Ramana Rao Well-Known Member Hi Uday, 'K' charts are graphs generated for the permissible deviations of form and lead errors, for spur and helical gears. These charts are based on the earlier AGMA standards, and do not appear in other standards as DIN, JIS etc. Each gear will have its own k-chart.

How do you read a gear profile?

Profile is the shape of the gear tooth curve and is measured from the root to the tip of the gear tooth. The functional, or operating, portion of the profile is the area that is in actual contact during tooth mesh. Typically, this area is from just above the root fillet to the tip of the tooth.

What is AGMA quality number?

In the ANSI/AGMA 2000 A88 Gear Classification and Inspection Handbook, quality numbers from Q3 to Q15 represent the accuracy of the tooth geometry; the higher the number the smaller the tolerance.

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).

Related Question What is gear k chart?

What is gear pitch?

The pitch of a gear is defined as the distance between two identical points on two adjacent gear teeth. Ideally, it is measured at the pitch line, labeled in Figure 1 as the reference line. This method of determining the size of the gear tooth is based on the unit circle.

What is addendum and Dedendum?

DEDENDUM Addendum is the height of the tooth above the pitch circle. Dedendum is the depth of the tooth below the pitch circle. Whole Depth is the total length of a tooth space equal to the sum of the addendum and dedendum.

Which gear precision rating is high?

There are 13 precision grades of gears, which are arranged from low to high by the numbers 0-12. Grade 0 is the highest and grade 12 is the lowest. Gear accuracy refers to the comprehensive error of gear shape, including some important parameters such as tooth shape, tooth direction, radial jump, etc.

What is AGMA rating?

Ratings are for 20 years of continuous operation, except ANSI/AGMA 6011-J14 specifies that ratings are for a minimum of 40,000 hours. Therefore, for comparison, ANSI/AGMA 6011 ratings are presented both for 40,000 hours and 175,200 hours (20 years). The ANSI/AGMA 6013 ratings are for 10,000 hours as stipulated.

What is backlash in gear?

Backlash refers to the angle that the output shaft of a gearhead can rotate without the input shaft moving. Backlash arises due to tolerance in manufacturing; the gear teeth need some play to avoid jamming when they mesh. Some gear types, notably harmonic drive gears (see Section 26.1.

What gears inclined teeth?

The helical gears have inclined teeth (teeth cut at an angle to the face of the gear) on the surface of the wheel. Its operation is smoother and quieter as compared with the spur gear. It is mostly commonly used in transmission gearboxes.

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 gear pitch error?

Normal Pitch Error (fpb) It is the difference between theoretical normal pitch and its actual measured value. The major element to influence the pitch errors is the runout of gear flank groove.

How do you measure gear size?

  • Figure 1 Left:pin and disk test rig.
  • for use in the tooth flank:
  • This determines the local wear in each point of the tooth contact area on the gear.
  • How do you check backlash between gears?

    What does 48 pitch gear mean?

    Well 48p is the pitch of the teeth and 90t is the number of teeth on the gear.so its a 48° pitch gear with 90 teeth. its always important to make sure the spur gear and pinion gear are the same pitch. The pitch of each gear must be the same as the other in order for them to mesh properly.

    What is pitch formula?

    PITCH-This is the distance from a point on the screw thread to a corresponding point on the next thread measured parallel to the axis of the thread. It is represented by the letter p. (p=1/n).

    How is gear pitch calculated?

    Divide the number of teeth on the gear by this measurement. For example, if the gear has 28 teeth: 28 / 6 = 4.67. Round this figure to the nearest whole number: 4.67 is approximately 5, so the gear has a pitch of 5.

    Which is greater addendum or Dedendum?

    2) Why dedendum is larger than addendum? Meshing of mating teeth should occur on the involute portion of teeth. The teeth have involute profile from the base circles to addendum circles. The dedendum circle is made smaller than the base circle and also lies below the pitch circle at distance, 'b'.

    What is Dedendum in gears?

    : the root of a gear tooth also : the distance between the dedendum circle and pitch circle of a gear wheel or rack — compare addendum.

    What is Dedendum in spur gear?

    Dedendum: Depth of the tooth between the pitch circle and the minor diameter. Pitch circle: The circle, the radius of which is equal to the distance from the center of the gear to the pitch point. This is where the gear's speed is measured.

    What are the 3 main types of gears?

    There are three major categories of gears in accordance with the orientation of their axes. Configuration : Parallel Axes / Spur Gear, Helical Gear, Gear Rack, Internal Gear.

    What is ratio of gear?

    A gear ratio is the ratio of the number of rotations of a driver gear to the number of rotations of a driven gear.

    Are gears accurate?

    The required gear accuracy is directly related to the costs of manufacture. The highest accuracy available by current processes is considered to be AGMA 15 (A2). On a 6-inch diameter gear, this is accuracy in the order of 0.00011″. There is also a limit on how wide tolerances can be to be economical.

    What is a bevel gear used for?

    2.4 Bevel gears. Bevel gears are used to connect shafts whose axes lie at an angle to each other, although in most applications the shafts are at right angles. The tooth profile is basically the same as used for spur gears except that the tooth gets progressively smaller as it approaches the apex of the projected cone.

    What is the use of Lewis equation in spur gears?

    The Lewis equation is used to estimate the bending stress in gear teeth (max. bending stress at the root of a gear tooth).

    What is gear factor?

    In simple terms, the service factor is the ratio of the gearbox rated horsepower (or torque) to the application's required horsepower (or torque). In general, the horsepower (or torque) rating of a gear tooth is based on the durability of the gear surface — its resistance to pitting — or on its bending fatigue.

    How do I choose a gearbox for my motor?

  • Service Factor. Before sizing an application, the customer should determine the service factor.
  • Ambient Temperature and Environment.
  • Shock Load or Type of Load.
  • Output Style or Mechanism.
  • Output Shaft or Hollow Bore Size.
  • Housing Styles.
  • What is sliding mesh gearbox?

    An obsolete type of transmission or gearbox in which the gears on the layshaft are fixed to the shaft rigidly, whereas the gears on the main shaft can slide on it by means of splines but are otherwise in permanent rotational mesh with the shaft. The figure below shows the arrangement of sliding mesh gear box.

    What is velocity of sliding?

    Definition. Sliding velocity is the relative velocity in a transverse plane of a common contact point between mating gear teeth. As shown in Fig. 1, it is the vectorial difference between the two rolling velocities that are tangential to the tooth profiles and perpendicular to the line of action.

    What is the unit of backlash?

    As a rule of thumb the average backlash is defined as 0.04 divided by the diametral pitch; the minimum being 0.03 divided by the diametral pitch and the maximum 0.05 divided by the diametral pitch. In a gear train, backlash is cumulative.

    Why is backlash bad?

    Backlash creates an issue in positioning when an axis changes direction. The slack in the threads/gears cause measureable error in axis positioning. The MachMotion software can compensate a small amount for this error and better track the true position.

    What is parallel gear?

    Gears involving two axis, which are parallel to each other, are called Parallel Axis Gears. For the transmission of rotation/power by parallel axis, Spur, Helical and Internal Gears are generally used. A spur gear is a cylindrical shaped gear, in which the teeth are parallel to the axis.

    What is helical gear?

    Helical gears are one type of cylindrical gears where the teeth are curved into a helix shape. Compared to spur gears (straight teeth), properly designed helical gears can have a larger total contact ratio which can improve vibration and noise. Badly designed helical gears can be noisier than well designed spur gears.

    Which gears produce a thrust load?

    Helical is the most commonly used gear in transmissions. They also generate large amounts of thrust and use bearings to help support the thrust load. Helical gears can be used to adjust the rotation angle by 90 deg. when mounted on perpendicular shafts.

    Do gears need the same pitch?

    Gears must have the same pitch or module in order to work together. To measure the pressure angle and pitch or module of a gear, use a Gear Tooth Pitch Identifier. If you don't have a gear tooth pitch identifier, you can estimate a spur gear's pitch or module.

    What is root clearance in gears?

    What is root clearance ? 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.

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