Gear-driven balance shaft apparatus with backlash control

An apparatus for controlling reaction comprising an intermediate gear coupling capable mesh adjustable between a first drive gear and a second driven gear, and a support body rotatably idler gear and capable of movement in a direction that reduces the center distance between the intermediate gear and either the first gear, second gear, or both. Body movement uses both resilient biasing elastic hysteresis damping to provide adequate light polarization while fortified against quick retraction or repulsion.

Cross Reference to Related ApplicationsThis application claims priority from Provisional Patent Application U.S. No. 60/694, 352 filed June 27, 2005, which is incorporated herein by reference.
Balance shafts that are used to counter cyclical forces mass waving rotary piston engine and are required to maintain timing relationships substantially fixed angle with the engine crankshaft. Transmissions chain and gear sets are both capable of this functionality, but both have problems of acoustic emission when it comes to do the job alone. Timing belts are viable, but generally do not meet the application requirements.Drive Systems Challenges of string "String" only have automatic tensioners typically required to accommodate a lifetime of wear components can comfortably handle the distance between work centers (hereinafter "wheelbase") variations challenge gear sets, but carry acoustic emission problems of their own. Inherent in any chain drive system is the movement called chordal action polygonal or engagement with segmented chain sprockets, which is exaggerated in the case of the smaller, lower toothcount sprockets. Excitations meshing become more severe with the square of increases in speed of the chain, as radial displacements and tangential velocity variations of chordal action be compressed into time frames increasingly stringent. A 2:01 step-up system of a single stage axle equilibrium rate transmission chain with 2:01 difference in tooth numbers is acoustically challenged by high chordal action driven sprocket relatively "poor "which is combined with the high speeds of the string associated with its much larger drive gear (crankshaft). The chain meshing engine forces excite structures, often resulting in audible emissions."Alone Game Gear" Challenges-In the case of gear trains connecting direct drive apparatus with balance shaft drive gear mounted on the crankshaft, the main engineering challenge is to manage the substantial variations in the center distance gears imposed by differential thermal expansion effects, tolerance stack-ups, and the movement of the crankshaft. The result of the change in the distance between the center of arts of a variation in the reaction, and the cleaning operation, coupling between teeth.Insufficient clearance (forced tight mesh) greatly increased meshing results in noise (or "ringing"), and the risk of fatigue of the tooth due to large cantilevered bending loads imposed by the wedging of the teeth together engaged. Permit excessive play magnitudes sufficient magnitude tooth gap under ubiquitous crankshaft torsional accelerations as to result in locking tooth impact energy is large enough to overcome the effects of oil film damping, resulting from unpleasant emissions acoustic (or "rattle").
Oil film damping effects are maximized gear geometry and alignment controls operation ensuring high values ​​of total effective contact ratio (the actual average of the teeth in contact, hereinafter called "contact ratio"). Low viscosity oils with current and elevated operating temperatures, however, the energy associated with locking tooth excessive play can overwhelm the energy absorbing capacity of the damping effects optimized oil film. The variations of the distance from the center of the thermal effects associated with contemporary engines alone are so large as to incur backlash changes that compromise the acoustic performance of the transmission gear train directly under conventional thermal operating ranges common.Scissors gears and called Vernier gear systems have been used to drive anti-lash in the case of relatively low speed, allowing the mesh packing space and cost constraints, but the gasoline engine crankshafts modern high speed not among these cases. The drawbacks of scissors gear meshing are known to include noise, durability, and high manufacturing cost. Meshing noise arises from the high loads of teeth accompanying elastic load two to two side-by-side (or "split") items of gear, and is exacerbated by contacting relationship commitments resulting from the division of the packaging space required for these gear elements side by side. Durability challenges posed by the abnormally high tangential tooth load needed to transmit directly the moments of inertia torsional vibration imposed on gear sets, in conjunction with packing narrow space-issued gear elements. Substantial manufacturing costs arising from the extreme accuracy required for locating and control element offset biasing gear with respect to the fixed element, and high property demands placed material by high shear loads teeth.Accordingly, a need exists for methods of the invention practical and cost effective and control structures of the reaction apparatus crankshaft balance shaft gear sets in a wide range of operating temperatures, without invoking the noise, durability, and manufacturing cost associated with the complexity compromises, tooth loading and packing swap space and scissors gear units comprise vernier.
Therefore, disclosed herein is the use of at least one motion control device that uses both hysteresis and resilient urging (or viscous) buffer, preferably in conjunction with the capture of the hydraulic fluid pressure as provided by the lubrication system of a host motor, to provide appropriately polarized light resistance of an intermediate gear, to a crank gear, and preferably also a coupling gear, the elastic load is fortified against rapid retraction and repulsion idler Crankshaft gear outside the hysteresis or viscous damping and / or capture fluid.
The invention may take physical form in certain parts and arrangements of parts with various embodiments described in detail herein and illustrated in the accompanying drawings in which:. Figure 1 is a first embodiment of an apparatus for controlling the reaction.. 2 is second embodiment of an apparatus for controlling reaction.. 3 is third embodiment of an apparatus for controlling reaction.. Figure 4 is a fourth embodiment of an apparatus for reaction control.. Figure 5 is a fifth embodiment of an apparatus for reaction control.. Figure 6 is a sixth embodiment of an apparatus for controlling the reaction.. Figure 7 is a seventh embodiment of an apparatus for controlling the reaction.. 8 is a eighth embodiment of an apparatus for the control reaction, which is currently the preferred embodiment.. 9 is a ninth embodiment of an apparatus for reaction control.. 10 is a tenth embodiment of an apparatus for controlling the reaction.. 11 is an eleventh embodiment of an apparatus for reaction control.. 12 is a twelfth embodiment of an apparatus for controlling the reaction.. 13 is a thirteenth embodiment of an apparatus for controlling the reaction.
Referring now to the drawings, which show various embodiments of the invention only for the purpose of illustration and not for purposes of limiting same, an apparatus for controlling reaction generally comprises an intermediate gear coupling capable of adjustably engaged between first drive gear and preferably also a second gear engaged, and a body rotatably supporting the intermediate gear in which the body is able to support the intermediate gear movement is adjustably engaged with the first gear engagement and preferably also the second gear.While the present invention can be used to minimize noise in many gear ratios, the preferred embodiment utilizes the invention with the balance shafts used in automotive applications. A common problem associated with balance shafts is a noise known as "gear rattle" that occur in the engine idling. Gear rattle occurs when the teeth of the timing gears lose balance shaft to re-establish contact with contact impact. Such a loss of contact is caused by a fluctuation in the speed of the crankshaft between the firing pulses of the successive cylinders. Obviously you want to remove this rattle noise art.As known in the art, the pair of balancer shafts can be carried in a housing below the crankshaft and oppositely rotated at twice crankshaft speed for generating a stirring force vertical offsetting forces inherent engine waving . One of the pair of balance shafts are typically driven by a gear or chain from the engine crankshaft while the other balance shaft is typically connected to reverse rotation by a pair of timing gears. A single balance shaft driven by the crankshaft is also known. It should be clear that the invention can be successfully used for any application in which it seeks to reduce the gear noise.With reference to FIG. 8, the presently preferred embodiment of the invention, the apparatus for the control reaction is described as follows. For simplicity, throughout the drawings like elements are referred to by numbers as elements. The apparatus 10 generally comprises a pulley or idler gear 15 rotatably supported by a shaft 20 about an axis 25. The intermediate gear 15 is of any size, and includes gear teeth to maintain proper gear ratio between the crankshaft gear 30 and the coupling gear 35. Similarly, the crankshaft gear 30 and the coupling gear 35 may be of any size and include gear teeth as any preferred configuration. As such, the idler is urged into engagement with both crank gear 30 and the coupling gear 35 to provide the appropriate clearance fit.As shown in the figure. 8, the body 20 may pivot about the eccentric link 45 which in turn is pivotable about a fixed axis 40. The two links (link 25,45 and 45,40) are preferably angled center distances from each other in order to provide two degrees of freedom for mobility intermediate gear 15 as it rotates about its axis 25. Intermediate gear 15 is free to seek minimum proximity gap both crankshaft gear 30 and gear coupling 35 by minimizing the distances from the center to each independently. Furthermore, for more compact package size, the pivot structure to the body 20 can be reversed, in which the shaft 25 is replaced with a link linking the cam eccentric 45 is replaced with only a fixed axis.A motion control device 50 preferably utilizes the functionality of a so-called "slack adjuster", as known, for example, to maintain the operating clearance valvetrains consisting internal combustion engine and is used herein to maintain close proximity of the gear teeth engagement, whereas substantial rigidity manifests against the load applied cyclical or intermittent rapidly acting to separate the coupling elements of gear. The motion control device 50 therefore acts as a ratchet preferably hydraulic auto-relaxing to strongly resist compression load transient without strongly urging the gears complementary.Such movement control device 50, hereinafter referred to as a "slack adjuster" and is shown in Fig. 1 preferably comprises a pressure transfer member movable seal or piston 55 which by its movement varies the captured volume of a hydraulic fluid or oil in a substantially rigid capture space 60. Oil is introduced under pressure from a fluid supply and pump system 67 in the capture space 60 by at least one opening 63 which preferably comprises at least one one-way valve or check valve 70 to resist oil leakage from capture space 60. . Figure 1 shows a unified configuration simple, but it is understood that conventional configurations having axially movable cylindrical bodies caught tightly adjacent deck structures can be used.The oil pressure acts to move the fluid in the capture space 60 beyond the check valve 70 is preferably controlled to be, consisting substantially lower value (for example, with less variation in engine speed and oil temperature) that the pump system 67, through the series combination of the invention, upstream of the valve lash adjuster in the lash adjuster 70, a restriction orifice or metering 65, upstream a pressure control valve normally passes or not the bypass valve 75. A device for regulating the upstream pressure, an example of which is shown in Fig. 1 is preferably designed to ensure that the operating pressure of the oil supply to be filled and refilled capturing space lash adjuster, is kept substantially constant in all operating conditions so as not to induce forced tight mesh meshing noise and the resulting cold and / or operating conditions of high speed when the oil pressure system of the motor 67 tends to be high, as regulated bypass valve 69 of the engine oil pump. As such, the upstream metering orifice and the bypass valve should return to normal feed pressure lash adjuster in the engine oil system 67, to near the low pressure of operation of motor 69, which occurs at the idle speed, when the outflow of the pump is at least in conditions of high operating temperature, when the oil viscosity is too close to its minimum. Physical proportions of a bypass valve lash adjuster such are atypical with hot idle system pressures in the order of 250 kPa, it takes a combination of spring pressure unusually light valve area unusually large enough to allow relief pressures of this magnitude.The piston 55 of the lash adjuster 50 is preferably also resiliently biased by a biasing member or spring 80 so that the slack adjusting function is maintained during times when the motor 69 stops and the oil pressure from said pump system 67 is poor. The piston 55 (or alternatively the body of an axially movable valve adjuster) is mobile communication jointly with the intermediate gear 15 so that its strength and pressure transfer urging action to substantially eliminate play between the intermediate gear 15 and the gear Crankshaft 30 and preferably also the coupling gear 35 without strongly urging the gears together (to reduce the distance to the center), and support considerable rigidity against rapid separation of the gears (towards a greater distance between axis) and greater slack. Hysteresis damping is above, in the preferred case of a device type lash adjuster oil capture of viscous resistance to leakage outside the capture space 60, leakage can be limited to that permitted past the clearance diameter piston and check valve, or may be augmented by a restricted flow passage or hole-resistance for a faster response to the mobility of the crankshaft, etc.With the lash adjuster spring 80 preferably be, for its design, which is able to maintain backlash gear intermediate gear 15 and the crankshaft sprocket 30, drive minimizing hydraulic lash adjuster preferably not to contribute further further meshing noise. This minimization of hydraulic bias depends in part on the plunger surface and partly on the constancy of the supply pressure above valve adjuster re-regulated.At least six basic categories defined kinematic structures in conjunction with the use of at least one adjuster flanges 50 to minimize the introduction of reaction without excessive radial load between gears (forced tight mesh), the first two can be grouped in the classification of two-degrees-of-freedom motion control, while the remaining four can be grouped into the classification of motion control of a single degree of freedom.The devices of the kind of two degrees of freedom allows two screens, for example, intermediate gear 15 with the crankshaft gear 30 and the intermediate gear 15 engaging with the gear of the balance shaft 35, to establish a minimum clearance, while at the same time the kind of degree of freedom allows only a single mesh for establishing minimum clearance, the other being held either as nearly constant as possible, or alternatively being tightened to a moving proportionally mainly directed towards setting the crankshaft gear mesh. Given the substantially greater reaction control challenge posed by the crankshaft gear mesh will be assumed hereinafter that the ability of real-time adjustment provided by the kind of degree of freedom only is applied to the meshing area of ​​the crankshaft, with the coupling gear mesh seating area dependent tighter. The shorter wheelbase and reduced mobility associated with the coupling gear allow pose less of a dilemma of physics as described above for the crankshaft gear.1 Variable Gear Intermediate Category Center. Figure 1 illustrates the simplest architecture apparatus two degrees of freedom to locate the intermediate gear 15 through the body 20 and locking tabs 50. The lash adjuster 50 acts to urge the idler gear 15 which meshes in contact with both the driving crank gear 30 and gear coupling 35 making the resultant force in a direction between the meshes. This category of motion control apparatus enables the intermediate gear 15 to achieve the best fit operating proximity with both of its mating gear, providing rotational centerline intermediate shaft with two degrees of freedom, ie the ability to migrate in any direction within a single plane, such as along path 61 such accurate. Aligning the axes of the gear tooth geometry with respect to one another is critical to the functionality of transmission gears, even more degrees of freedom are inhibited by appropriate structural configuration options.
Control gear idler shaft alignment required with respect to its two mating gears can be ensured by numerous structural arrangements, the simplest of which are captured either parallel surfaces of the body 20 or similar flat capture gear itself, or flat capturing a combination of each type face if necessary to packageability, between adjacent parallel surfaces, as required by the figure. One type configurations. Applying adjuster support tabs 50 to the intermediate gear 15 through the body 20 can be either directly, as illustrated in Fig. 1 wherein the curved surface 57 of piston 55 cooperates with the curved surface 59 of body 20 allowing the body to pivot about a pivot 56, or in conjunction with a rocker structure 87 that pushes the body 20 in the direction appropriate: see fig. 2 as a schematic illustration of a so-called two-bar linkage such.Alternatively, as shown in Fig. 3, a type of tensile strength of body 20 can be withdrawn in the right direction by a lash adjuster 50 or rocker apparatus 87 transfer the force of a lash adjuster 50 as shown in Figure . April. In any case, the two degrees of freedom of the centerline of rotation of the intermediate gear, required for the intermediate gear to be able to freely search minimization reaction at both its meshes characterize this sorting center gear floating intermediate motion control device. Structural arrangements to ensure the mobility of two degrees of freedom needed mainly belong to the general category of the two bar linkages, in which the functionality of a "mobility ratio" to provide mobility in a direction different from the loads main, comes through linking a current member, an eccentric or a contact sliding fulcrum.The ability to purge the air, oil uptake internal volume of a lash adjuster 50 is a valuable feature because the tendency of the moving parts of an engine to draw air into the oil micro-bubbles, a phenomenon commonly known as aeration. The inclusion of air bubbles in the oil acts to introduce captured compliance or springiness to an apparatus designed to be rigid against dimensional changes fast. Near the vertical orientation of a lash adjuster 50 facilitates the escape of air from a lash adjuster 50 includes a vent at the highest point of the capture space 60.The change in the nominal direction of the forces operating on near vertical, in an almost vertical lash adjuster 50, a nominal orientation ideals horizontal polarization direction of the load center of a floating intermediate gear, is easily achieved in If a mobility binding between the attack and input gear fitter by aligning nominal link support mobility with resultant Z direction of the two main load vectors, namely the force X, which opposes the resultant vector of nominal meshing force vectors A and B, and Y force, as applied by the lash adjuster 50 to the body 20. . Figure 5 shows an example of rocker type arrangement schematically body.Alignment control shaft at a floating idler gear, alternatively, may be secured by building the device with two bars pivot bearings parallel axes which have sufficient roll stability in conjunction with the rolling resistance of the intermediate gear shaft (s) and the deflection stiffness of the anchoring structure and link shaft the same links. . Figure 6 shows an example of such intermediate gear apparatus which uses a floating center eccentric sleeve as mobility binding. . Figure 7 shows a control apparatus for controlling movement of shaft alignment dual pivot axes remote. As described in detail above, FIG. Figure 8 shows a motion control device using a shaft alignment control with dual pivot axes.Category 2 axis dual independent lash adjustersThe addition of a second adjuster valve 50 enables different loads mesh between the crankshaft gear 30 and the coupling gear 35 and the body 20 is stabilized to a greater extent spatially the apparatus of FIGS. 1-8. . Figure 9 illustrates the simplest construction of this second category of motion control two degrees of freedom, with 50 lash adjusters run directly on the body 20. Alternative structures using rockers or the like to allow more vertical orientation tabs not separate adjustment of the scope of the category as long as they provide similar independent support each substantially of two directions mesh .This, in Category 1, ideal nominal orientation bias the address of a floating idler load or main load direction single lash adjuster unit can be varied to simulate different meshing nominal capacity load dual lash adjuster device, by design geometry options. Such deliberate diversion not, however, replicate the inherent stiffness, contrary repulsion of directly applied in the direction of the net, Category 2 devices.Category Center 3 fixed distance to balance gear shaft ApparatusIn the figure. 10, the first of several categories with only one degree of freedom, an extension of the body housing member 20, or alternatively a movement control mechanism, such as at least one sliding arcuate path constricts the body 20 for rotation about of a pivot axis substantially coincident with the centerline of the coupling gear 35 while providing variable wheelbase invention over the crank gear 30. This setting is a special case of the more general five category classification in Fig. 12 as discussed below. Fixed Wheelbase category 3 between the intermediate gear and gear coupling 35 provides in substantial hardware complexity and cost, game theory constant at constant temperature with the mating gear.4 Translation Category in direction substantially normal to the center DistanceThis sense of body 20 and intermediate travel gear 15 maintains substantially constant center distance between the intermediate gear 15 and mating gear 35 to the small range of travel required to maintain the constancy backlash with the crankshaft gear 30, thereby simplifying structural configurations to facilitate manufacture. . Figure 11 is a schematic representation of this category control motion of a single degree of freedom.Category 5 Arcuate Travel About substantially Coinident Center to Center Distance, Displacement in Direction intermediate gear meshing gearThe travel direction of the body 20, as illustrated schematically in Fig. 12 center distance remains more constant between the intermediate gear 15 and the coupling gear 35 which makes the apparatus of FIG. 11 but less than the special case of the apparatus of FIG. 10, while potentially further simplified structural configurations to facilitate manufacture.Category 6 Arcuate Center Travel About substantially coincident with the center Distance, Displacement in Direction gear coupling the intermediate gearThe travel direction of the body 20 remains approximately constant center distance between the intermediate gear 15 and the coupling gear 35 to make the apparatus of FIG. 11 and FIG. 12 while simplifying potentially more structural configurations to facilitate manufacture and packageability. . 13 illustrates a single degree of arcuate movement of movement body 20 may pivot about the pivot axis P1 and operated lash adjuster 50.While illustrations and text described herein gearsets parallel axes, the concept of the invention applies to other types of gear sets, as needed.Although the present invention is described with reference to several embodiments of the invention, there is nothing in the specification should be construed to limit the invention to any particular embodiment or common feature, except as expressly set forth in the appended claims.


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