“Shaft (mechanical engineering)”的意思、由来-开放百科全书

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Shaft (mechanical engineering)

释义

Types
Materials
Standard sizes
Machine shafts Transmission shafts
Stresses
Design stresses
References
External links

A shaft is a rotating machine element, usually circular in cross section, which is used to transmit power from one part to another, or from a machine which produces power to a machine which absorbs power.^[1] The various members such as pulleys and gears are mounted on it.

Types

They are mainly classified into two types.

Transmission shafts are used to transmit power between the source and the machine absorbing power; e.g. counter shafts and line shafts.
Machine shafts are the integral part of the machine itself; e.g. crankshaft.

Materials

The material used for ordinary shafts is mild steel. When high strength is required, an alloy steel such as nickel, nickel-chromium or chromium-vanadium steel is used.

Shafts are generally formed by hot rolling and finished to size by cold drawing or turning and grinding.

Standard sizes

Source:^[2]

Machine shafts

Up to 25 mm steps of 0.5 mm

Transmission shafts

25 mm to 60 mm with 5 mm steps
60 mm to 110 mm with 10 mm steps
110 mm to 140 mm with 15 mm steps
24.5 mm to 25 mm with 12 mm steps

The standard lengths of the shafts are 5 m, 6 m and 7 m.

Stresses

The following stresses are induced in the shafts.

Shear stresses due to the transmission of torque (due to torsional load).
Bending stresses (tensile or compressive) due to the forces acting upon the machine elements like gears and pulleys as well as the self weight of the shaft.
Stresses due to combined torsional and bending loads.

Design stresses

The maximum permissible (design) stresses in bending (tension or compression) may be taken as:

112 N/mm{{sup|2}} for shafts with allowance for keyways.
84 N/mm{{sup|2}} for shafts without allowance for keyways.

The maximum permissible (design) shear stresses may be taken as:

56 N/mm{{sup|2}} for shafts with allowance for keyways.
42 N/mm{{sup|2}} for shafts without allowance for keyways.

References

1. ^Khurmi R S, (2014), 'A text book of machine design', Eurasia publishing house(P) ltd., New-Delhi, {{ISBN|9788121925372}}
2. ^Mahadevan K and Reddy K.Balaveera, (2015), 'Design data hand book', CBS publishers and Distributors (P) ltd., New-Delhi, {{ISBN|9788123923154}}

External links

[https://www.mechanicalcheck.com/en/din743/calc/ Online verification of shafts according standard]

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