This application claims priority to German Application DE 101 48 696.0 filed on Oct. 2, 2001 and DE 102 23 296.2 filed on May 24, 2002.
1. Technical Field of the Invention
The invention relates generally to self-propelled machines and, more particularly, to a method and apparatus for prolonging the life of a clutch on such machines, especially agricultural or utility machine.
2. Description of the Related Art
EP 0 728 962 and its counterpart, U.S. Pat. No. 5,695,422, describe, inter alia, a hydrostatic-mechanical torque-divided transmission for agricultural machines, and other utility machines. To change direction of the machine the rotation of the input shaft is reduced to zero. Typically this is accomplished, at least in part, by reducing fuel feed and allowing the engine to gradually slow the rotation of the input shaft. Torque is transferred via a clutch inside the transmission. In the case of high torque transfer, this leads to both considerable heat generation in the clutch and to premature wear. To reduce heat generation and wear-related drawbacks, it is known that several clutches or braking elements can be integrated in the respective drive train. But this still leads to elevated heat generation in the drive train and has the disadvantage that a considerable number of additional assemblies are required.
The present invention is directed to overcoming one or more of the problems set forth above.
An aspect of the invention is to provide a method and an apparatus for the control of a self-propelled machine which, with little structural expenditure, minimizes wear of the drive train, reduces heat generation in the drive train, reduces the high power idle that occurs with ordinary methods for changing the direction of the machine, and/or lowers overall fuel consumption of the self-propelled machine.
Another aspect of the present invention is to control a self-propelled machine which includes a gearbox with an output shaft, a clutch, and a braking system. When a change of speed and/or direction of rotation of the output shaft is required, a management controller effects the change by at least partially bypassing the clutch and engaging the machine braking system.
When changes of speed and/or direction of rotation of the gearbox output shaft are assisted by the machine braking system, the braking function of the clutch is considerably reduced or completely excluded. This leads to a considerable reduction in wear of the clutch, so that its service life can be greatly increased, compared with known designs in the art. Also, apart from reducing the load on the clutch, a considerable reduction of engine idle power generated during deceleration is accomplished, so that the machine needs considerably less fuel, particularly in the case of changes in the direction of travel.
To not impair driving stability, it is of further advantage if associated with each land wheel or each axle of the machine are wheel brakes which are operated during changes of speed and/or direction of rotation of the gearbox output shaft.
A particularly advantageous embodiment arises if the self-propelled machine includes a traction machine and towed equipment. In this embodiment, the land wheels and/or axles of both the traction machine and the towed equipment are wheel brakes. For changes of speed and/or direction of rotation of the output shaft, the wheel brakes of both the traction machine and the towed equipment are operated. In this way, even with tractor/trailer combinations, it is ensured that, in addition to the wear-minimization of the clutch of the traction machine, high driving stability of the combination is accomplished.
To obtain high flexibility of the machine braking system in the case of changes of speed and/or direction, an advantageous embodiment includes a machine brake management system.
To obtain high driving stability independently of the driver""s wish to decelerate, machine-generated input signals delivered to the management controller can be used to monitor the driving stability and achieve the inputted wish to decelerate.
In accordance with the present invention there is provided an apparatus for prolonging the life of a clutch of a self-propelled machine having a drive train including an engine, a gearbox with an output shaft, and a machine braking system; means for generating an input signal relating to a function of the drive train; a management controller for receiving the input signal, analyzing the input signal for its effect on the drive train, and generating a plurality of output signals; and means for transmitting one of the output signals to the machine braking system and another of the output signals to the clutch, and for automatically and cooperatively engaging the machine braking system and disengaging the clutch to assist a change in the speed or direction of rotation of the output shaft.
Other aspects, objects and advantages of the present invention can be obtained from a study of the drawings, the disclosure and the accompanying claims.