What is line of action in gear?

Line of action is the common tangent line

tangent line

In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve.

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Tangent - Wikipedia

of the base circles of a pair of involute gears

involute gears

In an involute gear, the profiles of the teeth are involutes of a circle. The involute of a circle is the spiraling curve traced by the end of an imaginary taut string unwinding itself from that stationary circle called the base circle, or (equivalently) a triangle wave projected on the circumference of a circle.

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Involute gear - Wikipedia

in contact. When a pair of involute gears is meshed, the contact occurs on the line of action and the contact point moves along the line of action.

What is the line of action and pressure angle of gear?

Technically, the pressure angle is the angle formed between the line of action and the line tangent to the pitch point. Simply put, it refers to the angle through which forces are transmitted between meshing gears, as the line of action is the line where force acts on.

What is angle of action in gear?

Definition of angle of action

: the angle of revolution of either of two wheels in gear during which any particular tooth continues in contact.

What is line of contact in gears?

The distance actually covered on the line of action is then called line of contact. The line of contact begins at the intersection between the line of action and the addendum circle of the driven gear and ends at the intersection between the line of action and the addendum circle of the driving gear.

What is length of action in gears?

Length of Action (Z) – is the distance on an involute line of action through which the point of contact moves during the action of the tooth profiles. Line of Action – is that portion of the common tangent to the base circles along which contact between the mating involute teeth occurs.

LINE OF ACTION #TOM #GEAR

What is pitch point in gear?

Pitch Point. When a pair of gears are operating in mesh, the point of tangency between the two pitch circles is called the pitch point. Root Diameter (R.D.) is the diameter of a circle around the bottom (root) of the gear tooth spaces.

What is a point or line contact?

A contact point is where a pair of gears touch each other. In the diagram below P1, P2 and P3 are the contact points. As shown in the diagram below, when involute gears mesh, the contact points of both gears move along the line of action which is the common tangent of the two base circles.

What is profile of gear?

Gear Tooth Profile: One of the fundamental s of gear design is the profile of the gear tooth. Gears generally have an involute curve tooth profile. There are other types of gear profiles, but they are mainly utilized in specialty applications such as cycloidal gears in clocks and watches.

What is law of gearing?

The law of gearing states that common normal must always pass through the pitch point at the point of contact between a pair of teeth and the angular velocity ratio of all gears must remain constant throughout the gear mesh.

Why pressure angle is 14.5 and 20?

Standard values are 14.5 and 20 degrees. Earlier gears with pressure angle 14.5 were commonly used because the cosine is larger for a smaller angle, providing more power transmission and less pressure on the bearing; however, teeth with smaller pressure angles are weaker.

What is rack and pinion gear?

A rack and pinion is a type of linear actuator that comprises a circular gear (the pinion) engaging a linear gear (the rack), which operate to translate rotational motion into linear motion. Driving the pinion into rotation causes the rack to be driven linearly.

What are the 4 types of gears?

What is gear undercut?

The undercut of gears is also called deeper cutting and indicates the phenomenon of cutting the root of the gear deeper than the involute tooth curve. This can happen when there is interference between a tooth cutting tool and a gear or between the two meshing gears.

How do you calculate the PCD of a gear?

Pitch Circle Diameter (PCD) – Gear Terminology

The center distance of two meshing gears is expressed as the sum of the pitch circle radii of the two gears. Since the module of the meshing gears are the same, center distance a = (d1 + d2) / 2 = (z1m + z2m) / 2.

What is a pitch circle?

: a pitch line in a circular gear that forms a circle concentric with the axis of the gear.

What is lead & profile in gear?

In spur gearing, gear profile is the most sensitive feature. In respect to effects on noise, lead has little to no effect. In helical gearing, lead is the most sensitive feature—with profile, it is second. This is due to the way each type of gear meshes (Figure 3).

What is root clearance in gears?

The distance between the outside circle of a gear and the root circle of its mating gear (the gap) is called the root clearance. This distance (the gap) is also called the root clearance, top clearance, bottom clearance or simply the clearance.

What is gear interference?

When two gears are in mesh it is possible that an involute portion of one will contact a non-involute portion of the other gear. This phenomenon is known as "interference" and occurs when the number of teeth on the smaller of the two meshing gears is less than a required minimum.

What is called line?

A line is a one-dimensional figure, which has length but no width. A line is made of a set of points which is extended in opposite directions infinitely. It is determined by two points in a two-dimensional plane. The two points which lie on the same line are said to be collinear points.

What is a ray line?

A ray is a line segment that extends indefinitely in one direction.

What is called point?

A point is the most fundamental object in geometry. It is represented by a dot and named by a capital letter. A point represents position only; it has zero size (that is, zero length, zero width, and zero height). Figure 1 illustrates point C, point M, and point Q.

What is flank in gear?

In crossed-axes gearing, when a gear and a mating pinion rotate steadily, the gear tooth flank, , can be viewed as an envelope to consecutive positions of the mating pinion tooth flank, . Generated in this way, the gear tooth flank, , can be used to generate the mating pinion tooth flank, .

What is the hole in a gear called?

Pitch Point. The pitch point is the point of tangency of two pitch circles (or of a pitch circle and pitch line) and is on the line of centers. Plain Bore. This term is used to indicate that the center hole in a gear has no keyway, set screw(s), bushing or any other type of machined preparation for shaft mounting.

What is bull gear?

: a bull wheel having gear teeth.