Shafts keys and couplings ppt

A keyless coupling arrangement will always have an interference fit, while a keyed arrangement may have either a clearance or an interference fit. Theyre also better than ujoints for applications requiring precise movement and directional changes. The shafts are classified as straight, cranked, flexible or articulated. Keys, shafts and couplings free download as powerpoint presentation. The shaft used on the test is made of alloy steel type ss with max tensile stress of 723.

These are rarely used keys, to transmit lower power to the driven members e. Straight shafts are commonest to be used for power transmission. Shafts are breaking or cracking at or close to the inboard bearings or coupling hubs. The lovejoy coupling handbook lovejoy a timken company. Shafts are always made to have circular crosssection and could be either solid or hollow. Woodruff keys work well near shaft shoulders and on tapered shafts. Rigid couplings are used where shafts are already positioned in precise lateral and angular alignment. 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. The hub bore and key tolerances are adjusted to create the proper fit with the. Design and analysis of bushed pin flexible coupling. Safely and securly transport a person weighing 250 pounds. Use them in light duty applications to connect gears and other components to shafts. Shop shaft collars, couplings, mounts and keys at msc. What is the purpose of rigid and flexible couplings in a power transmission system.

But modern couplings, particularly those made from alloy steels, have shorter hubs than this. Video lecture on keys and its function from design of shafts, keys and couplings chapter of design of machine for mechanical engineering. A machine properly aligned will be a reliable asset to the plant, it will be there when it is needed and. Design of shaft a shaft is a rotating member usually of circular crosssection solid or hollow, which transmits power and rotational motion. Design of shaft a shaft is a rotating member usually of circular crosssection solid or hollow. How attach power transmission components to shaft to prevent rotation and axial motion. Allowable shear stress for the material of the shaft. Alternatively, a shaft may simply connect to another shaft via a coupling mechanism. Hrc couplings click here to download hrc pilot bore coupling information. A reference for the usage of these couplings is shown in the left illustraion. A key is a detail inserted axially between a shaft and a hub to prevent relative rotation of the parts. 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. 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.

Md15 keys and couplings university of northern iowa. Shaft keys, shaft key design, rectangular keys, square keys, woodruff keys, gib keys, taper keys. Couplings and keys objectives recognize different types of keys and their standard sizes. Keys and keyways 51 introduction university of babylon. 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. A slight clearance should be present from top to bottom when the hub is on the shaft. The preceding table is a general comparison of the skf range of couplings. Couplings, universal joints, and flexible shafts from sdpsi. Shaft keys types and their design brighthub engineering. Apr 15, 2017 the splined shafts are relatively stronger than shafts having a single keyway. Their design does not allow for any misalignment between shafts, but are generally able to transmit more power than flexible couplings. Economy statewide bearings design of the hrc coupling has been optimised so that power capacities are balanced to the appropriate shaft diameters. Tangent keys are used in hightorque heavyduty applications.

Determine torque in shafts from gears, pulleys, sprockets, clutches, and couplings. These types of keys have less strength as compared with the sunk keys. Design of shafts couplings ppt linkedin slideshare. Precise alignment of the shafts bolts in carry torque in shear. 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. Sunk keys half in the keyway of the shaft and half in the key way of hub. 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.

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. Shaft design objectives compute forces acting on shafts from gears, pulleys, and sprockets. Interference fit hubs use a 1 to 1 ratio between the hub contact length and the shaft diameter. 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. The diameter of shaft for flywheel is obtained from the maximum torque transmitted. 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. Couplings are normally furnished with an average interference fit of. On large couplings and shafts two halfheight keys are sometimes used to strengthen torque transmission. 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. In other words, a square key is equally strong in shearing and crushing.

Recognize many types of couplings and their advantages and disadvantages. 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. Flexible couplings are designed to accommodate misalignment between shafts and various types of load. Frequently asked questions on metric bores and keyways in couplings mpta primer. The flange coupling body is made of gray cast iron c. Keys are made from steel to resist adequately the high shearing and crushing stresses place on them. To be used in determining which coupling type or style may be best suited for an application. But modern couplings, particularly those made from. Used to connect two shafts together at their ends to transmit torque from one to the other. The key prevents relative rotation between the two parts and may enable torque transmission.

Couplings are used to connect two rotating shafts to transmit torque from one to the other. Compare combined stresses to suitable allowable stresses. In order to have a greater length, it becomes necessary to join two or more pieces of the shaft by means of. In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. 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.

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. A key is a piece of metal used to connect a rotating machine element to the shaft. Shafts are usually available up to 7 meters length due to inconvenience in transport. Shaft couplings are used in machinery for several purposes, 1. Why power transmission shafts have both keys and keyways. 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. Machine must have 1 power source, use 1 or more shafts, bearings, keys, gears, couplings, springs and fasteners.

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. The key should fit snugly against the sides of keyway. You get ms powerpoint 2003 presentation slides covering the key issues in good machinery shaft alignment practices. Shear in bolts similarly keys bolt circle flanged couplings bolt shaft. As shown by the last equation in the box, key stress equals shaft stress when the key or hub length is 1. 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. A key is a piece of mild steel inserted between the shaft and hub or boss of the pulley to connect these together in. These keys have a rounded shape that makes them easy to remove when parts need to be taken apart frequently. This article describes what is a coupling, types of couplings, rigid couplings, flexible couplings, universal couplings, hookes coupling, pin bush coupling, flanged coupling etc. The coupling key is usually made into two parts so that the length of the key in each shaft, l l 2 3. The alignment training is suitable for technicians undertaking machine alignment, coupling alignment, motor alignmnet, pump alignment, etc. 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. Good shaft alignment practice should be a key strategy in the.

Shaft alignment training course ppt presentation and machine. Design of shaft new jersey institute of technology. Flexible shaft couplings perform better than ujoints and flexible shafts in highspeed, lowtorque applications. 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. Shaft alignment training course ppt presentation and. Couplings can be rigid or flexible depending on the alignment accuracies of the system and torque requirements. Couplings are mechanical elements that couples two drive elements which enables motion to be transferred from one element to another. View and download powerpoint presentations on keys shafts and couplings ppt. Specify seals for shafts and other types of machine elements. 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. Design for key the length of the coupling key length of the sleeve i. There are several types of shaft keys, each with their own particular role and application.

It is always inserted parallel to the axis of the shaft. Design of shafts, keys and couplings, design the diameter of a shaft on the basis of equivalent twistingbending moment and al. 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. The power is transmitted from one shaft to the other shaft by means of a key and a sleeve. To provide for misalignment of the shafts or to introduce mechanical flexibility. For example coupling is used to connect the output shaft of an electric motor to the input shaft of a hydraulic pump. In order to find the length of the key to transmit full power of the shaft, the.

Clearance and interference coupling fits efficient plant. Friction will help transmit torque and provide resistance to axial motion of the hub relative to the shaft. By using splined shafts, we obtain axial move ment as well as positive drive is obtained. Keys and coupling many types of keys and couplings, however. Flanged coupling a key is used to to fix the coupling to the shaft, and then couplings are bolted together. Standard contains tables of recommended key sizes versus.

Ppt chapter 11 keys, couplings and seals powerpoint. Go from 030 mph in under 1 minute with a person weighing 250 pounds. The round keys have a circular crosssection and fit into holes drilled partly in the shaft and partly in the hub. A shaft coupling is a mechanical device used to connect rotating shafts and absorb misalignments between them. Similarly, the fits of couplings to shafts can be categorized as clearance or interference. Shaft couplings are available in different sizes and material finishes. Types of shafts, material for shafts, shaft design, torsional rigidity, lateral rigidity, maximum shear and principal stress theories, key design and. In this case shaft ends are coupled together and abutted against each other which are enveloped by muff or sleeve. In a shaft based system, the shaft and key are considered the fixed members of the system. Resilience transient peak loads are reduced by a flexible element, deflection of which is a prime design consideration. Twin shaft coupling a semifloating shaft coupling is combined with a. Such shafts are commonly designed as stepped cylindrical bars, that is, they have various diameters along their. 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. Find powerpoint presentations and slides using the power of, find free presentations research about keys shafts and couplings ppt.

Slot is drilled after the assembly so the shafts can be properly aligned. Skf shaft couplings the following table shows typical character istics for various coupling types. A48 with maximum shear and tensile strength 50000 nmm2 2, 151. Shaft coupling sometimes, join 2 shafts together flanged couplings torque in shaft torque in. Mechanical system design keys and keyways types of keys keys and keyways are given in ansi b17. A shaft is rotating machine element which is used to transmit motion or power from one place to another. These types of keys are generally attached to the driving member e. Download ppt keys and coupling many types of keys and couplings.