Endless belt power transmission systems or components – Guard or housing for belt or pulley – Connected to belt
Reexamination Certificate
2000-04-06
2002-08-20
Bucci, David A. (Department: 3682)
Endless belt power transmission systems or components
Guard or housing for belt or pulley
Connected to belt
C474S145000, C474S146000, C474S018000, C474S111000
Reexamination Certificate
active
06435994
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to transmissions, and more particularly to improvements in transmissions of the type wherein an endless flexible element (especially a chain) is trained over a plurality of rotary members in the form of pulleys or sheaves, wheels, gears or the like. Examples of transmissions of the type to which the present invention pertains are those known as infinitely or continuously variable transmissions (called CVTs) wherein an endless flexible belt, band or chain (herein-after called chain) is trained over adjustable pulleys or sheaves (hereinafter pulleys). Transmissions of such character are utilized in the power trains of numerous types of motor vehicles to transmit torque between a prime mover (such as an internal combustion engine or a hybrid employing a motor and an engine) and the axles of front and/or rear wheels, e.g., by way of a differential.
Continuously variable transmissions of the type to which the present invention pertains and which can be utilized in the power train of a motor vehicle are disclosed, for example, in German patent No. 42 34 294. Endless chains which can be utilized in such transmissions are disclosed in German patents Nos. 43 30 696 (this publication discloses a chain which is designed to transmit tractive or tensile force) and 26 43 528 (this publication describes endless chains designed for the transmission of thrust).
A continuously or infinitely variable transmission (hereinafter called transmission for short) of the type to which the present invention pertains is likely or bound to generate noise when in actual use. Such undesirable side effect is attributable primarily to at least one of the elongated portions (known as stretches or reaches) of an endless flexible chain which is trained over at least two rotary members. For example, a CVT normally employs first and second adjustable rotary pulleys which are rotatable about parallel axes. The chain is or can be a so-called link chain or pintle chain and includes a first arcuate portion having a variable radius of curvature and being trained over a first pulley, a second arcuate portion having a variable radius of curvature and being trained over a second pulley, a first elongated (e.g., substantially or exactly straight) reach or stretch extending between the two arcuate chain portions from one of the first and second pulleys to the other of these pulleys, and a second elongated reach or stretch extending between the two arcuate portions from the other to the one arcuate portion. The first stretch is acted upon by a pulling force when the second stretch is pushed, or vice versa, depending upon which of the pulleys is driven to transmit torque to the other pulley.
Noise is generated by at least one of the stretches of the chain as a result of transverse vibrations. Such vibrations are undesirable for numerous reasons. For example, if the vibrations are conveyed or communicated to the chassis of the motor vehicle, this can result in the generation of often readily detectable noise which is unpleasant to the driver as well as to other occupant(s) of the vehicle. Furthermore, vibrations cause extensive wear, e.g., upon the links and/or pintles and/or other constituents of the chain, i.e., they can unduly affect the useful life of the chain and of the entire transmission.
The disclosure of each U.S. and foreign patent and patent application identified in the specification of the present application is incorporated herein by reference. This also includes each priority application being relied upon by the present application.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a transmission wherein an endless flexible element (such as a chain) is less likely to generate noise and/or to cause pronounced or excessive wear than the endless flexible elements in presently known continuously variable transmissions.
Another object of the invention is to provide a continuously variable transmission wherein the likelihood of noise generation is reduced in a simple, inexpensive and space-saving manner.
A further object of the invention is to provide a continuously variable transmission which exhibits the just outlined features, advantages and attributes and can be incorporated into the power trains of motor vehicles in a simple and time-saving manner.
An additional object of the invention is to provide a novel and improved chain and chain guide combination which can be incorporated into a continuously variable transmission of the above outlined character.
Still another object of the invention is to provide a power train which embodies a novel and improved continuously variable transmission or an analogous transmission.
A further object of the invention is to provide a novel and improved method of reducing the likelihood of noise generation by the chain or another endless flexible element of a transmission, such as a transmission wherein an endless flexible element is trained over at least two pulleys, gears, wheels or analogous rotary torque transmitting and/or torque receiving members.
Another object of the invention is to provide a transmission which is designed to generate less noise than conventional transmissions irrespective of whether one of the rotary members transmits torque to the other rotary member(s) or vice versa.
An additional object of the invention is to provide a novel and improved infinitely variable transmission of the type known as CVT, and to construct and assemble the transmission in such a way that it can be installed in existing power trains of or for motor vehicles as a superior substitute for existing transmissions of such character without necessitating any, or any appreciable, alterations under the hood of the motor vehicle.
Still another object of the invention is to provide a continuously variable or an analogous transmission the parts of which can be mass produced in available machines or production lines.
A further object of the invention is to provide a novel and improved guide for an endless flexible element which can be utilized in a transmission of the above outlined character.
Another object of the invention is to provide novel and improved means for supporting the guide in a continuously variable transmission or in the housing or casing of such transmission.
SUMMARY OF THE INVENTION
The invention is embodied in a transmission, such as a continuously variable transmission, which comprises a first rotary member (e.g., a first adjustable pulley wherein a first conical flange is movable axially toward and away from a second conical flange), a second rotary member (e.g., a second adjustable pulley similar to or identical with the first pulley and rotatable about an axis which is parallel to the axis of the first rotary member), and and endless flexible torque transmitting element (hereinafter called chain for short) having first and second arcuate portions respectively trained over the first and second rotary members, and first and second elongated stretches or reaches each of which extends between the first and second arcuate portions. In accordance with a feature of the present invention, the transmission further comprises an elongated guide for at least one stretch of the chain.
If the rotary members are adjustable pulleys, each thereof can be designed in such a way that one of its conical flanges is movable axially toward and away from but cannot rotate relative to the other conical flange. The arcuate portions of the chain contact the conical surfaces of the flanges forming part of the respective pulleys.
The guide can be provided with means for limiting the at least one stretch of the chain to movements along one or more paths of a plurality of predetermined paths each of which extends between the first and second portions of the chain. The exact path of the at least one stretch can vary continuously during adjustment of the rotary members if such rotary members constitute adjustable pulleys wherein one of the flanges is movable axially toward or away from the other flange.
The limiting means of the gui
Faust Hartmut
Friedmann Oswald
Bucci David A.
Charles Marcus
Darby & Darby
LüK Lamellen und Kupplungsbau GmbH
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