Noise and Life of Helical Timing Belt Drives

1999 ◽  
Vol 121 (2) ◽  
pp. 274-279 ◽  
Author(s):  
H. Ueda ◽  
M. Kagotani ◽  
T. Koyama ◽  
M. Nishioka
Keyword(s):  
Noise Level ◽  
Helix Angle ◽  
Tooth Profile ◽  
Belt Drives ◽  
Timing Belt

A new helical timing belt has been developed to reduce noise. In the present study, three belts, each having a curvilinear tooth profile and helix angles of 3 deg, 5 deg and 10 deg, respectively, were designed. The noise and life of the helical timing belt under a constant transmission force are compared with those of a conventional timing belt, in which the helix angle is zero. The noise level of the new helical belts having helix angles of 5 deg or 10 deg was found to be around 5 dB(A) lower than the conventional belt. The belt life was found to be almost identical for each type when the installation tension was set while the slack side tension for the transmission force was lowest. The results of the present study showed that helical belts should be selected for applications in which noise is a crucial factor.

Transmission Error in Helical Timing Belt Drives (Case of a Period of Pulley Pitch)

2000 ◽  
Vol 123 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Masanori Kagotani ◽  
Hiroyuki Ueda ◽  
Tomio Koyama
Keyword(s):  
Helix Angle ◽  
Transmission Error ◽  
Face Advance ◽  
Experimental Conditions ◽  
Belt Drives ◽  
Noise Characteristics ◽  
Synchronous Rotation ◽  
Timing Belt ◽  
Belt Width ◽  
Static Conditions

Helical timing belts have been developed in order to reduce the noise that occurs when conventional timing belts are driven. Helical timing belts are characterized by synchronous rotation. Although several studies have been performed to clarify the noise characteristics and belt life of helical timing belts, the transmission error of these belts remains unclear. In the present study, the transmission error having a period of one pitch of the pulley was investigated both theoretically and experimentally for helical timing belt drives. Experimental conditions were such that the transmission force acts on the helical timing belts under quasi-static conditions and the belt incurs belt climbing at the beginning of meshing and at the end of meshing. Experimental results obtained for the transmission error agreed closely with the computed results. The computed results revealed that helical timing belts can be analyzed as a set of very narrow belts for which the helix angle is zero. The transmission error was found to decrease when the helix angle or the belt width increase within a range defined such that the face advance is less than one belt pitch. In addition, there exists an appropriate installation tension that reduces the transmission error.

Transmission Error in Helical Timing Belt Drives: Case of a Period of Pulley Pitch

2000 ◽  
Author(s):  
Masanori Kagotani ◽  
Hiroyuki Ueda ◽  
Tomio Koyama
Keyword(s):  
Helix Angle ◽  
Transmission Error ◽  
Face Advance ◽  
Experimental Conditions ◽  
Belt Drives ◽  
Noise Characteristics ◽  
Synchronous Rotation ◽  
Timing Belt ◽  
Belt Width ◽  
Static Conditions

Abstract Helical timing belts have been developed in order to reduce the noise that occurs when conventional timing belts are driven. Helical timing belts are characterized by synchronous rotation. Although several studies have been performed to clarify the noise characteristics and belt life of helical timing belts, the transmission error of these belts remains unclear. In the present study, the transmission error having a period of one pitch of the pulley was investigated both theoretically and experimentally for helical timing belt drives. Experimental conditions were such that the transmission force acts on the helical timing belts under quasi-static conditions and the belt incurs belt climbing at the beginning of meshing and at the end of meshing. Experimental results obtained for the transmission error agreed closely with the computed results. The computed results revealed that helical timing belts can be analyzed as a set of very narrow belts for which the helix angle is zero. The transmission error was found to decrease when the helix angle or the belt width increases within a range defined such that the face advance is less than one belt pitch. In addition, there exists an appropriate installation tension that reduces the transmission error.

Improving the Characteristics of Gear Pumps: Part A — Discharge

2003 ◽  
Author(s):  
Ahmed M. M. El-Bahloul ◽  
Yasser Z. R. Ali
Keyword(s):  
Correction Factor ◽  
Helix Angle ◽  
Tooth Profile ◽  
Radius Of Curvature ◽  
Circular Arc ◽  
Pressure Angle ◽  
Face Width ◽  
Angle Change ◽  
Number Of Teeth ◽  
Gear Pumps

The main objective of this paper is to study the effect of gear geometry on the discharge of gear pumps. We have used gears of circular-arc tooth profile as gear pumps and have compared between these types of gearing and spur, helical gear pumps according to discharge. The chosen module change from 2 to 16 mm, number of teeth change from 8 to 20 teeth, pressure angle change from 10 to 30 deg, face width change from 20 to 120 mm, correction factor change from −1 to 1, helix angle change from 5 to 30 deg, and radii of curvature equal 1.4, 1.5, 2, 2.5, 2.75, and 3m are considered. The authors deduced that the tooth rack profile with radius of curvature equal 2.5, 2.75, 3m for all addendum circular arc tooth and convex-concave tooth profile, and derived equations representing the tooth profile, and calculated the points of intersections between curves of tooth profile. We drive the formulas for the volume of oil between adjacent teeth. Computer program has been prepared to calculate the discharge from the derived formulae with all variables for different types of gear pumps. Curves showing the change of discharge with module, number of teeth, pressure angle, face width, correction factor, helix angle, and radius of curvature are presented. The results show that: 1) The discharge increases with increasing module, number of teeth, positive correction factor, face width and radius of curvature of the tooth. 2) The discharge increases with increasing pressure angle to a certain value and then decreases with increasing pressure angle. 3) The discharge decreases with increasing helix angle. 4) The convex-concave circular-arc gears gives discharge higher than that of alla ddendum circular arc, spur, and helical gear pumps respectively. 5) A curve fitting of the results are done and the following formulae derived for the discharge of involute and circular arc gear pumps respectively: Q=A1bm2z0.895e0.065xe0.0033αe−0.0079βQ=A2bm2z0.91ρ10.669e−0.0047β

Transmission Error in Helical Synchronous Belt Drives in Bidirectional Operation: Influence of Pulley Flange Under No Load

2003 ◽  
Author(s):  
Masanori Kagotani ◽  
Kenichi Makita ◽  
Hiroyuki Ueda ◽  
Tomio Koyama
Keyword(s):  
Theoretical Analysis ◽  
Helix Angle ◽  
Transmission Error ◽  
Belt Drive ◽  
Alignment Error ◽  
Belt Drives ◽  
The Difference ◽  
Case Transmission ◽  
Synchronous Belt Drive ◽  
Outside Diameter

Helical synchronous belt drives are more effective than conventional synchronous belt drives with respect to reducing noise and transmission error per single pitch of the pulley. However, the helix angle of the tooth trace causes axial belt movement. Therefore, a flanged pulley is used in a helical synchronous belt drive. In the present study, the transmission error in a helical synchronous belt drive using a flanged pulley under installation tension was investigated both theoretically and experimentally for the case where the pulley was rotated in bidirectional operation. The computed transmission error agrees well with the experimental results, thereby confirming the applicability of the proposed theoretical analysis for transmission error. In this case, transmission error is found to be generated by the difference in axial belt movement between the driving and driven sides, and by a change in the state of contact between the belt and pulley teeth flanks. The transmission error is reduced when the installation tension is set higher than the tension that causes a change in contact direction between the tooth flanks. In addition, transmission error does not occur when the driving and driven pulleys are of equal outside diameter and have no pulley alignment error.

Experimental/Numerical Analysis of the Timing Belt Drive Behavior of a V6 Engine

2003 ◽  
Author(s):  
Lionel Manin ◽  
Didier Remond ◽  
Jean-Philippe Gaborel
Keyword(s):  
Rotation Speed ◽  
Transmission Error ◽  
Strain Gauges ◽  
Belt Drive ◽  
Automotive Engine ◽  
Transmission Errors ◽  
Belt Drives ◽  
Harmonic Content ◽  
Timing Belt ◽  
The Time Domain

The timing belts used for automotive engine are asked to last more and more, and to be less noisy. In this way, it is necessary to simulate the behavior of the engine timing belt drives for optimization, but also to understand it from experimental analysis. The first objective of the work was to analyze experimentally the behavior of a V6 engine timing belt drive in terms of: pulley speeds, belt span tensions, transmission error. The second objective was to compare the measurements with simulations. The engine has four overhead camshafts and 4 valves per cylinder. The timing belt drive is composed of six pulleys, three idlers and an automatic tensioner. The crankshaft and the two first camshaft speeds are measured with optical encoders. Spans tensions are measured by means of strain gauges glued on the idler mounting axes. All the data are simultaneously recorded. Tests have been run from 800 rpm to 6000 rpm. Measured data are first analyzed in the time domain. Some phenomena like, nil span tensions, speeds acyclism and transmission error amplitude, are observed. Then, analyses of the harmonic content of the span tensions, pulley speeds and transmission errors between the crankshaft and the camshafts, are performed versus engine rotation speed. Finally, the tests have been simulated and comparisons are made between numerical and experimental results.

Load Distribution in Timing Belts

1978 ◽  
Vol 100 (2) ◽  
pp. 208-215 ◽  
Author(s):  
G. Gerbert ◽  
H. Jo¨nsson ◽  
U. Persson ◽  
G. Stensson
Keyword(s):  
Load Distribution ◽  
Test Procedure ◽  
Spring Constant ◽  
The Finite Element Method ◽  
Belt Drives ◽  
Exponential Character ◽  
Timing Belt ◽  
Steel Cord ◽  
The Subject ◽  
Theory And Experiment

A theory is presented for determining the distribution of the belt tension and the tooth load in timing belts. It appears that the distribution of both loads is of exponential character and one important parameter is the ratio between the spring constant of the tooth and the spring constant of the cord (a nondimensional number). Friction between the belt and the top of the pulley is also considered. This mostly influences the tooth load distribution. A criterion is presented for maximum tension ratio with respect to correct tooth action. Two belts are examined experimentally (steel cord-urethane and glass fiber cord-neoprene rubber). The spring constant of the tooth is determined both experimentally (a test procedure is presented) and theoretically (using the finite element method) and the agreement is good. The distribution of the belt tension in timing belt drives has been measured. The agreement between theory and experiment for the belts examined is satisfactory. Some discrepancies were observed. These will be the subject for further research.

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