The standard gear module is a toothed profile with an involute configuration on the sides. Such gearing has a lot of advantages over analogues, the teeth are easy to process and install, and the gears do not require jewelry precision installation. In addition, there are versions with a cycloidal shape of the working profile, including the Novikov gear. Ratchets often use asymmetrical tooth configurations.
Gear module parameters
The characteristic under consideration is denoted by the letter m, indicates the strength of the gears. The unit is measured in millimeters (the higher the gear load, the greater the modulus value). The following indicators are used in the parameter calculation:
- diameter of pitch circle;
- pitch and number of teeth;
- involute (base circle diameter);
- similar characteristic of dark gear cavities;
- tooth height of dark and light wheel.
In the engineering industry, calculations are carried out using standard values for ease of manufacture and replacement of gears with numbersfrom 1 to 50.
Spur and helical gears
The module and diameter of the spur gear is one of the most popular types. The teeth are placed in radial planes, and the contact area of a pair of wheels is parallel to the axis of rotation. The axes of both gears are located in the same way.
Helical wheels are an improved variation of the above modification. The teeth are at a certain angle to the rotational axis. The engagement is smoother and quieter, which allows the elements to be operated in low-noise applications, guaranteeing more torque at high speed. The disadvantages include an increased contact area of the teeth, which provokes increased friction and heating of parts. This is fraught with a weakening of power and increased lubricant consumption. In addition, mechanical action along the pinion axis requires the use of thrust bearings to mount the shaft.
Chevron modifications and analogues with internal gearing
Chevron gears solve problems with mechanical axial force. Unlike the straight and helical versions, the teeth are V-shaped. The specified model is independently installed along the axis, one of the working gearboxes is mounted on cylindrical shortened bearings (floating bearings).
The internal gear module is equipped with teeth havingcut inside. The operation of the part involves one-sided revolutions of the driving and driven wheels. In this design, less friction is spent, which contributes to increased efficiency. Such devices are used in mechanisms that are limited in overall dimensions, as well as planetary gears, special pumps and tank turrets.
Screw, circular, sector versions
The screw-type gear module is a cylinder with teeth that are placed in a helical direction. Such elements are installed on non-intersecting shafts located perpendicular to each other. The alignment angle is 90 degrees.
A sector gear is a part of any gear used in gears where the main element does not need to rotate a full turn. Such a detail makes it possible to save valuable space in the size of a full-fledged analogue.
Gears in terms of modulus and number of teeth with a circular arrangement are distinguished by contact contact at one point of engagement, located parallel to the main axes. The second name of the mechanism is Novikov's transmission. It provides good running characteristics, smooth and silent operation, increased hooking ability. At the same time, the efficiency of such parts is slightly lower than analogues, and the manufacturing process is much more complicated. These parts have a significantly limited industry due to their characteristics.
Bevel gear module
This type of gearshas various varieties, which differ from each other in the configuration of the lines of the teeth: straight, curvilinear, tangential, circular elements. Similar parts are used in units to transform the movement of the mechanism by transferring the effect of movement from one shaft to another. For example, in the differentials of cars during the transformation of torque from the power unit to the wheels.
Bevel gears are subdivided by modulus and number of teeth as follows:
- The rail design is distinguished by an infinite radius of the dividing part of the circle. As a result, such elements are parallel lines with an involute profile. This characteristic is most important in the production of gears. With a rack, the transmission is called rack or rack. This type is used to convert revolutions into translational rotation and vice versa. The main scope of application is rail transport.
- Star type wheel. It is used in most chain drives, which allows it to be combined with a flexible part that serves to transmit mechanical action.
- Diameter of the gear by the number of teeth and modules in crown design - a special kind of impellers. The teeth in this version are located directly on the side surface. This part functions in aggregation with a spur or drum counterpart, which includes special rods in the design. A similar knot is used in tower clock mechanisms.
How to calculate the indicator?
Determination of the gear module is fixed by the following formula:
- m=d/z=p/.
- The height of the tooth head and the similar parameter of the stem are marked with the symbols Hfp and Hap, the ratio is Hfp/Hap=1, 24.
- How to determine the gear module in another way? m=da/z+2.
Often, engineers are faced with the task of evaluating a gear in real performance for replacement or repair. Sometimes the documentation for the part is drawn up formally, which complicates the implementation of these manipulations. Among the proven diagnostic methods is the break-in method. A gear wheel with known parameters is inserted into the teeth of the element under test, after which a circular run-in is carried out. If the pair under test engages, this indicates the match of the pitch. If the result is negative, the process is repeated. With helical variations, choose a cutter that exactly matches the pitch.
Summarize
Calculated drawings and diagrams for gears of various configurations are mostly the same for oblique and spur versions. The main differences arise in strength calculations. In graphic displays, characteristics are used that are oriented to the typical overall dimensions of gears. Among the presented range on the market, it is quite possible to choose a gear with the necessary characteristics and strength indicators.
