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Identification of the Quality of Timing Belt Pulleys
Available online at www.sciencedirect.com
ScienceDirect Procedia Engineering 177 (2017) 275 – 280
XXI International Polish-Slovak Conference “Machine Modeling and Simulations 2016”
Identification of the quality of timing belt pulleys Grzegorz Domeka*, Andrzej Kołodziejb, Marian Dudziakb, Tadeusz Woźniaka a Kazimierz Wielki University, Chodkiewicza 30, 85-064, Bydgoszcz, Poland The President Stanisław Wojciechowski State University of Applied Sciences in Kalisz, Nowy Świat 4, 62- 800 Kalisz, Poland
b
Abstract The paper present a test result of the quality of timing belt pulley. The quality of the pulleys have a significant impact on coupling timing belt with pulley. This is connected with the problem of the accuracy of movement and displacement. The majority of transport is realized the use of conveyor belts. Parallel conveyors, manipulators, electric actuators use movement with timing belts. The accuracy of motion, transmission with timing belt depends on the quality of belt gears, a specially quality of pulley. Measurements of these show a number of errors, affecting the kinematics and dynamics of the whole system-transport. It is also one of the most important parameters affecting on the durability of the timing belt. The quality of the wheels also depends on the chosen production technology, which is linked to the material and possibilities of the manufacturer. © 2017 2017 The © The Authors. Authors. Published Publishedby byElsevier ElsevierLtd. Ltd. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the organizing committee of MMS 2016. (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of MMS 2016 Keywords:Timing belts; timing belts pulleys; gear with timing belt;
1. Introduction The growing of use of timing belts, increases also the design problems with which many engineers can’t solve. Watching the incorrectly work of belt (noise, the belt moves on wheels, has problems with meshing) they have no idea about the reasons. Main reason is the production and installation errors of the pulleys. Due to increasing number of manufacturers and their production potential, the timing belts have become cheaper and more accessible structural elements. They are used in many applications from automotive industry, robotics, mechatronics through transportation and production systems [10]. This increasing use of timing belt transmission gears is caused by high efficiency and high accuracy of the movement. The possibility to manufacture transmission components of different materials allows their application in various, often extreme ambient conditions. They are used in low and high temperatures, explosion hazard atmospheres, environments susceptible to electrostatic discharge, food processing and medical equipment industries[6]. The case of problems transmissions in wastewater treatment plants leads us to undertake research. 2. Measurement systems For measuring of pulleys are used the highest quality measuring tools, for geometry and surface condition. (Fig. 1,4).In first system, measuring head equipped with a sensor tip cone completed diamond or ruby ball moves across the surface of the recording consecutive points. On the basis of the generated charts and calculated roughness parameters. All parameters are
* Corresponding author. Tel.:+48 693 296 760; fax:+4852 3419331. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of MMS 2016
doi:10.1016/j.proeng.2017.02.224
276
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
measured in a single pass of the measuring tip. The impact of external factors on the measurement process is limited by isolating the equipment from: ground vibration (vibration damping system), air movement (glass enclosure). Test tips are detected electronically and automatically assigned to each measuring task. This eliminates measurement errors arising due to the use of incorrect measuring tips. Damage the tip is eliminated by means of an electronic speed limiter to avoid a sudden contact with the measured object. Force measuring tip can be adjusted electronically, depending on the measuring tip to avoid errors or damage to the tip. High precision positioning in the measurement of small holes or automatic measurements discontinuous surface.
Fig.1. Measuring system Nanoscan 855 Jenoplic.
General measurement accuracy: angle measurement: ± 0.5 'angle standard, the nominal 90 °. radius measurement: ± 0.01% of the calibration sphere, nominal R = 10 mm. distance measurement: ± 2 microns KN8, nominal 82 mm.
Fig.2. Research of geometry of teeth.
Technical data and measurement accuracy: • Measuring range / resolution Z axis: 24 mm / 0.6 nm or 48 mm / 1.2 nm. • Measuring range / resolution unit transverse: 200 mm / 10 nm. • Measuring force: electronically controlled within ± 1 ÷ 50 mN. • Accuracy straightness: ≤ 0.4 microns / 200 mm. • Measuring speed: 0.1 to 3 mm / s. • Repeatability of positioning: 10 microns. • Maximum positioning speed measuring tip: 9 mm / s. • The maximum lateral positioning speed: 50 mm / s. • Test tips: diamond cone with an apex angle of 60 ° and radiused 2 microns, ruby ball with a diameter of φ 1 mm. • The table CNC controlled measuring 160 x 160 x 96 mm: range: ± 12.5 mm (x / y coordinates). Rotation range: ± 5 ° around the vertical axis. The maximum weight of the item being measured 30 kg.
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
277
Fig.3. Measurement results.
Measurement results show too small radius of rounding of the tooth tips. Suspension point where is fixed radius describing of a notch of pulley, is engaged too low, therefore is not an appropriate opening angle of the tooth flanks (Fig.3).
Fig.4. Coordinate measuring machine Wenzel LH 65.
278
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
Coordinate measuring machine Wenzel LH 65 (Fig. 4) of the last design is equipped with the latest (continuously variable) measuring head rotary tilting RENISHAW PH20. With this solution achieved the ability to work in a 5-axis, which can significantly reduce the time of measurement element, and all measurements of detail can often be done using only one measuring tip. Information on the size of the element is seen as a set of coordinates (in the coordinate system specified) by the contact. As a result of receiving a set of data points by the computer, we get the dimensions of the characteristics of the measured object. One of the advantages of coordinate metrology is to perform measurements of various objects with complex shapes that can’t be measured with a basic instrument workshops (calipers, sensors, microscopes). In addition to the standard measurement geometry, using CMMs can measure pulleys with various features, as well as deviations of form and position in accordance with ISO 1101.[9]
Fig. 5. Measurement of the belt pulley geometry.
Belt diameter manufacturing inaccuracies, roundness and installation errors cause the belt linear speed variations which tremendously hinder the transport and control process. Changed diameter of mating between the belt and the pulley permanently changes the nature of this mating, changes the pitch and the linear speed of the belt Δv (Fig.5). The momentary change in speed v x depends on the change of the pulley radius Δrs and on the installation misalignment R and the relative offset angle of these errors Δ β.
Qx
G· § G· § Z s ¨ rs ¸ ¨ R ¸ 1 cos E ©
2¹ ©
2¹
(1)
In case of parallel transport, those errors shall cause product turning on the conveyor. This phenomenon is enhanced by the belt pitch errors Δh. and it is a big problem in precise transport and control systems.
Qx
G· § G· § Z s ¨ rs ¸ ¨ R ¸ 1 cos E + Δh ©
2¹ ©
2¹
(2)
This problem is emphasized in the complex systems comprising of cooperating toothed belt transmission gears. 3.Timing belt and pulleys cooperation conditions Fist designs of timing belt gears imitated chain transmissions, where a belt was supposed to fulfill the same function but emitting less noise. Therefore form-fitting meshing of a trapezoid timing belt with a pulley prevailed [3,4]. A belt rested on pulley teeth
279
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
tips and the circumferential forces were transmitted by pressure of belt teeth sides on pulley teeth [1]. The belt did not require large pre-stress forces, but its transmission capacity was not entirely used. In subsequent type schedules of belts the designers rounded teeth sides and aimed at changing the conditions of belt resting on the pulley. Accuracy of the pulleys manufacturing became more important. The optimum mating was obtained in the AT belt type which was the first belt the tooth tips of which rested on the bottom of the pulley teeth grooves. Accuracy of the pulley manufacturing and installation as well as manufacturing of the belt load-carrying layer have become more important in such transmission gear types . When analyzing the properties of the timing belt transmission gear one has to note that it consists of materials of various mechanical properties[5,7]. The pulleys are made of elastic materials, while belts are a composite of elastic fibers and viscoelastic materials of clearly nonlinear mechanical characteristics and clear hysteresis loop. The timing belt transmission gear contains a combination of cooperating materials[8]. There are hundreds of such combinations like wheels of steel or other metal alloys or plastics mating with belts of thermoplastic or thermosetting polymers reinforced with steel, glass or carbon fibers. Timing belt and pulleys mating conditions can be characterized by the following relationships:
dS1 dS2
f ( P P , FN , H N )
(3)
Given the relationships of engagement between the belt and the pulley one can design transmission gear so that it optimally fulfills its function in specific ambient conditions.
dS1 dS2
eP E
(4)
the condition defined by the Euler's formula is met: - the pulley contact angle β - μ friction factor, which - in the case of a timing belt - results from the product of the factor of friction between the belt and pulley μ kp and the friction factor inside the belt material and the load-carrying layer μ m.. Temporary change of the coupling depends largely of production errors and assembly of pulleys x.
dS1 dt dS 2
e P E xdt
(5)
where:
x
'rs 'R 1 cos E 'h
(6)
c
b
a
Fig. 6 Timing belt pulley surface: a) the bottom of the notch, b) tooth tip, c) edge of tooth.
280
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
The pulley surface condition is dependent on the selected material and production technology (Fig. 6) [8]. Its influence on mating with the pulley is decisive for the nature of the engagement and for the belt durability. To improve the life of the transmission gear it is important to reduce the friction factor on the teeth sides and tips, while groove bottoms should provide good belt adhesion. Belt surface is frequently covered with fabrics, that reduces friction during engagement with the pulley and also in meshing on total contact surface. 4. Conclusions Measurement results showed errors in the geometry of the timing belt pulley. The tested pulley is characterized by an excessive noise emissions. This phenomenon was caused by too small peaks diameter and of the wrong tooth geometry. Those errors are caused by improper production. Pulley was settling on axis with taper bushes and this is one of the most accurate method, and here should not be looked for reasons of wrong operation. The transmission gear manufacturing accuracy problems indicated above do not disqualify those transmission gears from "accurate" applications. The key properties to which special attention should be paid during engineering and production stage were pointed out. The designers should also remember about proper design of the gear operation process. Importance of the pulley surface condition and its deterioration in the gear operation process was also emphasized. References [1]
G. Domek , Research on the Contact Area between the Timing Belt and the Toothed Pulley, World Congress on Engineering (WCE 2011), Lectures Notes in Engineering and Computer Science, Vol. III, 2242-2244. [2] G. Domek, Meshing model in gear with timing belt, Journal of Advanced Materials Research, Vols. 189-193(2011) 4356-4360. [3] G. Domek, Timing belts dynamics model approach, Journal of Mechanics Engineering and Automation, 2, 8 (2012) 495-497. [4] G. Domek, Meshing in gear with timing belts, International Journal of Engineering and Technology (IJET), 3, 1 (2011) 26-29. [5] G. Domek, M. Dudziak, Energy dissipation in timing belts made from composite materials, Journal of Advanced Materials Research, 189-193 (2011) 44144418. [6] G. Domek, M. Dudziak, A. Kołodziej, Timing belt gear design for mechatronics system, Procedia Engineering 96 (2014) 39-43, Elsevier. [7] G. Domek, A. Kołodziej, Modification of Joints in Polymer Timing Belts, Machine Dynamics Research, 39 (2015) 15-20. [8] M. Dudziak, G. Domek, A. Kołodziej, Contact problems between the hub and the shaft with a three-angular shape of cross-section for different angular positions, Procedia Engineering 96 (2014) 50-58. [9] M. Dudziak, A. Kołodziej, G. Domek, Influence of Geometrical Deviation of Shape on Functionality and Reliability of Conical Joints, Machine Dynamics Problems 2009, Vol. 33, No 3. [10] H. Dressing, F. Holzweissig, Dynamics of Machinery, Theory and Applications, Springer Verlag, Berlin, Heidelberg 2010.
ScienceDirect Procedia Engineering 177 (2017) 275 – 280
XXI International Polish-Slovak Conference “Machine Modeling and Simulations 2016”
Identification of the quality of timing belt pulleys Grzegorz Domeka*, Andrzej Kołodziejb, Marian Dudziakb, Tadeusz Woźniaka a Kazimierz Wielki University, Chodkiewicza 30, 85-064, Bydgoszcz, Poland The President Stanisław Wojciechowski State University of Applied Sciences in Kalisz, Nowy Świat 4, 62- 800 Kalisz, Poland
b
Abstract The paper present a test result of the quality of timing belt pulley. The quality of the pulleys have a significant impact on coupling timing belt with pulley. This is connected with the problem of the accuracy of movement and displacement. The majority of transport is realized the use of conveyor belts. Parallel conveyors, manipulators, electric actuators use movement with timing belts. The accuracy of motion, transmission with timing belt depends on the quality of belt gears, a specially quality of pulley. Measurements of these show a number of errors, affecting the kinematics and dynamics of the whole system-transport. It is also one of the most important parameters affecting on the durability of the timing belt. The quality of the wheels also depends on the chosen production technology, which is linked to the material and possibilities of the manufacturer. © 2017 2017 The © The Authors. Authors. Published Publishedby byElsevier ElsevierLtd. Ltd. This is an open access article under the CC BY-NC-ND license Peer-review under responsibility of the organizing committee of MMS 2016. (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of the organizing committee of MMS 2016 Keywords:Timing belts; timing belts pulleys; gear with timing belt;
1. Introduction The growing of use of timing belts, increases also the design problems with which many engineers can’t solve. Watching the incorrectly work of belt (noise, the belt moves on wheels, has problems with meshing) they have no idea about the reasons. Main reason is the production and installation errors of the pulleys. Due to increasing number of manufacturers and their production potential, the timing belts have become cheaper and more accessible structural elements. They are used in many applications from automotive industry, robotics, mechatronics through transportation and production systems [10]. This increasing use of timing belt transmission gears is caused by high efficiency and high accuracy of the movement. The possibility to manufacture transmission components of different materials allows their application in various, often extreme ambient conditions. They are used in low and high temperatures, explosion hazard atmospheres, environments susceptible to electrostatic discharge, food processing and medical equipment industries[6]. The case of problems transmissions in wastewater treatment plants leads us to undertake research. 2. Measurement systems For measuring of pulleys are used the highest quality measuring tools, for geometry and surface condition. (Fig. 1,4).In first system, measuring head equipped with a sensor tip cone completed diamond or ruby ball moves across the surface of the recording consecutive points. On the basis of the generated charts and calculated roughness parameters. All parameters are
* Corresponding author. Tel.:+48 693 296 760; fax:+4852 3419331. E-mail address: [email protected]
1877-7058 © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of MMS 2016
doi:10.1016/j.proeng.2017.02.224
276
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
measured in a single pass of the measuring tip. The impact of external factors on the measurement process is limited by isolating the equipment from: ground vibration (vibration damping system), air movement (glass enclosure). Test tips are detected electronically and automatically assigned to each measuring task. This eliminates measurement errors arising due to the use of incorrect measuring tips. Damage the tip is eliminated by means of an electronic speed limiter to avoid a sudden contact with the measured object. Force measuring tip can be adjusted electronically, depending on the measuring tip to avoid errors or damage to the tip. High precision positioning in the measurement of small holes or automatic measurements discontinuous surface.
Fig.1. Measuring system Nanoscan 855 Jenoplic.
General measurement accuracy: angle measurement: ± 0.5 'angle standard, the nominal 90 °. radius measurement: ± 0.01% of the calibration sphere, nominal R = 10 mm. distance measurement: ± 2 microns KN8, nominal 82 mm.
Fig.2. Research of geometry of teeth.
Technical data and measurement accuracy: • Measuring range / resolution Z axis: 24 mm / 0.6 nm or 48 mm / 1.2 nm. • Measuring range / resolution unit transverse: 200 mm / 10 nm. • Measuring force: electronically controlled within ± 1 ÷ 50 mN. • Accuracy straightness: ≤ 0.4 microns / 200 mm. • Measuring speed: 0.1 to 3 mm / s. • Repeatability of positioning: 10 microns. • Maximum positioning speed measuring tip: 9 mm / s. • The maximum lateral positioning speed: 50 mm / s. • Test tips: diamond cone with an apex angle of 60 ° and radiused 2 microns, ruby ball with a diameter of φ 1 mm. • The table CNC controlled measuring 160 x 160 x 96 mm: range: ± 12.5 mm (x / y coordinates). Rotation range: ± 5 ° around the vertical axis. The maximum weight of the item being measured 30 kg.
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
277
Fig.3. Measurement results.
Measurement results show too small radius of rounding of the tooth tips. Suspension point where is fixed radius describing of a notch of pulley, is engaged too low, therefore is not an appropriate opening angle of the tooth flanks (Fig.3).
Fig.4. Coordinate measuring machine Wenzel LH 65.
278
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
Coordinate measuring machine Wenzel LH 65 (Fig. 4) of the last design is equipped with the latest (continuously variable) measuring head rotary tilting RENISHAW PH20. With this solution achieved the ability to work in a 5-axis, which can significantly reduce the time of measurement element, and all measurements of detail can often be done using only one measuring tip. Information on the size of the element is seen as a set of coordinates (in the coordinate system specified) by the contact. As a result of receiving a set of data points by the computer, we get the dimensions of the characteristics of the measured object. One of the advantages of coordinate metrology is to perform measurements of various objects with complex shapes that can’t be measured with a basic instrument workshops (calipers, sensors, microscopes). In addition to the standard measurement geometry, using CMMs can measure pulleys with various features, as well as deviations of form and position in accordance with ISO 1101.[9]
Fig. 5. Measurement of the belt pulley geometry.
Belt diameter manufacturing inaccuracies, roundness and installation errors cause the belt linear speed variations which tremendously hinder the transport and control process. Changed diameter of mating between the belt and the pulley permanently changes the nature of this mating, changes the pitch and the linear speed of the belt Δv (Fig.5). The momentary change in speed v x depends on the change of the pulley radius Δrs and on the installation misalignment R and the relative offset angle of these errors Δ β.
Qx
G· § G· § Z s ¨ rs ¸ ¨ R ¸ 1 cos E ©
2¹ ©
2¹
(1)
In case of parallel transport, those errors shall cause product turning on the conveyor. This phenomenon is enhanced by the belt pitch errors Δh. and it is a big problem in precise transport and control systems.
Qx
G· § G· § Z s ¨ rs ¸ ¨ R ¸ 1 cos E + Δh ©
2¹ ©
2¹
(2)
This problem is emphasized in the complex systems comprising of cooperating toothed belt transmission gears. 3.Timing belt and pulleys cooperation conditions Fist designs of timing belt gears imitated chain transmissions, where a belt was supposed to fulfill the same function but emitting less noise. Therefore form-fitting meshing of a trapezoid timing belt with a pulley prevailed [3,4]. A belt rested on pulley teeth
279
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
tips and the circumferential forces were transmitted by pressure of belt teeth sides on pulley teeth [1]. The belt did not require large pre-stress forces, but its transmission capacity was not entirely used. In subsequent type schedules of belts the designers rounded teeth sides and aimed at changing the conditions of belt resting on the pulley. Accuracy of the pulleys manufacturing became more important. The optimum mating was obtained in the AT belt type which was the first belt the tooth tips of which rested on the bottom of the pulley teeth grooves. Accuracy of the pulley manufacturing and installation as well as manufacturing of the belt load-carrying layer have become more important in such transmission gear types . When analyzing the properties of the timing belt transmission gear one has to note that it consists of materials of various mechanical properties[5,7]. The pulleys are made of elastic materials, while belts are a composite of elastic fibers and viscoelastic materials of clearly nonlinear mechanical characteristics and clear hysteresis loop. The timing belt transmission gear contains a combination of cooperating materials[8]. There are hundreds of such combinations like wheels of steel or other metal alloys or plastics mating with belts of thermoplastic or thermosetting polymers reinforced with steel, glass or carbon fibers. Timing belt and pulleys mating conditions can be characterized by the following relationships:
dS1 dS2
f ( P P , FN , H N )
(3)
Given the relationships of engagement between the belt and the pulley one can design transmission gear so that it optimally fulfills its function in specific ambient conditions.
dS1 dS2
eP E
(4)
the condition defined by the Euler's formula is met: - the pulley contact angle β - μ friction factor, which - in the case of a timing belt - results from the product of the factor of friction between the belt and pulley μ kp and the friction factor inside the belt material and the load-carrying layer μ m.. Temporary change of the coupling depends largely of production errors and assembly of pulleys x.
dS1 dt dS 2
e P E xdt
(5)
where:
x
'rs 'R 1 cos E 'h
(6)
c
b
a
Fig. 6 Timing belt pulley surface: a) the bottom of the notch, b) tooth tip, c) edge of tooth.
280
Grzegorz Domek et al. / Procedia Engineering 177 (2017) 275 – 280
The pulley surface condition is dependent on the selected material and production technology (Fig. 6) [8]. Its influence on mating with the pulley is decisive for the nature of the engagement and for the belt durability. To improve the life of the transmission gear it is important to reduce the friction factor on the teeth sides and tips, while groove bottoms should provide good belt adhesion. Belt surface is frequently covered with fabrics, that reduces friction during engagement with the pulley and also in meshing on total contact surface. 4. Conclusions Measurement results showed errors in the geometry of the timing belt pulley. The tested pulley is characterized by an excessive noise emissions. This phenomenon was caused by too small peaks diameter and of the wrong tooth geometry. Those errors are caused by improper production. Pulley was settling on axis with taper bushes and this is one of the most accurate method, and here should not be looked for reasons of wrong operation. The transmission gear manufacturing accuracy problems indicated above do not disqualify those transmission gears from "accurate" applications. The key properties to which special attention should be paid during engineering and production stage were pointed out. The designers should also remember about proper design of the gear operation process. Importance of the pulley surface condition and its deterioration in the gear operation process was also emphasized. References [1]
G. Domek , Research on the Contact Area between the Timing Belt and the Toothed Pulley, World Congress on Engineering (WCE 2011), Lectures Notes in Engineering and Computer Science, Vol. III, 2242-2244. [2] G. Domek, Meshing model in gear with timing belt, Journal of Advanced Materials Research, Vols. 189-193(2011) 4356-4360. [3] G. Domek, Timing belts dynamics model approach, Journal of Mechanics Engineering and Automation, 2, 8 (2012) 495-497. [4] G. Domek, Meshing in gear with timing belts, International Journal of Engineering and Technology (IJET), 3, 1 (2011) 26-29. [5] G. Domek, M. Dudziak, Energy dissipation in timing belts made from composite materials, Journal of Advanced Materials Research, 189-193 (2011) 44144418. [6] G. Domek, M. Dudziak, A. Kołodziej, Timing belt gear design for mechatronics system, Procedia Engineering 96 (2014) 39-43, Elsevier. [7] G. Domek, A. Kołodziej, Modification of Joints in Polymer Timing Belts, Machine Dynamics Research, 39 (2015) 15-20. [8] M. Dudziak, G. Domek, A. Kołodziej, Contact problems between the hub and the shaft with a three-angular shape of cross-section for different angular positions, Procedia Engineering 96 (2014) 50-58. [9] M. Dudziak, A. Kołodziej, G. Domek, Influence of Geometrical Deviation of Shape on Functionality and Reliability of Conical Joints, Machine Dynamics Problems 2009, Vol. 33, No 3. [10] H. Dressing, F. Holzweissig, Dynamics of Machinery, Theory and Applications, Springer Verlag, Berlin, Heidelberg 2010.