Planetary gear transmission systems or components – Fluid drive or control of planetary gearing – Pump and motor in series with planetary gearing
Reexamination Certificate
2001-09-18
2003-07-15
Marmor, Charles A. (Department: 3681)
Planetary gear transmission systems or components
Fluid drive or control of planetary gearing
Pump and motor in series with planetary gearing
C475S207000, C074S730100
Reexamination Certificate
active
06592485
ABSTRACT:
BACKGROUND AND SUMMARY OF THE INVENTION
The invention concerns a transmission assembly with an infinitely variable transmission module and a constant transmission module. The transmission ratio of the infinitely variable transmission module can be continuously adjusted within certain limits in the forward and if necessary also in the reverse direction, while the transmission ratio of the constant transmission module is fixed, or adjustable in discrete steps.
In the vehicle industry, besides drive systems with conventional gear changes, infinitely variable drive concepts are also used. In this, power-branched transmissions are also used, which provide acceptable efficiency that is often lacking in an infinitely variable transmission. In power-branched transmissions part of the combustion engine's power is transmitted via an infinitely variable transmission branch and another part of the power is transmitted via a constant, mechanical transmission branch. Having passed through their respective transmission branches, the two power flows are combined and superimposed again and then transmitted to the wheels of the vehicle via mechanical drive elements.
It is known to design the infinitely variable transmission branch as a hydrostatic, toroidal, chain, belt or electrical transmission, while the constant transmission branch can be made as a planetary gear system with integrated gear-change steps. In this context numerous combinations and variants are known to those familiar with the field.
In tractor construction, hydrostatic/mechanical power-branched transmissions are used as infinitely variable drive systems. A power-branched transmission is for example known from EP-A-0 465 752. However, the power-branched transmissions used in tractor construction have a number of disadvantages: particularly because of the large number of components and numerous variants involved, their manufacturing costs are essentially higher than the cost of ordinary part-load or full-load transmissions. The market promotes many transmission variants intended to cover different power requirements and applications. For this, in each case complete new transmissions are needed, since variants cannot be formed with known standard transmission components. The usable speed ranges are distributed in groups which can only be switched to while stationary or in ranges between which one can shift seamlessly. The seamless shift positions in question are often in the main working range of the tractor, in which the shift is perceived as unpleasant.
The objective of the present invention is to provide a transmission assembly with an infinitely variable transmission component and a constant transmission component, by means of which the aforesaid problems are overcome. In particular it must be possible to provide a large number of different transmission variants. The transmission system must satisfy various power requirements and application needs, must achieve optimum efficiency in the main working range, it must be inexpensive to manufacture, requiring a small number of different components, it must be easy to assemble, and shifting must be effected almost imperceptibly.
The transmission assembly according to the invention comprises an infinitely variable transmission component and a constant transmission component. The transmission components are formed as pre-assembled modular units that can be combined to form overall transmission systems as desired. The infinitely variable transmission module is a self-contained functional transmission unit with an adjustment gear housing, which is open on at least one side where it comprises a flange. The flange serves for the attachment, as desired, of constant transmission modules in various power categories and/or with various numbers of gear steps. Within the flange area there extends at least one infinitely variable output shaft of the variable transmission module.
The infinitely variable transmission module can produce infinitely adjustable speeds of its output shaft, and this preferably in both rotation directions. For the constant transmission modules, transmission components designed in various ways with different numbers of gear steps can be considered, in each case comprising a mechanical shift system between several gears and/or groups and if necessary including a reversing unit.
According to the invention, identical infinitely variable transmission modules can be combined with a variety of different constant transmission modules to form a series of transmissions of various power categories. In this, the constant transmission modules are designed for different powers and/or have different numbers of gear steps. The higher the nominal input power of the transmission assembly, the larger is the number of gear steps chosen for the constant transmission module.
It is particularly advantageous to design infinitely variable transmission modules for particular powers, so that they will satisfy the maximum power requirements expected from the transmission series. In this way, the number of gear steps of the constant transmission and the power loss of the transmission system overall can be kept low. Although it is more expensive to manufacture larger infinitely variable transmission modules than smaller ones, this is more than compensated by the variety of uses made possible and the associated considerable increase in the number of units manufactured. The size of the infinitely variable transmission can be restricted by the accommodation space available.
The infinitely variable transmission module is designed for a given power transfer (e.g. 200 kW for an agricultural tractor). By designing the constant transmission module with 1, 2, 3 or more transmission ratios (gears and/or groups), the infinitely variable transmission module can be adapted to the various power categories required for a tractor series. In this way, the same infinitely variable transmission module can be used in all the power categories. This is possible because, with an increasing number of gears and/or groups of the constant transmission module, the power in the infinitely variable transmission module remains the same. This means that for vehicles of lower power, the constant transmission module is made with one or only a few gears and/or groups. On transition to a vehicle the next higher power category, in each case a gear or a group is added to the constant transmission module.
The transmission series according to the invention comprises only a single infinitely variable transmission module, which can be used unchanged for a large range of vehicle categories. This enables a markedly modular structure and provides a wide variety of options for the customer, with a correspondingly more favourable cost structure. Thanks to the individuation of transmission components and the modular structure, the number of different components and the production costs are reduced to the point that they correspond to, or are even less expensive than the cost of conventional part-load transmissions in small and medium vehicle power categories and those of full-load transmissions in larger vehicle power categories. The transmission assembly or transmission series according to the invention makes it possible to assemble and dismantle the modules very simply, provides optimum efficiency in the main working range of the vehicle and has high overall efficiency throughout the speed range.
Preferably, on the side of the infinitely variable transmission module opposite the flange, a transmission input shaft is provided that can be connected to an engine and extends into the adjustment gear housing, also known as the variable transmission housing, and through the infinitely variable transmission module. The constant transmission module is fixed to the flange so that it is spatially adjacent to the infinitely variable transmission module. The infinitely variable and constant transmission branches are aligned with one another and come after one another in the axial direction. The transmission input shaft is at the same time used as an
Freund Ralf-R.
Otten Uli
Abdelnour Dennis
Deere & Company
Marmor Charles A.
LandOfFree
Transmission assembly with infinitely variable and constant... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transmission assembly with infinitely variable and constant..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transmission assembly with infinitely variable and constant... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3026370