Compensating couplings - Machine parts. Course design

Compensating couplings

To compensate for dangerous overloads that arise as a result of axial, radial, angular displacements of the connected shafts, compensating couplings are placed. They provide a permanent connection of the shafts with compensation for small radial, axial, angular and combined shaft displacements.

The following types of compensating couplings are used:

• Toothed;

• Chain;

• are articulated. Toothed clutches

Toothed couplings (figure 10.7) are used in high-loaded structures to connect shafts with diameters from 40 to 200 mm. The coupling consists of two bushings with external teeth and two clips with internal teeth.

The connection of the bushings to the shaft is effected by key and landing with interference or splines. The connecting rings, whose internal teeth are engaged with the involute teeth of the bushings, are interconnected rigidly by means of bolts fitted into the holes without clearance.

The heads of the teeth on the sleeves are spherical in shape along the length of the tooth and barrel-shaped in the longitudinal section. For couplings, involute engagement with a profile angle a = 20 ° and an altitude coefficient A * = 0.8 is used.

The centering of the cage relative to the bushing is usually performed with the outer diameter c1 a . A large number of simultaneously working involute profile teeth provides compactness and high load capacity. With this shape of the teeth and the provided lateral clearances, the axle of each shaft can be misaligned to 0 ° 30 'and some radial displacement of the shafts (in the absence of angular displacement) from 1.5 to 6.5 mm (depending on the diameter of the shaft)

The details of the gear couplings are made of steel 40 or steel castings. The teeth of the sleeves are heat-treated to a hardness of at least 42 ° C, and the teeth of the cages are not below 37 ° C. To reduce the wear rate of the teeth, a lubricant of high viscosity is poured into the coupling.

Fig. 10.7

Toothed clutches are standardized in GOST 5006-83.

Toothed couplings are manufactured in two types:

• normal M3;

• Extended MW with an intermediate shaft. Chain couplers

Chain couplings (Figure 10.8, GOST 20742-93) are used to connect shafts with a radial displacement of up to 1.2 mm and angular displacement of up to 1 °.

The torque (from 63 to 1600 N m) is transmitted with sprockets and a closed circuit.

The coupling of the half-couplings to the shafts can be carried out with the help of dowels or splines (rectilinear or involute).

Couplings are made of two types:

type 1 - with a single-row chain; type 2-d double-row chain.

Half couplings are manufactured in the following versions:

• with a cylindrical hole for short shaft ends in accordance with GOST 12080-66;

• a conical hole for short ends of shafts in accordance with GOST 12081-72;

• a hole on the shafts with involute splines but GOST 6033-80;

• a hole on the shafts with straight slots but GOST 1139-80.

It is possible to manufacture half couplings for long shaft ends by

GOST 12080-66 and GOST 12081-72.

Other types of coupler coupling with shafts are allowed.

Advantages of chain couplings - simplicity of design and maintenance, reliability, manufacturability, small size and weight, convenient installation and dismantling.

The lack of valuable couplings is the presence of the "dead" stroke, which limits their use in reverse gears.

Fig. 10.8 Joints

Joints (GOST 5147-97) (Figure 10.9) provide connection of non-axial shafts, allowing the greatest misalignment angles (up to 45 °) in comparison with other types of couplings, and the angle of inclination can vary during operation.

This is achieved with the help of hinges (1, 3) and an intermediate link (cross) 2, made in the form of a parallelepiped with two holes, whose axes intersect at right angles. The hinges and the cross are connected in semiaxes.

Couplings are manufactured for shafts with diameters from 8 to 40 mm, the transmitted moment is 11.2-1120 N m.

The disadvantage of the hinged coupling is the unevenness of rotation of the input shaft with a uniform rotation of the output shaft, if the shafts are not mounted (Fig. 10.9, b). To eliminate this drawback, double jointed couplings are used (Figure 10.9, c), but for parallel rotation of the driven shaft, parallel shafts connected to hinges (1) and (4) must be parallel.

Fig. 10.9

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