Friction gear transmission systems or components – Stepless ratio change – Intermediate idler between driving and driven gears
Reexamination Certificate
1999-08-18
2001-08-21
Estremsky, Sherry (Department: 3681)
Friction gear transmission systems or components
Stepless ratio change
Intermediate idler between driving and driven gears
C476S055000
Reexamination Certificate
active
06277048
ABSTRACT:
The present invention relates to a conical friction ring gear having at least two conical friction wheels mounted on parallel axles and opposite one another, and a friction device effectively connecting both conical friction wheels. The invention also relates to a process for regulating the transmission ratio in a conical gear.
Such conical friction ring gears are disclosed in DE 195 42 726 A1 and EP 0 657 663, for example. It is shown that with these conical friction ring gears smooth running cannot be guaranteed. Rather, these gears have a tendency to build up uncontrolled and uncontrollable vibrations, particularly in connection with internal combustion engines.
The object of the present invention is to make available a generic conical friction ring gear in which the risk of any uncontrollable vibration is reduced.
The first solution proposed by the present invention is a conical friction ring gear having at least two conical friction wheels mounted on parallel axles and opposite one another and a friction device effectively connecting both conical friction wheels, wherein a torque acts on the friction device with a component which lies vertically on a plane set by both conical friction axles. The friction device can be relocated along the conical friction wheels and can be designed such that it is pressed against the guide with torque.
Such an arrangement minimises the risk of any juddering of the friction device or reduces the risk to zero, because the friction device is subject to guying. In this way, a constant guide play is of no significance since the friction device lies closely on one side of the guide and is held in this adjacent position by the torque.
By way of advantage the torque is determined by forces applied to the friction device by the conical friction wheels. In this way the friction device is laid on the guide proportionally to the force acting on the friction device.
Such a solution is suited in particular to conical friction ring gears in which the friction device is disposed between the conical friction wheels. On the one hand this ensures that sufficient clearance is guaranteed for the guide of the friction device and that the friction device is stabilised all the same. On the other hand, this device still enables the friction device to be guided by displacement about an axis of rotation along both conical friction wheels.
A concrete embodiment can be produced in that the friction device is disposed between the conical friction wheels and comprises a first working area which revolves on the first of the two conical friction wheels, whereby both working areas are arranged offset relative to a rotational plane of the friction device. The term working area is understood to mean every geometrical region of the friction device revolving on a conical friction wheel. It is also understood that the working areas are subject to slight alteration during operation of the conical friction ring gear. According to the present invention, the term rotational plane is understood to mean a plane disposed vertically on a rotational axle of the friction device. Here, the term offset arrangement determines that both working areas are spaced apart variously from such a rotational plane.
Torque is applied to the friction device by the conical friction wheels adjacent to the working areas by means of such an offset arrangement of both working areas relative to a rotational plane. The guide only needs to be configured such for this torque to press the friction device against the guide.
In a relatively uncomplicated arrangement the friction device can comprise a friction ring, in turn comprising at least one bearing surface disposed radially outwards and one bearing surface disposed radially inwards, whereby each of the bearing surfaces revolves respectively on a conical friction wheel. If both bearing surfaces are arranged offset with respect to a ring plane, then torque according to the present invention occurs.
The friction device can be guided in a guide comprising a friction-type bearing between friction device and guide. Such an arrangement surprisingly ensures smooth running of the friction ring, although in the generic arrangements only little or even no lubricant is available for a guide of the friction device. Indeed, such a guide comprising a friction-type bearing is capable of advantageously calming the running of the friction device independently of the other characteristics of the conical friction ring gear. The advantages of this guide accumulate, however, with torque pressed against the guide into particularly even running of the friction device.
Because the friction device is generally fixed by means of the conical friction wheels, it should suffice for the friction device to be guided only by two guide positions. It has surprisingly eventuated that in a guide there is a tendency for any juddering to essentially decrease by means of three guide positions, whether a roller bearing or a friction-type bearing is provided at that position. This is particularly the case when the friction device is a friction ring disposed between the conical friction wheels. This friction ring can revolve only about its vertical axis so that one guide by means of one or two guide positions at most should suffice. A tendency for the ring to judder does not decrease through this alone, however, as this is the case only with three guide positions. A decrease in the tendency to judder occurs independently of the other characteristics of the conical friction ring gear, whereby the tendency to judder can be reduced through torque acting on the guide.
The friction device can be guided by a sliding carriage displaceable along at least one guide rod, whereby the sliding carriage is guided by a ball bearing guide on the guide rod. In this case any antifriction guide can act as ball bearing, where axial guiding occurs by means of revolving spheres. In particular, a spherical liner can be used. With such a bearing arrangement of the sliding carriage, which in the prior art is guided along the guide rod by means of a slide bearing, the friction device and in particular a friction ring acting as friction device can be guided more stably. Such an arrangement is particularly suited to conical friction ring gear in which the friction ring is displaced about an axis of rotation, in particular by displacement of guide rods bearing a sliding carriage guiding the friction ring. In such a mounting the forces for displacing the friction ring or the friction device stem from the conical friction wheels, as the sliding carriage is not driven particularly by itself. In this way, such an arrangement can ensure particularly smooth and even running of the friction device, in particular when it is displaced along the conical friction wheels. Such an arrangement also acts independently of the other characteristics of the conical friction ring gear of stabilisation or friction device guiding.
In order to further stabilise this guide, at least one guide rod can be profiled. Such a measure does not act directly on the guide of the friction device and it has been shown that this measure decreases the risk of vibration in the overall arrangement and thus also the risk of juddering of the friction ring. Preferably, the guide rod can be designed in profile as I-shaped or square. It is understood that such profiling serves advantageously to stabilise the overall arrangement independently of a ball bearing guide of the sliding carriage on the guide rod.
The guide rod can be attached to an adjusting frame made of sheet metal, diecast aluminium or synthetic material, especially high-performance synthetic material. Such an arrangement enables a reduction in weight. In addition, manufacture is considerably simplified, since a component comprising these materials only needs to be reshaped or formed into shape accordingly. It is true that use of such an adjusting frame is seen as an advantage for itself in order to achieve a corresponding decrease in weight and manufacturing costs. Particularly in connection with the abovede
Estremsky Sherry
Fuierer Marianne
Hultquist Steven J.
Lewis Tisha D.
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