Friction gear transmission systems or components – Forward and reverse – Variable speed in forward or reverse
Reexamination Certificate
1997-03-08
2001-08-07
Ta, Khol Q. (Department: 3681)
Friction gear transmission systems or components
Forward and reverse
Variable speed in forward or reverse
C476S036000, C475S196000
Reexamination Certificate
active
06270442
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to multi-function mechanical power transmissions, and more particularly, to speed reducers and the like with wide versatility.
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. Typically in these applications, a 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 an additional object of the present invention to provide a speed converter design which is adaptable to a variety of situations.
It is an additional object of the present invention to provide a washing machine drive design with a minimum of brakes, pulleys, belts, solenoids and the like.
SUMMARY OF THE INVENTION
New drive concepts, such as for washing machines, are disclosed. In a preferred embodiment, the spin and agitation functions are performed without the need for cycling the motor or altering its speed of rotation. The switch from agitation to spin mode involves only a change in the direction of rotation of the motor.
These concepts and the above and other objects are well met by the presently disclosed, highly efficient, speed converting assembly of the present invention.
A preferred embodiment includes a speed converter apparatus for translating an input at a first velocity to an output at a second velocity. The speed converter has a primary drive disk defining a primary cam (a “drive” “cam-gear”) for providing a rotary motion input at a first angular velocity.
The speed converter apparatus also includes a driven assembly. The driven assembly has a secondary cam (also a “cam-gear”) on a secondary disk, and an intermediate disk element. The intermediate disk is a direction-dictating, directional element, located between the primary and secondary disks. The intermediate disk has slots for receipt of transmission elements (balls) therein. The speed converter output is taken from a driven disk, which is either the intermediate disk or the secondary disk.
In various embodiments, the primary and secondary 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 disk. Each of the primary and secondary cam-gears has a respective flank. Projections of these flanks intersect at unique points upon rotation of the primary cam-gear, associated ones of these unique points defining respective ones of the slot paths in the intermediate disk.
A respective ball in a respective slot path is driven radially between a maximum and minimum radius by the primary cam-gear. In one embodiment, the slotted intermediate disk is a reaction disk for reacting the drive force on the balls in the slots, and the secondary cam-gear is driven into rotation by action of the oscillating balls. In another embodiment, the slotted intermediate disk is driven into rotation by action of the oscillating balls, with the drive force on the balls being reacted by the secondary cam-gear, where the secondary disk is a reaction disk.
Overall, the primary cam-gear is designed to cause a linear displacement of the balls for a given cam-gear rotation. The secondary cam-gear is configured for conjugate action with the primary cam-gear, and which results in constant linear velocity of the radially traveling balls. The primary and secondary cam-gears are thus referred to as a conjugate pair. The centerline of a respective slot is defined as the loci of the contact of the cam-gears at the slots' given angular location.
In one embodiment, the primary cam-gear contour varies substantially linearly with angular rotation at a first rate of variation. The secondary cam-gear 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 the apparatus can be determined by comparing the inverse of the number of cycles of the primary cam-gear to the number of cycles of the secondary cam-gear.
In such embodiment of the invention, the first cam-gear device is formed as a face cam-gear on the primary cam-gear disk, and in simplest form has one lobe (or cycle) starting at a base circle radius and proceeding about the center of the disk at a constantly increasing radius and at a constant angular rotation to a maximum radius at 180°, i.e., in the rise mode, and then proceeding in the fall mode at a decreasing radius of the same rate and constant angular rotation back to the original base circle radius, completing 360°.
The second cam-gear device is formed as a multi-cycle face cam-gear track on a second cam-gear disk, and is mounted in a position facing the face cam-gear track of the primary cam-gear disk. Each cycle of this face cam-gear track defines a rise mode and a fall mode. Each rise and fall mode of the plurality of cycles in the secondary cam-gear are configured to have the same radial displacement, for uniform conversion.
The invention also enables use of interim cam-gears, which enables staging of speed reduction. Specifically, a first face of an interim cam-gear has an interim secondary cam-gear which interacts with the primary cam-gear and a second face of the interim cam-gear has an interim primary cam-gear which interacts with the secondary cam-gear. Thus two or more stages of reduction can be created in a compact speed reducer of the invention.
The invention can produce constant rotational velocity for 360° rotation at the output, with torque transmission through each of the moving balls for 360° of rotation at the output. Ideally, all or substantially all of the balls share the load continuously, thereby decreasing the unit load on each ball, except for when for the moment when any one of the balls is in transition. The slopes at each of the primary and secondary cam-gear curve segments are designed for conjugate action so that essentially smooth and constant radial displacement of the moving balls occurs, in interaction with the intermediate disk and secondary cam-gear. The cross-over angles between the drive and secondary cam-gears is essentially the same at all ball locations without much variation over the entire ball movement, with the ball movement having substantially constant linear velocity, except for when the balls approach their transition at the minimum and maximum displacements for reversal of their direction of travel.
In the above embodiments, the intermediate disk is shown fixed relative to the conjugate pair of primary and secondary cam-gears/disks, but the present invention is not limited to constant motion output. In another embodiment of the invention, the intermediate disk is allowed to obtain an angular velocity at a controlled and variable rate, and this in turn provides speed conversion at a controllable and variable rate at the driven secondary disk output. By changing the angular velocity of the intermediate disk, a variance of output is achieved.
In a reversing embodiment of the invention, the primary cam-gear, intermediate disk and secondary cam-gear are still required, although with variation of the angles of the slots of the slotted disk. Thus it is possible to interchange a reverse-motion intermediate disk with a non-reversing intermediate disk, so as to convert from the smooth, continuous output of the ball drive in one direction to a smooth reversed-motion output, all with the same drive input rotation. (In this application, the non-reversing intermediate disk at times is referred to as a “conventional” intermediate disk.)
The slot locations and the slot angles are selected in recognit
Bursal Faruk H.
Cunningham Michael P.
Folino Frank A.
Maslow James E.
Cohen Jerry
Erlich Jacob N.
Perkins Smith & Cohen LLP
Synkinetics, Inc.
Ta Khol Q.
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