It can be used with the tapered shaft because it aligns itself in the seat. Keys and keyways 51 introduction university of babylon. Keys are machine elements used to prevent relative rotational movement between a shaft and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. For a shaft transmitting power po at a rotational speed n, the transmitted torque t can be found from t nm 9550 po kw n rpm or. 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. The diameter of shaft for flywheel is obtained from the maximum torque transmitted. These keys are temporary fastening elements and are subject to the crushing and the shearing stress. In a basic manual transmission design, the transmission gears are attached to the counter shaft permanently, spinning along with it. In mechanical engineering, a key is a machine element used to connect a rotating machine.
Basic concept a key is a fastening inserted into the keyway of two mating parts, it is used to transmit torque from a shaft to a hub or vice versa. Machine shafts are the integral part of the machine itself. This pa note will explain the uses of keys and keyways in pulleys and bushings, and present current industry standards for key and keyway component sizing. There are several types of shaft keys, each with their own particular role and application. Video lecture on definition of shaft and its explanation from design of shafts, keys and couplings chapter of design of machine for mechanical engineering students. It is always inserted parallel to the axis of the shaft. Sunk keys the sunk keys are provided half in the keyway of the shaft and half in the keyway of the hub or boss of the pulley. Shaft keys revisited dimensions of shaft keys, standardized many years ago, are commonly considered to be the main concern in applying these devices.
Beam couplings the beam coupling consists of single or multiple helical cuts in the coupling body which typically can accommodate parallel misalignments up to 0. The key will have a provision in both the shaft and the machine element which needed to be connected. Chapter 6 design of keys, splines and pins key terms. Type c keys with both ends round hole for one retaining screw for sizes 8 x7 and upwards and for key lengths above the stepped line in table 4 1. A comparison between militzer and this method where the surface pressure is even, gives about 80 % higher value for. In other words, key is a set of column s that is used to uniquely identify the record in a table. Shafts, splined shafts, keys, keyways, types of keys, light and heavy duty keys, comparision between keys and cotters, cotter joints and knuckle joints. Chapter 11 drive lines, differentials, drive axles, and power.
Most standards fail to discuss the important issue of key material, as well as their shape and installation. Mechanical shaft keys are used for transferring torque in automotive powertransmission systems. It is a taper key which fits in a keyway in the hub and is flat on the shaft. Chapter 11 drive lines, differentials, drive axles, and. Recognize many types of couplings and their advantages and disadvantages. Parallel keys zthe key seats in the shaft and the hub so that exactly. How to survive alone in the wilderness for 1 week eastern woodlands duration. The gearbox does this through a complex arrangement of gears and shafts. W d 4 clarification needed h 2d 3 clarification needed. Recognize and understand principles of miscellaneous shaft. There are 7 different keyways c,ce,e,ef,f,fg and g. In order to find the length of the key to transmit full power of the shaft, the. It is usually used for shafts less than about 60 mm diameter and the keyway is cut in the shaft using a milling cutter.
The larger depth of keyway prevents the tendency of the key to slip over the shaft, but it weakens the shaft more than that by the use of straight keys. A wide variety of types of shaft key options are available to you, such as gear, spline, and eccentric. The pictures shows the stress pattern in a shaft with a keyway under pure torque. The drive shaft, also called a propeller shaft, is commonly a hollow steel tube with yokes welded on the end. The circular segment can be cut directly by plunge cutting with a circular. Keys cotters and joints shafts splined shafts keys keyways. This consists of a pipe whose bore is finished to the required tolerance based on the shaft size. Shaft keys, shaft key design, rectangular keys, square keys, woodruff keys, gib keys, taper keys. It is also stated that a minimum key length should be 25 % larger than the shaft diameter. Pipe and pipe fittings, materials and applications, pipe joints, screwed joints, welded connections, cementing, flange joints, spigot. Mar 01, 2016 video lecture on definition of shaft and its explanation from design of shafts, keys and couplings chapter of design of machine for mechanical engineering students.
Scope covers the dimensions and tolerances for parallel keys and keyways. Understand basic types of universal joints and how and when they may be used. Keys connecting shafts to pulley hubs are commonly used to achieve reliable. Couplings and keys objectives recognize different types of keys and their standard sizes. The counter shaft lies parallel to the main shaft and is driven by the input shaft through a pinion gear. The difference between a shaft and an axle is that the shaft rotates to transmit power, and that it is subjected to fatigue.
There are many shaft keys for costeffective and efficient power transmission, which includes square keys, parallel keys, rectangular keys, woodruff k. In frontwheeldrive cars, the input and counter shafts are actually the same thing. Keys are used as temporary fastenings and are subjected to considerable crushing and shearing stresses. The purpose of a transmission gearbox is to transfer the high output of an automobiles engine to the wheels, and in the process reduce it to a compatible speed. A adapter sleeve components b ball joints balls bars bearings belts bushings bushings, taper bushings c calipers chain chain guides clamping plates conveyor rollers motorized corrosion protection couplings d e elements f fork joints g gear rack gears grease fittings grips h handles hexagon bars hydraulic i j k keyless locking rings keys knobs l. Insidepenton com electronic design adobe pdf logo tiny. Shaft keys that reduce manufacturing costs and machine. Objectives after studying this unit, you should be able to identify keys and their application, calculate forces on keys, and design keys.
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. Allowable shear stress for the material of the shaft. For making the joint, grooves or keyways are cut on the surface of the shaft and in the hub of the part to be mounted. It is used to fetch or retrieve records datarows from data table according to the conditionrequirement. Most shafts have circular cross sections, either solid or tubular. Our all stainless steel hubs are available in bore diameters ranging from 564 to 114. Shaft keys are available in a variety of types and include parallel keys, square keys, flat keys, rectangular. Keyways are still the most common of all joints between shaft and hub. Understand basic types of universal joints and how and when theymay be used.
This cuts the length of each shaft to avoid drive line vibration. Shaft and hub keyway and key sizes micromachineshop. The taper will impart a compressive contact pressure between the hub and the shaft. These types of keys are generally attached to the driving member e. Metric standard parallel keyway and key sizes shaft diameter mm keyway mm key mm from to width w depth h width w depth t 6 8 2 1. There are many types of couplings that fall under the rigid couplings category. Transmission shafts are used to transmit power between the source and the machine absorbing power. The key requires a circular type of keyway in the shaft. Keys aroused as temporary fastenings and are subjected to considerable crushing and shearing stresses. A simple shear stress calculation will demonstrate why these particular dimensions were chosen. Type c keys with both ends round hole for one retaining screw for sizes 8 x7 and. The hub is slightly larger than the shaft and key to allow it to slide over the shaft during assembly.
Berg has a wide selection of hub sizes and styles to select from. Key dimensions were standardized about 150 years ago. Shaft keys types and their design bright hub engineering. Square keys are used for smaller shafts and rectangular faced keys are used for shaft diameters over 6. In this article you will learn about different types of keys in database. The rounded ends make it easy to slide gears, hubs, and other components into place. Straight keys, with a square or rectangular cross section, are the most common type of key. Standard contains tables of recommended key sizes versus shaft. They are rigid sleeve or muff couplingsthis is the basic type of coupling. The sunk keys are provided half in the keyway of the shaft and half in the keyway of hub or boss of the pulley. The tubular design makes the drive shaft strong and light. Rigid couplings are mainly used in areas where the two shafts are coaxial to each other.
Shafts a shaft is an element used to transmit power and torque, and it can support reverse bending fatigue. Rather, there is a set of material property requirements and a range of steel alloys and heat treatment combinations that would meet those requirements. Friction will help transmit torque and provide resistance to axial motion of the hub relative to the shaft. Set screws often accompany parallel keys to lock the mating parts into place. Keys and keyways pdf, archived from the original pdf on 20100319, retrieved 20100319. What are the different types of keys in machine design. Shaft keys that reduce manufacturing costs and machine downtime. Therefore, it is used for comparatively light loads. Understand principles of splines and analyze appropriate loads.
Woodruff keys are semicircular, fitting partly into ab circular segment keyway with the remainder fitting into a longitudinal slot keyway in the mating part. Shaft and hub keyway and key sizes keys connecting shafts to pulley hubs are commonly used to achieve reliable noslip power transmission in belt drive systems. In other words, a square key is equally strong in shearing and crushing. The resulting friction is used to provide resistance to axial motion. Transmission shafts can be found in a manual transmission gearbox. When installed, these keys fill oval keyways completely, reducing stress on the key and shaft. Figure 1 shows the parts of a keyed joint and its assembly. A sunk key is a key in which half of the thickness of key fits into the keyway in the shaft and half in the keyway of the hub. The rectangular key is most common in either very small or very large shafts. The different styles and types of shaft couplings are summarized below.
Shaft keys are important machine components designed to transmit torque and rotative force. A key is a data item that exclusively identifies a record. The diagram shows the importance of having a big and smooth radius at the bottom of the keyway, this is. Understand basic types of universal joints and how and when theymay be. Jan 19, 2018 mechanical shaft keys are used for transferring torque in automotive powertransmission systems.