Endless belt power transmission systems or components – Pulley with belt-receiving groove formed by drive faces on... – Load responsive
Reexamination Certificate
2001-11-20
2004-07-06
Bucci, David A. (Department: 3682)
Endless belt power transmission systems or components
Pulley with belt-receiving groove formed by drive faces on...
Load responsive
C474S017000
Reexamination Certificate
active
06758775
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of German Patent Application Serial No. 100 58 475.6 filed on Nov. 24, 2000, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates an infinitely variable cone pulley transmission and generating of axial contact pressures exerted by the cone pulleys onto a traction means, rotating between these cone pulleys, via tensioning means arranged on the transmission shafts, which act in axial direction onto respectively one cone pulley that can be axially displaced along the respective transmission shaft. For this, hydraulic means are provided on a first transmission side for adjusting and maintaining the transmission ratio and a spring that is braced against a support, fixed relative to the shaft, is provided on the second transmission side.
A cone pulley transmission of this type is known, among other things, from German reference DE 43 00 879 and is used whenever a cost-effective transmission is desired for small vehicles and simple industrial applications. The disadvantage of the known transmission, however, is its inability to generate load-dependent contact pressure forces between cone pulleys and traction means. Rather, the spring that generates the contact pressure force on one of the transmission sides determines the output limit for the transmission. In other words, it means that the spring must be designed for a certain maximum output that can be transmitted by the transmission. With a low power transmission, the transmission therefore operates with an excess contact pressure between cone pulleys and traction means and thus with a more or less high loss.
In order to generate the above-mentioned contact pressure forces load-dependent and with the lowest possible losses, it is known that these contact pressure forces can be generated with corresponding control and exclusively with hydraulic means on both transmission sides. Another option is to generate the contact pressure forces purely mechanical, with the aid of so-called contact pressure mechanisms.
A third option consists in the combination of these two systems, for example as disclosed by the subject matter of German references 2 016 181 and 2 058 399. According to the aforementioned reference, the contact pressure forces on both transmission sides are generated load-dependent with contact pressure mechanisms of the aforementioned type. These mechanisms are parallel connected to a device for generating hydraulic contact pressure forces for adjusting and maintaining the transmission gearing. With respect to the design, it means that the respective axially displaceable cam sleeve of the contact pressure mechanism is also positioned axially displaceable on a neck-type extension of the cone pulley, which can be displaced in axial direction to vary the transmission ratio, and is stressed in the direction toward the contact pressure mechanism cam sleeve that is fixed relative to the shaft by a compression spring, arranged between displaceable cam sleeve and adjacent cone pulley. This type of design is extremely space consuming, especially in radial direction, and is thus too costly for simple cone pulley transmissions, especially when considering the scope of the hydraulic control required to adjust and maintain the transmission ratio.
It is the object of the invention to develop a more effective cone pulley transmission of the aforementioned type, which has a mechanical device for the load-dependent generating of contact pressure forces, but does not require additional space on the transmission side in question, particularly in radial direction.
SUMMARY OF THE INVENTION
This object is solved according to the invention by arranging on the second transmission side one axially fixed cone pulley and one axially movable cone pulley that is provided with an extended hub. The object is further solved by connecting the cone pulleys so as to rotate together and such that they rotate jointly on their transmission shaft and are coupled to this shaft via a contact pressure mechanism depending on the rotational moment or a rotational moment and the transmission ratio. The object is furthermore solved in that the contact pressure mechanism consists of a cam sleeve, fixed relative to the shaft, a cam sleeve formed by the free end of the extended hub, as well as roll bodies, which are inserted between the opposite-arranged cam tracks and rotate around axes that are positioned radial relative to the transmission shaft, so as to transmit the forces. The roll bodies are guided by rings, are held at a mutual distance to each other and arc adjusted in axial direction with spring force to remain in the region of the axial center between the cam sleeves by a spring that is arranged coaxial on the extended hub.
These measures according to the invention make it possible for the transmission side with mechanical generating of the contact pressure forces to generate these contact pressure forces load-dependent and thus only within the scope required for the momentary output transmitted by the transmission. The purpose of the spring that is now connected parallel to the contact pressure mechanism is reduced to providing a basic contact pressure in case the transmission is idling and no contact pressure force is generated by the contact pressure mechanism. The transmission thus can operate without specific losses.
Since the axially displaceable cam sleeve for the contact pressure mechanism is now integrated into the free end of the extended hub of the associated cone pulley, a design results that requires comparatively no additional space in radial direction. In particular, it is not necessary to arrange the axially displaceable cam sleeve of the contact pressure mechanism as additional component radially outside of the extended hub of the axially displaceable cone pulley, as is necessary for the above-described case.
Since the axially displaceable cam sleeve of the contact pressure mechanism is now an integral component of the axially displaceable cone pulley, as mentioned before, it means that this cam sleeve always assumes only an axial position that corresponds to the transmission-ratio dependent axial position of the displaceable cone pulley. In the event that no load is applied to the transmission, it would then be possible for the roll bodies to assume a position at the bottom of the cam curves formed by the cam sleeves. If a load is applied once more, a spinning of the cam sleeves could result, at least in those gearing positions of the transmission where the cone pulleys of the second transmission side are positioned close together. To keep this from happening, the additional feature of the invention ensures that the roll bodies are always kept in the region of the axial center between the cam sleeves, even in the case of a non-loaded transmission, meaning an idling transmission.
In a manner known per se, it has proven advantageous that the of the second transmission side are arranged on a hollow shaft, which is positioned so as to rotate on the transmission shaft but cannot be displaced in axial direction. It is furthermore advantageous that the axially fixed cone pulley is rigidly connected to the hollow shaft, the axially displaceable coney pulley is connected rotatingly to the hollow shaft and the cam sleeve that is fixed relative to the shaft is arranged next to the hollow shaft on the transmission shaft, such that it rotates along and cannot be moved axially, at least not in the direction away from the opposite arranged cam sleeve. The axially fixed cone pulley in this case can form one piece with the hollow shaft.
One embodiment of the invention advantageously provides that the roll bodies, having pinions that project radially from the roll bodies toward the transmission shaft and are coaxial to their rotational axes, engage in corresponding recesses in the rings. For this, a holding ring that is coaxial to the shaft can be arranged radial to the transmission shaft inside or outside of the roll b
Heinrich Johannes
Matzig Rainer
Schönnenbeck Gert
Wagner Peter
Anderson Chad C.
Bucci David A.
Johnson Vicky A.
Kinberg Robert
P.I.V. Antrieb Werner Reimers GmbH & Co. KG
LandOfFree
Bevel gear unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bevel gear unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bevel gear unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3244736