Digital inspection of fixed curvic coupling contact pattern. Equitable engineering uses cadcam engineering to manufacture a wide variety of precision gears, splines, and curvic couplings. 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. Design and production of a curvic coupling for testing purposes. You can chose from thousands of standard product options and the ability to customize for your needs whether youre looking for nonvalved.
The mating master curvic is also used to measure dimensions such as swash, radial runout and overall stacking height. The three basic types of curvic couplings are the fixed curvic coupling, the semiuniversal coupling and the relating coupling. 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. Schedule 40 longline coupling dia a b part number trade size carton qty. 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. A beam coupling, also known as helical coupling, is a flexible coupling for transmitting torque between two shafts while allowing for angular misalignment, parallel offset and even axial motion, of one shaft relative to the other. Cad drawings available for over,000 standard parts in various 2d and 3d formats to fit most systems.
In order to improve machining operation range, distance to the disk must increase as much as possible. The fixed curvic coupling is also sometimes referred to as a permanent curvic coupling due to. Inspection of curvic couplings using a cmm wit press. 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. Although the stage 2 aft curvic is modeled, similar techniques may be applied to other curvic locations. A study on the cadcam of curvic couplings request pdf. First introduced in 1942 by gleason works, a curvic is a precision ground face spline. The method permits conversion of radial and axial runout measurements into part dimensions that represent manufacturing errors for each stage. Curvic coupling use for turret of cnc lathe machining center, robot, gas turbine, airplane, etc feature. Once program and dataspecific parameters have been configured, komet5 is a fully automatic, intuitive correction program. 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.
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. Minimizing assembly runout in turbomachines made with. 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. A study on the cadcam of curvic couplings turbo expo. Single reduction curvic coupling differential carriers.
Th e serrated tooth circle divider uses two mat ing face gears. Gears, splines, curvic couplings equitable engineering. 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. Hirth couplings hirth serration precision cnc machining. 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. 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. 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.
One half of the coupling is mounted on the turret mounting body. Manufacturing method for fixed curvic coupling request pdf. 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. You have clicked a page that seems to be very popular. It can result in a decrease in the structural stiffness or the separation of curvic coupling and lead to the joint failure. 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. If the teeth of the 429012120101 curvic coupling were found improperly engaged per step 3, perform a rigging check of the directional control system.
Zn3r030m before the discs are eligible for reinstallation in an engine. 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. Shaft collar, rigid coupling, flexible coupling cad files. 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 single flexing coupling is for use in the case where shafts are supported by three bearings. Their application makes it possible to fulfil an accurate centering, as well as an improved reliability and good structural stability. Hirth coupling mechanical engineering general discussion.
The present study, as a further evolution, proposes an experimentally validated closed form. This design utilizes a single piece of material and becomes flexible by removal of material along a spiral path resulting in a curved flexible beam of helical. 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. We are a custom gear facility, manufacturing gears to customer supplied blueprint specifications andor samples. Nov 12, 2010 upon closer look the gap was just a slight chamfer on the back coupling.
Curvic coupling design novdec 1986 gear technology. Investigating curvic coupling behavior by utilizing the. 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. The curvature of the teeth give these couplings their. Buy best curvic coupling, hirth coupling with escrow buyer protection. 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 turbine and compressor rotors for aircraft and industrial gas or steam turbine engines. 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. Late in the day i did get a referall from the aerospace company to a smaller company. Our mindset will be concentrated on satisfying the needs of our customers and working hard to become a futureoriented company. I dont know how they ended up with a half of a curvic coupling set. 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.
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. However the allowable load differs to the size of the curvic coupling in use. Both haves are bottomed so the valleys will need work also. Hirth couplings are also known as vtooth couplings, hirth joint, or voith hirth couplings. These couplings, which provide optimum contact with the shaft, can accommodate high torque values.
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. Industrial grinding services machine centers by repairing or rebuilding mating areas and worn diameters. Provided coupling is known for its accurate alignment and precision centering capability whenever it is in mesh. We will lead this market at the head of this field. Grinding services including curvic coupling grinding services.
Then, it has been implemented through design and manufacture methods to be used for connecting shafts of gasturbine engine. 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. 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. Using a bright light, inspect the inboard and outboard curvic coupling teeth for proper engagement with the inboard and outboard flapping bearing teeth. Hirth or curvic couplings, used in serrated tooth circle dividers, shown in figure 3. A model accounting for stiffness weakening of curvic couplings. The most common method involves a curvic coupling mechanism. The stiffness and the accuracy of centering the coupling have become very important. 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.
Threedimensional models were created in beasy and ansys, and are described in the following subsections. A lecture on the method to compute the the stress of vtooth coupling under the actual operating conditions. Curvic coupling curvic coupling is product description. We provide prompt quotations, competitive pricing, and top quality gears. Since then, our couplings have been widely accepted in japanese market under the bland name of formflex coupling and have acquired a high reputation. A new method is presented for optimizing the assembly of turbomachine rotors manufactured with gleason fixed curvic couplings. 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.
Bending and vibration of a discontinuous beam with a. The fixed curvic coupling is used extensively in the con. An accurate curvic stress determination early in the design process is required. The three basic types of curvic couplings are i the fixed. Pdf digital inspection of fixed curvic coupling contact pattern. Pdf curvic couplings are frequently used in aeroengine rotors.
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. 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. Investigating curvic coupling behavior by utilizing the two and threedimensional. To connect the servomotor used in nc machine tools with the ball screw, an exceptional usage of the coupling as shown in the. But moment is increased by the lack of bearing capacity of the curvic coupling. Investigating curvic coupling behavior by utilizing two. Our main activity is the manufacturing of hirth couplings. 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.
Curvic couplings are similar in concept and appearance to hirth couplings, except that their teeth are curved instead of straight. The jet engine industry needed an ultra precise locating arrangement to assure the exact alignment of components along the main engine shaft. Bending and vibration of a discontinuous beam with a curvic coupling under different axial forces show more 10. Curvic coupling, hirth coupling manufacturers,curvic coupling. In order to ensure the coupling accuracy of aeroengines and gas turbines, curvic teeth and disk are usually formed integrally. 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. Hirth joints consist of radial teeth formed by grooves milled or ground into the end face of. Find manufacturers and distributors of curvic couplings. Rings with hirth couplings are primarily used for the accurate positioning of axialsymmetric components in the machine tool industry. Panjiva uses over 30 international data sources to help you find qualified vendors of curvic. Buy best curvic coupling with escrow buyer protection. The arrangement needed to be easy to work with, so that during maintenance, the alignment could be easily reestablished. Like hirth couplings, they lock the components together in an unlockableremovable way and provide indexability. Gleason model 887 cnc curvic coupling grinder with fanuc 18mb control.
Curvic manufacturers suppliers of curvic product and. The stiffness of the curvic couplings is of guiding significance to the. Dec 16, 2016 frost angle setting technology fast in use on a curvic coupling. Adaptation of these methods for use in estimating contact pattern between curvic couplings. This maintenance manual describes the correct service and repair procedures for all. Strength formula for curvic coupling division accuracy. Both are the same diameter and have equal tooth geometry and tooth size. March 2000 machine was sent to gleason for full mechanical and electrical overhaulupgrade.
A study on the stability of curvic coupling for distance. Curvics are sometimes used in aircraft engine design where multiple rotor stacks are required. 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. 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 engineering staff can help with analysis of new designs as well as improvements on existing designs. Relying on our stateoftheart manufacturing set up, we are offering premium quality range of curvic coupling. Investigating curvic coupling behavior by utilizing two and. I have searched the internet and there is not much in the way of how to document them. Experts in hirth serrations, we offer a complete range of services to meet almost any requirements.
Alibaba manufacturer directory suppliers, manufacturers. Analysis of the contact stresses in curvic couplings of. Flap the inboard and outboard tail rotor blades to gain visual access to the 429012120101 curvic coupling teeth. 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. Request pdf a study on the cadcam of curvic couplings the curvic coupling was first developed by gleason works about sixty years ago. 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. Frost angle setting technology fast in use on a curvic coupling. 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. The coupling provides a positive drive along with precision centering and high load carrying capacity. Our extensive machine center repair capabilities include id and od cylindrical grinding, wheel grinding, vertical grinding, plus. For large, heavy duty applications, skf has large size couplings. Stock spiral bevel gears a cost saving alternative. The coupling shown in the diagram on the right above is suitable for use in cases subject to great radial loads.
Curvic couplings are similar in concept and appearance to hirth couplings, except that. Curvic coupling, curvic coupling manufacturer in india. The fixed curvic coupling is also used today by many. 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.
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