RU2093740C1 - Gear transmission - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: side surface of one of the wheels is provided with a modified portion whose height is defined by a relationship presented in the invention description. The value of the maximum modification depends on roughness of the side surface, tolerance on profile error, and deviation of the engagement step. EFFECT: improved design. 3 cl, 5 dwg

Description

 The invention relates to mechanical engineering and can be used for the manufacture of power drive devices.

Known gear transmission with parallel axes and profile modification of the tooth head [1]
The disadvantage of this modification is the uncertainty in choosing the depth of modification, which can result in certain combinations of roughness, tooth profile errors and deviation of the pitch of engagement to the edge contact at the top of the tooth and premature tooth decay, i.e. to reduce gear strength.

Known hyperboloid gear with intersecting axes, having a profile modification, depending on the class of surface roughness [2]
The disadvantage of profile modification is the unaccounted for deviation of the shape of the tooth lateral surface from the nominal and deviation of the engagement step from the nominal when determining the depth of modification. This neglect can lead to edge contact on the tooth head, which reduces the strength of the gear train.

The initial producing circuit is known, which is used in the manufacture of involute wheels by the rolling method. In this case, worm cutters, gear racks [3]
The disadvantage of the manufacturing method using such a producing circuit is the unaccounted for manufacturing inaccuracies and the surface roughness of the teeth of the wheels, resulting in an edge contact at the top of the tooth during operation of the wheels, which ultimately reduces the transmission strength.

Known is a modified initial production circuit with a prominence or bevel, with the help of which the wheels are made by the rolling method [4]
When manufacturing using a modified manufacturing circuit, there is an uncertainty in the modification parameters, which can lead to edge contact and premature transmission failure at a shallow modification depth, and at a large modification depth, exclusion of the modified section from the contact, which also leads to a decrease in transmission strength.

 The invention solves the problem of increasing transmission strength by eliminating the possibility of an edge contact.

This problem is solved in that a gear transmission with a profile modification of the tooth, depending on the surface roughness class, has a modification of the head or tooth leg of one of the wheels equal to a height of 0.3 m _n , and the modified section is enveloped by an arc of circles of radius R with depth modifications equal to
δ = 3f _w + f _f + f _pb ,
where f _{w the} size depending on the roughness class,
f _{f the} tolerance on the profile error,
f _pb deviation of the pitch of engagement.

где m_n модуль в нормальном сечении,
δ - максимальная глубина модификации,
α_w- угол зацепления.According to the producing initial contour with a prominence or bevel for making teeth of one of the gear wheels with profile modification of the tooth, the problem is solved in that the modified section of the producing initial contour is made along an arc of a circle of radius r, which is equal to

where m _{n is the} module in normal section,
δ is the maximum depth of modification,
α _w is the angle of engagement.

Gears with maximum depth of modification
δ = 3f _w + f _f + f _pb ,
when f _W = 4,5 • 10 ^-5 • 2 ^(13-W) ,
where w is the roughness class (A.S. N 1372128),
and the producing contour with a prominence or bevel, used to manufacture the teeth of one of the gear wheels with profile modification of the tooth when performing a modified section of the producing initial contour along an arc of a circle of radius r, allow to take into account the tolerance on the profile error, deviation of the engagement pitch and eliminate the possibility of edge contact , and also allows you to have a minimum clearance between the modified area and the side surface of the tooth of the second wheel, which after running in will result to participate in the work and the modified site. All this leads to an increase in transmission strength.

 In FIG. 1 shows a tooth profile of a gear train with a modified portion of the tooth head, FIG. 2 a tooth profile with a modified portion of a tooth leg, in FIG. 3, the initial producing circuit with a bevel made along the radius r, in FIG. 4 initial generating circuit with a prominence made along the radius r.

In FIG. 1 tooth profile 1 has a modification 2, equal in height to 0.3 m _n , made envelope of an arc of circles of radius R with a maximum modification depth
δ = 3f _w + f _f + f _pb ,
where f _{w the} size depending on the roughness class,
f _{f the} tolerance on the profile error,
f _pb deviation of the pitch of engagement.

In FIG. 2 tooth profile 3 has a modification 4 of the tooth legs, equal to 0.3 m _n , with a maximum normal depth of modification δ which is determined by the above formula.

где m_n модуль в нормальном сечении,
δ - максимальная нормальная глубина модификации,
α_w- угол зацепления.In FIG. 3, the initial generating circuit 5 has a bevel 6 and is made according to the radius r, which is determined by the formula

where m _{n is the} module in normal section,
δ is the maximum normal modification depth,
α _w is the angle of engagement.

 In FIG. 4 shows the initial producing circuit 5 with a prominence 6 made along the radius r, determined by the formula above.

 During the rotation of the gears made with the modification proposed above, the side surfaces of the teeth do not touch along the entire side surface. Modified areas in contact at the initial moment of operation after assembly are not involved. During operation and wear of the lateral surface of the teeth, the modified areas come into contact.

 In FIG. 5 shows the preparation of a formula for the radius of the modified portion.

.The degree of point 0 is

.

On the other hand, p ² = OE • OF.

 Since OE is small (an order of magnitude smaller), then OF ≈ 2r.

 From the figure we see that OE ≅ d.

.Taking OE 0.3 d, we get

.

так как δ² мало, то получим

.After the conversion, we have

since δ ^{2 is} small, we obtain

.

In the manufacture of a gear train using a producing initial contour with a prominence or bevel for the manufacture of teeth of one of the gear wheels with profile modification of the tooth when performing a modified section of the producing initial contour along an arc of a circle of radius r, which is equal to
(0.09m $\genfrac{}{}{0ex}{}{\text{2}}{\text{n}}$ -0.6m _n • δ • sinα _w ) / 2.4δ • cos ² α _w ,
where m _{n is the} module in a normal section, δ is the maximum normal depth of modification, α _{w is the} angle of engagement, the possibility of an edge contact of the tooth head is excluded, since the modified portion of the initial producing contour cuts the metal on the head or tooth of one of the wheels when manufacturing wheels. At the same time, the amount of material removed will be minimal, which allows you to include a modified section in the work after running in.

Claims (2)

1. A gear transmission with a profile modification of the tooth, depending on the roughness class, characterized in that the amount of modification of the head or leg of the tooth of one of the wheels is 0.3 m _n in height, where m _{n is the} module in normal section, and the modified section is made around the arc envelope circles of radius R with a depth of modification equal to
δ = 3f _w + f _f + f _pb ,
where f _{w the} size depending on the roughness class;
f _f tolerance for profile error;
f _{p b} deviation of the pitch of engagement. 2. The producing initial contour with a prominence or bevel for the manufacture of teeth of one of the gear wheels with profile modification of the tooth, characterized in that the modified portion of the producing initial contour is made along an arc of a circle of radius r, chosen equal to
0.09m $\genfrac{}{}{0ex}{}{\text{2}}{\text{n}}$ - 0.6m _n • δ • sinα _w / 2,4δ • cos ² α _w ,
where m _{n the} module in normal section;
δ is the maximum modification depth;
α _w is the angle of engagement.

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