Borelli MLT 3.5 Speed Increaser – MLT 3.5 Series
The Borelli MLT 3.5 Speed Increaser – MLT 3.5 Series is designed to connect gear pumps to the power take-offs of agricultural tractors (540 rpm). It features a high-strength cast aluminium housing and UNI 18NiCrMo5 steel gears with a low-profile tooth design for exceptionally quiet operation. It supports output speeds of up to 3000 rpm and continuous operating temperatures of up to 120°C, ensuring reliability and a long service life in hydraulic applications. The available product codes are: 92001, 92002, 92003.
The Borelli MLT 3.5 Speed Increaser – MLT 3.5 Series is an essential mechanical transmission component designed to connect gear pumps to the power take-offs (PTOs) of agricultural tractors. Since the standard PTO output speed is 540 rpm, the device uses its transmission ratio to achieve the operating speeds required for the proper functioning of hydraulic pumps. Its mechanical design also allows operation at different input speeds, provided that the output speed of the speed increaser does not exceed the maximum limit of 3000 rpm.
The external structure of the speed increasers consists of cast aluminium and cast iron housings, materials selected to ensure high resistance to mechanical stress while maintaining a relatively low assembly weight of 16 kg. The core transmission system consists of gears carefully designed in full compliance with ISO/DIN 3990-80 standards. These components are manufactured from UNI 18NiCrMo5 steel. The gear geometry features a corrected, low-profile tooth design, an engineering solution that provides excellent wear resistance and significantly reduces operating noise during working cycles. Power transmission is handled by shafts manufactured from UNI 16CrNi4 steel. The shafts and gears are connected exclusively through splined sections, a technical solution that significantly increases their ability to withstand the torsional loads specified in the catalogue tables without structural failure.
The range offers several transmission ratios (2, 2.5, 3.1 and 3.7) to accommodate different system configurations, with a constant power rating of 40 kW. The torque values specified in the technical parameters (ranging from 80 to 105 daNm on the input shaft, depending on the ratio) refer to continuous-duty operating conditions. When the speed increaser operates under intermittent-duty conditions, the technical specifications allow the nominal torque ratings to be exceeded by up to 20%, providing an essential operating margin during pressure peaks in hydraulic circuits.
To ensure maximum efficiency and preserve the integrity of the internal components, SAE 90 lubricating oil must be used. The internal oil capacity of the housing is 0.600 litres. Routine maintenance requires visual inspection of the oil level through the dedicated sight glass every 1500 operating hours. The first lubricant change must be performed after the initial 60-80 hours of running-in and operation. Regarding thermal performance, the assembly is designed to withstand a maximum continuous operating temperature of 120°C. During installation, mounting the hydraulic pump requires a coupling half and a specific adapter flange. The power take-off connection can be made using a male shaft (1″ 3/8), a female shaft (1″ 3/8) or a female shaft with a quick coupling, depending on the available model configurations.
| Specification | Value |
|---|---|
| Standard Input Speed (PTO) | 540 rpm |
| Maximum Output Speed | 3000 rpm |
| Housing Material | Cast aluminium and cast iron |
| Gear Material | UNI 18NiCrMo5 Steel (ISO/DIN 3990-80 Standards) |
| Shaft Material | UNI 16CrNi4 Steel |
| Transmitted Power | 40 kW |
| Assembly Weight (G) | 16 kg |
| Lubricating Oil Type | SAE 90 |
| Maximum Oil Capacity | 0.600 litres |
| Maximum Operating Temperature | 120°C |
| Available Transmission Ratios | 2 / 2.5 / 3.1 / 3.7 |
| Model (Product Code) | PTO Shaft Type (Connection A/B) |
|---|---|
| 92001 | 1″ 3/8 Male Shaft (SAE 1 3/8″ DIN 9611) |
| 92002 | 1″ 3/8 Female Shaft (SAE 1 3/8″ DIN 9611) |
| 92003 | 1″ 3/8 26 Female Shaft with Quick Coupling (SAE 1 3/8″ DIN 9611) |