A revolute joint (also called pin joint or hinge joint) is a one-
degree-of-freedom kinematic pair used frequently in
mechanisms and
machines.
The joint
constrains the motion of two bodies to pure rotation along a common
axis. The joint does not allow
translation
Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...
, or sliding
linear motion, a constraint not shown in the diagram. Almost all assemblies of multiple moving bodies include revolute joints in their designs. Revolute joints are used in numerous applications such as door
hinges, mechanisms, and other uni-axial rotation devices.
A revolute joint is usually made by a
pin or
knuckle joint
A knuckle joint is a mechanical joint used to connect two rods which are under a tensile load, when there is a requirement of small amount of flexibility
Stiffness is the extent to which an object resists deformation in response to an applied fo ...
, through a rotary
bearing. It enforces a cylindrical contact area, which makes it a
lower kinematic pair, also called a full joint. However, If there is any
clearance between the pin and hole (as there must be for motion), so-called surface contact in the pin joint actually becomes line contact.
The contact between the inner and outer cylindrical surfaces is usually assumed to be
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding (motion), sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative la ...
less. But some use simplified models assume linear
viscous damping in the form
, where is the
friction torque, is the relative
angular velocity
In physics, angular velocity or rotational velocity ( or ), also known as angular frequency vector,(UP1) is a pseudovector representation of how fast the angular position or orientation of an object changes with time (i.e. how quickly an objec ...
, and is the friction constant. Some more complex models take stiction and stribeck effect into consideration.
See also
*
Cylindrical joint
*
Kinematics
*
Degrees of freedom (mechanics)
In physics, the degrees of freedom (DOF) of a mechanical system is the number of independent parameters that define its configuration or state. It is important in the analysis of systems of bodies in mechanical engineering, structural engineer ...
*
Kinematic pair
*
Mechanical joint
*
Prismatic joint
A prismatic joint is a one- degree-of-freedom kinematic pair which constrains the motion of two bodies to sliding along a common axis, without rotation; for this reason it is often called a slider (as in the slider-crank linkage) or a sliding ...
References
Kinematics
Rigid bodies
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