1、- 99FTM10 Design and Testing of a Low Noise Marine Gear by: J.J. Bos, Schelde Gear American Gear I J TECHNICAL PAPER COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling ServicesDesign and Testing of a Low Noise Marine Gear J.J. Bos, Scheide Gears The statements an
2、d opinions contained herein are those of the author and should not be construed as an official action or opinion of the American Gear Manufacturers Association. Abstract Schelde Gears is a Dutch gear manufacturer specialized in gear transmissions for merchant and marine naval applications, especiall
3、y those with special requirements for noise and vibration levels. Typical for naval application is the underwater noise requirement and for merchant ships the structural vibration level for the passenger comfort. The purpose of this paper is to give an overview of design, back to back testing and te
4、st results of gearboxes designed for low noise and vibration levels. In 1998 several designs for low noise gearboxes have been made such as for the Royal Dutch Navy, Spanish Navy and for a cruise ship. The presentation will focus on the design for the Royal Dutch Navy LCF frigate. This gearbox is of
5、 a propulsion mode of 5000 kW at 1000 rpm and a gasturbine propulsion mode of 19000 kW at 5450 rpm. The propeller speed for this gearbox will vary from 50 to 164 rpm, with a respective input power of 1200 kW to 19000 kW. The specific requirements for underwater noise are defined for diesel and gastu
6、rbine propulsion modes at a ship speed of 18 knots (93 rpm of the output shaft). In order to meet the design requirements for low noise special attention was paid to all aspects that will influence the noise and vibration performance of the gearbox. The design aspects, such as tooth corrections, too
7、th loading, gear lay-out, balancing, lubricating system and resilient mounting system will be discussed. The performance of the gearbox is tested for acceptance in a back to back test for both diesel engine and gasturbine drive modes. The tests were performed for an input power of 3000 kW, correspon
8、ding with a propeller speed of 93 rpm. The required tooth loading during testing is obtained by a means of a torque actuator. Typical results of the back to back test will be presented at the end of this presentation. Copyright O 1999 American Gear Manufacturers Association 1500 King Street, Suite 2
9、01 Alexandria, Virginia, 22314 October, 1999 ISBN: 1-55589-748-7 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling ServicesDESIGN AND TESTING OF A LOW NOISE MARINE GEAR J.J.Bos Schelde Gears, Vlissingen, The Netherlands Introduction Schelde Gears is a Dutch gear
10、 manufacturer cpecialised in gear transmissions for merchant naval and marine naval applications with special requirements for noise and vibration levels. Typical power ratings are 5 MW up to 40 MW, with centre distances ranging from 800 to 4500 mm. The dimensions of these gears vary from 2 x 2 x 2
11、to 5 x 5 x 5 (I x b x h) metre. Typical for marine naval applications is the underwater noise requirement and for merchant naval applications, passenger ships and car ferries, the structural vibration level for the passenger comfort. In 1998 several designs for low noise gearboxes have been made suc
12、h as for the Royal Dutch Navy, Spanish Navy and for a cruise ship. This presentation will give an overview of the practical design of a naval gear for combined diesel or gasturbine propulsion (CODOG type ). The performance of the gear regarding the vibration levels is tested in a back to back test.
13、The gear presented is a design for the Royal Dutch Navy LCF frigate. The gear has been designed for low noise. The design aspects for low noise operation were incorporated in the design, therefore special attention was required for all parameters of influence for the noise and vibration performance
14、of the gearbox. The design aspects, such as tooth corrections, tooth loading, gear lay-out, balancing, lubricating system and resilient mounting will be discussed. The back-to-back configuration was built with two gears, intermediate shafts and a torque actuator for load simulation. The tests were d
15、one for gasturbine and diesel engine propulsion modes at approximately 3000 kW power input corresponding with a propeller shaft-speed of 93 rpm. The torque actuator for this test configuration was rated for a maximum torque of 45 kNm and a maximum speed of 3500 rpm. The required torque during testin
16、g amounts to 33 kNm at 875 rpm. Desian requirements The propulsion system for the LCF consist of two independent opposite handed propulsion lines, one for the starboard and one for the portside propeller shaft line with Controlled Pitch Propeller (CPP), each with a boost gasturbine and a cruising di
17、esel engine propulsion mode. The design of each gearing had to meet the specific requirements of which the most important are listed below: 0 Gear ratings: Diesel engine propulsion: Power 5000 kW Input shaft speed: 1000 rpm 103 rpm Output speed Gasturbine propulsion Power 19500 kW Input speed 5450 r
18、prn Output speed 164 rpm 1 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling ServicesFigure 1 : Lay-out of the gear elements OUTPUT - DE- I DE GT QUILL SHAF DE WHEEL MAIN PINION 7 GT WHEEL 0 Propeller shaft speed 0 Input power range 0 Oil supply for the gear by
19、a gear driven pump in the propeller speed range of 64 - 164 rpm 0 Shock resistant for shocks up to 13 g 0 The structure borne noise requirements for above and below the resilient mounting are defined for a shaft speed of 93 rpm. Range min. 50 - max. 164 rpm min. 1200 kW - max. 19500 kW The fulfilmen
20、t of the structure borne and air borne noise requirement shall be demonstrated in a back to back test. Noise requirements for airborne and structure borne noise according to Navy specification In respect to the above mentioned design requirements special attention was given to minimize the number of
21、 rotating elements under load for both gasturbine and diesel engine propulsion, to have optimal corrections for loaded conditions and to optimize the tooth loading. The gears are mountedon a resilient 2 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling Servicesm
22、ounting in order to optimize damping of the higher frequency range vibrations and therefore to reduce the underwater noise level. The thrustblock for this design is a separate item rigid mounted in the propeller shaft line. The whole geartrain in the gear box has therefore the freedom of movement of
23、 15 mm to accommodate the relative movement of gearbox to shaftline. This movement is caused by displacements of. the gearcase due to the resilient mounting and due to shock loads. The site of the gear, overall dimensions appr. 5 x 5 x 4 (I x b x h) metre, and the number of flexible mounts ,35 in th
24、is case, require a rigid casing for optimal performance of the flexible mounting. The stiffness of the casing was checked by means of a FEA analysis. In combination with the flexible mounting the stiffness of the gear casing is an important feature. Lav-out . DE wheel Main pinion Main.wheel 30CrNiMo
25、8 17CrNiMo6 32CrMo12 Through Carburized Nitrided hardened 158 53 305 30CrNiMo8 3OCrNiMo8 63 a C50E+QT 1 The first objective was to design a gear lay-out, see figure 1, that could meet the requirements as specified within the available space in the gear compartment and the geometric positions for the
26、 input shafts of the diesel engine and gasturbine and the output shaft. Important features for the design are a balanced tooth load and to minimise the number of rotating elements together with the elimination of rotation of elements in an unloaded condition. The lay-out that was chosen for this pur
27、pose is a two stage reduction for both diesel and gasturbine propulsion. The second stage is a e Table 1: Overview of all rotating parts treatment Module Number of teeth Quill shafts Mains haft GTpinion I GT wheel 17CrNiMo6 1 17CrNiMo6 Carburized 1 Carburized 40 6,s common stage for both propulsion
28、modes. The thrustblock is an separate item in the shaftline. The whole geartrain is axially positioned by this thrust bearing. The first reductions of diesel and gasturbine input require therefore a connection to the second reduction pinion in axial direction for those conditions that the reductions
29、 are running disengaged or engaged. The clutches are therefore equipped with a axial bearings. The rotating parts therefore float in the gear casing in axial direction. Geardesinn The construction of the first reduction pinions and wheels is based on solid forgings. The construction of the second re
30、duction is based on assemblies. The main wheel is a fabricated structure shrunk on to the main shaft. A centre driven second reduction pinion was required to be able to establish a good tooth contact pattern in both gasturbine and diesel engine propulsion. The construction of the second reduction pi
31、nion is a centre shaft with a special designed intermediate sleeve on which the pinion body is shrunk. Due to this DE pinion 17CrNiMo6 Carburized 94 . 3 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling ServicesFigure 2: Top view of the portside gear All dimensi
32、ons in mm FORE a-wip i I Figure 3: Front view of the portsidegear All dimensions in mm - O O a O L 14d .- n 4200 SHIP 4 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling Servicese special design, the assembly of pinion, quill shafts and sleeve consists of 5 item
33、s. For the several operational modes, two clutches have been built in. The second reduction pinion is connected to these clutches by means of quill shafts, see also figure 1. The gasturbine reduction wheel is equipped with a self shifting synchronising clutch connected to the quill shaft of the seco
34、nd reduction pinion. The diesel engine reduction wheel is equipped with a hydraulically operated multi plate type friction clutch connected to the quill shaft of the second reduction pinion. Table 1 gives an overview of all rotating parts. The under water noise spectrum of the ship can be identified
35、 by the 1 and 2“d order tooth frequencies in case they are dominantly present in the noise spectrum. The distinctive role of the tooth frequencies in the vibration spectrum of the gear should be avoided. Therefore the gear design required a high total contact coefficient , which is realized with a d
36、ouble helical gear design with a pametrada tooth , a 16“ pressure angle and a module as small as possible with acceptable tooth load. All tooth calculations are based on Lloyds Rules of Shipping, DIN and IS0 regulations. The oil pumps mounted on the gear also required an optimal design with regard t
37、o noise generation. In our normal practise the tooth corrections are manufactured by correction of the helical angle and tip relief in combination with tooth end reliefs. The tooth corrections for this gear were based on our own experience and programs for tooth corrections and secondly on calculati
38、ons done by the Design Unit of the University of Newcastle,UK. The dedicated program for the tooth correction calculation is the DU-GATE program, designed for tooth correction calculations in order to minimize the transmission error. The accuracy level for the gear elements is in accordance with IS0
39、 1328 Class 3 requirements. All these design aspects contribute to a low air borne noise and structure borne noise level of the gearbox. The optimal tooth corrections are based on the full load conditions, the calculations for a transmission error were made for loads in the operational modes with no
40、ise requirements. The tooth corrections are based on bending, including shear, torsion and the bearing position. Other parameters such as wheel deformation and housing deformation were in this case neglectable. The design of the second reduction pinion requires a central driven construction in order
41、 to have a optimal tooth loading for both gasturbine and diesel propulsion. 0 Gear casing design The design of the total gear casing is based on a separate casing for the diesel first reduction, for the gasturbine first reduction, and for the second reduction. The casings are fabricated construction
42、s with solid walls. The decision for a solid wall was mainly based on noise requirements. For stiffness purposes a fabricated structure with a double wall should fit this purpose at best, however due to the fact that the distance between shaft centre lines and foundation is relative low ( al C O - 8
43、0 70 2 $ 60 50 40 1 16 31.5 63 125 250 500 1000 2000 4000 8000 Frequency (Hz) -c Diesel Engine Test Mode Portside Gear, master gear +Diesel Engine Test Mode Starboard Gear, slaw gear 12 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling Serviceseg gear driven pum
44、ps. The back to back testing of a gear can only be successfull and representative when all operational conditions can be reproduced. This is valid specially for balancing of all shafts and couplings, especially for the high speed shafts. The engagement sequences should be as close as possible to the
45、 conditions on board of the ship. In case these conditions are not met the result will give an approximation, but will be contaminatied with disturbances from the test rig. O References I A New Rotary Torque Actuator For High Rotational Speeds. J. Rosinski, J. Haigh and D.A Hofmann 1994 Internationa
46、l Gearing Conference, Newcastle 2 Development Of A New Three-Dimensional Mode Of Helical Gears. J.J. Burdess, J. Penne11 and J. Rosinski 1994 International Gearing Conference, Newcastle 3 High Performance Gearing For Modern Naval Gas Turbine Propulsion Systems J.B. Kerpenstein 1987 ASME Gas Turbine
47、Conference, ASME paper 87-GT-247 13 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling ServicesPUBUSHED BY AMERICAN GEAR MANUFACTURERS ASSOCIATION 1500 KING STREET, ALEXANDRIA, VIRGINIA 22314 COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling Services
