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
  • F16H55/32—Friction members
  • F16H55/36—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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D41/00—Freewheels or freewheel clutches
  • F16D41/20—Freewheels or freewheel clutches with expandable or contractable clamping ring or band
  • F16D41/206—Freewheels or freewheel clutches with expandable or contractable clamping ring or band having axially adjacent coils, e.g. helical wrap-springs

Definitions

• This invention relates generally to devices in the over-running clutch field, and more specifically to an improved over-running clutch pulley for use with an accessory device driven by an automotive engine with a belt drive.
• a drive belt is typically used to power and operate various accessory devices.
• One of these accessory devices is typically an automotive alternator, which provides electrical power to the automobile.
• the serpentine arrangement which drives several accessory devices, is currently most favored.
• Serpentine arrangements typically include a drive pulley connected to the crankshaft of the engine (the “output device") and a drive belt trained about the drive pulley.
• the drive belt is also trained about one or more conventional driven pulleys, which are connected to the input shafts of various accessories devices (the "input device").
• the drive belt may experience many instances of sudden deceleration relative to the input shaft. This situation may occur, for example, during a typical shift from first gear to second gear under wide open throttle acceleration. This situation is worsened if the throttle is closed or "back off immediately after the shift. In these situations, the drive belt decelerates very quickly while the driven pulley, with the high inertia from the accessory device, maintains a high rotational speed, despite the friction between the drive belt and the driven pulley.
• the drive belt may experiences other situations that cause audible vibration and undue wear.
• a serpentine arrangement with conventional driven pulleys may be used with an automobile engine that has an extremely low idle engine speed (which may increase fuel economy).
• the arrangement typically experiences "belt flap" of the drive belt as the periodic cylinder firing of the automotive engine causes the arrangement to resonate within a natural frequency and cause an audible vibration and an undue wear on the drive belt.
• the disadvantage of the conventional driven pulleys namely the audible squeal, the undue wear, and the vibration of the drive belt, may be avoided by the use of an over-running clutch pulley instead of the conventional driven pulley.
• An over-running clutch pulley allows the pulley to continue to rotate at the same rotational speed and in a same rotational direction after a sudden deceleration of the drive belt.
• the over-running clutch pulley functions like the rear hub of a typical bicycle; the rear hub and rear wheel of a conventional bicycle continue to rotate at the same rotational speed and in the same rotational direction even after a sudden deceleration of the pedals and crankshaft of the bicycle.
• An example of an over-running clutch pulley is described in U.S. Patent No. 5,598,913 issued to the same assignee of this invention and hereby incorporated in its entirety by this reference.
• This invention provides an over-running clutch pulley with a closed clutch cavity, which is intended to increase wear resistance while minimizing the costs and weight.
• FIG. 1 is a perspective view of an over-running clutch pulley of the invention, shown with a drive belt as the input device and a cylindrical shaft as the output device;
• FIG. 2 is a partial cross-section view, taken along the line 2-2 of FIG. 1 , of the overrunning clutch pulley of a first preferred embodiment
• FIG. 3 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley of a second preferred embodiment
• FIG. 4 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley of a third preferred embodiment
• FIG. 5 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley of a fourth preferred embodiment.
• FIG. 6 is a partial cross-section view, similar to FIG. 2, of the over-running clutch pulley of a fifth preferred embodiment.
• the invention includes an over-running clutch pulley 10 for rotationally engaging an input device 12 and an output device 14.
• the over-running clutch pulley 10 has been designed for use with a drive belt 16 as the input device 12, and with a cylindrical shaft 18 as the output device 14. More specifically, the over-running clutch pulley 10 has been particularly designed for use with a drive belt 16 with a grooved surface and a cylindrical shaft 18 of an automotive alternator.
• the over-running clutch pulley 10 may be used, however, in other environments, with other suitable input devices, such as smooth belt, a toothed belt, a V- shaped belt, or even a toothed gear, and with other suitable output devices, such as a polygonal shaft.
• the over-running clutch pulley 10 may be used in an environment with two devices that alternate their rotational input responsibilities, and in an environment with an "output device” that actually provides rotational input and with an "input device” that actually receives rotational input.
• the terms “input device” and “output device” are interchangeable.
• the over-running clutch pulley 10 of the preferred embodiment includes a sheave member 20, a hub member 22 located substantially concentrically within the sheave member 20, a bearing member 24, a sealing member 26, and a clutch member 28, which cooperate to rotationally engage the drive belt and the cylindrical shaft.
• the sheave member 20 preferably includes a sheave input section 30 adapted to the engage the input device, and a sheave clutch section 32 defining a sheave clutch surface 34.
• the hub member 22 preferably includes a hub output section 36 adapted to engage the output device, and a hub clutch section 38 defining a hub clutch surface 40.
• the bearing member 24 preferably positions the sheave member 20 and the hub member 22 such that the sheave member 20 and the hub member 22 define a radial gap 42.
• the sheave input section 30 of the sheave member 20 of the preferred embodiment functions to engage the drive belt.
• the sheave input section 30 preferably defines a sheave input surface 46 with two sheave input shoulders 48 and at least one sheave input groove 50.
• the sheave input section 30 may alternatively define other suitable surfaces, such as toothed surfaces or ribbed surfaces, to engage the input device.
• the sheave input surface 46 is preferably outwardly directed (away from the rotational axis of the over-running clutch pulley 10) and is preferably substantially cylindrically shaped.
• the sheave input section 30 is preferably made from conventional structural materials, such as steel, and with conventional methods, but may alternatively be made from other suitable materials (as described below) and from other suitable methods.
• the hub output section 36 of the hub member 22 of the preferred embodiment functions to engage the cylindrical shaft.
• the hub output section 36 preferably defines a hub output surface 52 with a smooth section 54 (which functions to ease and center the assembly of the over-running clutch pulley 10 onto the cylindrical shaft), a threaded section 56 (which functions to substantially prevent rotation and to axially retain the hub member 22 to the cylindrical shaft), and a hexagonal section 58 (which functions to mate with an alien wrench for easy tightening and loosening of the over-running clutch pulley 10 onto and off of the cylindrical shaft).
• the hub output section 36 may include other suitable devices or define other surfaces to prevent rotational and axial slippage, to engage the cylindrical shaft, and to engage a tool for tightening or loosening the over-running clutch pulley 10 onto and off of the cylindrical shaft.
• the hub output surface 52 is preferably inwardly directed (toward the rotational axis of the overrunning clutch pulley 10) and is preferably substantially cylindrically shaped.
• the hub output section 36 is preferably made from conventional structural materials, such as steel, and with conventional methods, but may alternatively be made from other suitable materials (as described below) and from other suitable methods.
• the sheave clutch section 32 and the hub clutch section 38 of the preferred embodiment function to provide the sheave clutch surface 34 and the hub clutch surface 40, respectively, for the engagement with the clutch member 28.
• the sheave clutch section 32 preferably extends radially inward from the sheave member 20. In this manner, the sheave clutch section 32 is preferably made from the same material and with the same methods as the sheave input section 30, but may alternatively be made from other suitable materials and with other suitable methods.
• the hub clutch section 38 preferably extends radially outward from and axially over the hub output section 36. In this manner, the hub clutch section 38 is preferably made from the same material and with the same methods as the hub output section 36, but may alternatively be made from other suitable materials and with other suitable methods.
• the sheave clutch surface 34 and the hub clutch surface 40 are located substantially adjacent with an axial gap 60 between each other.
• the sheave clutch surface 34 and the hub clutch surface 40 are preferably inwardly directed (toward the rotational axis of the over-running clutch pulley 10) and are preferably substantially cylindrically shaped.
• the sheave clutch surface 34 and the hub clutch surface 40 preferably have a similar radial diameter, a similar axial length, and a similar smooth finish. These features allow optimum performance of the clutch member 28.
• the sheave clutch surface 34 and the hub clutch surface 40 may alternatively have differences with each other on these, or other, design specifications.
• the bearing member 24 In addition to positioning the sheave member 20 and the hub member 22 such that the sheave member 20 and the hub member 22 define the radial gap 42 and the axial gap 60, the bearing member 24 also functions to allow relative rotational movement of the sheave member 20 and the hub member 22.
• the bearing member 24, which is preferably a rolling element type, preferably includes an outer race element 62 preferably press-fit mounted on the sheave member 20, an inner race element 64 preferably press-fit mounted on the hub member 22, ball bearing elements 66 preferably located between the outer race element 62 and the inner race element 64, and bearing seals 68 preferably extending between the outer race element 62 and the inner race element 64 on either side of the ball bearing elements 66.
• the bearing member 24 may alternatively omit the bearing seal 68 facing the clutch member 28 if the over-running clutch pulley 10 uses a grease material compatible with the bearing member 24 and the clutch member 28.
• the bearing member 24 may alternatively be of other suitable types, such as a journal bearing or a roller bearing, may alternatively include other suitable elements, such as a so-called "slinger" shield 69 to prevent direct impingement of water or contaminants, and may alternatively be mounted in other suitable manners.
• the bearing member 24 is a conventional device and, as such, is preferably made from conventional materials and with conventional methods, but may alternatively be made from other suitable materials and with other suitable methods.
• the axial gap 60 and the radial gap 42 are interconnected, which function to substantially prevent contact between the sheave member 20 and the hub member 22.
• the sealing member 26, which is preferably located within the radial gap 42, preferably functions to substantially prevent passage through the radial gap 42 of any fluid, namely a grease material (not shown) located in the closed clutch cavity 44 and subjected to centrifugal forces during the operation of the over-running clutch pulley 10.
• the sealing member 26 also functions to allow relative rotational movement of the sheave member 20 and the hub member 22.
• the sealing member 26 is a four-lobed O-ring 70 made from a conventional material and with conventional methods.
• the sealing member 26 is any suitable device made from any suitable material and with any suitable method that substantially prevents leakage of a fluid from the closed clutch cavity 44 while simultaneously allowing relative rotational movement of the sheave member 20 and the hub member 22.
• the hub clutch section 38 defines a hub outboard cavity 72 that functions to substantially contain the sealing member 26. Because of the nature of the hub outboard cavity 72, centrifugal forces on the sealing member 26 tend to further increase the ability of the sealing member 26 to substantially prevent passage of any fluid through the radial gap 42.
• both the sheave member 20 and the hub member 22 may define portions of a gland that functions to substantially contain the sealing member 26.
• the clutch member 28 of the preferred embodiment functions to engage the sheave clutch surface 34 and the hub clutch surface 40 upon the acceleration of the sheave member 20 in a first rotational direction relative to the hub member 22, and to disengage the sheave clutch surface 34 and the hub clutch surface 40 upon the deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22.
• the clutch member 28 is a coil spring 74.
• the coil spring 74 which is made from conventional materials and with conventional methods, accomplishes the above features by the particular size and orientation of the coil spring 74 within the closed clutch cavity 44.
• the clutch member 28 may include other suitable devices that accomplish the above features.
• the coil spring 74 is preferably designed with a relaxed spring radial diameter that is sized slightly greater than an inner diameter of the sheave clutch surface 34 and the hub clutch surface 40.
• the coil spring 74 frictionally engages with and exerts an outward force on both the sheave clutch surface 34 and the hub clutch surface 40.
• the coil spring 74 is preferably oriented within the closed clutch cavity 44 such that the coils extend axially in the first rotational direction from the sheave clutch surface 34 to the hub clutch surface 40. With this orientation, relative rotational movement of the sheave member 20 and the hub member 22 will result in an unwinding or winding of the clutch member 28.
• acceleration of the sheave member 20 in the first rotational direction relative to the hub member 22 will bias an unwinding of the coil spring 74 and deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22 will bias a winding of the coil spring 74.
• the unwinding of the coil spring 74 tends to increase the outward force of the coil spring 74 on the sheave clutch surface 34 and the hub clutch surface 40, thereby providing engagement, or "lock", of the sheave member 20 and the hub member 22.
• This engagement condition preferably occurs upon the acceleration of the sheave member 20 in the first rotational direction relative to the hub member 22.
• the winding of the coil spring 74 tends to decrease the outward force of the coil spring 74 on the sheave clutch surface 34 and the hub clutch surface 40, thereby allowing disengagement, or "slip", of the sheave member 20 and the hub member 22.
• This disengagement condition preferably occurs upon the deceleration of the sheave member 20 in the first rotational direction relative to the hub member 22.
• the coil spring 74 will lightly rub across the sheave clutch surface 34 or the hub clutch surface 40, which may cause wear of these surfaces.
• the coil spring 74 will forcefully engage with the sheave clutch surface 34 and the hub clutch surface 40, which may also cause wear of these surfaces.
• the sheave clutch surface 34 and the hub clutch surface 40 are preferably formed or treated to have a sufficient surface hardness value.
• the sheave member 20 includes a sheave collar section 76 defining a sheave collar surface 78, and the hub clutch section 38 defines a hub flange surface 80.
• the sheave collar section 76 preferably extends radially inward from the sheave input section 30 and adjacent the sheave clutch section 32.
• the sheave collar section 76 preferably extends partially into the closed clutch cavity 44.
• the inboard seal 68 preferably prevents the passage of debris and impurities between the grease material (not shown) for the bearing member 24 and the grease material (not shown) for the clutch member 28.
• the second preferred embodiment as shown in FIG.
• the sheave collar section 76' preferably substantially abuts the hub output section 36 and preferably prevents the passage of debris and impurities between the grease material (not shown) for the bearing member 24 and the grease material (not shown) for the clutch member 28, which allows for the absence of the inboard bearing seal (appropriately not shown).
• the sheave collar surface 78 and the hub flange surface 80 are preferably located on opposite ends of the clutch member 28. In this manner, the sheave collar surface 78 and the hub flange surface 80 cooperate to insure the proper placement of the clutch member 28 within the closed clutch cavity 44.
• the over-running clutch pulley 10 may, of course, use other suitable devices to insure the proper placement of the clutch member 28 within the closed clutch cavity 44. These devices may be surfaces defined by other sections of the sheave member 20 or the hub member 22, or surfaces defined by other suitable elements.
• the sheave collar section 76 and 76' is integrally formed with the sheave input section 30.
• the sheave clutch section 32 is preferably made from the same material and with the same methods as the sheave input section 30.
• the sheave collar section 76" may be separately formed and later connected to the sheave input section 30, as shown in FIG. 4.
• the sheave collar section 76" is preferably provided as a conventional washer 82 made from conventional materials and with conventional methods, but may alternatively be provided as any suitable device made from any suitable material and with any suitable method.
• the coil spring 74 is preferably positioned over the axial gap 60.
• the axial gap 60 is preferably less than 0.75 of a spring coil thickness of an individual spring coil. Further, because the contact between the sheave member 20 and the hub member 22 could cause undue wear, the axial gap 60 is preferably greater than 0.25 of the spring coil thickness to allow for normal flexing and dimensional variations of the over-running clutch pulley 10.
• the axial gap 60 may be greater than 0.75 or less than 0.25 of the spring coil thickness if other suitable devices or methods are used to substantially prevent undue wear caused by contact between the sheave member 20 and the hub member 22 and to substantially prevent jams and wear caused by an individual spring coil into the axial gap 60.
• the sheave input section 30 in the fourth preferred embodiment defines a sheave inboard gland 84 adapted to substantially collect and contain fluid from the axial gap 60.
• the fluid namely the grease material (not shown) for the clutch member 28, may be contaminated with debris particles created from wear between the clutch member 28 and sheave clutch surface 34 and the hub clutch surface 40. Since the debris particles are typically heavier than the grease material, providing the sheave inboard gland 84 allows centrifugal forces on the over-running clutch pulley 10 to pull the debris particles away from the clutch member 28, thereby reducing undue wear of the clutch member 28, the sheave clutch surface 34, and the hub clutch surface 40.
• the hub clutch section 38' in the fifth preferred embodiment defines a hub inboard gland 86, which functions like the sheave outboard gland of the fourth preferred embodiment.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Pulleys (AREA)
• Mechanical Operated Clutches (AREA)
• Transmissions By Endless Flexible Members (AREA)
• Sealing Devices (AREA)
• Transmission Devices (AREA)
• One-Way And Automatic Clutches, And Combinations Of Different Clutches (AREA)
• Lubricants (AREA)

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• 2001
  • 2001-05-28 EP EP01939729A patent/EP1208314A1/de not_active Withdrawn
  • 2001-05-28 WO PCT/US2001/017514 patent/WO2001092745A1/en not_active Application Discontinuation
  • 2001-05-28 JP JP2002500122A patent/JP2003535281A/ja active Pending
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  • 2001-05-31 EP EP01941714A patent/EP1208318A4/de not_active Withdrawn
  • 2001-05-31 EP EP01946024A patent/EP1208315A4/de not_active Withdrawn
  • 2001-05-31 EP EP01941715A patent/EP1208312A1/de not_active Withdrawn
  • 2001-05-31 WO PCT/US2001/017430 patent/WO2001092741A1/en not_active Application Discontinuation
  • 2001-05-31 WO PCT/US2001/017462 patent/WO2001091938A1/en not_active Application Discontinuation
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  • 2001-05-31 EP EP01939683A patent/EP1208310A4/de not_active Withdrawn
  • 2001-05-31 WO PCT/US2001/017639 patent/WO2001092740A1/en not_active Application Discontinuation
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