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WO2025085602A1 - Pignon à surface de support accrue - Google Patents

Pignon à surface de support accrue Download PDF

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Publication number
WO2025085602A1
WO2025085602A1 PCT/US2024/051726 US2024051726W WO2025085602A1 WO 2025085602 A1 WO2025085602 A1 WO 2025085602A1 US 2024051726 W US2024051726 W US 2024051726W WO 2025085602 A1 WO2025085602 A1 WO 2025085602A1
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WO
WIPO (PCT)
Prior art keywords
tooth
sprocket
area
teeth
land
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/US2024/051726
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English (en)
Inventor
Chris VASILIOTIS
Brian Stack
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gates Corp
Original Assignee
Gates Corp
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Filing date
Publication date
Application filed by Gates Corp filed Critical Gates Corp
Publication of WO2025085602A1 publication Critical patent/WO2025085602A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/17—Toothed wheels
    • F16H55/171—Toothed belt pulleys
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/30—Chain-wheels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H7/00—Gearings for conveying rotary motion by endless flexible members
    • F16H7/02—Gearings for conveying rotary motion by endless flexible members with belts; with V-belts
    • F16H7/023—Gearings for conveying rotary motion by endless flexible members with belts; with V-belts with belts having a toothed contact surface or regularly spaced bosses or hollows for slipless or nearly slipless meshing with complementary profiled contact surface of a pulley

Definitions

  • Toothed synchronous belts are often used for transmissions in mobility applications (such as bicycles) and also in power mobility applications (such as electric bicycles or E-bikes, powered wheelchairs, scooters, etc.).
  • the toothed belts are used with a toothed gear or sprocket that engages the teeth of the belt and moves the belt upon rotation of the gear or sprocket.
  • Tooth jump occurs when a tooth of the belt slips over a tooth of the engaged gear or sprocket. Tooth jump may occur when the belt/teeth are not sufficiently rigid and durable when under a load. For example, an insufficiently rigid belt/tooth may stretch under load, which may lead to tooth jump. To inhibit tooth jump, attempts have been made to vary the flexibility of the belt.
  • Tooth jump may also occur due to debris buildup between the belt teeth and/or the sprocket teeth.
  • T 'he present disclosure provides variations to the tooth of the gear or sprocket to inhibit tooth jump and reduce chordal action.
  • the present disclosure is directed to a sprocket having a debris shedding element between adjacent belt-engaging teeth, the sprocket having an increased radial tooth surface area designed to engage with teeth of a toothed belt.
  • the designs utilize a variety of combined approaches to maximize debris shedding while also minimizing chordal action from a lack of support of the belt teeth.
  • the designs minimize chordal action, minimize system noise, and prolong belt life.
  • the designs incorporate a combination of relief cut features at the sprocket tooth root and radial tooth support area to provided adequate belt support with debris shedding features.
  • a ratio of the debris shedding area to the radial tooth support area is in the range of about 1 : 1 to 3: 1, in other embodiments in the range of about 1.25: 1 to 2: 1, or the range of about 1.25 : 1 to 1.75 : 1.
  • the radial tooth support area is no greater than the debris shedding area.
  • a toothed gear sprocket having a center, a radius, and a first axial side and a second axial side, the sprocket also having a plurality of teeth, each tooth having a tooth root, a tooth wall, and a tooth tip, and a land between a pair of adjacent teeth, the land having a concave portion extending in from the first side and the second side to define a debris shedding area.
  • the land and the tooth root, the tooth wall and the tooth tip of each tooth of the pair of adjacent teeth define a radial tooth support area, wherein a ratio of the debris shedding area to the radial tooth support area is in the range of 1 : 1 to 3 : 1.
  • a toothed gear or sprocket having a center, a radius, and a first side and a second side, the sprocket also having a plurality of teeth, each tooth having a tooth root, a tooth wall, and a tooth tip, a land present between a pair of adjacent teeth, together the tooth root, the tooth wall, and the tooth tip of each tooth of the pair of adjacent teeth and the land therebetween defining a radial tooth support area, and a debris shedding area between the pair of teeth, wherein a ratio of the debris shedding area to the radial tooth support area is in the range of 1 : 1 to 3 : 1.
  • the gears or sprockets may be part of a belt drive system, which includes a belt (e.g., an endless belt) and the gear or sprocket.
  • a belt e.g., an endless belt
  • Some belt drive systems have a first sprocket accompanying a crank and a second sprocket accompanying a driven shaft, where one or both the sprockets have the features described herein.
  • the belt drive system has a belt having a plurality of longitudinally spaced belt teeth, and a sprocket, with the sprocket having a plurality of teeth, each tooth having a tooth root, a tooth wall, and a tooth tip, and a land between a pair of adjacent teeth, the land having a concave portion extending in from the first side and the second side to provide a debris shedding area.
  • the land and the tooth root, the tooth wall and the tooth tip of each tooth of the pair of adjacent teeth providing a radial tooth support area, wherein a ratio of the debris shedding area to the radial tooth support area is in the range of 1 : 1 to 3 : 1.
  • the belt drive system has a belt having a plurality of longitudinally spaced belt teeth, and a sprocket, with the sprocket having a plurality of teeth each tooth having a tooth root, a tooth wall, and a tooth tip, a land present between a pair of adjacent teeth, together the tooth root, the tooth wall, and the tooth tip of each tooth of the pair of adjacent teeth and the land defining a radial tooth support area, and a debris shedding area between the pair of adjacent teeth, wherein a ratio of the debris shedding area to the radial tooth support area is in the range of 1 : 1 to 3 : 1.
  • FIG. l is a perspective view of a generic sprocket.
  • FIG. 2A is an enlarged view of a portion of a generic sprocket
  • FIG. 2B is the view of
  • FIG. 2A highlighting the corresponding radial tooth support area
  • FIG. 2C is the view of FIGS. 2A and 2B highlighting the corresponding applied torque area.
  • FIG. 3A is an enlarged view of a portion of a generic sprocket having a central flange and side chamfers for debris-shedding;
  • FIG. 3B is the view of FIG. 3 A highlighting the corresponding radial tooth support area;
  • FIG. 3C is the view of FIGS. 3A and 3B highlighting the corresponding applied torque area.
  • FIG. 4A is an enlarged view of a portion of sprocket according to this disclosure having a central flange and side chamfers for debris-shedding;
  • FIG. 4B is the view of FIG. 4A highlighting the corresponding radial tooth support area.
  • FIG. 5A is an enlarged view of a portion of another sprocket according to this disclosure having a central flange and side chamfers for debris-shedding;
  • FIG. 5B is the view of FIG. 5A highlighting the corresponding radial tooth support area.
  • FIG. 6A is an enlarged view of a portion of another sprocket according to this disclosure having a central flange and asymmetrical side chamfers for debris-shedding;
  • FIG. 6B is the view of FIG. 6A highlighting the corresponding radial tooth support area.
  • FIG. 7A is an enlarged view of a portion of another sprocket according to this disclosure having a central flange, side chamfers for debris-shedding, and radial support wires;
  • FIG. 7B is the view of FIG. 7A highlighting the corresponding radial tooth support area.
  • FIGS. 9A through 9D are top views of four different sprocket portions.
  • FIG. 10A is an enlarged view of a portion of a sprocket according to this disclosure having a central flange and debris-shedding grooves highlighting the debris shedding area;
  • FIG. 10B is the view of FIG. 10A highlighting the corresponding applied torque area
  • FIG. 10C is the view of FIG. 10A highlighting the corresponding radial tooth support area.
  • the present disclosure is directed to toothed gears or sprockets for toothed belt systems, such as mobility applications (such as bicycles, electric bicycles or E-bikes, powered wheelchairs, scooters, etc ).
  • the gears or sprockets have debris-shedding elements that direct debris (e.g., dirt, dust, water, etc.) laterally out from the gear or sprocket; these debris- shedding elements may be bi-directional.
  • the gears or sprockets additionally or alternately include debris-shedding elements that direct debris radially.
  • sprocket will be used to include all of a toothed sprocket, gear, wheel, pulley, or the like that engage with a flexible, toothed belt.
  • the sprockets of this disclosure incorporate a combination of relief cut features at the sprocket tooth root and radial tooth support area that provide reduced belt wear and extended belt life, by inhibiting or reducing chordal action while providing for debris clearing.
  • Chordal action causes the linear velocity of a synchronous belt to vary cyclically as each belt tooth engages with the toothed sprocket. Such cyclical point loading can lead to premature failure of the belt.
  • outdoor riding or use subjects the belt system to collection of debris at the tooth roots of the sprockets.
  • the effective minor diameter of the sprocket at those points is increased and chordal action is increased, again leading to premature failing of the belt.
  • the sprockets of this disclosure have a reduced interface surface area and a polygonal shape imposed on the load transfer interface between the sprocket and belt.
  • FIG. 1 shows various features of a generic sprocket 100, such as for use in a mobility power system with a toothed belt, usually an “endless” belt.
  • FIG. 1 shows the sprocket 100 with a ring body 102 with a plurality of evenly spaced parallel teeth 110 around the outer periphery or circumference of the body 102.
  • the teeth 1 10 define the outer circumferential and radial edge of the sprocket 100 and typically extend laterally across the body 102 from the first axial side to the second axial side.
  • the teeth 110 are placed, sized, and shaped to engage with teeth, particularly between adjacent teeth, of a toothed belt.
  • This distance between adjacent teeth 110 may be adjusted based on the sprocket diameter, the width of the teeth 110 and on the wrap angle of the belt around the sprocket 100.
  • the distance between adjacent teeth 110 is equal to or essentially equal to (e.g., a little less, e.g., a little more) than the pitch length of the belt (the approximate length of a tooth) with which the sprocket will engage.
  • Each tooth 110 has a tip 112 and a base or root 114 with a side wall 116 extending from the tip 112 to the root 114.
  • the side wall 116 between the tip 112 and the root 1 14 is typically arcuate, sometimes with a straight segment.
  • the transition between the side wall 116 and the root 114 may be indicated by a change in profile (e.g., radius).
  • a land 120 which is the trough between the side walls 116 of the adjacent teeth 110.
  • the land 120 may be flat (planar) or may be arcuate, e.g., concave, as it is in FIG. 1.
  • the transition between the root 114 and the land 120 may be indicated by a change in profile (e.g., radius).
  • a pair of adjacent teeth 110 engage with one belt tooth.
  • a trailing tooth 104 of the pair exerts force against the engaged belt tooth, pushing or otherwise moving the toothed belt in the direction indicated by the arrow.
  • the other tooth 110 of the pair is referred to as the leading tooth 105.
  • This particular example of the trailing tooth 104 and the leading tooth 105 applies for a “driven” sprocket. For a “driving” or “driver” sprocket, the teeth would be reversed.
  • Full surface tooth profiles such as the profiles of the teeth 110 of the sprocket 100, provide an ideal surface area to uniformly support the belt profile from the base or root of the belt tooth through the tip of the belt tooth.
  • the design of the sprocket 100 has shortcomings; additionally, other features are desired, features such as a debris-shedding elements and tracking elements, to improve the operation of the sprocket with an engaging belt.
  • Many sprockets include a center or internal flange or side flanges to inhibit lateral displacement of the belt from the sprocket.
  • Center flanged sprockets include a circumferential flange, usually extending above the teeth of the sprocket, that engages with a lengthwise groove in the belt.
  • the flange is typically installed in a groove present through the teeth.
  • FIGS. 2A-2C through FIGS. 8A and 8B illustrate the total tooth support area for a sprocket configuration and the radial tooth support area for the same sprocket configuration.
  • the sprocket width, the distance between adjacent teeth, and the tooth height (from the tooth base to the tip) are the same.
  • the width of the sprocket, for each of the figures and examples, is about 11 mm.
  • the only changes are to the land and tooth root, which form a debris shedding feature.
  • FIGS. 2A, 2B and 2C show a portion of a sprocket (such as the sprocket 100) having a body 202 with a first axial side 201 and a second axial side 203.
  • the portion shown in FIGS. 2A, 2B and 2C has two adjacent teeth 210 and a land 220 therebetween, with each of the teeth 210 having a tip 212, a base or root 214 proximate the land 220 and a side wall 216 connecting the tip 212 and the root 214.
  • the teeth 210 define the outer circumferential and radial edge of the sprocket and extend laterally across the body 202 from the first axial side 201 to the second axial side 203.
  • One tooth 210 is a trailing tooth 204 and the other tooth 210 is a leading tooth 205, based on the direction of rotation indicated by the arrow, for a driven sprocket; a driver or driving sprocket will be the opposite arrangement.
  • a groove area 230 for receiving a center flange therein.
  • a flange would eventually be positioned in the groove area 230, for engaging with a lengthwise cut along the centerline of a belt to constrain the belt laterally.
  • this groove area 230 is not a physical feature but is a theoretical dead space where, regardless of the shape, size or position of the center flange, the lengthwise cut in the belt would eliminate any area of contact in this groove area.
  • one or two side flanges, at the outer edges of the sprocket are present.
  • FIG. 2A the total tooth support area for engaging with a belt tooth is highlighted with shading; this support area is three-dimensional, encompassing all of the tooth base or root 214, the side walls 216, and the land 220.
  • the tooth tip 212 is also indicated as support area, whereas the tooth tip 212 of the leading tooth 205 is not.
  • FIG. 2B shows the same portion as FIG. 2A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement; the radial tooth support area (which is two-dimensional) is a plan view of the total tooth support area (which is three- dimensional) viewed from the outer circumference, or radial location of the sprocket.
  • the radial tooth support area is approximately 46 mm 2 for this sprocket of FIGS. 2A and 2B.
  • FIG. 2C also shows the same portion, with the applied torque area (i.e., the area of the trailing tooth that engages the belt) highlighted with shading.
  • the torque area is also a two- dimensional area, a plan view viewed longitudinally, of the area of the leading tooth configured to engage with a tooth of a belt.
  • FIGS. 3 A, 3B and 3C show a portion of a sprocket with debris shedding elements or features.
  • FIGS. 3A, 3B and 3C show a portion of a sprocket having debris shedding features, the portion shown in FIGS. 3A, 3B and 3C including two adjacent teeth 310, one of the teeth 310 being a trailing tooth 304 and the other tooth 310 being a leading tooth 305, based on the direction of rotation indicated by the arrow.
  • Each of the teeth 310 has a tip 312 and a side wall 316.
  • a flange 330 is present between the teeth 310, the flange 330 having a concave channel 332 that provides fluid and particulate flow from one side of the flange 330 to the other.
  • This configuration also includes a symmetrical debris shedding element 340 (indicted with cross-hatch), which is a fully chamfered area of the land, present as a concave indent into the land, to the point that a minimal amount of land or tooth root is evident in the structure; that is, there is no (0 mm) radial surface area where the tooth root would be (where the wall 316 meets the land) or the flange 330.
  • a symmetrical debris shedding element 340 (indicted with cross-hatch), which is a fully chamfered area of the land, present as a concave indent into the land, to the point that a minimal amount of land or tooth root is evident in the structure; that is, there is no (0 mm) radial surface area where the tooth root would be (where the wall 316 meets the land) or the flange 330.
  • the total radial support area for engaging with a belt tooth is highlighted via shading; this support area is three-dimensional, encompassing the tooth tip 312 and the side walls 316. No evident portion of the tooth root or the land is highlighted, as any area that would be an engagement or support area is removed by the chamfered area forming the debris shedding element 340; however, a slight area of the radial support may be due to the tooth root, depending on the point of transition between the tooth side wall and tooth root.
  • the tooth tip 312 is indicated as support area.
  • FIG. 3B shows the same portion of the sprocket as FIG. 3A, with the engagement surface (shown shaded in FIG. 3A) now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area is only present as laterally extending narrow strips proximate the tooth tips 312, representing only approximately 16 mm 2 , which is insufficient to provide proper belt tooth engagement.
  • the large chamfered area forming the debris shedding element 340 eliminate belt tooth support, the decreased support results in increased chordal action.
  • FIG. 3C also shows the same portion, with the applied torque area (i.e., the area of the leading tooth that engages the belt tooth) highlighted with shading.
  • applied torque area i.e., the area of the leading tooth that engages the belt tooth
  • FIGS. 4A and 4B Through FIGS. 8 A and 8B and also in FIGS. 9A-9D.
  • FIGS. 4A and 4B show a portion of a sprocket having debris shedding features, the portion shown in FIGS. 4A and 4B being two adjacent teeth 410 and a land 420 therebetween, one of the teeth 410 being a trailing tooth 404 and the other tooth 410 being a leading tooth 405 based on the direction of rotation indicated by the arrow.
  • Each of the teeth 410 has a tip 412, a base or root 414 proximate the land 420 and a side wall 416 connecting the tip 412 and the root 414.
  • a flange 430 is present between the teeth 410, the flange 430 having a concave channel 432 that provides debris flow (e.g., fluid and particulate flow) from one side of the flange 430 to the other.
  • This configuration also includes a debris shedding element 440 (shown in cross-hatch), which includes a chamfered area of the land 420, extending concavely in from the edge of the sprocket; the surface of the channel 432 is also shown as a portion of the debris shedding element 440, as the channel 432 allows lateral debris flow.
  • the total tooth support area for engaging with a belt tooth is highlighted with shading; this support area is three-dimensional, encompassing all of the tooth base or root 414, the side walls 416, and the portion of the land 420 that does not have the chamfered area.
  • the tooth tip 412 is indicated as support area.
  • FIG. 4B shows the same portion as FIG. 4A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area resembles single sided, outwardly facing brackets, having a longitudinal portion and two lateral portions on each side of the flange; this radial tooth support area is approximately 31 mm 2 .
  • FIGS. 5A and 5B show a portion of another sprocket having debris shedding features (shown in cross-hatch), the portion shown in FIGS. 5A and 5B being two adjacent teeth 510 and the land 520 therebetween, one of the teeth 510 being a trailing tooth 504 and the other tooth 510 being a leading tooth 505 based on the direction of rotation indicated by the arrow.
  • Each of the teeth 510 has a tip 512, a base or root 514 proximate the land 520 and a side wall 516 connecting the tip 512 and the root 514.
  • a flange 530 is present between the teeth 510, the flange 530 having a concave channel 532 that provides lateral fluid and particulate flow from one side of the flange 530 to the other.
  • This configuration also includes angular debris shedding elements 540a, 540b, one of the elements 540a, 540b proximate each of the teeth 510.
  • the total tooth support area for engaging with a belt tooth is highlighted via shading; this support area is three-dimensional, encompassing all of the tooth base or root 514, the side walls 516, and the portion of the land 520 that does not have the debris shedding elements 540.
  • the tooth tip 512 is indicated as support area.
  • FIG. 5B shows the same portion as FIG. 5A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area has two laterally extending narrow strips as well as a longitudinally extending strip on each side of the flange 530, the lateral and longitudinal strips not connected, due to the angular debris shedding elements 540.
  • This radial tooth support area is approximately 25 mm 2 .
  • FIGS. 6A and 6B show a portion of another sprocket having debris shedding features, the portion shown in FIGS. 6A and 6B being two adjacent teeth 610 and a land 620 therebetween, one of the teeth 610 being a trailing tooth 604 and the other tooth 610 being a leading tooth 605 based on the direction of rotation indicated by the arrow.
  • Each of the teeth 610 has a tip 612 and a side wall 616; in this design, only the leading tooth 605 has a base or root 614 proximate the land 620, for reasons described below.
  • a flange 630 is present between the teeth 610, the flange 630 having a concave channel 632 that provides lateral fluid and particulate flow from one side of the flange 630 to the other.
  • This configuration includes an asymmetrical debris shedding element that includes an angular cutout area 640 (indicated in cross-hatch) proximate the trailing tooth 604, the area 640 occupying the entire distance from the outer edge of the tooth 604 to the flange 630, thus eliminating any base or root on that tooth 604.
  • the total tooth support area for engaging with a belt tooth is highlighted via shading; this support area is three-dimensional, encompassing all of the tooth base or root 614, the side walls 616, and the portion of the land 620 that does not have the angular cutout area 640.
  • the tooth tip 612 is indicated as support area.
  • FIG. 6B shows the same portion as FIG. 6A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area has laterally extending narrow strips as well as half of a single-sided bracket on each side of the flange 630; the half bracket and the lateral strip are not connected, due to the angular cutout area 640.
  • This radial tooth support area is approximately 26 mm 2 .
  • FIGS. 7A and 7B show a portion of another sprocket having debris shedding features, the portion shown in FIGS. 7A and 7B being two adjacent teeth 710 and a land 720 therebetween, one of the teeth 710 being a trailing tooth 704 and the other tooth 710 being a leading tooth 705 based on the direction of rotation indicated by the arrow.
  • Each of the teeth 710 has a tip 712, a base or root 714 proximate the land 720 and a side wall 716 connecting the tip 712 and the root 714.
  • a flange 730 is present between the teeth 710, the flange 730 having a concave channel 732 that provides fluid and particulate flow from one side of the flange 730 to the other.
  • This configuration also includes a fully chamfered debris shedding element 740 (shown in cross-hatch), where no land or tooth root are evident in the structure, and that includes the surface of the channel 732.
  • the structure also includes circumferentially extending radial support wires 750.
  • the total tooth support area for engaging with a belt tooth is highlighted via shading; this support area is three-dimensional, encompassing all of the tooth base or root 714, the side walls 716, and the portion of the land 720 that does not have the debris shedding areas.
  • the tooth tip 712 is indicated as support area.
  • This design also has the longitudinally extending wires 750 as a support area.
  • FIG. 7B shows the same portion as FIG. 7A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area resembles double-sided brackets on each side of the flange 730; this radial tooth support area is approximately 29 mm 2 .
  • FIGS. 8A and 8B show a portion of another sprocket having debris shedding features (shown in cross-hatch), the portion shown in FIGS. 8 A and 8B being two adjacent teeth 810 and a land 820 therebetween, one of the teeth 810 being a trailing tooth 804 and the other tooth 810 being a leading tooth 805 based on the direction of rotation indicated by the arrow.
  • Each of the teeth 810 has a tip 812, a base or root 814 proximate the land 820 and a side wall 816 connecting the tip 812 and the root 814.
  • a discontinuous flange 830 is present on the side wall 816 of each tooth 810; the discontinuity in the flange 830 coincides with a larger channel 822 that extends laterally across the land 820; this channel 822 provides both lateral and radially inward expulsion of debris from between the teeth 810.
  • the total tooth support area for engaging with a belt tooth is highlighted via shading; this support area is three-dimensional, encompassing all of the tooth base or root 814, the side walls 816, and the portion of the land 820 that does not have the debris shedding channel 822.
  • the tooth tip 812 is indicated as support area.
  • FIG. 8B shows the same portion as FIG. 8A, with the same engagement surface now indicated as a radial tooth support area, a two-dimensional measurement.
  • This radial tooth support area has four rectangular regions, one in each quadrant defined by the flange 830 and the channel 822. This radial tooth support area is approximately 46 mm 2 .
  • FIGS. 9A-9D provide four examples of similar designs, all similar to that of FIGS. 4A and 4B, but with different dimensions of land present adjacent the center flange. These figures provide a visual comparison of the designs.
  • the sprocket portion 900 has a trailing tooth 904 and a leading tooth 905 with a center flange 930 extending longitudinally between the teeth and a land 920 present on each lateral side of the flange 930, with a concave portion extending into the land 920 from the side of the flange.
  • These sprocket portions 900 are similar to that shown in FIGS. 4A and 4B.
  • Each of these sprocket portions 900 is based on a sprocket that has a total width of 11.0 mm, with a 1.7 mm wide center flange.
  • FIG. 9A shows a sprocket portion 900A having a 0.15 mm wide land support on either side of the flange 930.
  • FIG. 9B shows a sprocket portion 900B having a 0.65 mm wide land support on either side of the flange 930.
  • FIG. 9C shows a sprocket portion 900C having a 0.9 mm wide land support on either side of the flange 930.
  • FIG. 9D shows a sprocket portion 900D having a 1.25 mm wide land support on either side of the flange 930.
  • Table 1 below, compares the structures of FIG. 9C and FIG. 9D to the structure of FIGS. 2A-2C and FIGS. 3 A-3C, each of the teeth having a theoretical maximum tooth area of about 155 mm 2 .
  • Table 1 includes a measurement for tooth area, debris shedding area, radial tooth support area, and also torque area for these structures.
  • FIGS. 10A, 10B, and 10C generically show these areas.
  • the sprockets of this disclosure have an optimized combination of relief cut features at the sprocket tooth root for debris shedding yet have sufficient radial tooth support area; the two areas are inversely proportional.
  • one suitable sprocket (FIG. 9C) has a tooth area of about 107 mm 2 , thus a debris shedding area of about 43.72 mm 2 , and 27-28 mm 2 radial tooth support area for one pair of teeth; this is based on a 11.0 mm wide sprocket with a center flange that occupies 1.7 mm, with 3.75 mm inset at each side to provide a 0.9 mm support on each side of the center flange.
  • FIG. 9D Another suitable sprocket (FIG. 9D) has a tooth area of about 111.4 mm 2 , about 43.72 mm 2 of debris shedding area and about 31-32 mm 2 radial tooth support area, based on a 11.0 mm wide sprocket with a center flange that occupies 1.7 mm, with 3.4 mm inset at each side to provide a 1.25 mm support on each side of the center flange.
  • These are merely two specific examples, and other designs have a combination of relief cut features at the sprocket tooth root for debris shedding yet have sufficient radial tooth support area to inhibit chordal action.
  • the debris shedding area (between a pair of teeth) is in the range of 35-55 mm 2 and the radial tooth support area is in the range of 25-35 mm 2 .
  • the debris shedding area is in the range of 10.75-13.0 mm 2 per mm width of sprocket, and the radial tooth support area is in the range of 2.7-3.8 mm 2 per mm width of sprocket.
  • a ratio of the debris shedding area to the radial tooth support area is in the range of about 1 : 1 to 3: 1, in other embodiments in the range of about 1.25:1 to 2: 1, or the range of about 1.25 : 1 to 1.75 : 1.
  • the radial tooth support area occupies about 19-28% of the total width of the sprocket, in other embodiments about 19.5-27%, based on a concave debris shedding area, or even about 20-26%.
  • the concave area extends in about 73-81% of the side edge to the central flange, in other embodiments about 74-80%.
  • the sprockets and variations thereof described herein can generally be manufactured using any known and suitable techniques.
  • the sprockets may be machined, molded (e.g., injection molded), die cast, 3D printed.
  • suitable materials for the sprockets and variations thereof include thermoplastic and/or thermoset polymer(s) (e.g., polycarbonate, polyamide, polyethylene, polyphthalamide), including fiber-reinforced polymers, metal (e g., steel, stainless steel, nickel, iron, aluminum, alloys), and composite materials.
  • the sprockets and variations thereof could be molded, cast, 3D printed, or otherwise formed.
  • described herein is at least one specific example of a sprocket having at least one non-continuous flange with a debris-shedding element therein.
  • Spatially related terms including but not limited to, “bottom,” “lower”, “top”, “upper”, “beneath”, “below”, “above”, “on top”, “on,” etc., if used herein, are utilized for ease of description to describe spatial relationships of an element(s) to another.
  • Such spatially related terms encompass different orientations of the device in addition to the particular orientations depicted in the figures and described herein. For example, if a structure depicted in the figures is turned over or flipped over, portions previously described as below or beneath other elements would then be above or over those other elements.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Gears, Cams (AREA)

Abstract

L'invention concerne un pignon ayant un élément d'évacuation des débris entre des dents adjacentes de mise en prise avec la courroie, les dents des pignons ayant une surface radiale accrue conçue pour venir en prise avec les dents d'une courroie dentée. Les conceptions de pignon utilisent une variété d'approches combinées pour maximiser l'évacuation des débris tout en réduisant également au minimum l'action à la corde du fait d'un support des dents de courroie insuffisant. Les conceptions réduisent également au minimum le bruit du système et prolongent la durée de vie de la courroie.
PCT/US2024/051726 2023-10-17 2024-10-17 Pignon à surface de support accrue Pending WO2025085602A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202363591044P 2023-10-17 2023-10-17
US63/591,044 2023-10-17

Publications (1)

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WO2025085602A1 true WO2025085602A1 (fr) 2025-04-24

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030104889A1 (en) * 2001-11-30 2003-06-05 Redmond John D. Idler sprocket
US6666786B2 (en) * 2000-12-29 2003-12-23 Shimano Inc. Chamfered sprocket assembly
US20110049831A1 (en) * 2009-09-01 2011-03-03 Lumpkin Wayne R Belt Drive System
US20150298912A1 (en) * 2005-01-19 2015-10-22 Thermodrive Llc Low friction, direct drive conveyor belt
US20160059931A1 (en) * 2014-09-01 2016-03-03 Shimano Inc. Bicycle sprocket and bicycle sprocket assembly
US9625027B2 (en) * 2014-04-08 2017-04-18 Wolf Tooth Components, LLC Sprocket
US20180195598A1 (en) * 2017-01-12 2018-07-12 Shimano Inc. Bicycle rotor
US20210231208A1 (en) * 2020-01-23 2021-07-29 Cnh Industrial America Llc Sprocket for agricultural vehicle

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6666786B2 (en) * 2000-12-29 2003-12-23 Shimano Inc. Chamfered sprocket assembly
US20030104889A1 (en) * 2001-11-30 2003-06-05 Redmond John D. Idler sprocket
US20150298912A1 (en) * 2005-01-19 2015-10-22 Thermodrive Llc Low friction, direct drive conveyor belt
US20110049831A1 (en) * 2009-09-01 2011-03-03 Lumpkin Wayne R Belt Drive System
US9625027B2 (en) * 2014-04-08 2017-04-18 Wolf Tooth Components, LLC Sprocket
US20160059931A1 (en) * 2014-09-01 2016-03-03 Shimano Inc. Bicycle sprocket and bicycle sprocket assembly
US20180195598A1 (en) * 2017-01-12 2018-07-12 Shimano Inc. Bicycle rotor
US20210231208A1 (en) * 2020-01-23 2021-07-29 Cnh Industrial America Llc Sprocket for agricultural vehicle

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