gearbox, the Transplanter Transmission Case is a hybrid miracle of engineering. It must integrate Hydrostatic Transmission (HST) inputs for seamless variable speed control while simultaneously driving a mechanical PTO shaft to synchronize the planting arms. All of this happens while the lower half of the casing is submerged in abrasive, silty paddy water.
EVER-POWER's TC-Series (Transmission Case) is engineered to withstand the punishing “Stop-and-Go” cycle of commercial planting. Featuring a reinforced die-cast aluminum or cast iron housing, integrated differential locks for escaping bog-holes (atoleiros), and multi-stage reduction gears made from 20CrMnTiH alloy, these units define reliability in the amphibious farming sector.
Technical Specifications: TC-Series (Main Transmission)
| Parâmetro | Especificação | Parâmetro | Especificação |
|---|---|---|---|
| Potência de entrada | 15 HP – 45 HP (Diesel) | Drive System | HST (Hydrostatic) + Gear |
| RPM de entrada | 2400 – 3200 RPM | Speed Range | 0 – 1.8 m/s (Planting) |
| Material de construção | ADC12 Aluminum / HT250 Iron | Differential | Bevel Gear with Pedal Lock |
| Axle Output Torque | Max 1,800 Nm | Direção | Side Clutch / Power Steering |
| PTO Output | Synchro-Planting Speed | Axle Shaft | Hex 26mm / 32mm / 40mm |
| Material da engrenagem | 20CrMnTiH (Carburized 60HRC) | Sistema de freio | Internal Wet Disc / Band |
| Classificação de vedação | IP68 (Fully Submersible) | Lubrificação | Hydraulic Fluid / Gear Oil |
| Tipo de vedação | Triple Lip + Stainless Sleeve | Capacidade de óleo | 4.5 Liters – 12 Liters |
| Resfriamento | Passive (Water Contact) | Shift Control | Cable / Hydraulic Lever |
| Peso (seco) | 25 kg – 65 kg | Hydraulic Pump | Direct Mount Flange Option |
| Montagem | Chassis Center / Rear | Planting Clutch | Internal Dog Clutch |
| Compatibilidade | Kubota / Yanmar / Iseki | Garantia | 24 Months / 2000 H |
Engineering the “Wet Drive”
1. HST Integration Logic
Modern high-speed transplanters (6-row and 8-row) use Hydrostatic Transmission (HST) to control travel speed without gear shifting. The main gearbox acts as the reservoir and structural mount for the HST pump and motor. EVER-POWER optimizes the internal oil passages to ensure the HST unit receives de-aerated, cool oil, preventing cavitation bubbles that cause the jerky motion known as “kangaroo planting” (pulo de plantio).
2. The Mud-Escape Axle Seal
The wheel axle seal is the most vulnerable point. It is submerged in abrasive clay mud for 12 hours a day. We utilize a Multi-Barrier Sealing System: 1) An external steel labyrinth shield that physically chops and clears grass/straw. 2) A V-ring seal that acts as a flinger. 3) A specialized Cassette Seal with a stainless steel wear sleeve. This system prevents the microscopic silica particles from grinding down the axle shaft.
3. Differential Lock for Várzea
In the soft soils of the Brazilian Várzea, getting stuck is a constant risk. A standard open differential spins the wheel with the least traction. Our gearboxes feature a heavy-duty Mechanical Differential Lock (Bloqueio de Diferencial). When the operator steps on the pedal, a sliding dog clutch locks both axles together, ensuring 100% torque transfer to both wheels to power through the deepest mud.
4. Planting Synchronization
Planting density (hills per meter) must remain constant regardless of tractor speed. The gearbox mechanically links the Wheel Drive to the PTO Drive via a precise gear train. We use Ground Helical Gears to minimize vibration. If the wheel slips, the planting arm slows down proportionally, maintaining perfect spacing. This mechanical feedback loop is crucial for the high-yield precision required by export-grade rice varieties.
System Comparison: HST vs. Mechanical Gearbox
| Recurso | HST Transmission (Hydrostatic) | Mechanical Gearbox (Gear Shift) |
|---|---|---|
| Controle de velocidade | Infinite Variable (Smooth) | Fixed Steps (Jerky) |
| Operator Fatigue | Low (Single Pedal) | High (Clutch + Shift Lever) |
| Planting Precision | High (Constant RPM) | Medium (RPM varies with speed) |
| Maintenance Cost | Higher (Hydraulic Fluid/Filter) | Lower (Gear Oil only) |
| Suitability | Large Scale / High Speed | Small Scale / Walk-Behind |
*Analysis derived from operational efficiency data in Uruguaiana rice estates.
Localized Application: Brazil Rice Belt
Deep Mud (Pelotas)
In the Pelotas basin, mud depth can exceed 40cm. Standard transmissions bottom out (“belly drag”), causing loss of traction. Our High-Clearance Portal Axle design raises the gearbox housing 15cm higher than standard, allowing the machine to float over the deepest mud without dragging, reducing engine load by 20%.
Salt Corrosion (Laguna)
Coastal rice fields often have saline water intrusion. Aluminum housings corrode into white powder (“White Rust”). EVER-POWER uses an Electro-Ceramic Coating (E-Coat) on all aluminum transmission cases, providing a glass-like barrier that is impervious to salt water and acidic fertilizer residue.
📒 Field Engineer’s Log: The Overheating HST
“November 2025, Alegrete. A rice farm manager reported that their transplanters were slowing down after 3 hours of work. The HST units were losing power. We checked temperatures: the transmission case oil was hitting 105°C.”
“The cooling fan was clogged with straw, but the main issue was the oil type. They were using a cheap generic hydraulic oil that thinned out at heat, causing internal leakage in the HST pump.
Solution: We drained the system and refilled it with High-Viscosity Index (HVI) 46 Hydro-Transmission Fluid. We also installed a larger capacity external oil filter. The operating temperature dropped to 85°C, and the machines regained their full 1.6 m/s planting speed immediately.”
Perguntas frequentes (OEM/B2B)
1. Is the HST unit included with the gearbox?
It depends on the configuration. For OEM customers, we supply the complete “Transmission Pack” which includes the Mechanical Gearbox and the integrated HST Unit (sourced from reputable partners like Daikin or customized in-house). We also sell the bare mechanical gearbox for replacement.
2. How often should the differential oil be changed?
The first change should be at 50 hours (break-in). Afterwards, every 300 hours or once per season. In wet conditions, check for water emulsion (milky oil) weekly. If water is present, change immediately to save the bearings.
3. Are the axle seals compatible with Yanmar machines?
Yes, our TC-Series uses standard metric axle dimensions (Hex 26mm, 30mm, etc.) compatible with major brands like Yanmar, Kubota, and Dongfeng. Our seal kits are designed as direct upgrades to OEM rubber seals.
4. What happens if the differential lock gets stuck?
This usually happens due to wind-up on hard surfaces. Never use the diff-lock on dry ground or during turns. If stuck, drive slowly in reverse while gently steering left and right to relieve the tension on the dog clutch springs.
Complete Your Transplanter System
Planting Arms (Rotary Case)
High-precision planting units driven by the main transmission PTO.
Rubber Lug Wheels
Specialized narrow wheels designed to grip the hardpan without damaging seedlings.
Control Cables
Waterproof push-pull cables for HST, clutch, and hydraulic lift control.
Reliability for the Harvest Season
Eliminate downtime in the paddy with EVER-POWER’s sealed transmission technology.
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Major Markets: Brazil, Japan, China, India, Egypt.
