Machine element or mechanism – Gearing – Toothed gear and recirculated unconnected elements
Reexamination Certificate
1999-10-29
2001-11-13
Bonck, Rodney H. (Department: 3681)
Machine element or mechanism
Gearing
Toothed gear and recirculated unconnected elements
C475S168000
Reexamination Certificate
active
06314826
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to mechanical power transmissions, and more particularly, to speed converters and the like.
Speed conversion is an important capability in the efficient utilization of rotary motive force. The occasion often arises for increasing or reducing of the speed of a drive member to a higher or lower speed at a driven member. In automobiles, for example, a hydraulic transmission, with various combinations of gear assemblies, accomplishes the task of translating the high rotary speed of the gasoline engine to the lower rotational requirements at the driven axle. Typically, such transmissions are quite complex, requiring many parts to operate in sophisticated synchronization, and are quite labor intensive for both assembly and service. Other speed conversion applications include elevators, where an electric motor typically is employed for lifting and lowering the elevator cab, and robotics, where an electric motor is employed as an actuator to effect motion. Typically in these applications, the speed reducer housing is mounted (“grounded”) directly to the equipment housing. At times the effect of speed reduction is also referred to as torque amplification, and these concepts may be treated as interchangeable, for purposes of this disclosure.
It is therefore an object of the present invention to provide a speed converter which is simplified in nature but is robust in transmission capability.
It is a further object of the present invention to provide a speed converter which is relatively easy to assemble and service.
It is an additional object of the present invention to provide a speed converter design which is adaptable to a variety of situations.
SUMMARY OF THE INVENTION
These and other objects are well met by the presently disclosed nested speed converting transmission. In one aspect of the invention, rotary motion is translated from a first speed at the rotary input to a second speed at the output, using a nested set: including a pair of wavy devices, a slotted device between the pair, and an oscillatable translating arrangement, preferably using ball or roller type translating elements loaded in the slots of the slotted device. In a preferred embodiment of the invention, two of the devices are rotatable about a common axis with the third device fixed about that axis. In an alternative embodiment, the third device is also rotatable about the same axis.
In a preferred embodiment of the invention, a set of bearings supports the front and back sides of the rotary parts of the apparatus. The resulting invention provides both speed conversion function and the bearing support function of the rotary parts in a nested speed converter bearing apparatus.
For ease of description, the cam devices described herein may also be referred to as gears or cam gears and the cam cycles may be referred to as teeth or cam gear teeth, all interchangeably and without limitation. Devices with two cam gear parts, a slotted gear part and interacting rolling elements are described herein. These interacting elements may be balls, rollers, pins, bushings, ball bearing assemblies, or the like. The terms drive and driven may be applied to various ones of the three gear parts, depending upon an application.
In various embodiments of the invention, the inner and outer cam gears are each formed on a face of a respective primary and secondary disk, and the slots are formed as radial slot paths in the intermediate gear disk. Each of the primary and secondary cam gears has a respective flank. Projections of these flanks intersect at unique points upon rotation of at least one of the cam gears, associated ones of these unique points defining respective ones of the slot paths in the intermediate part.
A respective roller in a respective slot path is driven radially between a maximum and minimum radius by the rotary input. In one embodiment the inner cam gear is the rotary input and the slotted intermediate disk is a reaction disk for reacting the drive force on the rollers in the slots. The outer cam gear is driven into rotation by action of the sequence of radially oscillating rollers. In another embodiment, the slotted intermediate disk is driven into rotation by action of the rollers, with the drive force on the rollers being reacted by a fixed cam gear part.
In one embodiment of the invention, the cam gears are designed to cause a linear displacement of the rollers for a given cam gear rotation and cooperation of the cam gears results in essentially constant linear velocity of the radially traveling rollers during the bulk of their driving motion.
In one embodiment of the invention, the cams gears are designed as a conjugate pair in that the theoretical centerline of a respective slot is defined as the loci of the contact of the cam gears at the slot for a given angular location.
In one embodiment of the invention, the primary cam contour varies substantially linearly with angular rotation at a first rate of variation. The secondary cam contour varies substantially linearly with angular rotation at a second rate of variation. The relationship of these variations determines the speed conversion ratio of the apparatus. In accordance with the foregoing, the speed ratio of an embodiment of the invention can be determined by comparing the number of cycles of the secondary cam to the number of cycles of the primary cam.
In a preferred embodiment of the invention, the disclosed speed converter using cam gears is integrated with support bearings, in a compact drive mechanism. The center of the apparatus is preferably open for receipt of a drive shaft input or driven shaft output to a load.
In one embodiment of the invention, the first of the wavy pair of devices, and preferably a conjugate pair of devices, is coupled to an input of the translation arrangement and the second of the pair is coupled to an output of the translation arrangement, such that motion of the first of the devices can be translated to motion of the second of the devices by the translation arrangement, with the slotted device being part of the translating arrangement.
In another aspect of the invention, a method is provided for translating the speed of a drive shaft which is driven at a first speed to the speed of a driven shaft at a second speed. The method includes the steps of providing a drive element having a drive cam, a driven element having a driven cam, and at least one reciprocating transfer element interacting between the two cams in a slotted retainer, whereby the driven cam can be driven at the second speed by the drive cam driven at the first speed.
The inner cam gear part, the intermediate slotted part, and the outer cam gear part together can be thought of as disks or cylinders. In a pancake-type transmission embodiment of the invention, the rotary motion and angular velocity of one of the three disks is efficiently translated via the translating part into rotary motion and angular velocity of a second of the disks.
The surfaces of the rollers (or balls) and the flanks or surfaces of the cam gears and of the slots that interact with the rollers (or balls) may be referred to collectively as “working surfaces” of the apparatus. The term track herein should be understood as to refer to the path of the interacting element on a working surface. An ideally designed track and ball type speed converter described herein may offer zero backlash from perfect interaction of all working surfaces. The present invention is directed to provision of improved efficiency of power transmission and to improved volume utilization, in a speed converting device.
In a preferred practice of the invention, a stable, robust and well-spindled speed converting bearing apparatus is provided for converting rotary motion input to output having a conjugate pair of cam gear parts and a translating part. The translating part includes an intermediate gear part with slots defined therein, preferably radially extending slots. These three parts are mounted about a common axis, having an input and output rotatable about the
Bursal Faruk H.
Cunningham Michael P.
Folino Frank A.
Bonck Rodney H.
Cohen Jerry
Erlich Jacob N.
Perkins Smith & Cohen LLP
Synkinetics, Inc.
LandOfFree
Nested speed converter bearing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nested speed converter bearing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nested speed converter bearing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2617574