Abstract
An engine system with a gear train to provide synchronization of the engine is disclosed. One technique to minimize backlash and noise caused by the gear train is included. A set of anti-backlash gears useful to reduce slack in the gear train also disclosed. A gear assembly disclosed having at least two gear wheels with circular tooth thickness of a gear wheel being less than the thickness another circular gear wheel. A gear assembly is also disclosed having a pair of bias of at least about 100 foot-pounds. Also provided is a device carried out a series of anti-lash gears to align the teeth in general of the whole installation.
Description
Background of the Invention
The present invention relates to gears, and more particularly, but not exclusively, relates to the reduction of backlash in gearsets.When the tooth of a gear with fellow other gear gap, the gap provides additional space typically required to accommodate the tooth. This extra space is sometimes called "whiplash" or "reaction". Slack may vary with a number of factors including the radial bearings in gear, the eccentric gear shaft, separation center-to-center gear incorrect, and the variation of gear-to-gear typical of many processes gear manufacturing.Extra space associated with clearance usually leads to significant impact loads the gear teeth. This burden often causes excessive noise and can lead to other problems of the gear train. For example, the reaction may accelerate wear of gears. Clearance reduction is of particular interest for applications in internal combustion engines - particularly for gear trains used with diesel engines. U.S. Patent. Nos. 5,450,112 to Baker et al., 4,920,828 to Kameda et al., 4,700,582 to Bessette, and 3,523,003 to Hambric are cited as sources of background information on the application of the gear trains motors.One way to reduce the reaction is through precision machining and assembly of the gear. However, this approach is generally expensive and may still not adequately reaction changes with time due to wear. Another approach to reduce the reaction has been the introduction of one or more scissor gears in the gear train. Generally, scissor gears have teeth that fit in size to fit the available space between the teeth of a gear coupling. U.S. Patent. Nos. 5,056,613 to Porter et al. To Hannel 4,747,321, 4,739,670 of Tomita et al. Henden 3,365,973 and 2,607,238 to English et al. are cited as examples of different types of scissor gear.A housing clearance scissors gear is often limited when the scissors gear is engaged with two or more gears having different numbers of whiplash. Typically, the coupling gear having the fewest flanges determines the size of effective teeth scissors gear, however, this size is generally insufficient to carry the whip greater coupling gear or other gears. One potential solution to this problem is selecting the mating gears minimize whiplash difference, but this approach "whiplash game" is typically expensive and time consuming. Accordingly, there remains a need for a gear train assembly that accommodates differences resulting tabs multiple gears that mesh with a scissors gear.
SUMMARY OF THE INVENTION
The present invention relates to gear assemblies and anti-lash gear trains using one or more sets of anti-lash gears. Various aspects of the invention are novel, nonobvious, and provide various advantages. While the actual nature of the invention covered herein can only be determined with reference to the claims appended hereto, certain features which are characteristic of the preferred embodiments disclosed herein are described briefly as follows.
It is a further object to reduce the noise emitted by the engine gear trains
Another object of the present invention to provide a set of gear anti-whiplash reducing noise emissions of the gear train.Still
another object is to provide a gear assembly which improves
anti-whiplash noise emission by applying a torque thrust comparatively
high.It
is another object of the present invention to control the load sharing
between multiple gear wheels of a set of scissors gear.Yet another object is to provide a set of gears reliable anti-lash is easy to install.Other
objects, features, advantages and aspects of the present invention will
become apparent from the drawings and description contained herein.BRIEF DESCRIPTION OF THE DRAWINGS
DESCRIPTION OF THE PREFERRED EMBODIMENT
For the purposes of promoting an understanding of the principles of the invention, reference is now made to the embodiment illustrated in the drawings and specific language will be used to describe the same. However, it is understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described device, and any additional applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.. Figure 1 depicts the system of internal combustion engine 20 of the present invention. The system 20 includes an engine block 22 with a crankshaft 24 is shown in dashed lines. Engine system 20 also includes head 30 connected to the block 22. Head assembly 30 includes fuel injector camshaft 32 is shown in dotted line and the camshaft of the valve 34 is shown in dotted line. In one embodiment, the block 22 and the mounting head 30 is configured as a heavy-duty, inline six-cylinder diesel. The present invention is also applicable to other types of engines as would occur to one skilled in the art.The synchronization system 20 includes gears 40. The gear set 40 includes drive gear 42 connected to the crankshaft 24. Crankshaft 24 and the drive gear 42 with the rotation center 44 at the intersection of cross designated by reference numeral 44. For the referenced figures herein, centers of rotation are represented by a dashed line segment indicative of the corresponding rotation axis when the rotation axis is not perpendicular to the view plane and the spotlight when the axis of rotation is perpendicular to the plane of sight. Gear 42 rotates with the crankshaft 24 during operation of the motor 20 around the center 44 to drive the remaining gears of the gear train 40.Gear 42 has teeth 46 which are lower nuts 48 mesh with anti-lash gear 50. Gear 50 rotates about axis 53 having center of rotation 54. Shaft 53 is mounted on the block 22 by fasteners 55. Bearing 56 provides a support relative rotation between the gear assembly 58 by anti-lash gear 50 and shaft 53.Figures. 2-5 provide additional details on the structure and functioning of joint anti-lash gear 58 of gear 50. Referring to FIG. 2 shows several details of gear wheel 60 before the incorporation in the gear assembly 58. Gear wheel 60 includes a hub 63. Web 64 defines seven circumferentially spaced openings 65. Furthermore, for each aperture 65, web 64 defines an edge 65a opposite fingers at one end edge 65b at the other end. Opening 65 and the edges 65a, 65b are generally equally spaced along the circumference of an imaginary circle around the center 54. Gear wheel 60 includes a number of circumferentially spaced gear teeth 66 defined by edge 67. Ass 67 is integrally connected to the hub 63 by the web 64. Adjacent members of gear teeth 66 are generally evenly spaced apart from each other by spaces 68. Only a few of the teeth 66 and gaps 68 are designated to preserve clarity. Each gear tooth member 66 is generally sized and shaped the same as the others. Likewise, each hole 68 has generally the same size and shape.Referring to FIG. 3 illustrates the gear assembly 70 anti-whiplash 58. Gear wheel 70 includes hub 73 which is configured to form a rotatable bearing relationship with the shaft 53 through the bearing 56 (see fig. 1). Shaft 63 of gear wheel 60 engages hub 73. The interface between the hubs 63 and 73 is adapted to permit rotation of the gear wheels 60 and 70 relative to each other. Gear wheel 70 also includes web 74. Tabs 74a project from the fabric 74 in a direction generally perpendicular to the plane of view of Fig. 3 and has one side connected to the rim 77 to define corresponding recesses 75. At least one flange 74a defines a threaded bore 79 therethrough. Bore 79 has a longitudinal axis generally parallel to the plane of view of Fig. Three. Web 74 also defines lightening holes 75a each corresponding to one of recesses 75. Flanges 74a and recesses 75 are generally evenly spaced along the circumference of an imaginary circle around the center 54.Wheel 70 includes a series of gear teeth 76 defined by the edge 77. Ass 77 is integrally connected to the hub 73 Web 74. Adjacent members of gear teeth 76 are generally evenly spaced apart from each other by spaces 78. Only a few of the teeth 76 and gaps 78 are designated to preserve clarity. Each gear tooth member 76 is generally sized and shaped the same as the others. Similarly each space 78 generally has the same shape and size. Preferably, the number of teeth 76 of the wheel 70 is the same as the number of teeth 66 of the wheel 60.. Figure 4 defines anti-lash of the gear assembly 58 in a non-aligned configuration is commonly before preparation for installation in the gear train 40. In this configuration, the wheels 60 and 70 are loosely coupled together so that each aperture 65 of the wheel 60 generally overlies a corresponding recess 75 of the wheel 70 to define a series of pockets 80. A series of helical springs 81 are provided each having end 82 opposite end 84. Each spring 81 is positioned in a corresponding pocket 80 with one end 82 engaging corresponding tab 74a and alignment of end 84 with a corresponding edge 65a. However, the ends 84 are not coupled edges 65a typically in this configuration.Assembly 58 also includes adjusting bolt 90 threaded screw head 92 opposition 94. Stem 92 is shown fully threaded into the hole 79 in Fig. 4 with the head 94 in contact with the 74th tab. By convention, the teeth 66 and 76 are in a "non-aligned" so that the teeth 66 overlap the gaps 78 defined between teeth 76 and the teeth 76 overlap the gaps 68 defined between teeth 66. Axis 73 of the wheel 70 forms a rotary bearing relationship with the axis 63 of the wheel 60 so that the wheels 60 and 70 are allowed to rotate relative to each other. Head 94 defines contact surface 95 configured to abut adjacent edge 65b of the wheel 60 when the wheel 60 is rotated counterclockwise with respect to the wheel 70. When the wheel 60 is rotated in the direction clockwise with respect to wheel 70, spring 84 eventually ends engage corresponding edges 65a. Preferably, each edge 65a defines a finger dimensioned to fit within each spring coil 81 to facilitate proper alignment with the disc 60. When rotated in the direction of clockwise with sufficient force, the springs 81 are compressed between the flanges corresponding edges 65a and 74a, as illustrated in Fig. May.. Figure 5 represents a position "aligned" sprocket 60 and 70 reflects a configuration suitable for installation in the gear train 40. When aligned, the teeth 76 and 66 are approximately centered one on the other as shown in Fig. May. Springs 81 are also in highly compressed between the edges of the flanges 65a and 74a to provide a corresponding high spring force. Adjustment assembly 58 of the configuration of FIG. 4 to the configuration of FIG. 5 is provided by unscrewing bolt 90 so that the head 94 moves away from the orifice 79 along the shaft axis S. As this continues unscrewed, 95 abuts the adjacent edge surface 65b and the springs 81 are compressed between adjacent edges aligned tabs 74a and 65a.Unscrewing the bolt 90 extends beyond the associated flange edge 74a and 65b to rotate the wheels 60 and 70 rotate relative to each other and move the teeth 66 and 76 on one another. A given tooth of the wheel 66 can be moved in and out of register with several teeth 76 before reaching highly skewed configuration of FIG. 5 in the configuration of FIG impartial. April.. Figure 5 also represents the face 66a of each tooth 66 of the wheel 60 some of which are depicted. Each tooth 76 of wheel 70 likewise has a face 76a, some of which are depicted. W60 width represents the width of a typical face 66a. Similarly, the width W70 represents the width of a typical face 76a. Preferably, the width W60 is less than the width W70. More preferably, the width W70 is at least about 50% greater than the width W60. Most preferably, the width W70 is at least about twice the width W60.Referring collectively to FIGS. 4 and 5, the joint gear wheel 58 anti-whiplash wheel 70 is constructed by providing and mounting one of the springs 81 to align with the hole 79. Bolt 90 is screwed into the hole 79 so that head 94 contacts the tabs 74a associated. The remaining springs 81 are placed in the recesses 75 of the wheel 70. Wheel 60 is positioned on the wheel 70 to define corresponding pockets 80 generally evenly spaced along the imaginary circle 86 (shown in dashed lines in Fig. 4). Edges 65a are aligned with the ends 84 of the corresponding springs 81.Before mounting assembly 58 on shaft 53, it is preferred that the teeth 66 and 76 align. To provide this alignment, the bolt 90 is partially unscrewed from the bore 79 so that head 94 contacts the adjacent edge 65b of the wheel 60 and correspondingly compresses springs 81. In response, the teeth 66, 76 move over each other. Unscrewing the screw 90 continues this motion until the aligned position of Fig. 5 is generally achieved. As a result, the wheel 60 is removed from the wheel 70 along the shaft axis S by a distance D, as shown in Fig. May. In particular, a stem portion 92 of the pin 90 is held in the threaded bore 79 in both the non-aligned position of FIG. 4 and in the aligned position of Fig. May. In other embodiments, more than one or all of the tabs 74a can be adapted to define an orifice 79 suitable for the screw coupling 90. Similarly, several bolts 90 can be used with embodiments having multiple orifices 79.Once the teeth 66 and 76 are aligned in the configuration of FIG. 5, the assembly 58 is mounted on the shaft 53 through bearing 56. When mounted so aligned teeth 66, 76 mesh shape 48 with teeth 46 of gear 42. However, the mesh 48 is typically a significant amount of the tabs when the teeth 66, 76 are aligned to the force by the extension bolt 90. To take up the lash in the gear 50, wheels 60 and 70 are preferably permitted to rotate relative to one another under the influence of the bias provided by springs 81 compressed. Threaded bolt 90 back in 79 gauge, 58 once assembled is mounted on a mesh 48 with the drive gear 42 allows rotation. As a result, the bias spring offsets the teeth 66 and 76 from one another to generally occupy the entire space between adjacent teeth 46 engaged in mesh 48. In particular, the mesh 48 does not allow the teeth 66, 76 to return to the unloaded position of Fig. 4 configuration.Each pair of teeth aligned initially 66, 76 operate collectively as a composite tooth with an effective size variable or "thickness" depends on the space between the coupling teeth 46. By varying the thickness, these teeth compounds can reduce, or even effectively eliminate, 48 mesh reaction. To complete the installation of the assembly 58, the pin 90 may be pulled down so that the head 94 abuts the associated tab 74a. Bolt 90 is preferably carried by the wheel 70 throughout the adjustment process and the use of assembly 58 as part of the gear 50.Preferably, the wheel 60 and 70 are machined from a metallic material suitable for long term use on a train engine diesel timing gear. It is also preferred that the pin 90 and the springs 81 may be selected from compatible materials suitable for long term use in a diesel engine. However, in other embodiments, different materials can be utilized as would occur to one skilled in the art.Although gear 50 is illustrated in Fig. 1 as an idler gear, in other configurations that may be configured as a drive gear, a driven gear, or otherwise adapted or modified as would occur to a skilled artisan. In all these ways, the gear 50 can be considered a new type of "scissors gear."Returning to FIG. 1, the gear 50 engaged in the gear train 40 to form 96 mesh with intermediate gear 100. Idler gear 100 rotates around the center of rotation 104 and 106 defines the circumferential teeth 108 separated by spaces to form 96 mesh with the gear 50.Referring additionally to FIG. 6 provides more details on intermediate gear 100. Idler gear 100 includes teeth 107 which define rim 106 integrally connected to the Internet 114. Web 114 defines lightening holes 116. Web 114 is also integrally connected to the hub 118, as shown in cross-sectional view of FIG. 6, has a thickness slightly less than along the axis of rotation corresponding to the center 104 of the rim 107. Cylindrical hub 119 provides a bearing surface for rotation between the shaft 103 and hub 118. Shaft 105 103 defines four passages used to mount intermediate gear 100 to block 22.Intermediate gear assembly 100 is provided by the adjustable positioning mechanism 120. Mechanism 120 includes a mounting plate 130 which is located between the shaft 103 of gear 100 and the intermediate block 22. In particular, the plate 130 is configured to provide clearance with the hub 118 of the idler gear 100, so that idler gear 100 is freely rotatable about the axis 103.The intermediate gear 100 and the mounting plate 130 are positioned between the block 22 and the retaining plate 140. Clamping plate 140 includes mounting holes 145 which are generally aligned with the steps 105 of the shaft assembly 103, mounting passages 135 of plate 130 and the threaded holes 25 of block 22. Importantly, the passages 105 have a larger dimension along an axis perpendicular to the axis of rotation of the gear 100 of passages 135, the holes 145 and the holes 25. The intermediate gear 100 is fixed between the plates 130 and 140 by inserting the screw fasteners 150 through holes 145, passages 105 and passages 135 and screwing the threaded end of shafts 152 in the bores 25. Fasteners 150 are each 154 head 152 opposite threaded rod. Head 154 is sized to contact the retaining plate 140 when deriving 152 are fully threaded into holes 25 to fix the plate 140 against the shaft 153 and to hold the shaft 153 against the plate 130.In operation the mechanism 120 is configured to position the intermediate gear 100 with respect to a plane region that is preferably parallel to the plane of view of Fig. 1 and perpendicular to the plane of view of Fig. June. Within this region, the gear 100 can be positioned with two degrees of freedom as symbolized by the arrows X and Y in Fig. 1.Idler gear mount 100, the mounting plate 130 is secured to block 22 using first fasteners (not shown) in a conventional manner, so that the passages 135 are aligned with the holes 25. Once the plate 130 is fixed to block 122, intermediate gear 100 is in the plate 130 so that they overlap passages passages 105 135. Then, the retainer plate 140 is positioned on the shaft 103 to locate over 145 holes corresponding passages 105 and 135, and the bores 25. Fasteners 150 are then each placed through an aligned hole 145, step 105 and step 135 and loosely threaded into a corresponding hole 25. Preferably, fasteners 150 are initially threaded into the bores 25 an amount sufficient to contact the plate 140 and idler gear 100 elastically maintain in position. In this configuration, the position of the idler gear 100 relative to the flat region symbolized by the arrows X and Y direction can be selected within the range permitted by the separation of fasteners 150 in passages 105. Once you select an XY position, fasteners 150 are tightened down to secure intermediate gear 100 and the mechanism 120.The teeth 106 of idler gear 100 meshed with gear 196 anti-lash 200. Gear 200 is mounted to the fuel injector camshaft 32 of the head assembly 30 and is configured to rotate about the pivot 204. Gear 200 is preferably configured similar to gear 50 having gear teeth pairs of compounds represented by the reference number 266. Also, the springs 281, gear 200 is shown configured in a manner similar to the springs 81 of gear 50, although less in number (three are shown). Also shown is an adjusting bolt 290 installation. This adjusting screw can be used for installation purposes similar to bolt 90 of gear 50. Gear 50, the gear 200, or Belleville washers can be used both to provide a spring bias, either with or without coil.Gear 200 forms 296 mesh with the coupling gear 300. Coupling gear 300 is attached to the camshaft 34 of the valve to rotate about the center of rotation 304. Gear teeth 300 defined 306 pairs interact with gear teeth 266 mesh 200 to form 296.In operation, drive gear 42 rotates with the crankshaft 24 to rotate gear 50. In response, the idler gear 50 rotates gear 100 through 96 mesh. 100 Idler Gear units 200 through 196 mesh to regulate the time of fuel injectors (not shown) for the engine system 20 by rotating the fuel injector camshaft 32. Moreover, gear 200 drives gear coupling 300 through 296 mesh for rotating the valve camshaft 34 therewith for time engine valves (not shown) for mounting the head 30. Therefore, gear train 40 turns the cam 32 and 34 of the head assembly 30 in response to rotation of the crankshaft 24 for controlling the timing system of the engine 20.In other embodiments, different numbers and arrangements of gears in the gear train 40 can be used as would occur to one skilled in the art. In an alternative embodiment a conventional scissors gear may be used in place of gear 50, the gear 200, or both. In still other embodiments may not be necessary with an idler gear positioning mechanism adjustable.In one embodiment of the gear train 40, the number of teeth 46 is approximately 48 to the drive gear 42, the number of teeth 66, 76 is approximately 70 to the gear wheels 60, 70, respectively, number of teeth 106 of idler gear 100 is approximately 64 adjustable, the number of teeth 266 for composite gear 200 is approximately 76 and the number of teeth 306 is approximately 76 for the gear 300. Also, for this configuration, the gears 42, 50, 100, 200, 300 are of a configuration of spur gears are made of metallic materials suitable for long term use with internal combustion engines, and have rotational axes generally parallel intersect perpendicularly to the view of FIG. 1.Having described selected structural and operational features of system 20, certain aspects of system assembly 20 is described below in connection with the schematic representations of FIGS. 7A and 7B. In the figures. 7A and 7B, like reference numerals represent schematically the structure identified by reference numerals in the figures. 1-6, however, gear meshes have been expanded to highlight selected features of the present invention. . 7A illustrates an erection step of the intermediate gear 40. At this stage, the drive gear 42 has been previously mounted to rotate around the center 44 in the direction indicated by the arrow R1. Similarly, coupling gear 300 is mounted for rotation about the center 304 in the direction indicated by the arrow R5.After gears 42 and 300 are mounted, the gears 50 and 200 are assembled to form 48 mesh between gears 42 and 50, and 296 mesh between gears 200 and 300. Forming stitches 48, 296 determines the size of the teeth effectively composite corresponding pairs of teeth of the gears 50 and 200, occupying spaces between the teeth 46 and 42 gears 306 and 300, respectively. To the gear 50, the teeth 76 of the wheel 70 are represented by dashed lines, and the teeth 66 of the wheel 60 are represented by solid lines for illustrative purposes. Also shown is the effective circulating thickness T50 of the pair of composite gear tooth 50. This compound circular thickness is determined by a pitch circle of the gear 50 mesh 48. Notably, in the absence of intermediate gear 100, the thickness T50 is defined by the distance of engagement of the teeth 46 of the gear 42.About 296 mesh, 200 forming teeth gear pairs 266 compounds. Each pair 266 has an element represented by a dashed line and member represented by a solid line for clarity. Circular tooth thickness effective tooth pair composite 266 is shown as circular thickness T200 with respect to a pitch circle for gear 200.Arrows R4, R5 indicate the direction of rotation in which the gears 200, 300 are driven, respectively. Also shows the mounting hole 25 of the engine block 22 as a reference.Having defined the thickness composite circular T50 and T200, intermediate gear 100 is installed in a 96 mesh with the gear 50 and 196 mesh with the gear 200 as shown in FIG. 7B. The tooth thicknesses T50 and T200 are typically different corresponding to a difference in the value of the clearance in 48 and 296 mesh. Using mechanism 120 for adjusting the XY position of the center of rotation 104 with respect to the fixed rotation centers 54 and 204, intermediate gear 100 can be located optimally mesh with the predefined size of the gear teeth 50 and 200 despite any difference tabs. Fasteners 150 of mechanism 120 are illustrated in Fig. 7B for reference.Position adjustment intermediate gear 100 relative to the other gears results in significant control over the amount of slack 96 and 196 mesh. When the difference resulting reaction T50 and T200 different widths is within a certain range, the backlash can be reduced or effectively eliminated through proper placement of idler gear 100 along a perpendicular to the flat region axes of rotation of the meshing gears.Notably, while the preferred embodiment has two meshes 96, 196 with the intermediate gear 100, in other embodiments this mounting method can be practiced to control reaction for a different number of meshing gears. For example, this assembly technique finds application in gearing which has only three gear oriented similar to gears 42, 50, and 100.Referring to the figures. 8A-8C, the selected operational states of gears 42, 50, and 100 are represented schematically with reference numbers which represent the structure designated by similar numerals in the figures. 1-6, however, fewer and larger teeth are illustrated schematically in these figures to emphasize different characteristics. Referring to the figures. 8A, the gears 42, 50, 100 are on a static (non-moving) state relative to the other. Referring to the mesh 48, step imaginary circles C1, C2, C3 are represented by dashed lines for gears 42, 50, 100, respectively. The circular thickness T50a a pair of gear teeth 76, 66 of gear 50 is shown as an arc along the pitch circle C2 partner. DF1 arrows represent the forces acting counter to the thrust gear 50 to the static condition shown in Fig. 8A. Static reaction forces gear 100 are shown by arrows RF1. Also represents the circular thickness of a selected tooth T60 66 and the thickness T70 selected circular tooth 76. Thickness T60 is preferred that nominally circular circular thickness of less than T70 for each tooth 60, 70, respectively. In a preferred embodiment, T60 is at least about two thousand (0002) of an inch less than T70. More preferably, this difference is at least four thousand (0004) of an inch. Most preferably, this difference is within a range of about two to six thousand (0.002-0.006) inch.In the figure. 8B, the drive gear 42 is rotating in the direction indicated by arrow R1 to provide a resultant drive force represented by arrow DF2. In response, the gear 50 is rotating in the direction indicated by the arrow R2 and the gear 100 is rotating in the direction indicated by the arrow R3. The resulting reaction force presented by the gear 100 is represented by arrow RF2. The resultant forces DF2 and RF2 are of sufficient intensity to partially overcome the spring bias, causing compression of the springs 81 of the gear 50. As a result, the circular thick T50b pairs composed of gear teeth 50 decreases relative to the thickness T50a (T50a T50b is less). As the magnitude of the force transmitted from drive gear 42 increases, the teeth of gears 66, 76 continue to approach alignment.In the figure. 8C, the resultant force DF3 driving gear 42 and the reaction force RF3 gear 100 compresses the spring 81 by an amount sufficient to align the teeth of the gears 66 and 76. When so aligned, composite thickness T50C results. T50C is less than both T50a and T50b, and is generally equal to the thickness T70 of the teeth run 76. Springs 81 are fully compressed generally in FIG. 8C configuration, store energy in an amount generally equal to the springs 81 in the configuration of FIG. May.The smaller circular thickness of teeth 66 as compared to the teeth 76 (T60 <T70) prevents load of teeth 66 beyond the load provided by the compressed springs of FIG. 8C. In contrast, the teeth 76 have no load in excess of the spring load. Limiting the load on the teeth 66 to the spring bias generally reduces reverse bending loads that often result from differences in dimensions random pairs of teeth each member having nominally the same thickness sized to circulate. Preferably, the wider tooth face of each tooth 76 W70 is selected to withstand the highest driving loads in excess of the spring pressure, however, the increased overall width (W60 + W70) for the gear 50 is typically less than the increase of the width required to withstand reverse bending loads by a scissors gear with the same nominal circular thickness for all teeth.. Figure 9 graphically depicts the typical effect of reducing the thickness T60 vs. Circular Circular thickness T70 with the load lines 400. The dashed line 400 represents sprocket 60 and the solid line represents 400 gear 70. Horizontal segments 410 correspond to the pre-loaded bias of gear 50 under the static conditions of Fig. 8A. Angled segments 420 correspond to the load of the teeth 66, 76 between the static condition of Fig. 8A and the aligned position of Fig. 8C. . Figure 8B represents a point along the segments 420. Compressing once the loading docks to align teeth 81 as illustrated in Fig. 8C, the load on the teeth 66 of the gear wheel 60 is flattened at the maximum load of the springs 81, as indicated by the segment 430. At the same time, the thicker side of the teeth 76 W70 high intensity takes charge as indicated by the slope segment 440. Allowing the wheel 70 to handle high loads and limiting the wheel load 60 with the difference circular thickness (T70-T60), reverse bending loads are normally reduced.It is found that most of the unpleasant noise such as "hammering" sounds associated with diesel engines of high power, due to the high impact noise of the gear trains associated with those engines. Unexpectedly dramatic change in sound quality is experienced, typically including a reduction in the overall intensity of noise, when a relatively high torque bias is provided by a scissors gear engaged in the gear train. As used herein, "bias torque" is the amount of torque provided by a gear set of spring-biased scissors. The pair of bias is determined as the magnitude of the vector product of vectors corresponding to a radial distance from the center of rotation of the sprocket teeth and the force acting tangentially to a circle corresponding to the radio. Typically, the pair of bias varies as a function of the amount of charge bias scissors gear. Preferably, the pair of bias is at a maximum when the gear teeth are generally aligned in opposition to the polarization. Configuration of aligned teeth 66, 76 in Fig. 5 a radial vector T and a force vector F is illustrated which can be used to determine torque bias for the assembly 58.Found that a maximum torque bias of at least 100 ft-lbs (ft-lbs) provides improved gear train and the intensity noise character. More preferably, it provides a maximum torque bias of at least about 200 foot-pounds. Most preferably, there is provided a torque bias at least about 500 foot-pounds. In a more preferred embodiment, the gear 50 is configured with a maximum torque bias of about 700 foot-pounds, and the gear 200 is configured with a maximum torque bias of about 200 foot-pounds. In many cases, the torque bias of the present invention avoids the need to use expensive panels and boxes to mute the objectionable noise.. Figure 10 provides a perspective exploded view of a whole anti-lash gears 558 about rotation center 554 of an alternative embodiment of the present invention. Assembly 558 includes sprocket 560 with slots 561 defined by the inner cylindrical surface 564 of the hub 563. Hub 563 defines opening 563A therethrough. Splines 561 are helical-type 554 oriented about the center and inclined to the axis of rotation of the wheel 560. Shaft 563 is integrally connected to web 564. A number of circumferentially arranged teeth 566 are defined by the rim 567 which is also integrally connected to web 564. The teeth 566 are generally equally spaced apart from each other on the center 554 and each has generally the same size and shape. Between adjacent teeth 566 are holes 568 which are also generally evenly spaced apart from one another and have generally the same shape and size. Web 564 of wheel 560 defines two opposed openings 569 therethrough.Assembly 558 also includes wheels 570. Wheel 570 includes grooves 571 defined by the outer cylindrical outer surface 572 of the hub 573. Splines 561 are helical-type 554 oriented about the center and inclined to the axis of rotation of the wheel 570. Splines 571 are generally inclined in the same manner as splines 561 to engage the same. Hub 573 is configured to fit within the center opening 563 563A partner grooves 561 and 571. Shaft 573 defines opening 573A surrounded by the inner cylindrical surface 574 to establish a relationship of a rotational bearing assembly axis. Wheel 570 also includes 574 web integrally connected to the hub 573. The teeth 576 are defined by the rim 577 that is integrally connected to web 574. Teeth 576 are generally evenly spaced apart from one another about the center of rotation 554 and each have generally the same size and shape. The teeth 576 define openings 578 therebetween. Gaps 578 are generally evenly spaced apart from one another and each has generally the same size and shape. Collectively, the hub 573, web 574 and edge 571 define a cylindrical recess 575. Web 564 defines two opposite threaded recesses 579 for each of the openings 569.Coil springs 580 are each positioned in the recess 575 and are generally uniformly spaced apart from one another about the center 554 between the hub 573 and rim 577. Adjustment devices 590a, 590b are included that each have screw threaded rod 590 to 592. Stem 592 has 593 head 594 opposite end. Devices 590a, 590b each include washer 596 configured for passage of the rod 592 therethrough. In contrast, head 594 is sized so that it will pass through the washer 596. Furthermore, the outer diameter of the washer 596 is dimensioned so that it will pass through the opening 569. Opening 569 is sized to provide ample space for the shaft 592, enabling selective positioning of the stem 592 therein. Threaded recesses 579 are each configured for engagement by a corresponding one of the rods 592.
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