Rexroth High Efficiency Traction Control HET

© Bosch Rexroth AG, RE98708

High Efficiency Traction Control HET for compact vehiclesOn demand 4-wheel drive

Customer benefits ▶ Compact and straightforward design ▶ Optimal vehicle traction in the field ▶ All functions integrated, including flushing ▶ On demand activated 4-wheel drive ▶ Works automatically without any action by the driver ▶ Standard hydraulic components (variable displace-

ment pumps and wheel motors) ▶ No additional sensors or control electronics required ▶ Versatile applicability

Applications

Sometimes drivers of compact vehicles are faced with critical situations when driving on wet, icy or contami-nated ground. In these situations the risk of traction loss is greatest. Bosch Rexroth has developed the High Efficiency Traction Control (HET) to increase driving safety under these unfavorable surface conditions. HET is automatically activated without any intervention by the driver. During normal driving operation, the Rexroth High Efficiency Traction Control drives a single axle and achieves fuel savings compared to a permanently activated 4-wheel drive.

HET is a purely hydraulic system with a compact design that requires neither sensors nor control electronics. It is based on proven standard components from the Rexroth mobile hydraulics range. HET is designed for a variety of compact vehicles which are equipped with a hydrostatic single wheel drive such as dumpers, farm loaders and sweepers.

Function and benefits

With HET it is possible to install a hydrostatic 4-wheel drive quite easily. HET uses the already installed hydro-static travel drive and its hydraulic components. In compact vehicles two radial piston motors on either side of the vehicle are typically already mounted and the hydraulic oil flows through one after the other. The HET control block with integrated flow control valves creates a bypass with a constant flow from the connection between the first and second wheel motor to the low pressure side of the hydrostatic drive. In normal driving situations, the HET control block transfers nearly the entire torque through the wheel motor on the rear axle which optimizes efficiency.

If the rear wheel comes into contact with a smooth surface and rotates slightly faster, the flow rate through the rear wheel motor increases without proportional movement of the vehicle. This generates pressure and

RE98708/10.2014

© Bosch Rexroth AG, RE98708

High Effi ciency Traction Control (HET) for compact vehiclesOn demand 4-wheel drive

torque to the wheel motor on the front axle. At this point, the front wheel, which still has grip on the ground, takes over the drive. As soon as the rear wheel regains grip, it takes back the drive. The entire control mechanism works hydraulically. HET intervenes automatically, the operator does not need to take any action.

Rexroth HET has a compact and straightforward system design. It consists of a newly developed valve block that is available in both medium- and high-pressure versions (350 / 420 bar). This valve block integrates all functions such as a secondary supply, pressure protection and fl ushing.

HET consists of proven components from the Rexroth product portfolio: a control block, radial piston motors for an individual wheel drive and an axial piston pump A10VG or A4VG. The A10VG covers the maximum pressure range up to 350 bar, while the A4VG works up to 450 bar. A broad range of Rexroth A4VG and A10VG variable axial piston pumps and MCR radial piston motors with fi xed or shiftable displacement off er a high degree of fl exibility for use of HET in a variety of compact vehicles. As a result, a large number of requirements are met in terms of driving speed and installation space.

Rexroth defi nes all settings in line with customer’s specifi -cation prior to initial commissioning. Thus, Rexroth High Effi ciency Traction Control (HET) for compact vehicles is a plug-and-play solution for on demand all-wheel drive activation.

HET control block Variable axial piston pump A4VG

Technical data

HET control block

Pressure level: 350 and 420 bar

Variable axial piston pump A4VG series 32

Sizes: 28, 40, 56, 71, 90, 125, 180, 250 cm3

Maximum pressure: 450 bar

Data sheet: RE92003

Variable axial piston pump A10VG series 1

Sizes: 18, 28, 45, 63 cm3

Maximum pressure: 350 bar

Data sheet: RE92750

Radial piston motor MCR-F, MCR-W

Sizes: 160 up to 3000 cm3

Maximum pressure: 420 / 470 bar

Data sheet: RE15198, RE15200

© This document, as well as the data, specifi cations and other informationset forth in it, are the exclusive property of Bosch Rexroth AG. It may not be reproduced or given to third parties without its consent. The data specifi ed above only serve to describe the product. No state-ments concerning a certain condition or suitability for a certain application can be derived from our information. The information given does not release the user from the obligation of own judgment and verifi cation. It must be remembered that our products are subject to a natural process of wear and aging.Subject to change.

Bosch Rexroth AGMobile ApplicationsGlockeraustraße 489275 Elchingen, GermanyTel. +49 7308 82-0info.ma@boschrexroth.dewww.boschrexroth.com

Radial piston motor MCRVariable axial piston pump A10VG