JP3522645B2 - Gear assembly, gear train assembly and assembling method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to gears, and more particularly but not exclusively to reducing gear train backlash.

[0002]

BACKGROUND OF THE INVENTION When the teeth of one gear mesh with the gap of another gear, the gap typically has more space than is required to accommodate the teeth. This excess space is sometimes called rush or backlash. Backlash varies with many factors, which are typical of many gear manufacturing processes: radial clearance of gear bearings, eccentricity of gear shafts, inaccuracy of gaps between gear centers and inter-gear variations. It depends on many factors, including.

The extra clearance associated with backlash is
It usually causes excessive impact load on the gear teeth. This load creates excessive noise or other gear train problems. For example, backlash accelerates gear wear. Reducing backlash is especially important in the case of internal combustion engines, especially in gear trains of diesel engines. U.S. Pat. Nos. 5,450,112, 4,920,828 and 4,770,582.
No. 3,523,003 gives background information on the application of gear trains to various engines.

One way to reduce backlash is in the precision machining and mounting of gears. However, this method is usually expensive and does not adequately deal with the time-varying backlash due to wear. Another way to reduce backlash is to insert one or more scissor gears between the gear trains. Usually, the teeth of the scissor gear are adjustable to occupy the space between the teeth of the meshing gears. US Patent No. 4
No. 747321, No. 4739670,
No. 3,365,973 and No. 2,607,238 show examples of various types of scissor gears.

[0005]

Backlash control with scissor gears is limited when the scissor gear meshes with two or more gears having different amounts of backlash. Typically, the effective tooth size of a scissor gear is determined by the gear with the smallest backlash,
This is usually unsuitable if the other meshing gear has a large backlash. One solution to this problem is to select meshing gears to minimize the difference in backlash, but this backlash adaptation method is usually time consuming and expensive. Therefore, in the case of a gear train, it is necessary to deal with the difference in backlash in a large number of gears that mesh with the scissor gear.

One form of scissor gear is one in which two gears rotatable about a common center are spring biased relative to each other. In this configuration, the gear teeth of each pair of gears expand to fill the gap between the teeth of the meshing gears. In some gear trains, the load exerted on the tooth pairs by the intermeshing gears is great enough to force the gear pairs into alignment against the biasing force of the springs. Typically, each gear of a matched pair of gears has the same nominal tooth thickness and is shaped to proportionally share a high load. Random deviations from the nominal value, however, usually cause one or the other tooth of each pair to deform under unusually high load to conform to the other gear. During this deformation process, the gear teeth are often subjected to reverse loads and wear more rapidly than if they were subjected to unidirectional bending loads. In addition, such deformation causes a large change between the teeth, which deteriorates the performance and increases the noise of the gear train. Therefore, there is a need for a backlash-free gear assembly that is capable of high loads without these drawbacks.

Knocking occurs in the combustion stroke in the case of heavy-duty diesel engines, which may be due to gear tooth noise due to high impact. Typically this noise cannot be adequately removed by conventional scissor gears. Therefore, improvement of the gear train is also required for this type of noise.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a backlash-free gear assembly and gear train that employs one or more backlash-free gear assemblies. The various aspects of the present invention are novel, non-obvious and have various advantages. While the essence of the invention is to be determined solely by the appended claims, some of the characteristics that characterize the preferred embodiments are outlined below.

In one form of the invention, the gear train is assembled by defining a first gear and establishing a first mesh between the first gear and the second gear. Second
Is a scissor gear type, and the effective value of the tooth size is determined by the first meshing. The mounting position of the third gear is selected to form a second mesh with the second gear. This mounting position is determined as a function of the effective tooth size and controls the backlash of the second mesh.

In another form, an engine system including a gear train is provided. The device includes an internal combustion engine to which first, second and third gears are pivotally connected. The second gear engages the first gear by a first mesh and the third gear engages the second gear by a second mesh. The second gear is a scissor gear type. The apparatus includes an adjustable positioning mechanism and is adapted to provide a range of positions of a third gear axis of rotation relative to a second gear axis of rotation to control the second mesh backlash. Includes possible positioning mechanism. One advantage of this form of the invention is that it shows the difference in backlash between two gears that mesh with the scissor gear.

In another aspect of the invention, an anti-backlash gear assembly is provided that includes a first gear having a first number of circumferentially disposed teeth and a first gear subjected to a spring biasing force. And a second gear engaged with the second gear, the spring biasing force causes the first gear and the second gear to rotate relative to each other about a substantially common center of rotation. The second gear includes a number of circumferentially arranged teeth, each paired with a corresponding tooth on the first gear. Each tooth pair has a compound tooth thickness determined by the force acting against the biasing force. The first teeth each have a first arc tooth thickness,
The second teeth each have a second arcuate tooth thickness, which is nominally less than the first tooth thickness. In general, this difference in tooth thickness reduces the reverse bending load by utilizing a load that exceeds the biasing force on the first gear.

In yet another aspect of the invention, an anti-backlash gear assembly, such as a scissor gear, is provided with a high maximum excursion torque to reduce the knocking noise of a diesel engine. Usually, the maximum bias torque required to reduce these sounds is selected as a function of the particular engine design and expected load. In the preferred embodiment, the maximum bias torque is at least about 135 N-m.
(About 100 ft-lbs). In a more preferred embodiment, the maximum bias torque is at least about 270N.
-M (about 200 ft-lbs). In a more preferred embodiment, the maximum bias torque is at least about 675.
Nm (about 500 ft-lbs). Contrary to conventional wisdom, it has been found that this relatively high bias torque is effective in reducing the unpleasant hammering and knocking noises often found in diesel engines.

In yet another form, an anti-backlash gear assembly includes a first gear having teeth arranged in a first number of circumferential ways and a first number of splines.
The assembly further includes a second gear wheel having teeth arranged in a second number of circumferential ways and a second number of splines.
The first and second splines engage each other about a substantially common axis of rotation and are inclined with respect to the axis to provide a first
And relatively rotating the second gear. The first and second teeth are paired to change size with relative rotation of the first and second gears.

In another form of the invention, an anti-backlash gear assembly includes a first gear having teeth arranged in a first number of circumferential ways and a first gear subject to spring bias. A second gear that engages with the first and second gears for relative rotation about a common axis of rotation. The second gear includes a second number of teeth, each of which is paired with a corresponding tooth of the first gear to form a number of variable tooth thickness compound teeth to reduce backlash. An aligning device is provided having a threaded stem carried on a first gear and a head. The head is selectively positioned on the first gear,
An adjustable support relationship is provided to the second gear to oppose the biasing forces which correspondingly change the alignment of the first and second teeth. Desirably, the head has one position that substantially aligns the first and second teeth to facilitate mounting the assembly in a gear train.

In another form of the invention, an anti-backlash gear assembly is incorporated into the gear train for use with an internal combustion engine.

[0016]

In accordance with the present invention, backlash in a gear train assembly having a scissor gear is reduced by placing a mating gear that meshes with a scissor gear having an effective tooth size determined by another meshing.

According to the invention, the noise generated by the gear train of the engine is reduced.

According to the present invention, an anti-backlash gear assembly in which the generation of noise in the gear train is reduced can be obtained.

According to the present invention, a backlash preventive gear assembly in which noise generation is reduced by applying a relatively high bias torque can be obtained.

According to the present invention, it is possible to control the load sharing between the plurality of gears of the scissor gear assembly.

Further, according to the present invention, an anti-backlash gear assembly which is easy to install and has high reliability can be obtained.

Other objects, features, effects and aspects of the present invention will become apparent from the following description with reference to the drawings.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT To facilitate the understanding of the present invention, an embodiment is shown in the accompanying drawings and special terminology is used for explaining the same. However, these do not limit the present invention.
That is, the scope of the present invention is not limited. Variations and modifications of the described apparatus and applications of the principles of the invention described below that are readily available to those skilled in the art are within the scope of the invention.

FIG. 1 shows an internal combustion engine system 20 according to the present invention. The device 20 includes an engine block 22 having a crankshaft 24 shown in dashed lines. In addition, the device 20 includes a head assembly 30 coupled to the engine block 22. The head assembly 30 includes a fuel injection cam shaft 32 shown by a broken line and a valve cam shaft 34 shown by a broken line. In one embodiment, block 22 and head assembly 30 are high capacity inline 6 cylinder diesel engines. The present invention is applicable to other types of institutions known to those skilled in the art.

The device 20 includes a timing gear train 40.
The gear train 40 is a drive gear 42 connected to the crankshaft 24.
including. The crankshaft 24 and the drive gear 42 have a rotation center 44 indicated by a cross line. In the drawings, the center of rotation is shown as a chain line or a broken line when the axis of rotation is not perpendicular to the drawing, and is shown as a crosshair when it is perpendicular to the drawing. Gear 42 rotates with crankshaft 24 about center 44 during operation of engine system 20 to drive the remaining gears in gear train 40.

Gear 42 has teeth 46 which mesh with lower anti-backlash idle gear 50. Gear 5
Zero rotates about an axis 53 having a center of rotation 54. Shaft 53 is attached to block 22 by fasteners or fasteners 55. Bearings 56 provide rotational support between shaft 53 and anti-backlash gear assembly 58 of gear 50.

2-5 show additional details regarding the construction and operation of anti-backlash gear assembly 58 of gear 50. In FIG. 2, details of the gear 60 prior to being incorporated into the gear assembly 58 are shown. The gear 60 includes a hub 63. Web 64 defines seven circumferentially spaced openings 65. Further, for each opening 65, the web 64 has an edge portion 65a with a finger portion at one end and an edge portion 65b facing the other end. Opening 65, edges 65a, 65
The b's are approximately evenly spaced along the circumference of an imaginary circle around the center 54. Gear 60 has a number of circumferentially spaced gear teeth 66 limited to rim 67.
The rim 67 is connected to the hub 63 by the web 64.
Adjacent members of the gear teeth 66 are substantially evenly spaced from each other by a gap 68. The teeth 66 and gaps 68 are only numbered for clarity of the drawing. The components of the gear tooth 66 are sized relative to each other,
The shapes are almost the same. Similarly, the gaps 68 are also sized relative to each other,
The shapes are almost the same.

Referring to FIG. 3, the gear 70 of the anti-backlash gear assembly 58 is shown. The gear 70 includes a hub 73, and the hub 73 is in a rotational support relationship with the shaft 53 via a bearing 56 (see FIG. 1). The hub 63 of the gear 60 is engaged with the hub 73. The interference between the hub 63 and the hub 73 allows the gear wheels 60, 70 to rotate relative to each other. The gear 70 includes a web 74. A tab 74a projects from the web 74 in a direction substantially perpendicular to the plane of the paper of FIG. At least one tab 74a defines a threaded hole 79 therethrough. The threaded hole 79 has a longitudinal axis that is substantially parallel to the plane of the drawing of FIG. The webs 74 each have a recess 7
The weight reducing holes 75a corresponding to each of 5 are limited.
The recess 75 and the tab 74a are substantially evenly spaced along the circumference of an imaginary circle around the center 54.

Gear 70 includes a number of gear teeth 76 defined by a rim 77. The rim 77 is integrally attached to the hub 73 by the web 74. Adjacent members of gear teeth 76 are spaced apart from one another by substantially uniform gaps 78. Only a few teeth 76 and gaps 78 are shown. The gear teeth 76 are substantially equal in size and shape to each other. Similarly, the gap 78 has substantially the same shape and size. Desirably, the number of teeth 76 on gear 70 is the same as the number of teeth 66 on gear 60.

FIG. 4 illustrates an out-of-alignment anti-backlash gear assembly 58 normally found prior to mounting on gear train 40.
Indicates. The gears 60, 70 loosely engage each other and the gear 60
Each of the openings 65 substantially overlaps a corresponding recess 75 in the gear 70 to define a plurality of pockets 80. 82 at each end
A large number of coil springs 81 having the other end 84 are provided. Each spring 81 is respectively positioned in a corresponding pocket 80, an end 82 engages a corresponding tab 74a and an end 84 aligns with a corresponding edge 65a. However, the end 84 need not engage the edge 65a.

Assembly 58 further includes threaded stem 9
Includes an adjustment bolt 90 having a head 94 that opposes two. The stem 92 is threaded so that it is fully screwed into the hole 79 in FIG. 4, and the head 94 contacts the corresponding tab 74a. Normally, the teeth 66, 76 are in a misaligned position and the teeth 6
6 overlaps with a gap 78 defined between teeth 76, and tooth 76 overlaps with a gap 68 defined between teeth 66. Gear 7
The hub 73 of 0 forms a rotational support relationship with the hub 63 of the gear 60, and the gears 60 and 70 are relatively rotatable.
Head 94 defines a contact surface 95 shaped to support an adjacent edge 65b of gear 60 when gear 60 rotates counterclockwise with respect to gear 70. As the gear 60 rotates clockwise with respect to the gear 70, the spring ends 84 come into engagement with the corresponding edges 65a. Desirably, each edge 65a defines a finger sized to fit within the coil of each spring 81 to facilitate proper alignment with gear 60. When rotated clockwise with sufficient force, the spring 81 is compressed between the corresponding edge 65a and the tab 74a, as shown in FIG.

FIG. 5 shows the alignment positions of the gears 60 and 70,
The state suitable for attaching to the gear train 40 is shown. In alignment, the teeth 76, 66 overlap one another as shown in FIG. Spring 81 is highly compressed between edge 65a and tab 74a, producing a correspondingly high spring force. The adjustment assembly 58 changes from the configuration of FIG. 4 to the configuration of FIG. 5 by loosening the bolt 90 so that the head 94 moves away from the hole 79 along the axis S of the stem. If this loosening motion continues,
Surface 95 is supported on adjacent edges 65b and spring 81 is compressed between adjacent mating tabs 74a and edges 65a.

Tabs 74a associated with loosening bolt 90
And the edge 65b separate to cause the gears 60, 70 to rotate relative to each other and the teeth 66, 76 to move relative to each other.
Gear teeth 66 pass through a number of teeth 76 between the non-biasing position of FIG. 4 and the high biasing position of FIG.

FIG. 5 shows the surface 66a of the tooth 66 of the gear 60. The teeth 76 of the gear 70 also have a surface 76a, some of which are shown. A typical face 66a has a tooth width of W
Shown as 60. Similarly, the tooth width W70 is a representative surface 76a.
Shows the tooth width of. Desirably, the tooth width W60 is smaller than the tooth width W70. More desirably, tooth width W70 is at least about 50% greater than tooth width W60. More preferably, the tooth width W70 is at least about twice the tooth width W60.

With particular reference to FIGS. 4 and 5, an anti-backlash gear assembly 58 provides a gear 70 and a spring 81.
By aligning one of them with the hole 79. Bolt 90 is screwed into hole 79 to bring head 94 into contact with associated tab 74a. The remaining spring 81 is placed in the recess 75 of the gear 70. Gear 60 is located on gear 70 and defines corresponding pockets 80 substantially evenly spaced along imaginary circle 86 (shown in phantom in FIG. 4). The edge 65a is aligned with the corresponding end 84 of the spring 81.

Prior to mounting assembly 58 on shaft 53, it is desirable to align teeth 66,76. To provide this alignment, the bolt 90 is partially loosened from the hole 79 and the head 94 contacts the adjacent edge 65b of the gear 60, correspondingly compressing the spring 81. Tooth 6 in response
6, 76 move past each other. This movement continues by loosening the bolt 90 until the alignment position shown in FIG. 5 is nearly reached. As a result, as shown in FIG.
0 separates from gear 70 by distance D along axis S.
In both the unaligned position of FIG. 4 and the aligned position of FIG.
Note that the stem 92 of is partially threaded into the hole 79. In another embodiment, one or all tabs 74 a align holes 79 with bolts 90. Similarly, multiple bolts 90 may be used with multiple holes 79.

Once the teeth 66,76 are aligned in the configuration of FIG. 5, the assembly 58 is attached to the shaft 53 via the bearing 56. When the installation is complete, the aligned teeth 66, 76 form an engagement 48 with the teeth 46 of the drive gear 42. However, the mesh 48 has a significant amount of backlash when the teeth 66, 76 are forced into alignment by the extension of the bolt 90. In order to eliminate the backlash of the gear 50, the gear 60 and the gear 70 are relatively rotatable due to the biasing force of the compressed spring 81. It is made rotatable by screwing a bolt 90 into the hole 79 after mounting the assembly 58 to form a mesh 48 with the drive gear 42. As a result, the biasing force of the spring causes the teeth 66, 76 to occupy the entire space between adjacent teeth 46 which are offset from each other to form the mesh 48. Of particular note, the mating 48 does not allow the teeth 66, 76 to return to the unloaded position shown in FIG.

Each pair of initially aligned teeth 66, 76 generally acts as a compound tooth with a variable effective dimension, or tooth thickness, which "tooth thickness" varies with the dimension between the teeth 46 to be combined. . Meshing when changing the "tooth thickness" 4
A backlash of 8 is reduced or substantially zero by the compound teeth. To complete the assembly 58, the bolt 90 is tightened so that the head 94 contacts the associated tab 74a. The bolt 90 is preferably carried on the gear 70 during the adjustment process and the assembly 58 is utilized as part of the gear 50.

Gears 60, 70 are preferably machined from a metal material suitable for long term use as a timing gear train for diesel engines. Bolt 90 and spring 81 are also preferably made of materials suitable for long term use for diesel engines. However, other materials known to those skilled in the art may be used.

Although gear 50 is shown in FIG. 1 as an idle gear, it may be a drive gear, a driven gear, or any other arrangement known to those skilled in the art. Gears 50 in all cases
Is a new type of scissor gear.

Referring to FIG. 1, the gear 50 is a gear train 40.
A mesh 96 with the idle gear 100 is formed therein. The idle gear 100 rotates about a center of rotation 104 and circumferential teeth 1 spaced by a gap 108.
06 to form a mesh 96 with the gear 50.

With additional reference to FIG. 6, the idle gear 1
00 details are shown. Idle gear 100 is web 1
Rim 10 integrally connected to 14 to define teeth 106
Including 7. The web 114 has a weight reduction hole 116.
The web 114 is integrally connected to the hub 118, and the hub 1
18, the tooth thickness along the axis of rotation corresponding to the center 104 is somewhat less than the rim 107, as shown in the cross-sectional view of FIG.
Cylindrical bushing 119 provides a rolling bearing surface between shaft 103 and hub 118. Shaft 103 is idle gear 100
Defines four passages 105 that attach to the block 22.

The idle gear 100 is mounted by an adjustable positioning mechanism 120. The mechanism 120 includes a mounting plate 130, which is the shaft 1 of the idle gear 100.
It is located between 03 and block 22. It should be noted that the plate 130 has a clearance between the idle gear 100 and the hub 118 so that the idle gear 100 can freely rotate around the shaft 103.

The idle gear 100 and the mounting plate 130 are located between the block 22 and the holding plate 140. The holding plate 140 has a mounting hole 145 for mounting the shaft 103.
05, the mounting hole 135 of the plate 130, and the screw hole 25 of the block 22 are substantially aligned with each other. Note that the holes 105 are the mounting holes 135, the mounting holes 145 and the screw holes 25 with respect to the axis perpendicular to the rotation axis of the gear 100.
It has larger dimensions. Idling gear 100 has cap screw fasteners or fasteners 150 inserted between plates 130 and 140 through holes 145, passages 105 and passages 135 and the ends of threaded stems 152 screwed into holes 25. Fixed by. Fastener 1
50 is a head 1 that opposes the threaded stem 152.
54. When the stem 152 is fully screwed into the hole 25, the head 154 contacts the holding plate 140 to grip the holding plate 140 on the shaft 153 and the shaft 153 to the plate 130.

In operation, the mechanism 120 operates the idle gear 100.
Are preferably arranged in a plane area parallel to the plane of FIG. 1 and perpendicular to the plane of FIG. In this area, the gear 100 is shown in FIG.
2 has two degrees of freedom indicated by arrows X and Y.

To mount the idle gear 100, the mounting plate 130 is first secured to the block 22 in a conventional manner using fasteners not shown, and the passage 135 is the hole 2.
Matched to 5. When the plate 130 is fixed to the block 22, the idle gear 100 is positioned on the plate 130, and the passage 105 and the passage 135 overlap each other. The retaining plate 140 is then placed on the shaft 103 and the holes 145 overlap the corresponding passages 105, 135 and the holes 25. Fasteners or fasteners 150 have matching holes 145 and passages 10, respectively.
5 and passages 135 and are loosely screwed into corresponding holes 25. Desirably, fixture 150 initially has holes 25
It is screwed in a sufficient amount to contact the plate 140 and dynamically hold the idle gear 100 in place. In this configuration, the position of the idle gear 100 relative to the plane area indicated by the arrows X, Y is selected within the range allowed by the clearance of the fixture 150 in the passage 105. When the XY position is selected, the fixture 150 is tightened and the idle gear 100 and the mechanism 120 are fixedly attached.

The teeth 106 of the idle gear 100 form a mesh 196 with the anti-backlash gear 200. The gear 200 is attached to the fuel injection cam shaft 32 of the cylinder head assembly 30 and rotates about a rotation center 204. Gear 200 preferably has a pair of compound gear teeth, designated by reference numeral 266, similar to gear 50. Further, the spring 281 of the gear 200 has the same shape as the spring 81 of the gear 50, but the number thereof is small (three are shown). Similarly, mounting adjustment bolt 290 is shown. The adjusting bolt has a mounting function similar to that of the bolt 90 of the gear 50. Bereville washers may be used on one or both of gear 50 and gear 200 to provide a spring biasing force with or without a coil spring.

The gear 200 meshes with the gear 300 29
6 is formed. The gear 300 is attached to the valve cam shaft 34 and rotates about a rotation center 304. Gear 300 has teeth 3
06, which interferes with the tooth pair 266 of the gear 200 to form a mesh 296.

During operation, the drive gear 42 rotates with the crankshaft 24 causing the gear 50 to rotate. In response to this, the gear 50 moves through the mesh 96 to the idle gear 100.
Rotate. The idle gear 100 rotates the gear 200 through the meshing 196, and the fuel injection cam shaft 32 is rotated.
The timing of a fuel injector (not shown) for the engine device 20 is adjusted by rotating the. Further, gear 200 causes gear 300 to rotate through meshing 296, which causes valve camshaft 34 to rotate to timing engine valves (not shown) for head assembly 30. That is, the gear train 40 controls the timing of the engine device 20 by rotating the cam shafts 32 and 34 of the head assembly 30 in response to the rotation of the crank shaft 24.

As another example, it is easy for one skilled in the art to have different numbers and arrangements of gears in the gear train 40.
As yet another example, a normal scissor gear is a gear 50.
Alternatively, it is used instead of the gear 200 or both. In yet another embodiment, the idle gear with adjustable positioning mechanism may be omitted.

In one embodiment of the gear train 40, the number of teeth 46 on the drive gear 42 is about 48, and the teeth 6 on the gears 60, 70.
The number of 6, 76 is about 70 each, and the number of teeth 106 of the adjustable idle gear 100 is about 64.
The number of compound teeth 266 of the gear 300 is about 76,
The number of 06 is about 76. Furthermore, in this case, the gears 42, 50, 100, 200, 300 are spur gears, made of a metallic material that can be used for a long time with an internal combustion engine, and have substantially parallel rotation axes that are substantially orthogonal to the plane of FIG.

Having described the structure and operation of device 20, assembly of device 20 will now be described with reference to FIGS. 7A and 7B. Reference numerals in FIGS. 7A and 7B are equivalent to those shown in FIGS. 1-6, but tooth engagement is shown as an enlarged view, highlighting selected features of the invention. FIG. 7A shows an intermediate assembly stage of the drive gear train 40. At this stage the drive gear 42 is already mounted and rotates about the center 44 in the direction indicated by arrow R1. Similarly, meshing gear 300 is mounted for rotation about center 304 in the direction indicated by arrow R5.

After the gears 42, 300 are mounted, the gears 50, 200 are mounted to form a mesh 48 between the gears 42, 50 and a mesh 296 between the gears 200, 300. The meshing 48, 296 is formed by the gear 5
When 0,200 teeth occupy the gap between the teeth 46,306 of the gears 42,300, respectively, the effective composite dimension of the corresponding tooth pair is determined. For clarity, for gear 50, teeth 76 of gear 70 are shown in dashed lines and teeth 66 of gear 60 are shown in solid lines. Also shown is the effective arc tooth thickness T50 of one composite tooth pair of gear 50. The effective arc tooth thickness is determined for the mesh 48 along the pitch circle of the gear 50. Note that in the absence of idle gear 100, tooth thickness T50 is determined by the mesh clearance of teeth 46 of gear 42.

At mesh 296, gear 200 forms a compound tooth pair 266. Each pair 266 has a member shown in broken lines and a member shown in solid lines for clarity. The effective arc tooth thickness of one compound tooth pair 266 teeth is shown as arc tooth thickness T200 relative to the pitch circle of gear 200.

Arrows R4 and R5 indicate gears 200 and 3 respectively.
00 shows the direction of rotation when driven. For reference,
The mounting holes 25 in the engine block 22 are also shown.

The combined arc tooth thicknesses T50, T200 are limited and the idle gear 100 is mounted to form a mesh 96 with the gear 50 and a mesh 196 with the gear 200 as shown in FIG. 7B. The tooth thicknesses T50, T200 of the teeth have a difference corresponding to the difference in the amount of backlash in the meshes 48, 296. The mechanism 120 is used to adjust the XY position of the center of rotation 104 relative to the fixed centers of rotation 54, 204 to optimally mesh the idle gear 100 with the predetermined tooth dimensions of the gears 50, 200. But this is not related to the difference in backlash. The fasteners or fasteners 150 of the mechanism 120 are shown in Figure 7B for reference.

Position adjustment of the idle gear 100 relative to other gears is important for controlling the amount of backlash in the meshes 96,196. Different tooth thickness T50, T200
The backlash is reduced or eliminated by placing the idle gear 100 at an appropriate position along a plane area perpendicular to the rotation axis of the meshing gears, if the backlash difference is within a certain range. You can

It should be noted that in the preferred embodiment two meshings 96, 196 with the idle gear 100 are provided.
However, it is possible to control the backlash when the number of meshing gears is different. For example, three gears 4
This technique can be applied to a gear train composed of 2, 50, and 100.

Referring to FIGS. 8A-8C, the gear 4
Selected operating states of 2, 50, 100 are shown schematically using like reference numerals as in FIGS. 1 to 6, but with large teeth and a small number of teeth to highlight various features. Shown. In FIG. 8A, gears 42, 50, 1
00 are in a stationary (non-moving) position relative to each other. Mesh 4
8, the virtual pitch circles C1, C2, C3 are the gears 4
2, 50 and 100 are indicated by broken lines, respectively. The arc tooth thickness T50a of the pair of gear teeth 76, 66 of the gear 50 is shown as an arc along the pitch circle C2. An arrow DF1 indicates a force acting against the biasing force of the gear 50 in the static state shown in FIG. 8A. The static reaction force of gear 100 is shown as arrow RF1. The arcuate tooth thickness T60 of the selected tooth 66 is also shown. Arc tooth thickness T7 of selected tooth 76
0 is also shown. For each tooth 60, 70, the arc tooth thickness T60 is preferably nominally less than the arc tooth thickness T70. In one preferred embodiment T60 is T
It should be at least about 0.002 inch smaller than 70. Even more preferably, the difference is at least about 0.1016 mm (0.004 inch). Most preferably, this difference is between 0.0508 and 0.15.
The range is 24 mm (0.002 to 0.006 inch).

In FIG. 8B, the drive gear 42 is indicated by the arrow R1.
It rotates in the direction of and gives the resultant driving force shown by arrow DF2. In response, gear 50 rotates in the direction indicated by arrow R2, and gear 100 rotates in the direction indicated by arrow R3. The reaction force shown on gear 100 is shown as arrow RF2. The resultant forces DF2, RF2 are sufficiently large to partially overcome the spring biasing force and compress the spring 81 of the gear 50. As a result, the circular arc tooth thickness T50 of the composite pair of teeth of the gear 50
b decreases in comparison with the tooth thickness T50a (where T50b
Is less than T50a). As the magnitude of the force transmitted from the drive gear 42 increases, the gear teeth 66,76 approach alignment.

In FIG. 8C, the resultant driving force D of the gear 42
F3 and the reaction force RF3 of the gear 100 compress the spring 81 to align the gear teeth 66,76. When the matching is performed, the composite tooth thickness T50c is obtained. T50c is T50
a and T50b, and the arc tooth thickness T7 of the tooth 76 is smaller than
It is almost equal to zero. Spring 81 is substantially fully compressed in FIG. 8C and is arranged to store approximately equal energy to spring 81 in the state of FIG.

The small arc tooth thickness of tooth 66 relative to tooth 76 (T60 <T70) prevents the load on tooth 66 from exceeding the load provided by the compression spring of FIG. 8C. In contrast, the teeth 76 bear a load that exceeds the spring load. Limiting the loading of the teeth 66 to spring bias forces typically reduces the reverse bending load due to the random dimensional differences of each member of a pair of teeth that nominally have the same arc tooth thickness. Desirably, the wider tooth width W70 of each tooth 76 is selected to bear a high drive load which exceeds the spring bias force, but for gear 50 an increase in total tooth width (W60 + W70).
Is usually less than the increase in tooth width required to withstand reverse bending loading with a scissor gear having the same nominal arc tooth thickness for all teeth.

FIG. 9 is a graph showing the effect of the gear having the reduced arc tooth thickness T60 in comparison with the gear having the arc tooth thickness T70 with respect to the load curve 400. Here, the broken line indicates the gear 60, and the solid line indicates the gear 70. Horizontal portion 410 corresponds to the preloaded biasing force of gear 50 in the static state of FIG. 8A. The ramped portion 420 corresponds to the loaded condition of the teeth 66, 76 between the static condition of FIG. 8A and the aligned position of FIG. 8C.
FIG. 8B shows a point along the beveled portion 420. When the load compresses the spring 81 and aligns the teeth as shown in FIG. 8C, the load on the teeth 66 of the gear 60 flattens at the maximum load of the spring 81 and is shown as dashed line 430 in FIG. At the same time, the thick tooth width W70 of the tooth 76 carries a high load, shown in FIG. The gear 70 receives a high load, and the load of the gear 60 is a difference in arc tooth thickness (T70-T60).
Bending load is limited by being limited by.

Unpleasant noise, such as the hammering noise of heavily loaded diesel engines, is due to the high impact noise of the gear trains associated with these engines. By providing a relatively high biasing torque by providing a scissor gear in the gear train, an unexpected dramatic change in loudness was experienced, including a reduction in overall noise intensity. Here, "biased torque" means the torque given by the spring biased scissor gear. The bias torque is determined by the product of the radial distance from the center of rotation of the gear to the teeth and the force tangentially acting on the circle corresponding to the radius. The bias torque typically changes as a function of the amount of bias load on the scissor gear. Desirably, the bias torque is maximized when the gear teeth are substantially aligned against the bias force. Teeth 66, 76 in FIG.
The radial vector T and the force vector F are shown in the alignment form of FIG. 1 and can be used to determine the biasing torque of the assembly 58.

At least about 135 N-m (100 ft-
It has been found that a maximum deviation torque of 1 lbs) can improve the noise characteristics and strength of the gear train. More preferably, the maximum bias torque is about 270 N-m (200 f
t-lbs). More preferably, the maximum bias torque is about 675 N-m (500 ft-lbs).

FIG. 10 is an exploded perspective view showing the rotation center 554 of the anti-backlash gear assembly 558 shown as another embodiment of the present invention. Assembly 558 includes splines 561 on inner cylindrical surface web 564 of hub 563.
A gear 560 having a. The hub 563 has an opening 563a penetrating therethrough. Spline 561 is center 55
4 has a spiral shape and is inclined with respect to the rotation axis of the gear 560. The hub 563 is integrally connected to the web 564. A rim 567 integrally connected to the web 564 is provided with a number of circumferentially arranged teeth 566. The teeth 566 are substantially evenly spaced from each other about the center 554 and each have substantially the same size and shape. Gaps 568 are also generally evenly spaced from one another between adjacent teeth 566 and have substantially the same size and shape. The web 564 of gear 560 is 2
Two opposing openings 569 are defined.

Assembly 558 also includes gear 570.
Gear 570 includes splines 571 provided on the outer cylindrical surface 572 of hub 573. Spline 571 is center 5
It is helical with respect to 54 and is inclined with respect to the axis of rotation of gear 570. Spline 571 is spline 56
The slopes are similar to 1 and are combined with each other. The hub 573 is provided with an opening 573a surrounded by an inner cylindrical surface web 574 and has a rotational support relationship with the mounting shaft. Gear 570 includes a web 574 integrally connected to hub 573. Teeth 576 are provided on a rim 577 integrally connected to the web 574. The teeth 576 are substantially evenly spaced about the center of rotation 554 and have substantially the same size and shape. Tooth 57
6 has a gap 578. The gaps 578 are substantially evenly spaced from each other and have substantially the same size and shape. That is, the hub 573, the web 574, and the rim 57.
7 defines a cylindrical recess 575. The web 564 defines two opposing threaded recesses 579, each corresponding to one of the openings 569.

A plurality of coil springs 581 are provided in the recesses 5 respectively.
75, and are spaced approximately evenly from one another about the center 554, between the hub 573 and the rim 577. Adjusters 590a, 590b each include an adjustment bolt 590 having a threaded stem 592. The stem 592 has a head 594 and an opposite end 593. Adjusters 590a, 590b each include a washer 596 through which stem 592 extends. The head 594 is sized so that the washer 596 does not pass through. Washer 596
The outer diameter of is not large enough to pass through the opening 569.
The size of the opening 569 has a sufficient margin with respect to the stem 592, and the stem 592 can be selectively positioned. Threaded hole 579 is shaped to engage a corresponding one of stems 592.

Referring to FIG. 11A, the misaligned position of the assembly 558, that is, the teeth 566, 576 of the gears 560, 570.
However, similar to the embodiment shown in FIG. 4, a state in which they are not aligned is shown. Referring additionally to FIG. 11B, assembly 5
A side elevational view of 58 in an unaligned position is shown. Gear 560
Spline 561 engages with spline 571 of gear 570. For each device 590a, 590b, the stem 592 has a corresponding longitudinal axis S1, S2. The stem 592 has a corresponding washer 596 and opening 569.
To first engage the threaded hole or recess 579. Spring 581 is substantially uncompressed in FIGS. 11A and 11B.

12A and 12B, there is shown a perspective view and a side elevational view, respectively, of the assembly 558 in an aligned condition. This alignment corresponds to the alignment of assembly 58 of FIG. The stem 592 of the adjustment devices 590a, 590b is recessed 579 to bring the assembly 558 into alignment.
Fully screwed into the spring 581 and the gears 560, 570
Compress in between. When the spring 581 is compressed, the tilting of the combination splines 561, 571 causes a lateral movement action which causes the translational movement of the devices 590a, 590b to the gear 5.
It is converted into the rotational movement of 60 and 570. Device 590a,
When the stem 592 of 590b is unscrewed, the force of the compressed spring 81 causes the gears 560, 570 to rotate in the opposite direction, due to the engagement of the splines 561, 571. The assembly 558 has a stem 592 with a recess 5
The teeth 566, 576 are adapted to be substantially aligned when fully screwed into 79. The alignment orientation of this assembly 558 is shaped to provide the selected maximum biasing torque.
The distance occupied by the gears 560, 570 along the stem axes S1, S2 varies from D1 in the unaligned position in FIG. 11B to D2 in the aligned position in FIG. 12B, where D1 is D2.
Is greater. Notably, D2 is an assembly 558.
Is the minimum distance occupied by the gears 560, 570 along the stem axes S1, S2. That is, the gears 560 and 57
The zeros rotate relative to each other by the distance they occupy along the axis of rotation corresponding to the center 554.

Preferably, the number of teeth 566 is the same as the number of teeth 576. The number of spiral splines 561 and 571 is also the same as the number of teeth 566 and 576. Having the same number of teeth and splines eliminates the need for indexing the splines 561 and 571 to ensure that the alignment of the teeth 566 and 576 matches the high spring compression force. In another embodiment, the openings 569 may be non-circular rather than circular as shown in FIG. In another embodiment,
The opening 569 is arcuate with an arc around the center 554.

The splines 561 and 571 are hubs 563 and
It may be provided at a position other than 573. As a non-limiting example, one gear is provided with an arcuate slot, the inner surface of which is provided with a spline, which engages a spline provided on a flange extending into the slot from the other gear. By placing one or more pieces of the mating splines about the axis of rotation, relative rotation of the gears is possible without surrounding the axis.

As with assembly 58, assembly 558
An aligning device for selectively aligning the teeth of the two gears of the anti-backlash gear assembly against the spring bias of the assembly. The stem 592 is tightened and is shown in FIG.
The alignment state of A and FIG. 12B is given to facilitate the attachment.
When the assembly 558 meshes with another gear, for example, the gear 42, the stem 592 of each device 590a, 590b is loosened to allow relative rotation of the gears 560, 570 to take up the backlash of the meshing gears. To be This loosened position is the same as that of the embodiment shown in FIGS. 11A and 11B,
Desirably, there is a gap between the head 594 and washer 596 of each bolt 590 to accommodate changes in the backlash condition of the corresponding mesh. In one embodiment, the devices 590a, 590b are removed when the assembly 558 is mounted in mesh with another gear. This embodiment resists the biasing force by meshing.

Each assembly 58, 558 has an adjusting device connected to one gear and having a threaded stem extending along the axis of the stem. The device further includes a head coupled to the stem to provide relative positioning with respect to the gear. Generally, the assemblies 58,558 are compatible with respect to other features of the invention. Further, the assemblies 58, 5
58 can be used with anti-backlash gear 200. Also, in another embodiment of the assembly 58, 558, the bolts 90, 590 may be a threaded stem fixed to one of the gear wheels and a nut screwed into this may be a movable head. The nut is positioned along the stem to selectively engage the other gear. In yet another embodiment, the anti-backlash assembly is omitted.
In a variant of the invention, a normal scissor gear is used.

Publications, patent specifications cited in this specification,
Although the patent application specifications are given as references, each individual publication, patent specification, and patent application specification constitutes a part of the present specification.

While the invention has been illustrated and described in detail by the foregoing description and drawings, these are for purposes of illustration and not limitation. That is, all variations and modifications within the spirit of the invention should be protected.

[Brief description of drawings]

FIG. 1 is a front elevation view of an internal combustion engine device shown as an embodiment of the present invention.

2 is a top plan view of components of the anti-backlash gear assembly of the embodiment of FIG. 1. FIG.

3 is a top plan view of components of the anti-backlash gear assembly of the embodiment of FIG.

FIG. 4 is a top plan view of the components of FIGS. 2 and 3 assembled in misaligned relationship with an anti-backlash gear assembly.

5 is a perspective view of the anti-backlash gear assembly of FIG. 4 in an aligned state.

6 is a cross-sectional view taken along line 6-6 of FIG. 1, showing the idle gear and the adjustable positioning mechanism.

7A and 7B are schematic front elevational views showing different stages of assembly of the apparatus of FIG.

8A, 8B and 8C are schematic front elevational views showing selected operating states of a portion of the apparatus of FIG.

FIG. 9 is a graph showing a relationship relating to the operating state shown in FIGS. 8A to 8C.

FIG. 10 is an exploded perspective view of an anti-backlash gear assembly shown as another embodiment of the present invention.

11A is a top plan view of the non-matching configuration of the anti-backlash gear assembly of FIG. 10. FIG. FIG. 11B is shown in FIG.
1B is a side elevational view of the backlash prevention gear assembly of FIG.

12A is a top plan view of the aligned form of the anti-backlash gear assembly of FIG. 10. FIG. FIG. 12B is shown in FIG.
The side elevation view of the backlash prevention gear assembly of A.

[Explanation of symbols]

20 internal combustion engine device 40 gear train 50 anti-backlash gear 58 anti-backlash gear assembly 60, 70 gear 65 opening 75 recess 66, 76 gear teeth 67, 77 rim 81 coil spring 90 adjusting bolt 92 stem 94 head 100 idle Gear 120 Positioning mechanism 130 Mounting plate 140 Holding plate 150 Screw fixture

─────────────────────────────────────────────────── ───Continued from the front page (72) Inventor David P. Genter, Birmingham Road, Kenilworth, England, The Burleigh House at Chase Farm (72) Inventor, Kevin El Miller USA Indiana State 47265, North Vernon, South County Road 580 West 355 (72) Inventor Charles E Long United States Indiana 47201, Columbus, South 700 West 10535 (72) Inventor Ilia El Pilana Acorn Drive 6064, Columbus, USA 60201 (72) Inventor Dennis Earl Tibbets Indiana 47201, Colombia , Sycamore 2645 (56) Reference JP-A-4-25657 (JP, A) JP-A-5-340465 (JP, A) JP-A-60-95272 (JP, A) JP-A-63-243566 (JP , A) Actual opening Sho 55-37195 (JP, U) Actual opening Sho 62-54367 (JP, U) Actual opening Flat 7-10606 (JP, U) Actual opening Sho 56-122855 (JP, U) Actual opening Sho 56-173245 (JP, U) Actually open 7-19657 (JP, U) Actually open 62-115558 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 55/18 F01L 1/02 F02B 67/04 F02M 39/02 F16H 1/06

Claims (6)

(57) [Claims] 1. A first gear (70,570) having a number of first teeth (76,576) circumferentially arranged.
And a large number of second teeth (66, 56) arranged circumferentially.
6) having a second gear (60, 560), the first gear and the second gear having a spring or a plurality of springs arranged between the two gears. Under the action of the spring biasing torque acting between them, the common rotation center (54,
554) rotatable relative to one another, each of the first teeth (76, 576) pairing with each of the opposing second teeth (66, 566) to form a compound tooth. And a compound tooth formed in the anti-backlash gear assembly (58,558) that is variable in size according to the force acting against the biasing torque. Adjusting device (9) having a stem (92, 592) with a head and a head (94, 594) connected to the stem (92, 592).
0,590a, 590b), and the head (94, 5
94) a second gear (60, 560) having a supporting relationship for aligning the first (76, 576) and second (66, 566) teeth against the spring bias torque for mounting.
An anti-backlash gear assembly including an adjustment device (90, 590a, 590b) having a selectable first position formed relative to the anti-backlash gear assembly. 2. The head (94, 594) is responsive to the spring bias torque after mounting the gear assembly (58, 558) for meshing with another gear (42, 100). The first (70, 570) and second (60,
5. The gear assembly of claim 1 having a selectable second position that allows the gears of 560) to rotate relative to each other. 3. The adjustment device (90) comprises the stem (9).
2) and a head (94) having a bolt (90), the first gear (70) having a threaded hole (79), and at least a portion of the stem (92). The head (94) is screwed into the hole (79) and the head (94) is inserted into the hole (7).
Gear assembly according to claim 2, characterized in that it is positioned between 9) and the second gear (60). 4. The head (94, 594) contacts the second gear (60, 560) in the first position and the first gear (70, 5) in the second position.
70) The gear assembly of claim 3 in contact with 70). 5. The first gear (570) has a threaded hole (579) and has a first number of helical splines (57).
1) forming a first hub (573), the second gear (560) being the threaded hole (579).
A second hub (56) having an opening (569) shaped to overlap with and forming a second number of spiral splines (561).
3), the first spline (571) and the second spline (561) engage each other, and the adjusting device (590a, 590b) includes the head (5).
94) with a bolt (5) having a stem (592) that opposes
90) and a washer (596), the stem (59)
2) penetrates through the washer (596) and the opening (569) and is screwed into the hole (579), and the washer (5
96) and the second gear (560) to the head (59).
Gear assembly according to claim 1 or 2, characterized in that it is selectively clamped in the first position between 4) and the first gear (570). 6. The spring bias torque is at least about 13.
It has a maximum bias torque of 5 N-m (100 ft-1 bs), and the first tooth (576) has a first arc tooth thickness (T7).
0), the second tooth (566) has a second arc tooth thickness (T60), and the first tooth thickness (T70) is at least about less than the second tooth thickness (T60). 0.0508mm
2. Larger (0.002 inch).
A gear assembly according to any one of claims 5 to 10.