1 / 10

Topics

Topics. Introduction Shaft Design Stresses and Loads on Shafts Shaft Fits Shaft Locking Devices Exercise Questions Note: Refer to Chapter 7 in the text. Introduction. Shafts are used to transmit mechanical power such as the propeller shafts in vehicles. Applications of shafts:

Download Presentation

Topics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Topics • Introduction • Shaft Design • Stresses and Loads on Shafts • Shaft Fits • Shaft Locking Devices • Exercise Questions • Note: Refer to Chapter 7 in the text.

  2. Introduction • Shafts are used to transmit mechanical power such as the propeller shafts in vehicles. • Applications of shafts: • - To transmit power • - To extend other shafts • - To provide the rotary motion needed by other components such as in rollers and printing press machines. • Shafts are usually made of steel. • Some materials are used in making shafts: - Cold Rolled Steel: most common due to its low cost - Hardened Steel: heated rolled steel. Stronger than the cold rolled shaft. - Stainless steel Reference: Amatrol Mechanical Drives 1, LAP 3

  3. Shaft Design • Shafts may be designed with ‘turn downs’ • These shafts have smaller diameters at the ends. • When shafts are turned down, a large shaft fillet is used to reduce stresses as possible. • Refer to figures 7-2 and 7-3 in the text (pp. 134-135) Fillet Turn Down

  4. Loads and Stresses on Shafts Shear Forces Tensile Forces Compressive Forces Bending Moments Torsions

  5. Shaft Fits • When two objects are mated, there will be a difference between their actual size and the dimensional tolerance limit – know as the “fit” or amount of tightness

  6. Shaft Fits • Clearance fit: the mating parts have a clearance between them. Also known as slip, slide, or loose fit. • Transition fit: no clearance is present. It is also known as line-to-line fit. In this case pressing is required. • Interference fit: The shaft diameter is larger than the diameter of the hole of the component to be mounted. Some types of it are: press and shrink fits. An Arbor Press is used to mount the components onto the shafts

  7. Shaft Locking Devices used to mount sheaves, and sprockets • Taper-Lock Bushings – Bushing squeezes the shaft as bolts are drawn in. 8 degree taper Quick Detachable (QD) Tapered Bushings – Same as taper- lock with 4 degree taper A Quick Detachable (QD) Tapered Bushing

  8. Shaft Locking Devices • Split-Taper Bushing • Keyless/Compression Bushings have high torque holdings

  9. Exercise Questions • What is the purpose of the propeller shaft in a car? Transmitting mechanical power in the form of torque to the rear axle. • Name five types of loading and moments that shafts can be subjected to: 1) Compressive forces 2) Tensile forces 3) Shear forces 4) Bending moments 5) Torsion

  10. What three types of shaft fits? Clearance, line-to-line, and interference fits • Name three types of bushings that can be used to mount components on shafts? 1. Taper-Lock Bushuings 2. Quick Detachable Tapered Bushings 3. Split-Taper Bushings 4. Keyless/Compression Bushings 5. Describe how to mount a component on a shaft with a shrink fit? The shaft may be freezed in liquid nitrogen to shrink, then the component is mounted on it. 6. What is a disadvantage of shrink fitting? You are limited by time needed to mount the component on the shaft before the shaft retains its regular dimensions.

More Related