A continuously variable transmission (CVT) is a transmission that continuously varies a speed ratio between an output speed and an input speed. One type of a CVT is a belt-type that varies the speed ratio by varying the distance between sheaves of a pulley so the distance of the belt to a rotational axis of the pulley varies. Another type of CVT is a spherical-type that utilizes spherical speed adjusters, such as power adjusters, balls, planets, spherical gears or rollers. The spherical speed adjustors in this embodiment have tiltable axis of rotation that are adapted to be adjusted to achieve a desired ratio of input speed to output speed.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an effective and efficient method of controlling the variable shifting of a CVT.
The above-mentioned problems of current systems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. The following summary is made by way of example and not by way of limitation. It is merely provided to aid the reader in understanding some of the aspects of the invention.
In one embodiment, a continuously variable transmission is provided. The continuously variable transmission includes an input assembly, an output assembly, an input/output planetary ratio assembly, an input speed feedback control assembly, a torque feedback control assembly and a shifting member. The input assembly is configured to be coupled to receive input rotational motion. The output assembly is used to provide a rotational output. The output assembly is configured to be rotationally coupled to a load. The input/output planetary ratio assembly is configured and arranged to set an input to output speed ratio between the input assembly and the output assembly. The input speed feedback control assembly is configured and arranged to provide an axial speed force in response to a rotation from the input assembly on a shift rod. The torque feedback control assembly is configured and arranged to provide an axial load force on the shift rod in an opposite direction from the axial speed force in response to a torque of a load coupled to the output assembly. The shifting member is coupled to the shift rod. The shifting member is further configured and arranged to control the input/output planetary ratio assembly based on the position of the shift rod.
In another embodiment, another continuously variable transmission is provided. The continuously variable transmission includes an input assembly, an output assembly, an input/output planetary ratio assembly, an input speed feedback control assembly, a torque feedback control assembly and a shifting member. An input assembly is configured to be coupled to receive input rotational motion. The output assembly is used to provide a rotational output. The output assembly is configured to be rotationally coupled to a load. The input/output planetary ratio assembly is configured and arranged to set an input to output speed ratio between the input assembly and the output assembly. The input/output planetary assembly has a first carrier having a first central passage and a second carrier having a second central passage and plurality of planets rotationally engaged between the first and second carriers. The shift rod extends through the first central passage of the first carrier and the second central passage of the second carrier. The input speed feedback control assembly is configured and arranged to provide an axial speed force in response to a rotation from the input assembly on a shift rod. The torque feedback control assembly is configured and arranged to provide an axial load force on the shift rod in an opposite direction from the axial speed force in response to a torque of a load coupled to the output assembly. In addition, the shifting member is coupled to the shift rod. The shifting member is positioned to rotate the planets between the first carrier and the second carrier based on a position of the shift rod to control the input/output planetary ratio assembly.
In still another embodiment, another continuously variable transmission is provided. The continuously variable transmission includes an input assembly, an output assembly, an input/output planetary ratio assembly, an input seed feedback control assembly, a torque feedback control assembly and a shifting member. The input assembly is configured to be coupled to receive input rotational motion. The output assembly is used to provide a rotational output, the output assembly configured to be rotationally coupled to a load. The input/output planetary ratio assembly is configured and arranged to set an input to output speed ratio between the input assembly and the output assembly. The input/output planetary assembly has a first carrier having a first central passage and a second carrier having a second central passage and plurality of planets rotationally engaged between the first and second carriers via axles. The input/output planetary ratio assembly further includes at least one set of legs coupled to at least one axle. The shift rod extends through the first central passage of the first carrier and the second central passage of the second carrier. The input speed feedback control assembly is configured and arranged to provide an axial speed force in response to a rotation from the input assembly on a shift rod. The torque feedback control assembly is configured and arranged to provide an axial load force on the shift rod in an opposite direction from the axial speed force in response to a torque of a load coupled to the output assembly. The shifting member is coupled to the shift rod. The shifting member is positioned to engage the at least one set of legs of the at least one axle based on a position of the shift rod to control the input/output planetary ratio assembly.
The present invention can be more easily understood and further advantages and uses thereof will be more readily apparent, when considered in view of the detailed description and the following figures in which:
In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the present invention. Reference characters denote like elements throughout Figures and text.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof.
Embodiments of the present invention provide a continuously variable transmission (CVT) 100 that includes a novel shifting assembly. A cross-sectional side view of the CVT 100 is illustrated in
Referring to
As discussed above, the CVT 100 can change ratio from the input to the output. The ratio is calculated by dividing a distance 228 from the contact point, 222 to the axis 236 of the axle 214 by the distance 230 from the second contact point 226 to the axis 236 of the axle 214. As shown in
A mechanism that controls the translation of the sun idler 212 is described below. Referring to the input speed feedback control assembly 300 illustrated in
In an additional embodiment, shift-weights that travel radially between the spider and the stationary member produce a centrifugal radial force as a function of input rotational speed that is transformed into an axial force as a result of the angles of contact between the shift-weights and the spider and stationary member. In yet another embodiment a generator output such as a magneto electrically operatively connected to an electromagnetic actuator such as a DC motor or solenoid exerts an axial force in opposing direction to the torque feedback control assembly. In yet another embodiment an electronic proximity sensor such as a hall-effect, reed, variable reluctance can be interfaced with a microprocessor to detect and calculate input shaft rotational rate and deliver an electrical power signal to an electrically controlled actuator. This electrical power signal may be a linear or non-linear function of input shaft rotational rate. The algorithm may also be a function of atmospheric barometric pressure in order to compensate for engine power output changes that occur as a result of altitude changes. An electrically controlled actuator may apply an axial force directly or indirectly to the torque feedback control assembly or may control a valve in a hydraulic circuit that regulates the hydraulic pressure and thus control the axial force. An electrically controlled actuator may apply piston hydraulic pressure that is in communication with a piston that may exert an axial force in opposing direction to the torque feedback control assembly 400. A hydraulic pump, driven at a rotational rate proportional to the input shaft assembly 110, that is in communication with a piston and valve may exert an axial force in opposing direction to the torque feedback control assembly 400.
Input/output ratio shaft 402 is the output shaft from the input/output planetary ratio assembly 200. Input/output ratio shaft 402 is operatively connected to a second traction ring 204 as best illustrated in
If you have relatively high engine speed, you have relatively high input speed feedback control assembly 300 speed and relatively high axial force. For a given input RPM, if the load increases (i.e. more torque is transmitted through the torque feedback control assembly 400) a larger axial force will be created, opposing the input speed feedback control assembly 300, the torque feedback control assembly 400 moves until forces balance. This change in axial location of the torque feedback control assembly 400 results in an axial location change in the shift control assembly 800 which in turn results in an axial location change in sun idler 212 that results in a change in CVT ratio. The shift control assembly 800 illustrated in
The preferred embodiments have been shown and described above. An additional embodiment interchanges the straight 408 and helical 410 tracks. Additionally the two tracks may both be helical with different angles where the difference in the angles will provide the phase change between the two spiders 404 and 406. Moreover, additional embodiments include using splines, screw threads, face cams, ball-ramp cams or tracks cut into the operative shafts along with cam followers, mating splines, mating threads to realize the function of the spiders and straight and helical tracks previously described.
Input Speed Feedback Control Assembly Force[Input Assembly 110 Rotational Speed,Translational Position]−Torque Feedback Control Assembly Force[Output Assembly 120 Torque,Translational Position]−Bias Spring Force[Translational Position]=0.
The input speed feedback control assembly 904, the torque feedback control assembly 906, the bias spring 908 and the cam 910 are translationally operatively connected. The translational position of cam 910 dictates the translational position of the shift control assembly 912, which outputs a phase relationship of the first and second carriers of a input/output planetary ratio assembly 914 that in turn dictates a specific shift ratio of a CVT 916.
In summary, as the force balance of the input speed feedback control assembly 300 and torque feedback control assembly 400 balance at a particular axial location, the shift control assembly 800 is correspondingly axially located, and in response sun idler 212 changes axial location, and the CVT 100 changes ratio. In embodiments, shifting of the CVT 100 is accomplished with an input speed feedback control assembly 300 that uses rotational motion from an engine or other input to create an axial force that force balances with a torque feedback control assembly 400 that is operatively connected to the torque load, such as the tires of a vehicle. This shifting design has applications to other transmission devices such as Infinitely Variable Transmission (IVT) of similar designs as well as a CVT system where the input and output are both coaxial to the CVT 100 and on the same side of the CVT 100.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.
Number | Name | Date | Kind |
---|---|---|---|
2526435 | Teigman | Oct 1950 | A |
2727396 | Haugwitz | Dec 1955 | A |
4270415 | Dickinson et al. | Jun 1981 | A |
4345486 | Olesen | Aug 1982 | A |
4391156 | Tibbals, Jr. | Jul 1983 | A |
6120399 | Okeson et al. | Sep 2000 | A |
6322475 | Miller | Nov 2001 | B2 |
6569043 | Younggren et al. | May 2003 | B2 |
6733406 | Kitai et al. | May 2004 | B2 |
6813553 | Nakamura et al. | Nov 2004 | B2 |
7074154 | Miller | Jul 2006 | B2 |
7204777 | Miller et al. | Apr 2007 | B2 |
7581467 | Peterman et al. | Sep 2009 | B2 |
7727106 | Maheu et al. | Jun 2010 | B2 |
7762919 | Smithson et al. | Jul 2010 | B2 |
7762920 | Smithson et al. | Jul 2010 | B2 |
7770674 | Miles et al. | Aug 2010 | B2 |
7963880 | Smithson et al. | Jun 2011 | B2 |
7976426 | Smithson et al. | Jul 2011 | B2 |
8087482 | Miles et al. | Jan 2012 | B2 |
8360917 | Nichols et al. | Jan 2013 | B2 |
8496551 | Mueller et al. | Jul 2013 | B2 |
8585528 | Carter et al. | Nov 2013 | B2 |
8668623 | Vuksa et al. | Mar 2014 | B2 |
20020123400 | Younggren et al. | Sep 2002 | A1 |
20040171452 | Miller et al. | Sep 2004 | A1 |
20070270265 | Miller et al. | Nov 2007 | A1 |
20070270267 | Miller et al. | Nov 2007 | A1 |
20070270272 | Miller et al. | Nov 2007 | A1 |
20070270278 | Miller et al. | Nov 2007 | A1 |
20090164076 | Vasiliotis et al. | Jun 2009 | A1 |
20100056322 | Thomassy | Mar 2010 | A1 |
20100093480 | Pohl et al. | Apr 2010 | A1 |
20100267510 | Nichols et al. | Oct 2010 | A1 |
20100314184 | Stenberg et al. | Dec 2010 | A1 |
20110034284 | Pohl et al. | Feb 2011 | A1 |
20110088503 | Armstrong et al. | Apr 2011 | A1 |
20110092325 | Vuksa et al. | Apr 2011 | A1 |
20110172050 | Nichols et al. | Jul 2011 | A1 |
20110220453 | Mueller et al. | Sep 2011 | A1 |
20120115667 | Lohr et al. | May 2012 | A1 |
20120238386 | Pohl et al. | Sep 2012 | A1 |
Number | Date | Country |
---|---|---|
WO 02088573 | Nov 2002 | WO |
Entry |
---|
Model N360 NuVinci® CVP, Bicycle Drivetrain. Fallbrook Technologies Inc. 2010, 2 pages. |
NuVinci Deltaseries Supercharger Drive. Fallbrook Technologies Inc. 2012, 2 pages. |
NuVinci® N360 CVP Drivetrain Owner's Manual. Fallbrook Technologies Inc. Jul. 2010, 6 pages. |
NuVinci® Parts Catalog, NuVinci N360 and NuVinci Harmony Parts Catalog—*B35-N360-12* Fallbrook Technologies Inc. 2012, 11 pages. |
NuVinci® N360 Technical Manual. *B35-N360-02* Fallbrook Technologies Inc. 2012, 15 pages. |
NuVinci® N360 Test Summary. Fallbrook Technologies Inc. 2010, 1 page. |
NuVinci® Range and Gear Inch Comparison, NuVinci N360. Date unknown. 1 page. |
Pohl, Brad, et al. “Configuration Analysis of a Spherical Traction Drive CVT/IVT”. Fallbrook Technologies. Date unknown, 6 pages. |
Non-Final Office Action of Corresponding U.S. Appl. No. 13/804,287 mailed on Mar. 13, 2014. |
Notice of Allowance U.S. Appl. No. 13/828,046, mailed Jun. 16, 2014, 9 pages. |
Search Report/Written Opinion of International Application Serial No. PCT/US2014/021861 mailed Jun. 4, 2014. |
Final Office Action, U.S. Appl. No. 13/804,287 mailed Jun. 30, 2014. |