Such failure would do harm to the structural integrity of curvic coupling and result in higher maintenance expense, costly downtime, and can be catastrophic in rotor. On british jet engines the hirth coupling fullfilled a similar roll to the curvic coupling, though all the ones i worked on had a supporting compressor shaft on which the compressor discs were mounted sliding fit with the hirth couplings transmitting the drive from disc to disc, and maintaining the correct spacing between the individual compressor discs which carried the aerofoil section. Curvic coupling of mill turret should maintain disk weight and the cutting resistance, which occurs when the machining operation must have a power transmission function. Size check select a gear coupling to connect a 500 hp, 1170 rpm electric motor to a drive high speed shaft of a maneuvering winch. The coupling provides a positive drive along with precision centering and high load carrying capacity. Their application makes it possible to fulfil an accurate centering, as well as an improved reliability and good structural stability. As the coupling obtains a significant level of clamp force and hardness, it is optimally used for index tables at machining centers for heavy cuttings and in torque transfers. Inspection of curvic couplings using a cmm wit press. Privy to only bits and pieces of the design details it was never any consideration of using anything other than a curvic even though the hirth coupling was brought up several times. The curvic coupling was first developed by gleason works about sixty years ago. Curvic coupling, 2 the semiuniversal coupling, and 3 the releasing coupling or dutch, the. Th e serrated tooth circle divider uses two mat ing face gears. An accurate curvic stress determination early in the design process is required.
Adaptation of these methods for use in estimating contact pattern between curvic couplings. We are a custom gear facility, manufacturing gears to customer supplied blueprint specifications andor samples. Zn3r030m before the discs are eligible for reinstallation in an engine. Analysis of the contact stresses in curvic couplings of. Bending and vibration of a discontinuous beam with a curvic coupling under different axial forces show more 10.
Gleason model 887 cnc curvic coupling grinder with fanuc 18mb control. March 2000 machine was sent to gleason for full mechanical and electrical overhaulupgrade. The three basic types of curvic couplings are i the fixed. Hirth couplings, also regarded as curvic couplings, are widely used for torque transmission between mating discs in turbine machinery and are not covered by international standards for instance iso, din or agma. The inspection of curvic coupling geometry is usually done by using a mating master curvic to check the transfer of a very thm coating of engineering blue. Our extensive machine center repair capabilities include id and od cylindrical grinding, wheel grinding, vertical grinding, plus. Then, it has been implemented through design and manufacture methods to be used for connecting shafts of gasturbine engine.
Investigating curvic coupling behavior by utilizing the two and threedimensional. You have clicked a page that seems to be very popular. One half of the coupling is mounted on the turret mounting body. Our main activity is the manufacturing of hirth couplings. Strength formula for curvic coupling division accuracy. Request pdf a study on the cadcam of curvic couplings the curvic coupling was first developed by gleason works about sixty years ago. Provided coupling is known for its accurate alignment and precision centering capability whenever it is in mesh. In order to improve machining operation range, distance to the disk must increase as much as possible. I have searched the internet and there is not much in the way of how to document them. In a typical curvic coupling of a shaft, the teeth are generally located at the end faces of annular shafts, showing a hub andspoke pattern, as. Frost angle setting technology fast in use on a curvic coupling. Using a bright light, inspect the inboard and outboard curvic coupling teeth for proper engagement with the inboard and outboard flapping bearing teeth. Bending and vibration of a discontinuous beam with a.
Curvic couplings are similar in concept and appearance to hirth couplings, except that their teeth are curved instead of straight. Rings with hirth couplings are primarily used for the accurate positioning of axialsymmetric components in the machine tool industry. For the purposes of this a d, access to the hp turbine rotor discs is defined as the removal of the hp turbine rotor assembly from the engine. Curvics are sometimes used in aircraft engine design where multiple rotor stacks are required. Curvic manufacturers suppliers of curvic product and. Finally, a computer program is developed for designing curvic couplings with design parameters as input variables to predict the contact patterns of designed curvic couplings and to show them in. Like hirth couplings, they lock the components together in an unlockableremovable way and provide indexability. The contact pressure distribution of the curvic couplings in a heavy duty gas turbine under a bladeoff load condition is investigated in a threedimensional finite element model. A hirth joint or hirth coupling is a type of mechanical connection named after its developer albert hirth.
The fixed curvic coupling is used extensively in the construction of builtup. Design and production of a curvic coupling for testing purposes. A model accounting for stiffness weakening of curvic couplings. These couplings, which provide optimum contact with the shaft, can accommodate high torque values. Relying on our stateoftheart manufacturing set up, we are offering premium quality range of curvic coupling. The arrangement needed to be easy to work with, so that during maintenance, the alignment could be easily reestablished. Pdf curvic couplings are frequently used in aeroengine rotors.
Stock spiral bevel gears a cost saving alternative. Find manufacturers and distributors of curvic couplings. Experts in hirth serrations, we offer a complete range of services to meet almost any requirements. The method permits conversion of radial and axial runout measurements into part dimensions that represent manufacturing errors for each stage. A study on the stability of curvic coupling for distance. The inspection of curvic coupling geometry is usually done by using a mating master curvic to check the transfer of a very thm coating of engineering blue from the master to the curvic being inspected. Curvic couplingcurvic coupling is product description curvic coupling use for turret of cnc lathemachining center, robot, gas turbine, airplane, etc feature accurate and precise centering the curvature of the teeth give these couplings their very own and unique selfcentering feature.
Curvic coupling curvic coupling is product description. Investigating curvic coupling behavior by utilizing two and. Fixed curvic couplings the fixed curvic coupling is a precision face spline for joining two members, such as two sections of a shaft, to form. The most common method involves a curvic coupling mechanism. The article curvic coupling design appeared in the novemberdecember 1986 issue of gear technology summary curvic couplings were first introduced in 1942 to meet the need for permanent couplings and releasing couplings clutches, requiring extreme accuracy and maximum load carrying capacity, together with a fast rate of production. Our engineering staff can help with analysis of new designs as well as improvements on existing designs. Curvic coupling examples not having much experience with curvic couplings, is there anyone that would be willing to share a model and drawing of a curvic coupling style fixed curvic coupling. The curvature of the teeth give these couplings their. Digital inspection of fixed curvic coupling contact pattern. Industrial grinding services machine centers by repairing or rebuilding mating areas and worn diameters. Both are the same diameter and have equal tooth geometry and tooth size. Hirth couplings are also known as vtooth couplings, hirth joint, or voith hirth couplings.
It is used to connect two pieces of a shaft together and is characterized by tapered teeth that mesh together on the end faces of each half shaft. Panjiva uses over 30 international data sources to help you find qualified vendors of curvic. We provide prompt quotations, competitive pricing, and top quality gears. The stiffness of the curvic couplings is of guiding significance to the. To ensure stability in a threegroove kinematic coupling, the grooves must be arranged in a triangular fashion, such that the normals to the planes created by the two contact points of each coupling, intersect within the coupling triangle 9 as shown in figure 3.
Dec 16, 2016 frost angle setting technology fast in use on a curvic coupling. In order to ensure the coupling accuracy of aeroengines and gas turbines, curvic teeth and disk are usually formed integrally. Dlc is a specialized manufacturer of curvic coupling such as curvic, index curvic coupling, turret curvic coupling, airplane curvic coupling, 2pieces curvic coupling, 3pieces curvic coupling. The single flexing coupling is for use in the case where shafts are supported by three bearings. Alibaba manufacturer directory suppliers, manufacturers. This maintenance manual describes the correct service and repair procedures for all. Both haves are bottomed so the valleys will need work also. Hirth couplings hirth serration precision cnc machining. In order to manufacture the curvic coupling on a homemade cnc spiral bevel gear cutting or grinding machine, the manufacturing method for fixed curvic coupling was investigated. Investigating curvic coupling behavior by utilizing the. Pdf digital inspection of fixed curvic coupling contact pattern. A study on the cadcam of curvic couplings request pdf. Curvic coupling is also sometimes referred to as a permanent curvic coupling due to its use in applications where the components being coupled are. However the allowable load differs to the size of the curvic coupling in use.
Several bladeoff positions on each stage disk may develop the different characters on the contact pressure distributions of the curvic couplings during the application of a bladeoff load. Late in the day i did get a referall from the aerospace company to a smaller company. The present study, as a further evolution, proposes an experimentally validated closed form. The fixed curvic coupling is used extensively in the construction of builtup turbine and compressor rotors for aircraft and industrial gas or steam turbine engines. Fixed curvic couplings the fixed curvic coupling is a precision face spline for joining two members, such as two sections of a shaft, to form a single operating unit. The stiffness and the accuracy of centering the coupling have become very important. A new method is presented for optimizing the assembly of turbomachine rotors manufactured with gleason fixed curvic couplings. Schedule 40 longline coupling dia a b part number trade size carton qty. The mating master curvic is also used to measure dimensions such as swash, radial runout and overall stacking height.
Flap the inboard and outboard tail rotor blades to gain visual access to the 429012120101 curvic coupling teeth. Hirth or curvic couplings, used in serrated tooth circle dividers, shown in figure 3. Shaft collar, rigid coupling, flexible coupling cad files. Nov 29, 2007 curvic coupling examples not having much experience with curvic couplings, is there anyone that would be willing to share a model and drawing of a curvic coupling style fixed curvic coupling. Curvic coupling, 2 the semiuniversal coupling, and 3 the releasing coupling or dutch, the coupling provides a positive drive along with precision centering and high load carrying capacity. Since then, our couplings have been widely accepted in japanese market under the bland name of formflex coupling and have acquired a high reputation. Investigating curvic coupling behavior by utilizing two.
Buy best curvic coupling, hirth coupling with escrow buyer protection. The coupling shown in the diagram on the right above is suitable for use in cases subject to great radial loads. Komet5 is used in bevel gear gearing and face type coupling production curvic couplings to calculate corrections for machine settings andor tool data in order to reduce variations between nominal and actual geometry. Finally, a computer program is developed for designing curvic couplings with design parameters as input variables to predict the contact patterns of designed curvic couplings and to show them in the form of 3d models. Skf cou plings cover a wide range of coupling types, sizes and capacity ratings for many applica tions and factory environments. An investigation into using coordinate measuring machines cmms to measure gear geometry. Finally, a computer program is developed for designing curvic couplings with design parameters as input variables to predict the contact patterns of designed curvic couplings and to.
The jet engine industry needed an ultra precise locating arrangement to assure the exact alignment of components along the main engine shaft. Digital inspection of fixed curvic coupling contact pattern bradley james nielson this report focuses on providing a foundation for further. Nov 12, 2010 upon closer look the gap was just a slight chamfer on the back coupling. Buy best curvic coupling with escrow buyer protection. Hirth joints consist of radial teeth formed by grooves milled or ground into the end face of.
Hirth couplings can also be used in a variety of different applications including fixture indexing, medical, coupling impellers, compressors to their driven turbine shaft, and many more. Threedimensional models were created in beasy and ansys, and are described in the following subsections. It can result in a decrease in the structural stiffness or the separation of curvic coupling and lead to the joint failure. Pdf a model accounting for stiffness weakening of curvic.
Once program and dataspecific parameters have been configured, komet5 is a fully automatic, intuitive correction program. Curvic coupling, hirth coupling manufacturers,curvic coupling. Single reduction curvic coupling differential carriers. We repair and rebuild machine components such as shafts, curvic coupling rings, spindle heads, and sleeves. But moment is increased by the lack of bearing capacity of the curvic coupling. Grinding services including curvic coupling grinding services. Curvic coupling, curvic coupling manufacturer in india. Our mindset will be concentrated on satisfying the needs of our customers and working hard to become a futureoriented company. We will lead this market at the head of this field. Curvic couplings were first introduced in 1942 to meet the need for permanent couplings and releasing couplings clutches, requiring extreme accuracy and maximum load carrying capacity, together with a fast rate of production. Gear main product introduce bull gear marine engine gear pcc curvic coupling t curvic coupling seoam machinery industry we will make a great effort to satisfy customers with selfconfidence of the best. Equitable engineering uses cadcam engineering to manufacture a wide variety of precision gears, splines, and curvic couplings.
If the teeth of the 429012120101 curvic coupling were found improperly engaged per step 3, perform a rigging check of the directional control system. I dont know how they ended up with a half of a curvic coupling set. Although the stage 2 aft curvic is modeled, similar techniques may be applied to other curvic locations. Cpc couplings and fittings are ideal connectors for your plastic tubing applications in multiple industries, including medical, biopharmaceutical, chemical handling, liquid cooling of electronics, industrial, printing and food processing. Curvic coupling use for turret of cnc lathe machining center, robot, gas turbine, airplane, etc feature. Hirth coupling mechanical engineering general discussion. A study on the cadcam of curvic couplings turbo expo.
Thanks to our accumulated experience and technical knowhow, we manufacture outstanding gears, cylinders, curviccouplings and reducers, which pave the way for a global manufacturer of machine tool parts. Precision passive alignment of wafers by alexis christian weber submitted to the department of mechanical engineering on february 20, 2002 in partial fulfillment of the. First introduced in 1942 by gleason works, a curvic is a precision ground face spline. For large, heavy duty applications, skf has large size couplings. Cad drawings available for over,000 standard parts in various 2d and 3d formats to fit most systems. A lecture on the method to compute the the stress of vtooth coupling under the actual operating conditions. To connect the servomotor used in nc machine tools with the ball screw, an exceptional usage of the coupling as shown in the. You can chose from thousands of standard product options and the ability to customize for your needs whether youre looking for nonvalved. Curvic coupling design novdec 1986 gear technology. The three basic types of curvic couplings are the fixed curvic coupling, the semiuniversal coupling and the relating coupling. Arrow gear is a precision gear manufacturer, specializing in custom gearing and producing a wide variety of spiral bevel, straight bevel gears, stock gears, spur and helical gears as well as complete gearboxes. Minimizing assembly runout in turbomachines made with.