SPRING PRELOAD FOR TRACTION ACTUATION.

Abstract

A preload spring for a planetary drive transmission designed for a turbocharger-driven engine is described. The planetary drive transmission's annular roller has two parts with a spring between them to generate a preload force on the annular roller assembly. The spring provides an expansion force on the annular roller, allowing a desired preload force to be set on the drive mechanisms' traction surfaces during assembly and operation, even with variations in the manufacturing of the different drive mechanism components.

Description

SPRING PRELOAD FOR TRACTION DRIVE CROSS-REFERENCE TO RELATED APPLICATIONS This non-provisional patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 164,812, entitled SPRING PRELOAD FOR TRACTION DRIVE, filed with the U.S. Patent and Trademark Office on March 23, 2021, and U.S. Provisional Patent Application No. 63 / 214,630, entitled Spring Preload for Traction Drive, filed on June 24, 2021, all of which are specifically incorporated herein by reference for all that they disclose and teach. BACKGROUND OF THE INVENTION Driven turbochargers are an improvement over standard turbochargers because they utilize more than just the exhaust gas turbine, reducing turbo lag in boosted engines. Driven turbochargers can also direct excess turbine power back to the engine to increase efficiency. One type of driven turbocharger uses a planetary drive transmission that interacts with the turbo shaft to provide torque to and from the turbo shaft. BRIEF DESCRIPTION OF THE INVENTION Therefore, an embodiment of the present invention may comprise a planetary drive transmission comprising: a sun shaft; a plurality of planetary rollers having outer roller traction surfaces that interact with the sun shaft; an annular roller assembly comprising: a ring gear; a spring-loaded traction ring and a second traction ring located concentrically with said ring gear that interacts with the traction surfaces of the inclined inner rollers of the plurality of planetary rollers; a preload spring located between the ring gear and the suspended traction ring that provides a preload force on the inclined traction surfaces of the inner rollers of the plurality of planetary rollers during the assembly and operation of the planetary drive mechanism;An anti-rotation mechanism connects the spring-loaded traction ring and the toothed ring such that the spring-loaded traction ring can slide axially on the anti-rotation mechanism, wherein the anti-rotation mechanism transmits torque between the spring-loaded traction ring and the toothed ring. Therefore, an embodiment of the present invention may further comprise a method for establishing a preload in a planetary traction transmission comprising: interconnecting the traction surfaces of the outer rollers of a plurality of planetary rollers with a sun shaft; assembling an annular roller assembly comprising a toothed ring, a spring-loaded traction ring, and a second traction ring; and interfacing the suspended traction ring and the second traction ring with the traction surfaces of the inclined inner roller of the plurality of planetary rollers.placing a preload spring between the ring gear and the suspended traction ring that provides a preload force on the traction surfaces of the inclined inner roller of the plurality of planetary rollers during the assembly and operation of the planetary drive mechanism; connecting the spring-loaded traction ring and the ring gear through an anti-rotation mechanism so that the spring-loaded traction ring can slide axially on the anti-rotation mechanism, in which the anti-rotation mechanism transmits torque between the spring-loaded traction ring and the ring gear. Therefore, an alternative embodiment of the present invention may comprise a planetary traction transmission comprising: a sun axis assembly comprising: a central axis; a two-piece traction cylinder located around the central axis and concentric to and connected to rotate with the central axis, the two-piece traction cylinder comprising: a first traction cylinder piece with a first inclined traction surface that is connected to the central axis; a spring-loaded traction cylinder piece with a second inclined traction surface that is coupled to the first traction cylinder piece via an anti-rotation mechanism that allows the spring-loaded traction cylinder piece to slide axially on the anti-rotation mechanism and transmit torque between the spring-loaded traction cylinder barrel piece and the first traction barrel piece;a preload spring located between the first traction cylinder piece and the suspended traction cylinder piece that provides a preload force on the first inclined cylinder traction surface and the second inclined cylinder traction surface during the assembly and operation of the planetary traction mechanism; a plurality of double-roller planetary rollers with outer roller traction surfaces that interact with the first inclined cylinder traction surface and the second inclined cylinder traction surface of the sun axis assembly; an annular roller assembly comprising: a toothed ring; a first traction ring and a second traction ring located concentrically with the toothed ring that interact with the inner roller traction surfaces of the plurality of double-roller planetary rollers. Therefore, an alternative embodiment of the present invention may comprise a planetary drive comprising: a sun axis; a plurality of double planetary roller assemblies, each double planetary roller assembly comprising: a spring-loaded planetary roller and a second planetary roller rotationally coupled concentrically via an anti-rotation mechanism that allows the spring-loaded planetary roller to slide axially on the anti-rotation mechanism while transmitting torque between the suspended planetary roller and the second planetary roller, wherein both the suspended planetary roller and the second planetary roller have outer roller traction surfaces that interact with the sun axis, as well as inclined inner roller traction surfaces;a preload spring located externally to the suspended planetary roller that provides a preload force on the traction surfaces of the inclined inner roller of the suspended planetary roller and the second planetary roller during the assembly and operation of the planetary traction mechanism; an annular roller assembly comprising: a toothed ring; a first traction ring and a second traction ring located concentrically with the toothed ring that interacts with the traction surfaces of the inclined inner rollers of the suspended planetary rollers and the second planetary rollers of the plurality of double-roller planetary roller assemblies. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an isometric view of a turbocharger driven by a planetary drive transmission coupled to an engine. Figure 2 is a cross-section of an embodiment of a planetary traction mechanism with a preload spring located in an assembly of annular rollers. Figure 3A is a cross-section of an embodiment of a planetary drive mechanism with a preload spring and a ball ramp integrated into the annular roller assembly with the preload spring providing clamping force in the planetary drive mechanism. Figure 3B is a cross-section of the embodiment of a planetary drive mechanism of Figure 3A with a preload spring and a ball ramp integrated into the annular roller assembly with the ball ramp providing clamping force in the planetary drive mechanism. Figure 4 is an exploded view of an embodiment of an annular roller assembly for a planetary drive in which the anti-rotation mechanism of the annular roller assembly is composed of a series of guide pins. Figure 5 is an exploded view of an embodiment of an annular roller assembly for a planetary drive in which the anti-rotation mechanism of the annular roller assembly is composed of a series of flanged bolts. Figure 6 is an exploded view of an embodiment of an annular roller assembly for a planetary drive transmission where the anti-rotation mechanism in the annular roller assembly consists of a splined connection between the spring-loaded traction ring and the toothed ring. Figure 7 is an exploded view of an embodiment of an annular roller assembly for a planetary drive transmission where the anti-rotation mechanism in the annular roller assembly is composed of internal gear teeth formed in the spring-loaded traction ring that mesh with the toothed ring, teeth on the ring. Figure 8 is a cross-section of an alternative embodiment of a planetary drive transmission with a preload spring integrated into a two-piece drive cylinder of a sun shaft assembly. Figure 9 is a cross-section of an alternative embodiment of a planetary traction drive with preload springs integrated into a plurality of double-roller planetary roller assemblies. DETAILED DESCRIPTION OF THE MODALITIES Figure 1 is an isometric view of a driven turbocharger 100 with a planetary drive transmission 102 coupled to a motor 116. The operation of the driven turbocharger 100 is taught in U.S. Patent 8,561,403, issued October 22, 2013, entitled “Super-Turbocharger Having a High-Speed ​​Drive Transmission and a Continuously Variable Transmission,” U.S. Patent 8,668,614, issued March 11, 2014, entitled “High Torque Drive Transmission,” U.S. Patent 9,670,832, issued June 6, 2017, entitled “Thrust-Absorbing Planetary Drive Transmission,” U.S. Patent 10,539,159, issued January 21, 2020, entitled “Two-Piece Shaft Assembly for Driven Turbocharger,” and Patent U.S. Patent No. 10,655,711, issued on May 19, 2020, entitled “Single Angular Contact Ball Ramp for Turbocharger Driven.” U.S. patents8,561,403, 8,668,614, 9,670,832, 10,539,159, and 10,655,711 are specifically incorporated here for reference to all that they describe and teach. The driven turbocharger 100 comprises a turboshaft 104 with a compressor 106 attached to one end and a turbine 108 attached to the other end. The planetary drive transmission 102 interacts with the turboshaft 104 to transmit torque to and from the turboshaft 104. The ring gear 110 acts as a low-speed output of the planetary drive transmission 102 and meshes with the transfer gear 112. The transfer gear 112 is coupled to the transmission 114, which transmits torque between the driven turbocharger 100 and the engine 116.The turbo shaft 104 is a sun shaft of the planetary drive transmission 102, and connects the turbine 108 and the compressor 106 to the turbo shaft 104. The coupling transmission 114 to the ring gear 110 via the transfer gear 112 forms a driven turbocharger 100 when power transfer between the motor 116 and the turbine 108 and compressor 106 is enabled. During assembly and operation, it is necessary to establish a preload on the planetary drive mechanism 102 to provide force at each drive interface, allowing the planetary drive mechanism 102 to transmit torque correctly. The present invention uses a preload spring 118 to establish this preload during assembly and maintain it during operation in a manner that can account for variations in the manufacturing of the different parts of the planetary drive mechanism 102. Figure 2 is a cross-section of an embodiment of a planetary drive transmission 202 with a preload spring 218 located in an annular roller assembly 222. The planetary drive transmission 202 comprises a sun shaft 204, corresponding to the turbo shaft 104 of Figure 1, a plurality of planetary rollers 220, and an annular roller assembly 222. The plurality of planetary rollers 220 has outer roller drive surfaces 224 that interact with the sun shaft 204 to transmit torque to and from the sun shaft 204. The sun shaft 204 may also be composed of a center shaft and a drive cylinder, as taught in U.S. Patent 10,539,159, issued January 21, 2020, entitled "Two-Piece Shaft Assembly for Driven Turbocharger." The annular roller assembly 222 comprises a toothed ring 210, as well as a spring-loaded traction ring 230 and a second traction ring 234 is located concentrically with the toothed ring 210, which interacts with the traction surfaces of the inclined inner roller 226 of a plurality of planetary rollers 220. The spring-loaded traction ring 230 is largely in the form of a simple ring, with the addition of an annular traction surface 231 formed on an inner portion, as well as features for mating with the preload spring 218 and the anti-rotation mechanism 232. These features are described in the figures as pin holes, splines, or other similar features. The annular traction surface 231 interacts with a set of inclined inner roller traction surfaces 226 of a plurality of planetary rollers 220. The preload spring 218 is located between the toothed ring 210 and the traction ring suspended 230 from the annular roller assembly 222.As shown, the preload spring 218 is a wave spring, but other types of springs could also be used. The preload spring 218 deforms when the spring-loaded traction ring 230 moves axially toward the ring gear 210, and this deformation provides an axial force on the spring-loaded traction ring 230 to create preload forces in the planetary drive transmission 202. The preload spring 218 is shown in the shape of a ring to match the shapes of the ring gear 210 and the suspended traction ring 230, but other shapes could be used. The preload spring 218 provides a specific amount of preload force on the traction surfaces of the inclined inner rollers 226 of a plurality of planetary rollers 220 during the assembly and operation of the planetary drive transmission 202.This specific amount of preload force generated by the preload spring 218 is a quantity of preload force that is sufficient to load all the traction interfaces in the planetary traction drive 202 so that these traction interfaces transmit torque without excessive slippage, thus enabling operation and torque transfer through the planetary traction drive 202. The forces required at these traction interfaces can be calculated based on the design and operating specifications of the planetary traction drive 202, and the required preload force can also be calculated to specify an appropriate preload spring 218, the preload forces on the traction surfaces of the inclined inner roller 226 of the plurality of the planetary rollers 220.These preload forces are then transmitted to all drive interfaces in the planetary drive transmission 202, enabling torque transfer through the planetary drive transmission 202. Since the preload spring 218 can operate over a variable width, it can achieve the appropriate planetary drive preload 202 even with variations in the dimensions and tolerances of the manufactured parts. Furthermore, the variable width of the annular roller assembly 222 created by incorporating the preload spring 218 allows for easier assembly of the planetary drive transmission 202 by providing a narrower profile for the annular roller assembly 222 during assembly. Along with the preload spring 218, an anti-rotation mechanism 232 is used between the spring-loaded tension ring 230 and the toothed ring 210. The anti-rotation mechanism 232 connects the spring-loaded tension ring 230 and the toothed ring 210 in such a way that the spring-loaded tension ring 230 can slide axially on the anti-rotation wheel. The rotation mechanism 232 and the anti-rotation mechanism 232 transmit the torque between the suspended tension ring 230 and the toothed ring 210. The anti-rotation mechanism 232 can be implemented in a variety of different ways, as described in the figures. The anti-rotation mechanism 232 allows the preload spring 218 to push the spring-loaded traction ring 230 axially away from the toothed ring 210 to obtain preload forces in the planetary traction transmission 202, while rotationally connecting the spring-loaded traction ring 230 and the toothed ring 210.The toothed ring 210 meshes with the transfer gear 212 to a low-speed output of the planetary drive transmission 202, to transmit torque and power to and from the motor 116 of Figure 1. Figure 2 also shows an optional ring wedge 236 that is inserted between the spring-loaded tension ring 230 and the ring gear 210 during the assembly of the planetary drive transmission 202. While it is necessary to allow the spring-loaded tension ring 230 to slide in the anti-rotation mechanism 232, it is beneficial to minimize this sliding distance to reduce wear caused by this sliding action. Inserting the ring wedge 236, which is located between the spring-loaded tension ring 230 and the ring gear 210, can minimize the operating distance between the spring-loaded tension ring 230 and the ring gear 210, thus limiting the sliding distance of the spring-loaded tension ring 230 in the anti-rotation mechanism 232. Minimizing this operating distance is especially important when the preload spring 218 is combined with an active ball ramp, as described in the figures.The annular wedge 236 can be sized in thickness to allow the required axial movement of the spring-loaded tension ring 230, but with additional compression of the preload spring 218, it will contact both the spring-loaded tension ring 230 and the toothed ring 210 to prevent excessive axial sliding movement of the spring-loaded tension ring 230 in the anti-rotation mechanism 232. The use of the annular wedge 236 can also allow for larger clearances during assembly of the planetary drive transmission 202, and then minimize those clearances during operation. The annular wedge 236 can be a single piece or can be composed of a series of smaller parts positioned around the annular roller assembly 222.The annular wedge 236 can take a variety of forms: an annular ring, a series of pads, or even features formed in the spring-loaded traction ring 230 and the toothed crown 210. Other forms of annular wedge 236 are also possible. Figure 3A is a cross-section of an embodiment of a planetary drive transmission 302 with a preload spring 318 and a ball ramp 340 integrated into the annular roller assembly 322, with the preload spring 318 providing clamping force in the planetary drive transmission 302. In this embodiment, the ring gear 310 is engaged with the second traction ring 334 via a ball ramp 340. The ring gear 310 engages with the suspended traction ring 330 via the preload spring 318 and the anti-rotation mechanism 332 as described in Figure 2. The preload spring 318 and the ball ramp 340 both function to vary the forces at the inclined traction interfaces 338 and the shaft traction interfaces 339 of the planetary drive transmission 302.The preload spring 318 is used to establish a preload on the traction surfaces of the inclined internal rollers 326 of a plurality of planetary rollers 320 during assembly and under torque. The operation of the planetary drive 302 and the ball ramp 340 dynamically varies the forces as the planetary drive 302 operates, as taught in U.S. Patent 10,655,711, issued May 19, 2020, entitled Single Angular Contact Ball Ramp for Driven Turbocharger.The use of the spring-loaded traction ring 330 with preload spring 318 and the second traction ring 334 with ball ramp 340 in the annular roller assembly 322 allows both the preload forces in the planetary drive transmission 302 and the variable dynamic forces based on torque transmission to enable appropriate forces at the inclined traction interfaces 338 and the shaft traction interfaces 339 throughout the operation of the planetary drive transmission 302. As shown in Figure 3A, the planetary drive transmission 302 is operating in a neutral, low-torque, or rest position, with the preload spring 318 providing the clamping force in the planetary drive transmission 302 necessary to transmit torque through the inclined traction interfaces 338 and the shaft traction interfaces 339.The preload spring 318 is designed to provide sufficient preload force to allow the planetary drive transmission 302 to operate without excessive slippage at the inclined drive interfaces 338 and the shaft drive interfaces 339 under near-zero torque conditions. Assembly tolerances in the planetary drive transmission 302 or surface wear on the inclined drive interfaces 338 or the shaft drive interfaces 339 can be compensated for by the preload spring 318, which ensures that the inclined drive interfaces 338 and the shaft drive interfaces 339 do not disengage or slip. The preload force ensures the engagement of the inclined drive interfaces 338.A small amount of slippage is normal during operation of the planetary drive 302, but the preload spring 318 prevents the amount of slippage from becoming excessive. The spring-loaded tension ring 330 is at or near a nominal axial position in the anti-rotation mechanism 332, and as such, the ring wedge 336 is not active in locating the spring-loaded tension ring 330. This nominal axial position of the spring-loaded tension ring 330 is assembled and in a rest position. At this point, the gap between the spring-loaded tension ring 330 and the ring gear 310 is slightly larger than the thickness of the ring wedge 336. Figure 3B is a cross-section of the embodiment of a planetary drive 302 of Figure 3A with a preload spring 318 and a ball ramp 340 integrated into the annular roller assembly 322 with the ball ramp 340 providing clamping force in the planetary drive. 302. Once torque is applied to the planetary drive transmission 302, the ball ramp 340 is activated, providing additional clamping force through the annular roller assembly 322. Until the ball ramp 340 is activated under the torque output through the drive transmission 302, the preload spring 318 generates sufficient preload forces to prevent excessive slippage at the inclined drive interfaces 338 and the shaft drive interfaces 339. The preload spring 318 ensures the engagement of the inclined drive interfaces 338 and the shaft drive interfaces 339 until the ball ramp 340 is activated.A small amount of slippage is normal during operation of the planetary drive 302, but the preload spring 318 prevents the amount of slippage from becoming excessive. Generally, a normal amount of slippage during operation of the planetary drive mechanism 302 is approximately 1–2%, and slippage values ​​exceeding 5% should be avoided. Initially, this additional clamping force compresses the preload spring 318, causing the spring-loaded pull ring 330 to slide axially over the anti-rotation mechanism 332 toward the ring gear 310. The ring wedge 336 is sized to quickly stop the axial movement of the spring-loaded pull ring 330, minimizing the distance the pull ring 330 slides over the anti-rotation mechanism 332 and thus minimizing wear due to slippage.Once the spring-loaded pull ring 330 moves an axial distance sufficient to compress the ring wedge 336 between the spring-loaded pull ring 330 and the ring gear 310 and stops sliding on the anti-rotation mechanism 332, the ball ramp 340 dynamically provides variable levels of clamping force to the planetary drive transmission 302 based on the torque performance of the planetary drive transmission 302. The variable levels of clamping force provide normal forces at the inclined pull interfaces 338 and the shaft pull interfaces 339 that are sufficient to transmit the required torque through the planetary drive transmission 302.Figure 3B shows the annular roller assembly 322 with preload spring 318 in a compressed position, with annular wedge 336 housing the axially suspended traction ring 330 and ball ramp 340 acting in accordance with the transmission of torque through the planetary traction drive 302. Figure 4 is an exploded view of an embodiment of an annular roller assembly 422 for a planetary drive transmission 402 where the anti-rotation mechanism 432 in the annular roller assembly 422 is composed of a series of guide pins 450. Sets of holes 452 are machined in the spring-loaded traction ring 430 and the toothed ring 410 to fit the series of guide pins 450.Mounting the spring-loaded tension ring 430 on the guide pin series 450 allows the spring-loaded tension ring 430 to move axially toward and away from the ring gear 410, enabling the spring preload 418 to establish the preload forces in the planetary traction drive 402. Meanwhile, the spring-loaded tension ring 430 is rotationally engaged with the ring gear 410, so that the spring-loaded tension ring 430 and the ring gear 410 rotate together, and a series of guide pins 450 transmits the torque between the spring-loaded tension ring 430 and the ring gear 410. The guide pin series 450 can be composed of a variety of pins; however, it is important that a uniform spacing be used to maintain the rotational balance of the annular roller assembly 422, although secondary balancing operations can also be performed if a non-uniform spacing is not used.The guide pin series 450 can be press-fitted into the ring gear 410 for positive positioning and have a tight tolerance fit to the spring-loaded ring roller 430 to allow axial sliding movement of the spring-loaded ring roller 430. Also shown is a series of ring shims 436 that fit between the spring-loaded ring 430 and the ring gear 410. The width of the ring shim series 436 can be determined during assembly to limit the operating distance that the spring-loaded ring 430 slides over the anti-rotation mechanism 432 during operation of the planetary drive 402, when the ball ramp 440 is actuated during torque transmission through the planetary drive 402. Alternatively, the groove features 453 formed in the spring-loaded tension ring 430 can be used as an anti-rotation mechanism 432. These groove features 453 of the spring-loaded tension ring 430 engage with the ring gear 410 to prevent the spring-loaded tension ring 430 from rotating against the ring gear 410. In this alternative embodiment, the series of dowel pins 450 functions only to retain the series of annular wedges 436 in place between the spring-loaded tension ring 430 and the ring gear 410. Figure 5 is an exploded view of an embodiment of an annular roller assembly 522 for a planetary drive transmission 502, where the anti-rotation mechanism 532 in the annular roller assembly 522 comprises a series of stop bolts 554. The spring-loaded traction ring 530 is rotated in the view to better show the features of the spring-loaded traction ring 530. The series of flanged bolts 554 functions effectively equivalently to the series of pins 450 in Figure 4, but provides a positive screw thread engagement in the threaded holes 556 in the ring gear 510. The traction ring 530 has a series of holes 552 for mounting the spring-loaded traction ring 530 on a series of flanged bolts 554.The series of flanged bolts 554 are rotationally coupled and transmit torque between the spring-loaded tension ring 530 and the toothed ring 510 while allowing the spring-loaded tension ring 530 to slide axially on a series of flanged bolts 554 to allow the preload spring 518 to provide preload clamping forces to the planetary traction drive 502. Figure 5 also shows an adjustable stepped ring wedge option 564 located between the spring-loaded tension ring 530 and the toothed ring 510 to minimize the operating distance between the spring-loaded tension ring 530 and the toothed ring 510, limiting the sliding distance of the spring-loaded tension ring 530 in the anti-rotation mechanism 532 before spring-loaded tension. The ring 530 makes direct contact with the toothed ring 510. The adjustable stepped ring wedge 564 comprises a series of steps 560 formed in the spring-loaded tension ring 530 that engage with a corresponding series of pads 562 formed in the toothed ring 510, so that when the spring-loaded tension ring 530 rotates during assembly relative to the toothed ring 510, different discrete levels of wedge are achieved.Each of the series of steps 560 formed on the spring-loaded tension ring 530 includes multi-step features that protrude a different amount from the inner face of the spring-loaded tension ring 530, such that each step level represents a discrete width of the spring-loaded tension ring 530. The corresponding series of pads 562 formed on the toothed ring 510 are uniform protrusions from the face of the toothed ring 510 that engage with the various step levels of the step series 560 when the suspended tension ring 530 rotates about the toothed ring 510 during assembly. Because the width of the spring-loaded pull ring 530 varies depending on the selected step level, the axial operating distance between the spring-loaded pull ring 530 and the toothed ring 510 varies. This adjustable step ring wedge 564 can be used as an alternative device to the ring wedge 236.Figure 2 allows for variable clearance during assembly between the spring tension ring 530 and the sprocket 510. Different discrete steps allow for variation of this clearance to minimize the sliding distance of the spring tension ring 530 on a series of shoulder bolts 554, thereby minimizing wear associated with this sliding. The series of steps 560 and the series of pads 562 are formed around the entire circumference of the spring tension ring 530 and the sprocket 510, respectively, to provide uniform clearance and forces across the roller assembly of the ring 522. Multiple sets of hole series 552 are located in the spring tension ring 530, corresponding to each level in the series of steps 560.The adjustable step ring wedge 564 can also be used with other embodiments of the invention, and is not limited to use with the anti-rotation mechanism 532 consisting of a series of shoulder bolts 554. Figure 6 is an exploded view of an embodiment of an annular roller assembly 622 for a planetary drive transmission 602, where the anti-rotation mechanism 632 in the annular roller assembly 622 comprises a splined connection 670 between the spring-loaded tension ring 630 and the ring gear 610. The spring-loaded tension ring 630 is rotated in the view to better show its features. Splines 672 are formed on the spring-loaded tension ring 630 and mesh with corresponding splines 674 formed on the ring gear 610. As shown, the splines 672 on the spring-loaded tension ring 630 are external splines, and the corresponding splines 674 on the ring gear are internal splines. However, the reverse can also be used, with internal splines on the spring-loaded tension ring 630 and the corresponding splines on the ring gear 610. external ridges on the crown 610.The rotating splined connection 670 couples the spring-loaded traction ring 630 to the toothed ring 610 and transmits torque between the spring-loaded traction ring 630 and the toothed ring 610, while allowing the spring-loaded traction ring 630 to slide axially to allow springs 618 to establish preload forces in the planetary traction transmission 602. Figure 7 is an exploded view of an embodiment of annular roller assembly 722 for a planetary drive transmission 702, where the anti-rotation mechanism 732 in the annular roller assembly 722 comprises internal gear teeth 780 formed in the spring-loaded tension ring 730, which mesh with the teeth of the ring gear 782 on the ring gear 710. The spring-loaded tension ring 730 is rotated in the view to better show the features of the spring-loaded tension ring 730. This anti-rotation mechanism 732 is similar to the splined connection 670 of Figure 6, but utilizes the teeth of the ring gear 782 already present on the ring gear 710 to reduce the number of machined features on the roller assembly components 722.The teeth of the ring gear 782 can be made wider than necessary to mesh with the transfer gear 712, leaving gear width 784 available for use by the anti-rotation mechanism 732. The spring-loaded pull ring 730 has internal gear teeth 780 formed into it that mesh with the ring gear teeth 782 in the additional gear width section 784 of the ring gear teeth 782. This method works for spur gears, as they are straight-cut, but it would not work with helical or other curved gears.The internal gear teeth 780 rotationally engage the spring-loaded pull ring 730 to the ring gear 710 and transmit torque between the spring-loaded pull ring 730 and the ring gear 710 while allowing the spring-loaded pull ring 730 to slide axially over the teeth of the ring gear 782 to allow the preload spring 718 to provide preload forces in planetary pull drive 702. Figure 8 is a cross-section of an alternative embodiment of a planetary drive transmission 802 with a preload spring 818 integrated into a two-piece drive cylinder 886 of a sun shaft assembly 804. The planetary drive transmission 802 comprises a sun shaft 804, a plurality of double-roller planetary rollers 820 with outer roller traction surfaces 824 interacting with the sun shaft assembly 804 as well as with the inner roller traction surfaces 826, and annular roller assembly 822 comprising a toothed ring 810 as well as a first traction unit 830 and a second traction ring 834 located concentrically with the toothed ring 810 interacting with the inner roller traction surfaces 826 of a plurality of double-roller planetary rollers 820.The solar axis assembly 804 comprises a central axis 805 and a two-piece traction cylinder 886 located around the central axis 805. The two-piece traction cylinder 886 consists of a first traction cylinder piece 887 with a first inclined cylinder traction surface 888 connected to the central axis 805, a spring-loaded traction cylinder piece 889 with a second inclined cylinder traction surface 890 coupled to the first traction cylinder piece 887 via an anti-rotation mechanism 832, and a preload spring 818 located between the first traction cylinder piece 887 and the spring-loaded traction cylinder piece 889. The anti-rotation mechanism 832 allows the suspended traction cylinder piece 889 to slide axially on the anti-rotation mechanism 832 and transmits torque between the suspended traction cylinder piece 889 and the first cylindrical traction piece 887.The preload spring 818 provides a specific amount of preload force on the first inclined cylinder traction surface 888 and the second inclined cylinder traction surface 890 during the assembly and operation of the planetary drive mechanism 802, ensuring that the planetary drive mechanism 802 transmits torque correctly during operation. The preload spring 818 pushes the spring-loaded traction cylinder piece 889 axially away from the first traction cylinder piece 887, thereby increasing the normal forces on the first inclined cylinder traction surface 888 and the second inclined cylinder traction surface 890 as they push against the outer roller traction surfaces 824 of a plurality of double planetary roller cylinders 820.This, in turn, increases the normal forces between the traction surfaces of the inner roller 826 of a plurality of double planetary rollers 820 and the first traction ring 830 and the second traction ring 834. The spring rate of the preload spring 818 is designed to provide sufficient forces in the planetary traction drive 802 to transmit torque. As shown in Figure 8, the anti-rotation mechanism 832 may consist of a splined connection 870 between the first traction cylinder piece 887 and the spring-loaded traction cylinder piece 889. This splined connection rotatably couples the first traction cylinder piece 887 and the spring-loaded traction cylinder piece 889 and transmits torque between the first traction cylinder piece 887 and the spring-loaded traction cylinder piece 889, while allowing the spring-loaded traction cylinder piece 889 to slide axially. This allows the preload spring 818 to provide preload forces in the planetary traction transmission 802. Other implementations of the anti-rotation mechanism 832, such as those shown in previous figures, may also be used. An optional ball ramp 840 located between the ring gear 810 and the second traction ring 834 is also shown in Figure 8. The toothed ring 810 engages with the second drive ring 834 via the ball ramp 840 in the same manner as described in Figures 3A and 3B. The ball ramp 840 provides dynamically variable clamping forces on the planetary drive transmission 802 as a function of the torque across the planetary drive transmission 802. In this way, the preload spring 818 provides clamping forces on the planetary drive transmission 802 during idle and low-torque operation of the planetary drive transmission 802, and the ball ramp 840 provides clamping forces on the planetary drive transmission 802 during moderate and high-torque operation of the planetary drive transmission 802. Figure 9 is a cross-section of an alternative embodiment of a planetary drive transmission 902 with preload springs 918 integrated into a plurality of double-roller planetary roller assemblies 920. The planetary drive transmission 902 comprises a sun shaft 904, a plurality of double-roller planetary roller assemblies 920, and an annular roller assembly 922. As shown, three double-roller planetary roller assemblies 920 can be used.but other numbers of double planetary roller assemblies 920 may also be used. Each double planetary roller assembly 920 comprises a spring-loaded planetary roller 992 and a second planetary roller 993 rotationally coupled concentrically via an anti-rotation mechanism 932 that allows the spring-loaded planetary roller 992 to slide axially on the anti-rotation mechanism 932 while transmitting torque between the spring-loaded planetary roller 992 and the second planetary roller 993, wherein both the spring-loaded planetary roller and the second planetary roller have outer roller traction surfaces 924 that interact with the sun axis 904, as well as inclined inner roller traction surfaces 926,and a preload spring 918 located externally to said spring-loaded planetary roller 992 that provides a specific amount of preload force on the traction surfaces of the inclined inner roller 926 of the spring-loaded planetary roller 992 and the second planetary roller 993 during the assembly and operation of the planetary drive transmission 902. The ring roller assembly 922 comprises a toothed ring 910, and a first traction ring 930 and a second traction ring 934 located concentrically. A toothed ring 910 interacts with the traction surfaces of the inclined inner rollers 926 of the spring-loaded planetary rollers 992 and the second planetary rollers 993 of a plurality of double-roller planetary roller assemblies 920. For each of the plurality of double-roller planetary roller assemblies 920,A preload spring 918 is located externally to the spring-loaded planetary roller 992 such that the preload springs 918 push the spring-loaded planetary rollers 992 axially inwards towards the annular roller assembly 922, generating normal forces on the traction surfaces of the inclined inner roller 926 of the spring-loaded planetary rollers 992 and the second planetary rollers 993. As the roller assembly 922 is effectively sandwiched between the suspended planetary rollers 992 and the second planetary rollers 993, this provides preload clamping forces for all traction interfaces in the planetary traction transmission 902, enabling torque transfer and proper operation. Figure 9 also shows an optional ball ramp 940 located on the annular roller assembly 922. The ring gear 910 engages with the second traction ring 934 via the ball ramp 940 to provide dynamic loading based on the torque of the planetary drive transmission 902. Preload springs 918 on a plurality of double planetary roller assemblies 920 provide preload clamping forces for idle and low-torque operation of the planetary drive 902, and the ball ramp 940 provides dynamic clamping forces for medium- and high-torque operation of the planetary drive 902. Furthermore, the anti-rotation mechanism 932 can consist of a splined connection 970 between the spring-loaded planetary roller 992 and the second planetary roller 993, as shown, but other implementations of the anti-rotation mechanism 932 are also possible. The foregoing description of the invention has been presented for illustrative and descriptive purposes. It is not intended to be exhaustive nor to limit the invention to the precise form described, and other modifications and variations may be possible in light of prior learning. The embodiment was chosen and described to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to make better use of the invention in various embodiments and modifications suited to the particular use contemplated. The appended claims are intended to be interpreted to include other alternative embodiments of the invention, except to the extent that they are limited by prior art.

Claims

1. A planetary drive transmission comprising: a sun shaft; a plurality of planetary rollers having outer roller traction surfaces interacting with said sun shaft; an annular roller assembly comprising: a ring gear; a spring-loaded traction ring and a second traction ring located concentrically with said ring gear that interacts with the traction surfaces of the inclined inner rollers of said plurality of planetary rollers; a preload spring located between said ring gear and said suspended traction ring that provides a preload force on said inclined inner roller traction surfaces of said plurality of planetary rollers during the assembly and operation of said planetary drive;an anti-rotation mechanism connecting said suspended traction ring and said toothed ring such that said suspended traction ring can slide axially on said anti-rotation mechanism in which said anti-rotation mechanism transmits torque between said suspended traction ring and said toothed ring.; 2. The planetary traction mechanism of claim 1, wherein said anti-rotation mechanism is composed of a series of guide pins.

3. The planetary traction transmission of claim 1, wherein said anti-rotation mechanism is comprised of grooved features formed in said spring-loaded traction ring that engage with said toothed ring.

4. The planetary traction mechanism of claim 1, wherein said anti-rotation mechanism is composed of a series of flanged bolts.

5. The planetary traction drive of claim 1, wherein said anti-rotation mechanism comprises a splined connection between said suspended traction ring and said toothed ring.

6. The planetary traction transmission of claim 1, wherein said anti-rotation mechanism is comprised of internal gear teeth formed in said suspended traction ring that mesh with annular gear teeth in said annular gear.

7. The planetary traction transmission of claim 1 further comprising: at least one annular wedge located between said suspended traction ring and said toothed ring to minimize the operating distance between said suspended traction ring and said ring to limit the sliding distance of said suspended traction ring on said anti-rotation mechanism.

8. The planetary drive transmission of claim 1 further comprising: an adjustable stepped annular wedge located between said spring-loaded drive ring and said toothed ring to minimize the operating distance between said spring-loaded drive ring and said toothed ring to limit the sliding distance of said spring-loaded drive ring in said anti-rotation mechanism before said spring-loaded drive ring makes direct contact with said toothed ring, said adjustable stepped annular wedge comprising: a series of steps formed in said suspended drive ring that engage with a corresponding series of shoes formed in said toothed ring, such that when said suspended drive ring rotates with respect to said toothed ring, different levels of discrete wedges are achieved.

9. The planetary drive transmission of claim 1, wherein said toothed ring is coupled with said second drive ring via a ball ramp.

10. The planetary traction transmission of claim 1 further comprising: a turbine and a compressor coupled to said sun axis and a transmission coupled to said ring gear to form a driven turbocharger.

11. A method for establishing a preload in a planetary drive transmission comprising: connecting outer roller traction surfaces of a plurality of planetary rollers to a sun shaft; assembling an annular roller assembly comprising a ring gear, a spring-loaded traction ring, and a second traction ring; interfacing said suspended traction ring and said second traction ring with inclined inner roller traction surfaces of said plurality of planetary rollers; placing a preload spring between said ring gear and said suspended traction ring which provides a preload force on said inclined inner roller traction surfaces of said plurality of planetary rollers during the assembly and operation of said planetary drive;connecting said spring-loaded traction ring and said crown through an anti-rotation mechanism so that said spring-loaded traction ring can slide axially on said anti-rotation mechanism in which said anti-rotation mechanism transmits torque between said spring-loaded traction ring and said crown.; 12. The method of claim 11, wherein said anti-rotation mechanism is composed of a series of guide pins.

13. The method of claim 11, wherein said anti-rotation mechanism comprises grooved features formed in said suspended traction ring that engages with said toothed ring.

14. The method of claim 11, wherein said anti-rotation mechanism is composed of a series of flanged bolts.

15. The method of claim 11, wherein said anti-rotation mechanism is comprised of a splined connection between said suspended traction ring and said toothed crown.

16. The method of claim 11, wherein said anti-rotation mechanism is comprised of internal gear teeth formed in said suspended traction ring that mesh with annular gear teeth in said annular gear.

17. The method of claim 11 further comprising: placing at least one annular wedge between said suspended traction ring and said toothed ring to minimize the operating distance between said suspended traction ring and said ring to limit the sliding distance of said suspended traction ring in said anti-rotation mechanism.

18. The method of claim 11 further comprising: locating an adjustable stepped ring wedge between said spring-loaded traction ring and said toothed ring to minimize the operating distance between said spring-loaded traction ring and said toothed ring to limit the sliding distance of said spring-loaded traction ring in said anti-rotation mechanism before said spring-loaded traction ring makes direct contact with said toothed ring, said adjustable stepped ring wedge comprising: a series of steps formed in said suspended traction ring that engage with a corresponding series of shoes formed in said toothed ring, such that when said suspended traction ring rotates with respect to said toothed ring, different levels of discrete shims are achieved.

19. The method of claim 11, wherein said toothed ring is coupled with said second traction ring via a ball ramp.

20. The method of claim 11 further comprising: attaching a turbine and a compressor to said solar axis and coupling a transmission to said toothed ring to form a driven turbocharger.

21. A planetary drive mechanism comprising: a sun axis assembly comprising: a central axis; a two-piece drive cylinder located around and concentric to said central axis and connected to rotate with said central axis, said two-piece drive cylinder comprising: a first drive barrel piece with a first inclined drive barrel surface connecting to said central axis; a suspended drive barrel piece with a second inclined drive barrel surface coupled to said first drive barrel piece via an anti-rotation mechanism allowing said suspended drive barrel piece to slide axially on said anti-rotation mechanism and transmit torque between said suspended drive barrel piece and said first drive barrel piece;a preload spring located between said first traction cylinder piece and said suspended traction cylinder piece that provides a preload force on said first inclined cylinder traction surface and said second inclined cylinder traction surface during the assembly and operation of said planetary traction mechanism; a plurality of double-roller planetary rollers with outer roller traction surfaces that interact with said first inclined cylinder traction surface and said second inclined cylinder traction surface of said sun axis assembly; an annular roller assembly comprising: a toothed ring; a first traction ring and a second traction ring located concentrically with said toothed ring that interact with the inner roller traction surfaces of said plurality of double-roller planetary rollers.

22. The planetary traction drive of claim 21, wherein said anti-rotation mechanism comprises a splined connection between said first traction cylinder piece and said suspended traction cylinder piece.

23. The planetary traction transmission of claim 21, wherein said toothed ring is coupled with said second traction ring via a ball ramp.

24. The planetary traction transmission of claim 21 further comprising: a turbine and a compressor attached to said central shaft of said sun shaft assembly and a transmission coupled to said ring gear to form a driven turbocharger.

25. A planetary drive mechanism comprising: a sun axis; a plurality of double-roller planetary roller assemblies, each double-roller planetary roller assembly comprising: a suspended planetary roller and a second planetary roller rotatably coupled to each other concentrically via an anti-rotation mechanism that allows said suspended planetary roller to slide axially on said anti-rotation mechanism while transmitting torque between said suspended planetary roller and said second planetary roller, wherein both the spring-loaded planetary roller and the second planetary roller have outer roller drive surfaces that interact with said sun axis, as well as inclined inner roller drive surfaces;a preload spring located externally to said suspended planetary roller that provides a preload force on said traction surfaces of the inclined inner roller of said suspended planetary roller and said second planetary roller during the assembly and operation of said planetary traction drive; an annular roller assembly comprising: a toothed ring; a first traction ring and a second traction ring located concentrically with said toothed ring that interact with said traction surfaces of inclined inner rollers of said suspended planetary rollers and said second planetary rollers of said plurality of double-roller planetary roller assemblies.

26. The planetary traction drive of claim 25, wherein said anti-rotation mechanism comprises a splined connection between said suspended planetary roller and said second planetary roller.

27. The planetary drive transmission of claim 25, wherein said toothed ring is coupled to said second drive ring via a ball ramp.

28. The planetary traction transmission of claim 25 further comprising: 15 a turbine and a compressor coupled to said sun axis and a transmission coupled to said ring gear to form a driven turbocharger.

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