Shafts keys and couplings ppt

The preceding table is a general comparison of the skf range of couplings. Shafts are usually available up to 7 meters length due to inconvenience in transport. Tangent keys are used in hightorque heavyduty applications. Twin shaft coupling a semifloating shaft coupling is combined with a. Interference fit hubs use a 1 to 1 ratio between the hub contact length and the shaft diameter. Ppt chapter 11 keys, couplings and seals powerpoint. Design of shaft a shaft is a rotating member usually of circular crosssection solid or hollow, which transmits power and rotational motion. Couplings and keys objectives recognize different types of keys and their standard sizes.

Allowable shear stress for the material of the shaft. In other words, a square key is equally strong in shearing and crushing. Good shaft alignment practice should be a key strategy in the. A key is a detail inserted axially between a shaft and a hub to prevent relative rotation of the parts. In this case shaft ends are coupled together and abutted against each other which are enveloped by muff or sleeve. The shafts are classified as straight, cranked, flexible or articulated. Straight shafts are commonest to be used for power transmission.

For a key to function, the shaft and rotating machine element must have a keyway and a keyseat, which is a slot and pocket in which the key fits. In order to have a greater length, it becomes necessary to join two or more pieces of the shaft by means of. Find powerpoint presentations and slides using the power of, find free presentations research about keys shafts and couplings ppt. Their design does not allow for any misalignment between shafts, but are generally able to transmit more power than flexible couplings. Design of shafts couplings ppt linkedin slideshare. Couplings can be rigid or flexible depending on the alignment accuracies of the system and torque requirements. Keys and keyways 51 introduction university of babylon.

What is the purpose of rigid and flexible couplings in a power transmission system. You get ms powerpoint 2003 presentation slides covering the key issues in good machinery shaft alignment practices. To provide for the connection of shafts of units that are manufactured separately such as a motor and generator and to provide for disconnection for repairs or alternations. Design for key the length of the coupling key length of the sleeve i. For example coupling is used to connect the output shaft of an electric motor to the input shaft of a hydraulic pump. Shaft alignment training course ppt presentation and machine. The hub bore and key tolerances are adjusted to create the proper fit with the. Design and analysis of bushed pin flexible coupling. Standard contains tables of recommended key sizes versus. A48 with maximum shear and tensile strength 50000 nmm2 2, 151. Types of shafts, material for shafts, shaft design, torsional rigidity, lateral rigidity, maximum shear and principal stress theories, key design and.

Rigid couplings are used where shafts are already positioned in precise lateral and angular alignment. A shaft is rotating machine element which is used to transmit motion or power from one place to another. Shaft misalignment is responsible for as much as 50 percent of. A gib head sunk keys hold the two shafts and sleeve together this is the simplest type of the coupling it is made from the cast iron and very simple to design and manufacture. A machine properly aligned will be a reliable asset to the plant, it will be there when it is needed and. These keys have a rounded shape that makes them easy to remove when parts need to be taken apart frequently. You can change slides around as you wish and develop new presentation arrangements to create an alternate shaft alignment training course powerpoint presentation suited to your specific needs. It is always inserted parallel to the axis of the shaft. Shafts are breaking or cracking at or close to the inboard bearings or coupling hubs. In order to have a greater length, it becomes necessary to join two or more pieces of the shaft by means of a coupling 3. In order to find the length of the key to transmit full power of the shaft, the. Splines cont zthere are many advantages of splines over keys.

The alignment training is suitable for technicians undertaking machine alignment, coupling alignment, motor alignmnet, pump alignment, etc. Flexible shaft couplings perform better than ujoints and flexible shafts in highspeed, lowtorque applications. A practical guide to shaft alignment plant services. Our shaft collars are easy to install and can save time and money, giving you a fix where disassembly might otherwise be required.

Keys and coupling keys a key is a piece of metal inserted between shaft and hub to connect these together in order to prevent relative motion between them. Slot is drilled after the assembly so the shafts can be properly aligned. Understand principles of splines and analyze appropriate loads. There are several types of shaft keys, each with their own particular role and application. View and download powerpoint presentations on keys shafts and couplings ppt. Shaft couplings shaft couplings are used to connecetwo shafts in such away that when both shafts rotate, they act as one unit and transmit power from one shaft to other shafts to be coupled may have collinear axes, intersecting axes or parallel axes at a small distance. Video lecture on keys and its function from design of shafts, keys and couplings chapter of design of machine for mechanical engineering. Mar 01, 2016 video lecture on problem 1 on design of shaft from design of shafts, keys and couplings chapter of design of machine for. Shafts and couplings shafts and couplings through the use of the appropriate joints, at and atm shafts can be mounted even after the application and the fixing of the screw jack. Shaft keys are important machine components designed to transmit torque and rotative force. Couplings are mechanical elements that couples two drive elements which enables motion to be transferred from one element to another. In a shaft based system, the shaft and key are considered the fixed members of the system. Safely and securly transport a person weighing 250 pounds. Shaft design objectives compute forces acting on shafts from gears, pulleys, and sprockets.

Economy statewide bearings design of the hrc coupling has been optimised so that power capacities are balanced to the appropriate shaft diameters. The key prevents relative rotation between the two parts and may enable torque transmission. Mechanical shaft keys are used for transferring torque in automotive powertransmission systems there are many shaft keys for costeffective and efficient power transmission, which includes square keys, parallel keys, rectangular keys, woodruff keys, taper and gribhead keys, and feather keys. Why power transmission shafts have both keys and keyways. The main purpose of shaft alignment is to make sure that the center line of the motor rotor shaft coincides with the center line of the driven machinery i. Couplings are used to connect two rotating shafts to transmit torque from one to the other.

Similarly, the fits of couplings to shafts can be categorized as clearance or interference. Download ppt keys and coupling many types of keys and couplings. A device that is used to connect two shafts together for the purpose of power transmission. Design of shaft a shaft is a rotating member usually of circular crosssection solid or hollow. Keys are made from steel to resist adequately the high shearing and crushing stresses place on them. On large couplings and shafts two halfheight keys are sometimes used to strengthen torque transmission. Shaft keys, shaft key design, rectangular keys, square keys, woodruff keys, gib keys, taper keys. But modern couplings, particularly those made from. Flexible couplings are designed to accommodate misalignment between shafts and various types of load. Compare combined stresses to suitable allowable stresses. These types of keys are generally attached to the driving member e. Clearance and interference coupling fits efficient plant. Precise alignment of the shafts bolts in carry torque in shear.

The splined shafts are used when the force to be trans mitted is large in proportion to the size of the shaft as in automobile transmission and sliding gear transmis sions. In this case, the shaft of the coupling is supported with a single bearing, arranged as closely as possible to the outer sprocket or pulley. Rigid coupling flange driven shaft driving shaft key hub rigid couplings are used when precise shaft alignment is required simple in design and are more rugged generally able to transmit more power than flexible couplings shaft misalignments cannot be compensated flanged coupling. The shaft used on the test is made of alloy steel type ss with max tensile stress of 723. Couplings nizwa college of technology couplings coupling is a device used to connect two shafts together at their ends for the purpose of transmitting power motor coupling pump uses of coupling to provide connection of shafts of units made separately to allow misalignment of the shafts or to introduce mechanical flexibility. Recognize many types of couplings and their advantages and disadvantages. Find bending moments from gears, pulleys, or sprockets that are transmitting loads to or from other devices.

Couplings are normally furnished with an average interference fit of. The coupling key is usually made into two parts so that the length of the key in each shaft, l l 2 3. Shaft coupling sometimes, join 2 shafts together flanged couplings torque in shaft torque in. Use them in light duty applications to connect gears and other components to shafts. Sunk keys half in the keyway of the shaft and half in the key way of hub. How attach power transmission components to shaft to prevent rotation and axial motion. These types of keys have less strength as compared with the sunk keys.

Shafts are always made to have circular crosssection and could be either solid or hollow. Apr 15, 2017 the splined shafts are relatively stronger than shafts having a single keyway. A shaft coupling is a mechanical device used to connect rotating shafts and absorb misalignments between them. The flange coupling body is made of gray cast iron c. A slight clearance should be present from top to bottom when the hub is on the shaft. A key is a piece of mild steel inserted between the shaft and hub or boss of the pulley to connect these together in order to prevent relative motion between them. The round keys have a circular crosssection and fit into holes drilled partly in the shaft and partly in the hub. Couplings, universal joints, and flexible shafts from sdpsi. A reference for the usage of these couplings is shown in the left illustraion. Resilience transient peak loads are reduced by a flexible element, deflection of which is a prime design consideration. A key is a piece of mild steel inserted between the shaft and hub or boss of the pulley to connect these together in. Specify seals for shafts and other types of machine elements.

Machine elements such as gears, pulleys sheaves, flywheels, clutches, and sprockets are mounted on the shaft and are used to transmit power from the driving device motor or engine through a machine. The lovejoy coupling handbook lovejoy a timken company. Skf shaft couplings the following table shows typical character istics for various coupling types. Youll find flexible couplings in a range of styles and sizes, plus shaft locking devices that can be used as dropin replacements for keyless bushings. Shop shaft collars, couplings, mounts and keys at msc. Alternatively, a shaft may simply connect to another shaft via a coupling mechanism. In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. Woodruff keys work well near shaft shoulders and on tapered shafts.

To be used in determining which coupling type or style may be best suited for an application. By using splined shafts, we obtain axial move ment as well as positive drive is obtained. Go from 030 mph in under 1 minute with a person weighing 250 pounds. As shown by the last equation in the box, key stress equals shaft stress when the key or hub length is 1. Shaft couplings are available in different sizes and material finishes.

The diameter of shaft for flywheel is obtained from the maximum torque transmitted. Keys, shafts and couplings free download as powerpoint presentation. Friction will help transmit torque and provide resistance to axial motion of the hub relative to the shaft. Shaft alignment training course ppt presentation and. Torque resistance keys, splines, pins, weld, press fit, etc axial positioning retaining rings, locking collars, shoulders machined into shaft, etc. That ratio may vary in applications prone to high cyclic loads or sudden peaks in the torque from transitory conditions. Shaft couplings are used in machinery for several purposes, 1. Md15 keys and couplings university of northern iowa. Determine torque in shafts from gears, pulleys, sprockets, clutches, and couplings. Maintenancefree operation attachment of the coupling to the shafts with keys coupling without spacer nonstandard spacers many applications for ringflex couplings require special spacer lengths and dimensions. Excessive amount of grease or oil inside coupling guards. This article describes what is a coupling, types of couplings, rigid couplings, flexible couplings, universal couplings, hookes coupling, pin bush coupling, flanged coupling etc. Shear in bolts similarly keys bolt circle flanged couplings bolt shaft. The key should fit snugly against the sides of keyway.

The power is transmitted from one shaft to the other shaft by means of a key and a sleeve. Keys and coupling many types of keys and couplings, however. Design of shaft new jersey institute of technology. A key is a piece of metal used to connect a rotating machine element to the shaft. This video lecture gives an information about the design of shaft and different theories of failure in the design of shaft in a conceptual manner. These are rarely used keys, to transmit lower power to the driven members e.

Design of shafts, keys and couplings, design the diameter of a shaft on the basis of equivalent twistingbending moment and al. Mechanical system design keys and keyways types of keys keys and keyways are given in ansi b17. Ppt coupling ppt powerpoint presentation free to download. Frequently asked questions on metric bores and keyways in couplings mpta primer. Shaft keys types and their design brighthub engineering. A keyless coupling arrangement will always have an interference fit, while a keyed arrangement may have either a clearance or an interference fit. But modern couplings, particularly those made from alloy steels, have shorter hubs than this. Theyre also better than ujoints for applications requiring precise movement and directional changes. The parts carried by axle or shaft are fastened to them by means of keys or splines and for this purpose the shaft and axle are provided with key ways or splines. Flanged coupling a key is used to to fix the coupling to the shaft, and then couplings are bolted together. Hrc couplings click here to download hrc pilot bore coupling information. To provide for misalignment of the shafts or to introduce mechanical flexibility. Access to both ends of tapered keys are required so that the key can be inserted and driven out when the key is being removed. Used to connect two shafts together at their ends to transmit torque from one to the other.