Cloyes Gear and Products, Inc.

Darren J Stewart

James D Young

John E Minden

An inverted tooth chain and sprocket drive system in which the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), the link plate entrance angle Beta (&#x3b2;), and other aspects of the meshing geometry are controlled and optimized to reduce noise and vibration by using a particular chain link plate form and, in preferred cases, by modifying the sprocket tooth pressure angle. The system can include first and second sprockets for which the pressure angle can be controlled to ensure that the desired values for the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), and the link plate entrance angle Beta (&#x3b2;) are equal for both sprockets even though the sprockets have different tooth counts. For a chain pitch P in the range of 6.35 mm to 8.0 mm, the initial contact distance ICis controlled such that 0.49P&#x2266;IC&#x2266;0.53P, the meshing impact angle Sigma (&#x3c3;) is controlled such that &#x3c3;&#x2266;34&#xb0;, and the link plate entrance angle Beta (&#x3b2;) is controlled such that &#x3b2;&#x2266;9&#xb0;. For certain alternative chain and/or sprocket configurations, &#x3c3;&#x2266;33&#xb0; and &#x3b2;&#x2266;9&#xb0;, or &#x3c3;&#x2266;31&#xb0; and &#x3b2;&#x2266;7&#xb0;.

Inverted tooth chain and sprocket drive system with reduced meshing impact

An inverted tooth chain and sprocket drive system in which the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), the link plate entrance angle Beta (&#x3b2;), and other aspects of the meshing geometry are controlled and optimized to reduce noise and vibration by using a particular chain link plate form and, in preferred cases, by modifying the sprocket tooth pressure angle. The system can include first and second sprockets for which the pressure angle can be controlled to ensure that the desired values for the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), and the link plate entrance angle Beta (&#x3b2;) are equal for both sprockets even though the sprockets have different tooth counts. For a chain pitch P in the range of 6.35 mm to 7.7 mm, the initial contact distance ICis controlled such that 0.49 P&#x2266;IC&#x2266;0.53 P, the meshing impact angle Sigma (&#x3c3;) is controlled such that &#x3c3;&#x2266;34&#xb0;, and the link plate entrance angle Beta (&#x3b2;) is controlled such that &#x3b2;&#x2266;9&#xb0;. For certain alternative chain and/or sprocket configurations, &#x3c3;&#x2266;33&#xb0; and &#x3b2;&#x2266;9&#xb0;, or &#x3c3;&#x2266;31&#xb0; and &#x3b2;&#x2266;7&#xb0;.

An inverted tooth chain drive system includes an inverted tooth chain structured for inside flank engagement. The chain includes link rows each including leading inside flanks that project outwardly relative to trailing outside flanks of a preceding link row. The system further includes a sprocket with which said inverted tooth chain is drivingly engaged. The sprocket includes a plurality of teeth circumferentially spaced about an axis of rotation, each tooth comprising an engaging flank and a disengaging flank. Some of the teeth are defined with a first tooth form in which said engaging flank thereof is defined with a first pressure angle and others of said teeth are defined with a second tooth form in which the engaging flank thereof is defined with a second pressure angle that is different from the first pressure angle in order to stagger or modulate the initial meshing impacts between the leading inside flanks of the chain and engaging flanks of the sprocket teeth. The sprocket can be optimized for manufacture by a hobbing process, by arranging the different tooth forms in a specific 'hob-compatible' pattern.

Inverted tooth chain sprocket with frequency modulated meshing

An inverted tooth chain drive system defines a meshing contact angle Tau (&#x3c4;) between the tangent line TL and an initial contact reference line that passes through a controlling pin center and the initial contact location. A link plate entrance angle Beta (&#x3b2;) is defined between the initial contact reference line and an inside flank reference line that passes through an arc center of the inside flank radius and the initial contact location. A meshing impact angle Sigma (&#x3c3;) is defined between the tangent line and the inside flank reference line such that &#x3c3;=&#x3c4;+&#x3b2;, wherein &#x3b2;&#x2266;9&#xb0; and &#x3c3;&#x2266;34&#xb0;. The pressure angle of the sprocket tooth can be adjusted and the chain optimized such that &#x3b2;&#x2266;7&#xb0; and &#x3c3;&#x2266;31&#xb0;. The system thus provides a reduction of the link impact force Fand the resultant impact energy E. The inverted tooth chain, itself, defines a pitch P and an inside flank projection Lamda (&#x3bb;) such that 0.007&#xd7;P&#x2266;&#x3bb;&#x2266;0.017&#xd7;P when said chain is pulled straight. The outside flanks include a chamfer to ensure that initial contact between the chain and sprocket is always on the leading inside flanks of the chain.

A chain tensioner assembly includes a bracket with a main wall and a ramp surface. A blade assembly is connected to the bracket and includes a blade located adjacent the main wall of the bracket. The blade includes: (i) a first blade end with a pivot aperture; (ii) a second blade end contacting the ramp surface; and, (iii) a central blade portion that extends between the first and second blade ends. The central blade portion includes a chain engaging surface. A first spring-retaining slot is located in the first blade end and includes inner and outer open sides that open respectively through inner and outer faces of the blade. A second spring-retaining slot is located in the second blade end. A spring includes a first end located in the first spring-retaining slot, a second end located in the second spring-retaining slot; and, a central portion that abuts the central blade portion. A pivot fastener extends through the pivot aperture and obstructs the outer open side of the first spring-retaining slot such that the pivot fastener captures the first end of the spring in the first spring-retaining slot.

Blade tensioner with captured spring

An inverted tooth chain and sprocket drive system in which the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), the link plate entrance angle Beta (&#x3b2;), and other aspects of the meshing geometry are controlled and optimized to reduce noise and vibration by using a particular chain link plate form and, in preferred cases, by modifying the sprocket tooth pressure angle. The system can include first and second sprockets for which the pressure angle can be controlled to ensure that the desired values for the initial contact distance IC, the meshing impact angle Sigma (&#x3c3;), and the link plate entrance angle Beta (&#x3b2;) are equal for both sprockets even though the sprockets have different tooth counts. For a chain pitch P in the range of 6.35 mm to 7.7 mm, the initial contact distance ICis controlled such that 0.49P&#x2266;IC&#x2266;0.53P, the meshing impact angle Sigma (&#x3c3;) is controlled such that &#x3c3;&#x2266;34&#xb0;, and the link plate entrance angle Beta (&#x3b2;) is controlled such that &#x3b2;&#x2266;9&#xb0;. For certain chain and sprocket configurations, &#x3c3;&#x2266;31&#xb0; and &#x3b2;&#x2266;7&#xb0;.

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Howell, MI, United States of America

Darren J Stewart