A taper key is uniform in width but tapered in height. The bottom surface is straight and the top surface is tapered. Taper keys are often used with Gib head for easier removal of key during disassembly. When it’s firmly driven, it acts to prevent relative axial motion.
Why is taper given to key?
(i)Taper keys : It is tapered (standard taper of this key is 1 in 100) in thickness but uniform in width. A taper key joint prevents relative rotational as well as axial movement between the two pieces.
Which key is used for tapered shaft fitting?
Woodruff key
The top portion of the key projects out and fits in the keyway cut on the hub. This key is particularly useful on tapered fittings of shafts.
What is the purpose of a Woodruff key?
A woodruff key is a half?moon shaped machine key that prevents gears, hubs, or other components from moving independently of a rotating shaft or spindle. They also act as a fail?safe that protects expensive parts by shearing under excessive loads.
What is a feather key?
Definition of feather key
in machinery. : a sunk key without taper that is permanently fixed in one of the connected pieces and that is a sliding fit in a keyway in the other so as to permit relative longitudinal motion. called also spline.
How much torque can a keyway handle?
The limiting pressure point of a keyed shaft is the keyway side of the male shaft, provided the proper key material is selected. Thus, 270 Nm is the maximum torque that can be transmitted before the 19 mm diameter keyed shaft plastically deforms.
What is the disadvantage of keyed joint?
Too much securely fixed keyed joint might become difficult to dismantle. Causes shaft imbalance. They introduce stress points due to the notch effect and reduce shaft strength. Possible axial displacement of hub unless locked by an extra component such as circlip or set screw.
Which key does not require keyway?
Hollow and flat keys
These are long bodies with a rectangular cross-section with inclined back surface and small taper. They are only used for transmitting little rotary forces. For these no keyway must be made: – The bottom of hollow keys is concave in longitudinal direction.
What is Kennedy Key?
The Kennedy key consists of two square keys. The hub is bored off the centre and the two keys force the hub and the shaft to a concentric position. Kennedy key is used for heavy duty applications.
Which among the following key is used in Taper shaft assemblies?
Explanation: Normally in Automobile shafts Woodruff key is used.
Where the circular taper key is used?
This key is particularly useful on tapered fittings of shafts. It is a semicircular key used for transmitting light torque.
What is saddle key?
Definition of saddle key
: a key for securing a member to a machine shaft that fits into a keyway in the secured member and is concave to grip the shaft by friction compare flat key, sunk key.
How tight should a Woodruff key be?
It is important for key to be somewhat snug and stable in the key seat. If key is not snug/stable then key can easily slide out of key seat due to the curved profile on the bottom. This is very inconvenient in cases where it is difficult to see as the pulley is installed.
What does a Woodruff key look like?
Woodruff keys are semicircular shaped, such that, when installed, leave a protruding tab. The keyway in the shaft is a semi-circular pocket, the mating part, a longitudinal slot. They are used to improve the concentricity of the shaft and the mating part, which is critical for high speed operation.
What are Half Moon keys?
Woodruff keys work well near shaft shoulders, where a standard open keyway would create too much stress. They are also often used on tapered shafts.Use them to connect gears and other components to shafts. Also known as half moon keys.
What is sunk key?
Definition of sunk key
: a key that fits into keyways in both the shaft and the secured member in machinery compare saddle key.
What is Barth key?
Barth key. Barth key is modified from the square key. Barth key has a bevel shaped smooth edges at the upper part. This bevel shaped smooth edges help the key to fit tightly. Like a square key, the Barth key is also used in many applications.
What is the difference between a saddle key and a sunk key?
Compared to sunk keys, saddle keys are not sunk into the shaft and hub instead they are only sunk into the hub. They either sit on a flat or circumference of the shaft. Power transmission is achieved through friction between the shaft and the key.
How do I choose a shaft key?
The key and key seat cross section are ISO standardized. The key length should be less than about 1.5 times the shaft diameter to ensure a good load distribution over the entire key length when the shaft becomes twisted when loaded in torsion.
What is the difference between keys and splines?
The main difference between splines and keys is that splines are integral with the shaft but keys are inserted between shaft and hub. As compared with one or two keys used for load transmission, there are usually four or more splines on a shaft.
What is the ratio of keyway taper?
Standard inch-sized tapered pins have a taper on diameter of 1:48[1] while metric ones have a taper of 1:50.
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