Sprocket with cantilever teeth

Abstract

This utility model relates to mechanical engineering, specifically to chain drives equipped with roller chains. A sprocket with cantilever teeth has a toothed ring with teeth separated by slots formed in the tooth gullets, each slot having a width of c = 1 mm, an angle of δ = 45° to the tooth axis, and a depth of l calculated based on the bending strength of the tooth cantilever base. Elastic wedges are installed in the slots. The technical result is a reduction in vibration and noise during chain drive operation.

Description

[0001] The utility model relates to mechanical engineering, in particular to chain transmissions equipped with roller chains.

[0002] The main disadvantages of chain drives are noise during operation and the faceted shape of the sprockets. Noise is caused by the impact of the chain joints when engaging the sprocket teeth. The faceted shape of the sprockets, caused by the chain links being arranged on the arc of the sprocket's grip like the sides of a polygon, leads to periodic vertical displacement of the end joints of the chain, causing lateral vibrations (https: / / reductory.ru / literatura / detali-mashin-ivanov / kinematika-i-dinamika-cepnoi-peredachi / ).

[0003] A chain drive sprocket (Russian Federation Patent 1350 - similar) has radial grooves filled with a viscoelastic material (rubber, etc.) that dampens tooth vibrations and reduces noise during chain drive operation. However, the radial grooves and holes separating the cantilever teeth do not allow for changes in the hinge radius when the cantilever teeth bend. Furthermore, deformation of the cantilever teeth can cause the elastic material in their groove to be squeezed beyond the toothed ring along its width and cause friction against the chain plates meshing with the sprocket, reducing transmission efficiency.

[0004] A sprocket with cantilever teeth is known (RU Patent No. 2844194 - prototype), having a gear ring with teeth separated by slots made in the tooth gullets. Each slot has a width of c = 1 mm, is angled at δ = 45° to the tooth axis, and has a depth of l, which is calculated based on the bending strength of the tooth console base, taking into account the chain parameters and the transmitted torque. Using a sprocket with cantilever teeth reduces the vertical movement of the end joints of the chain branches due to the sprocket's faceted shape, which leads to a decrease in the amplitude of transverse oscillations of the chain branches and an increase in the service life of the chain drive. However, the sprocket's cantilever teeth are prone to vibration due to their increased compliance, which leads to increased noise during chain transmission.

[0005] The technical result is a reduction in vibration and noise during chain transmission operation.

[0006] The technical result is achieved in that the sprocket with cantilever teeth (hereinafter referred to as the sprocket) has a toothed rim with teeth separated from each other by slots that are made in the tooth cavities, each slot has a width of c = 1 mm, is made at an angle of δ = 45° to the tooth axis and has a depth l, which is calculated from the condition of the bending strength of the base of the tooth console according to formula (1)

[0007]

[0008] where t is the chain pitch, mm; D is the outer diameter of the chain joint, mm; T is the torque on the sprocket shaft, N⋅mm; b is the width of the sprocket ring gear, mm; z is the number of sprocket teeth; - thickness of the base of the tooth console, mm; [σ F ] - permissible bending stress for the sprocket material, MPa,

[0009] moreover, elastic wedges are installed in the slots.

[0010] Fig. 1 shows a sprocket with cantilever teeth and chain hinges on the arc of the chain in an unloaded state. Fig. 2 shows the movement of the chain hinge, as well as the deformation of the elastic wedges in the sprocket slots when the cantilever tooth of the sprocket bends (in a running chain drive).

[0011] A sprocket with cantilever teeth has a toothed crown 1 with teeth 2 separated from each other by slots 3, which are made in the cavities of teeth 4, and each slot has a width of c = 1 mm, is made at an angle of δ = 45° to the tooth axis and has a depth l, which is calculated from the condition of the bending strength of the base of the tooth console 5 according to formula (1)

[0012]

[0013] where t is the chain pitch, mm;

[0014] D - outer diameter of the 6 chain joint, mm;

[0015] T - transmitted torque on the sprocket shaft, N⋅mm;

[0016] b - width of the toothed ring of 1 sprocket, mm;

[0017] z - number of sprocket teeth;

[0018] - thickness of the base of the console 5 teeth, mm;

[0019] [σ F ] - permissible bending stress for the sprocket material, MPa.

[0020] Moreover, elastic wedges 8 are installed in the slots 3.

[0021] The asterisk works as follows.

[0022] In the unloaded state of the chain transmission, the centers of the hinges 6 of the chain, located on the arc of the sprocket girth, are located on the pitch circle of the sprocket with a diameter d д (Fig. 1), the bases of the consoles 5 of the teeth 2 are not deformed, the working branch 7 of the chain is at the level of a circle with a diameter d Г .

[0023] In the working state of the chain transmission (Fig. 2), with each rotation of the sprocket by half of its angular pitch π / z, the center of the hinge 6 of the chain, which comes out of engagement with the sprocket, must move along the arc of the pitch circle with a diameter d д and take position O1, raising the working branch of the chain by the value Δ Г.However, when hinge 6 reaches the loaded working branch 7 of the chain, hinge 6 of the chain acts on tooth 2 of the sprocket with force F, causing elastic deformation of the bend at the base of console 5 of tooth 2. In this case, the center of hinge 6 moves to position O2, reducing the vertical movement of the chain branch Δ Г , due to the faceted nature of the star, up to the value Δ Гmin .

[0024] The presence of elastic wedges 8 in slots 3 allows to dampen the vibration of the cantilever teeth and reduce the noise level during the operation of the chain transmission.

[0025] Thus, the placement of elastic wedges in the slots of the sprocket with cantilever teeth allows to reduce vibrations and noise levels during the operation of the chain transmission while maintaining high efficiency.

Claims

A sprocket with cantilever teeth, having a toothed rim with teeth separated from each other by slots, which are made in the tooth cavities, each slot has a width of c = 1 mm, is made at an angle of δ = 45° to the tooth axis and has a depth l, which is calculated from the condition of the bending strength of the base of the tooth console according to formula (1) , (1) where t is the chain pitch, mm; D - outer diameter of the chain hinge, mm; T – torque on the sprocket shaft, N⋅mm; b - width of the sprocket toothed ring, mm; z - number of sprocket teeth; - thickness of the tooth console base, mm; [σ F ] - permissible bending stress for the sprocket material, MPa, characterized by the fact that elastic wedges are installed in the slots.

Images