MX2008009476A - Worm-gear assembly having a pin raceway - Google Patents

Abstract

A worm-gear assembly including a worm screw ()280 having at least one groove ()280a and a wheel (275) having a plurality of rotatable pins (75a) along its periphery for engaging the worm screw. The pins are able to rotate in a direction other than a direction of wheel rotation. At least one raceway (265) is provided for contacting pins that are not engaged with the worm screw during operation of the assembly.

Description

HELICAL ASSEMBLY ASSEMBLY WHICH HAS A PIN ROLLER RING CROSS REFERENCE TO RELATED REQUESTS This application claims the benefit of the filing date of US Patent Application No. 11 / 340,920, filed January 26, 2006, the description of which is incorporated herein by reference.

FIELD OF THE INVENTION The present invention relates to helical gear assemblies, and more particularly, to helical gear assemblies wherein a helical screw is engaged through pins in the periphery of a wheel.

BACKGROUND OF THE INVENTION An important consideration in the design of gear systems is the minimization of friction between the gear components. By minimizing the friction between gear components, the efficiency of a gear system is increased. For example, in a gear system that is used for power transmission, the transmission loss due to friction within the system is reduced when the friction within the system is reduced. In addition, by minimizing the friction between the gear components, the longevity of a gear system is increased. That is, by reducing the friction between components in the gear system, the frictional wear rate on the components is reduced, thus increasing the amount of time the system can operate before it fails. A common gear system of the prior art includes two or more gears having a circular body. Each gear includes a plurality of "teeth" along the periphery of its circular body. The teeth of the two gears are engaged, so that force can be transmitted from one of the gears to the other through the gear teeth. In this way, if a torque is applied to one of the gears causing the gear to rotate, the teeth of the gear will exert a force on the teeth of the other gear, causing the other gear to rotate. The sliding of the respective groups of teeth against each other is a source of friction of the gear system. One way in which designers have reduced the friction between components of a gear system is by replacing rotating pins with gear teeth. Figure 1 is an isometric view of a prior art gear system, where rotating pins were used instead of teeth. As can be seen in the figure, a plurality of rotating pins 5 are positioned along the periphery of a wheel 10 and couple a helical screw 15. The pins are arranged in an individual "row" along the circumference of a wheel. the wheel. He The helical screw has an hourglass shape and has a spiral groove 20 cut in its surface. The pins couple the helical screw moving through the spiral groove. The gear system of Figure 1 is typically used to transmit power from a conductive arrow 25 to an axis 30. More specifically, as a torque is applied to the arrow 25 in the direction shown by the arrow 35, the The slot exerts a force on the pins that it engages, causing the wheel to rotate in the direction shown by the arrow 40. The bearings 45a and 45b support the wheel while allowing it to rotate. As the pins 5 rotate through the slot, they are free to rotate about their longitudinal axes by virtue of the bearings 50. For example, as the pin 7 moves through the slot, it rotates in the direction shown by arrow 55. Since the pins are free to rotate about their longitudinal axes, the friction between the pins and the walls of the slot is reduced. That is, since the pins can rotate around their longitudinal axes, they can rotate around the walls of the slot. Whereas, if the pins could not rotate around their longitudinal axes, they could slip against the walls of the slot. Although the gear system of Figure 1 has the advantage of replacing rotating pins with fixed teeth, it has several disadvantages. Three of the problems associated with the system of Figure 1 relate to "pin slip", "start of skid "and" wheel misalignment. "The problem of" pin slip "is caused by the centrifugal force acting on the pins 5 as the wheel 10 rotates Figure 2 is a plan view in profile of some of the the elements of the gear system of Figure 1. In particular, Figure 2 shows pins 5, bearings 50 and helical screw 15. Also shown are the spiral groove 20, conductive arrow 25 and a plurality of internal bearings 60. The inner bearings they are inside the wheel 10 and help to support the pins As can be seen in Figure 2, the rotation of the helical screw in the direction shown by the arrow 65 causes the movement of the pins 5 in the rotational direction shown by the arrows 70. This movement gives rise to a centrifugal force on the pins, which is illustrated by the arrows 75. The centrifugal force pushes the pins radially outward from the center of the pin. a wheel, and if the pins are not protected against radial movement outward, the force moves the pins radially outward. This radially outward movement of the pins is due to the centrifugal force which is termed "pin slip". Figure 3A illustrates the effect of the pin slide. The figure shows a sliding pin that enters the spiral groove of the helical screw. As can be seen in Figure 3A, the pin does not enter the spiral groove 20 moderately. Rather, as the pin moves towards the position to enter the slot, this can hit the base of the slot. The rigorous entry of the pin into the slot, and any accompanying rigidity in the rest of the pin path through the slot, reduce the efficiency of the gear system and increase the rate of wear and tear. Figure 3B is provided as a contrast to Figure 3A. Figure 3B shows how a pin that has not slipped into the spiral groove of the helical screw. The "skid start" problem is explained with reference to Figure 1. The skid start refers to the start of the rotation shown by the arrow 55. More specifically, as the pin 7 leaves the spiral groove 20, there is no force on the pin to keep its rotation around its longitudinal axis, in this way the rotation of the pin will be reduced or stopped during the time in which it is not inside the spiral groove. In this way, as the pin travels about the center of the wheel 10 and once again enters the slot 20, the slot exerts a torque on the longitudinal axis of the pin. The torque is exerted on the pin through the wall of the slot (see, for example, Figure 3B). The initiation of torque between the slot wall and the pin causes the pin to skid rather than coil in the slot, resulting in rigidity in the operation of the system, which reduces efficiency and longevity.

The problem of "wheel misalignment" is explained with reference to Figure 1. Referring to Figure 1, the rotation of the helical screw in the direction of the arrow 35 applies a force on the pins 5 in the direction shown by the arrow 80. More specifically, during the rotation of the helical screw in the direction 35, the force exerted on the pins 5 by the slot 20 can be described as including two components, a first component that pushes the pins to move in the direction shown by the arrow 40, and a second component that pushes the pins to move in the direction of the arrow 80. Both component forces are transmitted to the wheel 10, the first component pushing the wheel to rotate in the direction 40 and the second component pushing the top of the wheel to move it in the direction 80. Any movement of the wheel in the direction 80 is a source of wheel misalignment. That is to say, any movement of the wheel in the direction 80 changes the trajectory of the pins in relation to the helical screw. The change in trajectory takes the pins out of their intended trajectory and gives rise to rigidity and / or inefficiency of operation. It is important to note that in Figure 1 it is typical that the forces associated with the arrow 80 exert force on the top of the wheel, so that they push the top of the wheel to move it in the direction of arrow 80. But for the fixed central axis of the wheel, this force could cause the bottom of the wheel to move in the opposite direction, as shown by the arrow 85. In a real operation of the gear system during extended periods at high speeds, the force at the top of the wheel tends to exceed the wheel axis restriction; thus causing the wheel axle to flex, which results in wheel misalignment. For example, if in normal operation, the wheel axis is aligned with the horizontal direction in Figure 1, the wheel misalignment can flex the axis so that there is some angle between the axis and the horizontal direction. It is presumed that the dynamic pin slipping, skid start, and wheel misalignment instabilities have previous failed attempts to successfully commercialize rotary pin worm gear assemblies.

BRIEF DESCRIPTION OF THE INVENTION The present invention is presented to overcome the above problems. A helical gear assembly according to the present invention includes a helical screw having at least one groove and a wheel having a plurality of rotating pins along its periphery for coupling the helical screw. The pins are capable of rotating in a direction other than the direction of rotation of the wheel. At least one race ring is provided to make contact with pins that are not coupled with the helical screw during assembly operation. By including a running ring for the contact of rotating pins which are not engaged with the helical screw, the invention makes many advantages over the helical gear assemblies of the prior art. By eliminating or substantially reducing the problems associated with pin slip, skid initiation and wheel misalignment, the invention makes possible a rotary pin type helical gear assembly capable of moderate operation on a full scale of operation, substantially with less wear and tear, greater efficiency, and longer life BRIEF DESCRIPTION OF THE DRAWINGS The following detailed description, given by way of example, but is not intended to limit the invention only to the specific embodiments described, may be better understood together with the accompanying drawings, in which like reference numbers denote elements and similar parts. , in which: Figure 1 is an isometric view of a prior art gear system where rotating pins have been used in place of teeth. Figure 2 is a plan view in profile of some of the elements of the gear system of Figure 1. Figure 3A illustrates the effect of pin sliding.

Figure 3B shows how a pin that has not slipped enters the spiral groove of the helical screw. Figure 4 is an exploded view of a gear system according to the first embodiment of the present invention. Figure 5 is an isometric view of the gear system of Figure 4 in assembled form. Figure 6 is a profile view of the assembled gear system illustrated in Figure 5, with one of the rolling rings removed for illustration purposes. Figure 7 is an exploded view of a gear system according to a second embodiment of the present invention. Figure 8 is a detailed view of a rotating pin portion of the first and second embodiments. Figure 9 is a detailed view of how a rotating pin interconnects with a race ring according to the present invention. Figure 10 is an isometric view of a gear system according to a third embodiment of the invention. Figure 11 is a cross-sectional view of the gear system of Figure 10. Figure 12 is an isometric cross-sectional view of the gear system of Figure 10. Figure 12A shows an interconnected raceway ring. with a mechanical displacement mechanism. Figure 12B shows the running ring of Figure 12A separated from the movement mechanism. Figures 12C-12F illustrate how the displacement mechanism of Figure 12A works. Figure 13 is an exploded view of a gear system according to a fourth embodiment of the present invention. Figure 14 is an isometric cross-sectional view of the gear system illustrated in Figure 13. Figure 15A is a cut-away view of the gear system of Figure 13 with a portion removed for purposes of illustration. Figure 15B is a cut away view of a portion of the elements of Figure 15A. Figure 15C is a cut-away view of a portion of the elements of Figure 15B. Figure 16 shows a fifth embodiment of a gear system according to the invention. Figure 17 shows a first alternative embodiment of a pin according to the invention. Figure 18 shows a second alternative embodiment of a pin according to the invention.

DETAILED DESCRIPTION Figure 4 is an exploded view of a gear system according to a first embodiment of the present invention. The gear system includes a helical screw 100, a helical wheel 105 and two running rings 110a and 110b. The helical screw has an hourglass shape and has a multitude of spiral grooves 115 cut into its surface. The wheel includes a multitude of rotating pins 120 positioned along its circumference. The pins are arranged in an individual "row" along the circumference of the wheel and engage the helical screw moving through the spiral grooves. As the pins 120 rotate through the slots, they are free to rotate about their longitudinal axes in a manner similar to that described with respect to the system of Figure 1. In particular, the use of bearings 125 allows the pins turn around their longitudinal axes. Since the pins are free to rotate about their longitudinal axes, the friction between the pins and the walls of the slots is reduced. That is, since the pins can rotate around their longitudinal axes, they can rotate around the walls of the slots. Meanwhile, if the pins can not rotate around their longitudinal axes, they could slide against the walls of the slots. The running rings 110a and 110b of Figure 4 include rolling ring bearing surfaces 130a and 130b. In the figure, the surface 130a is clearly visible, while the surface 130b is obscured. As the worm wheel of Figure 4 rotates, one of the running rings contacts the pins 120 that are not engaged with the worm screw. That is, as the worm wheel rotates on one of the raceway surfaces 130a or 130b it contacts those pins 120 that are not engaged with the slots 115. It is preferred that the raceway makes contact with all the pins that are not coupled with the helical screw. However, the running ring can make contact with less than all the pins that are not engaged with the helical screw. If the worm wheel is rotating or stationary, any running ring can make contact with all pins that are not engaged with the worm, less than all the pins that are not engaged with the worm or any of the pins. Figure 5 is an isometric view of the gear system of Figure 4 in assembled form. As can be seen in Figure 5, the race rings are positioned on opposite sides of the worm wheel, in order to easily engage those pins 120 that are not engaged by the slot 115. Figure 6 is a profile view of the assembled gear system illustrated in Figure 5, with one of the rolling rings removed for illustration purposes. In particular, the rolling ring 110a is not shown in Figure 6, so that the rolling ring 110b and the running ring surface 130b are clearly visible. The relative positioning of the pins 120 and the raceway surface 130b is also clearly visible. Figure 7 is an exploded view of a gear system according to a second embodiment of the present invention. The embodiment of Figure 7 is similar to the embodiment of Figure 4, with the exception that the running ring 110b and the rolling ring bearing surface 130b are not included in the embodiment of Figure 7. In this way , the embodiment of Figure 7 includes a helical screw 135, a helical wheel 145 and a running ring 155. The helical screw has an hourglass shape and has a multitude of spiral grooves 140 formed on its surface. The wheel includes a multitude of rotating pins 150 that are positioned along the circumference of the wheel. The pins are arranged in an individual "row" along the circumference of the wheel and engage the helical screw moving through the spiral grooves. The raceway includes a raceway bearing surface 160. As the worm wheel rotates, the raceway contacts those pins 150 that are not engaged with the worm. That is, as the helical wheel rotates, the raceway bearing surface contacts those pins 150 that are not engaged with the slots 140. Preferably, the raceway makes contact with all the pins that are not coupled with the helical screw. However, the running ring can make contact with less than all the pins that are not engaged with the helical screw. If the worm wheel is rotating or is stationary, the running ring can make contact with all the pins that are not engaged with the worm, less all pins that are not engaged with the worm, or none of the pins. Figure 8 is a detailed view of a pivoting pin portion of the first and second embodiments. The pins can be rotated exclusively in one direction counter-clockwise, can rotate exclusively in the clockwise direction, or can rotate in the directions both clockwise and counter-clockwise. clock. As can be seen from Figures 7 and 8, the pins are rotatably supported on the wheel 145 through bearings 157. Having described two preferred embodiments of the invention, the operation of the rolling rings of the invention in those two modalities will now be described in more detail. When the gear systems of Figures 4-8 are in operation, the race rings function to alleviate the problems of pin slip, skid start and wheel misalignment. More specifically, since the rotation of the helical screw causes the wheel to rotate about its axis, the pins that are not engaged with the helical screw and in contact with a rolling ring are driven by the rolling ring in a way that keeps them rotating around their longitudinal axes, against the centrifugal force of the rotating wheel, and against the force of the helical screw that pushes the wheel towards misalignment (the "misalignment force"). For the purposes of describing how the raceway and the pins interact, reference is made to Figure 9. Figure 9 is a detailed view of how a rotary pin 165 interconnects with a raceway section 170. The figure is applicable to race rings 110a, 110b and 155, and raceway bearing surfaces 130a, 130b, and 160. As can be seen in Figure 9, since the wheel on which pin 165 is mounted rotates in a direction that takes the pin "to" the page, the contact between the pin 165 and the race ring imparts a counter torque to the pin (represented by arrow 175). Torque 175 keeps the pin rotating about its longitudinal axis when it is not in contact with the helical screw, so that the pin is already ready to rotate about its longitudinal axis when it makes contact with the helical screw and the pin is not starts the skating. In addition, the running ring imparts a downward force (represented by the arrow 180) against the centrifugal force due to the rotation of the wheel (represented by arrow 185). Even more, the race ring imparts a force from left to right (represented by arrow 190) against the force of misalignment. Figure 10 is an isometric view of a gear system according to a third embodiment of the invention. The system includes a helical screw 200 having spiral grooves 205, a helical wheel 210 including rotating pins 215, and a running ring 220. The running ring 220 is a one-piece component having two ring bearing surfaces. rolling 220a and 220b formed inside its internal surface. Figure 11 is a cross-sectional view of the gear system of Figure 10. The cross section has been taken along the line AA 'of Figure 10 and the view of Figure 11 is that view when viewed in the direction of the arrows shown in Figure 10. Figure 12 is an isometric cross-sectional view of the gear system of Figure 10. The cross section has been taken along line AA 'of Figure 10 and the view is one that faces away from the direction of the arrows in Figure 10. Referring to Figure 11, since the helical screw 200 rotates in the direction indicated by the arrow 230, a pin 215a is pushed in one direction "towards" the page as a pin 215b is pushed in an "outward" direction from the page. In addition, the pin 215b is in contact with the bearing surface 220b. The contact between pin 215b and surface 220b causes the pin to rotate about its longitudinal axis (represented by line 217) as it moves outwardly from the page. In this way, the rolling ring maintains the rotation of the pin about the longitudinal axis of the pin as the pin exits the spiral groove of the helical screw. In this way, at the moment that the wheel rotation causes the pin to re-enter the slot, the pin is rotating about its longitudinal axis in a manner complementary to the rotation of the longitudinal axis that the pin experiences when in contact with the slot. In this way, when the pin enters the slot, the pin does not start skidding. Also, since the portion of the pin that extends from the periphery of the wheel and makes contact with the surface 220b (ie, the "pin head") has a truncated cone shape, and the surface 220b contacts the lateral surface of the truncated cone, the surface 220b applies a force to the pin in an action contrary to the centrifugal force (represented by arrow 235). In addition, as the screw rotates the slot where the pin 215a sits, a force (shown by the arrow 240) is caused, which pushes the pin 215a to the right of the page. The force of the screw on the pin 215a gives rise to a reaction force (shown by arrow 245), the which pushes the pin 215b to the left. However, since the pin 215b is in contact with the raceway bearing surface 220b, the surface 220b applies a force (shown by the arrow 250) in reaction to the force 245. In addition, the force 250 gives rise to a reaction force (shown by arrow 255). In this way, the force of the screw that pushes the pins out of alignment (force 240) is resisted by a reaction force (force 255) caused by the running ring. The dynamics illustrated in Figure 11 are mirror images in Figure 12. It should be noted that while Figures 11 and 12 were described in the context of the helical screw rotating in the direction indicated by arrow 230, the invention is equally applicable to the rotation of the helical screw in the opposite direction. In this regard, if the helical screw is rotating in the opposite direction 230, the pin 215b is pushed against the raceway bearing surface 220a, either by the "force of misalignment" that the screw imparts to the wheel, or by some mechanism of displacement. Once the pin 215b makes contact with the surface 220a, the misalignment force caused by the rotation of the helical screw in an opposite direction 230 is found by a force transmitted through the surface 220a. It should also be noted that a gear system according to the invention can be employed in a vehicle drive system, such that a direction of rotation of the helical screw corresponds to the "forward" direction of the vehicle and the other direction of rotation of the helical screw corresponds to the "inverse" direction of the vehicle. In such an application, the engagement system is preferably employed in conjunction with a movement mechanism, the displacement mechanism is used to push pins against a first bearing surface of a race ring when the rotation of the helical screw corresponds to the direction "forward". "of the vehicle and to push pins against a second bearing surface of the race ring when the rotation of the helical screw corresponds to the" inverse "direction of the vehicle. An illustrative scroll mechanism is shown in Figure 12A. The displacement mechanism shown in Figure 12A is a mechanical displacement mechanism. However, the invention is not limited to mechanical displacement mechanisms. After reviewing Figure 12A and its description, one skilled in the art of the invention will readily appreciate the wide scale of displacement mechanisms that can be employed to displace opposing raceway surfaces to make contact with opposite sides of the pins on sides. opposite of the wheel in the context of a drive system that has "forward" and "reverse" directions. For example, suitable displacement mechanisms include revolving threaded arrows driven by electric motor. Hydraulic actuators, electric solenoids, and mechanisms and displacement levers operated manually. It should also be noted that the invention is not limited to the case of the helical screw driving the worm wheel. Rather, the helical wheel can drive the helical screw so that a rotational torque applied to the worm wheel moves the rotary pins through the slot (s) in the helical screw, and thus makes the helical screw turn Furthermore, it should be noted that the invention is not limited to bearing surfaces of a rolling ring of any particular geometry. In this way, the invention is not limited to rolling ring bearing surfaces having a flat cross section as shown in Figure 9, or a concave cross section as shown in Figure 14. In reality, after viewing In this disclosure, one skilled in the art of the invention will readily appreciate the wide scale of suitable ring geometries. Furthermore, it should be noted that the helical screw of the present invention is not limited to an hourglass shape.

For example, the helical screw may have a cylindrical shape. After viewing this description, one skilled in the art of the invention will readily appreciate the wide scale of suitable helical screw geometries. Also, the groove or grooves formed in the helical screw are not limited to a spiral shape. Although spiral grooves are preferred, a wide variety of slot configurations is suitable for use with the invention. After viewing this description, one skilled in the art of the invention will readily appreciate the wide scale of suitable slot shapes. Returning to 12A, the embodiments of the movement mechanism of the invention will now be discussed in greater detail. Figure 12A shows a running ring 265 of the invention interconnected with a mechanical movement mechanism 270. The movement mechanism is used to position the running ring relative to rotating pins of a worm wheel. Figure 12B is provided for comparison purposes, and shows the running ring of Figure 12A separated from the movement mechanism. As can be seen from Figure 12A, the mechanical displacement mechanism includes a set screw 270a, a barrel 270b and a closing notch 270c. The adjusting screw is in threaded engagement with the barrel, which is fixedly attached to the rolling ring. By turning the adjusting screw inside the barrel, the barrel moves relative to the adjusting screw, and in this way the rolling ring moves relative to the adjusting screw. The locking notch is also in threaded engagement with the adjusting screw, and when the rolling ring is correctly positioned through the rotation of the adjusting screw, the locking notch rotates into place to secure the adjusting screw. Figures 12C-12F illustrate how the mechanism of displacement of Figure 12A works. Figures 12C-12F show a gear system including the running ring 265, the mechanical movement mechanism 270, a helical wheel 275 and a helical screw 280. The running ring includes a bearing ring bearing surface 265a. The helical wheel includes a multitude of rotary pins 275a. The helical screw includes a spiral slot 280a. Figures 12C and 12D show the helical wheel positioned so that the rotating pins are not in contact with the bearing surface of the raceway. Accordingly, Figure 12D shows that the adjusting screw of the displacement mechanism has been rotated inside the barrel of the mechanism in order to move the rolling ring away from the worm wheel. Figures 12E and 12F show the helical wheel positioned so that the rotating pins are in contact with the raceway bearing surface. Accordingly, Figure 12E shows that the adjusting screw of the displacement mechanism has been rotated inside the barrel of the mechanism in order to move the rolling ring towards the worm wheel. In the illustrative displacement mechanism of the Figures 12A-12F, as an alternative to manual rotation of the adjusting screw, the screw can be rotated through a motor or hydraulic driven, or through an electric motor. In such a configuration, the closing notch can be replaced by a hydraulic braking mechanism or a fixed stop which is attached to the rolling ring or that is part of the rolling ring. Figure 13 is an exploded view of a gear system according to a fourth embodiment of the present invention. The system includes a helical screw 300 having a spiral groove 305, a worm wheel 310 including rotating pins 315, and a pin race 325 having a bearing ring bearing surface 325a. The components are secured within a housing 320. The housing is a one-piece housing. The running ring 325 is formed within the inner surface of the housing and is an integral part of the housing. Figure 14 is an isometric cross-sectional view of the gear system illustrated in Figure 13. Figure 15A is a cut-away view of the gear system of Figure 13 with a portion removed for purposes of illustration. Figure 15B is a cut away view of a portion of the elements of Figure 15A. Figure 15C is a cut-away view of a portion of the elements of Figure 15B. It should be noted that the embodiment of Figure 13 is not limited to a running ring or race rings that are an integral part of the housing. One or more race rings can be secured to or attached to the housing, instead of being an integral part of the housing. In view of this description, an expert in The technique of the invention will readily appreciate a wide range of methods of manufacturing a ring or race rings that are secured to or attached to the housing. It should also be noted that the housing of the gear system of the embodiment of Figure 13 is preferably formed from a relatively hard, durable and commercially available material, such as hardened steel, stainless steel or a metal composite. It should also be noted that the housing of the embodiment of Figure 13 is not limited to a one-piece housing. For example, the housing can be made of two or more pieces. Figure 16 shows a fifth embodiment of the gear system according to the invention. The embodiment of Figure 16 includes a helical wheel 400, a helical screw 405, and two pin race rings 410a and 410b. The worm wheel has two groups of rotating pins arranged in respective rows 415a and 415b, and the helical screw has a spiral groove 405a cut in its surface for the purpose of coupling the pins. The running rings are formed on the inner surface of a housing 420 and couple those pins that are not coupled by the helical screw. Only a portion of the housing is shown in cross section for purposes of clarity of presentation. The gear system of Figure 16 is used to drive a shaft 425. The operation of the gear system of Figure 16 is easily seen in view of the detailed description of Figures 1-15. It should be noted that the embodiment of Figure 16 is merely illustrative of an embodiment of multiple race rings / multiple pin-rows of the invention, and that a worm wheel of the invention may have more than two race rings and / or more of two rows of pins. In addition, the rotating pins of the present invention are not limited to any geometry. To illustrate, two examples of alternative pin geometries are provided, in Figures 17 and 18. Figure 17 shows a first alternative embodiment of a pin according to the invention. The drawing shows a pin 500 placed on a helical wheel 505 and coupling a helical screw 510. The pin has a head 515 in the shape of a truncated sphere. The head of the pin engages a slot 520 in the helical screw. The pin is supported on the wheel 505 by a first bearing 525, a flange 530 and a second bearing 535. The bearings and flange are seated in a hole inside the wheel, the hole includes three sections, a lower section 540, a section half 545, and a top section 550. The longitudinal axis of the pin is indicated by line 555. Figure 18 shows a second alternative embodiment of a pin according to the invention. The figure shows a pin 600 placed on a wheel 605 and coupling a helical screw 610. The pin has a head 615 in the shape of a doubly truncated sphere. The head of the pin engages a slot 620 in the helical screw. The longitudinal axis of the pin is indicated by the line 655. For each type of pin that can be used, the slot (s) of the corresponding helical screw and the bearing surface (s) of the rolling ring have a matching shape. For example, the pin of Figure 17 can "match" and "roll along" a concave helical screw slot, and can "match" and "roll along" a ring bearing surface of Concave rolling Since these and other variations and combinations of the aspects described above can be used without departing from the present invention as defined by the claims, the above description of the preferred embodiments should be taken by way of illustration rather than by way of limitation. of the invention as defined by the claims.

Claims (26)

1. A helical gear assembly, comprising: a helical screw having at least one slot; a wheel having a plurality of rotating pins along its periphery for coupling the helical screw, the pins being able to rotate in a direction other than the direction of rotation of the wheel; and at least one race ring for contacting the pins that are not engaged with the helical screw during assembly operation.

The helical gear assembly according to claim 1, wherein the helical screw has an hourglass shape.

3. The helical gear assembly according to claim 1, wherein the helical screw has a cylindrical shape.

The helical gear assembly according to claim 1, wherein the pins are capable of rotating about their longitudinal axes.

The worm gear assembly according to claim 1, wherein at least one race ring makes contact with all pins that are not engaged with the worm gear.

6. The helical gear assembly according to the claim 1, wherein at least one running ring makes contact with a portion of the pins that are not engaged with the helical screw.

The helical gear assembly according to claim 1, wherein the helical screw has a spirally shaped groove.

The helical gear assembly according to claim 1, wherein the helical screw has a plurality of spirally shaped slots.

The worm gear assembly according to claim 1, wherein each of the pins has a truncated cone-shaped head.

The helical gear assembly according to claim 1, wherein each of the pins has a head in the shape of a truncated sphere.

The helical gear assembly according to claim 1, wherein each of the pins has a head in the form of a double, truncated sphere.

The worm gear assembly according to claim 1, wherein the assembly includes a first rolling ring and a second running ring, the first running ring making contact with the pins that are not engaged with the helical screw. when the helical screw rotates in a first direction, and the second rolling ring makes contact with the pins that are not coupled with the screw helical when the helical screw rotates in a second direction.

13. The worm gear assembly according to claim 1, wherein for at least one rolling ring, the surface contacting the pins has a flat cross section.

The helical gear assembly according to claim 1, wherein for the at least one running ring, the surface contacting the pins has a concave cross section.

15. The helical gear assembly according to claim 1, further comprising a housing.

The helical gear assembly according to claim 15, wherein the housing is a one-piece housing.

17. The worm gear assembly according to claim 15, wherein the housing is made of two or more pieces.

18. The worm gear assembly according to claim 15, wherein at least one race ring is formed as an integral part of the housing.

The worm gear assembly according to claim 15, wherein at least one race ring is formed as a separate component that is attached to the housing.

20. The worm gear assembly according to claim 1, further comprising bearings for supporting the pins for rotation in a direction other than a direction of rotation of the wheel.

21. The helical gear assembly according to claim 1, wherein the pins are arranged in a single row.

22. The worm gear assembly according to claim 1, wherein the pins are arranged in a multitude of rows.

23. The worm gear assembly according to claim 1, wherein the pins are capable of rotating about their longitudinal axes either in a clockwise or counterclockwise direction.

The worm gear assembly according to claim 1, further comprising a displacement mechanism, and wherein at least one running ring includes a first raceway surface and a second raceway surface, the Displacement mechanism can operate to push the pins that are not engaged with the helical screw against the first rolling ring surface when the helical screw rotates in a first direction and to push the pins that are not engaged with the helical screw against the second Rolling ring surface when the helical screw rotates in a second direction.

25. A method to operate a gear assembly helical including a helical screw having at least one groove and a wheel having a plurality of pins along its periphery for coupling the helical screw, the pins being able to rotate in a direction different from the direction of wheel rotation , comprising the step of providing at least one race ring for contacting the pins that are not engaged with the helical screw during the operation of the assembly.

26. A method for operating a helical gear assembly that includes a helical screw having at least one groove and a wheel having a plurality of pins rotatably mounted along its periphery for coupling the helical screw, comprising the step of providing at least one race ring for contacting at least some of the pins that are not engaged with the helical screw during the operation of the assembly.