Reconstruction of VAZ-2110 gearbox

Contents

Contents

Introduction

1 Initial data

2 Materials

3 Determination of geometric and kinematic

parameters

4 Contact endurance calculation

5 Bending endurance calculation

6 Calculation of screw connection

Conclusion

List of literature

Introduction

The VAZ 2110 car has a two-shaft five-speed gearbox with synchronizers in 1,2,3 and 4 gears. In this course design, it is proposed to replace the indiscriminate primary shaft with an assembly unit. In particular, install (press) removable rims on gear gears 2, 3 and 4, replace the material of the primary shaft.

This innovation will allow us to increase the gearbox resource as a whole, reduce the cost of repair in the event of a failure of any of the gears 2, 3 or 4 gears.

The calculation is carried out on the basis of GOST 164391 in particular, the calculation for contact and bending endurance was carried out, as well as the calculation of the screw connection allowing to confirm the expediency of this innovation.

Source Data

1.1 Engine torque Mkr. dv. = 103.9 N • m

1.2 Gear ratios of gearbox:

i1 = 3.636

i2 = 1.95

i3 = 1.357

i4 = 0.941

i5 = 0.789

1.3 Engagement modulus m = 2.5 mm.

1.4 Number of gear teeth of gearbox:

1.5 Kinematic diagram:

1 - primary shaft, 2 - secondary shaft, 3 - driven gear 1, 4 - driven gear 2 gears, 5 - driven gear 3 gears, 6 - driven gear 4, 7 - driven gear 5, 8 - drive gear 1, 8 - drive gear 2, 10 - drive gear 3, 11 - drive gear 3, 12 - drive gear 4, 13 - drive gear 5, 14 - synchronizer of 1 and 2 transmissions, 15 - synchronizer of 3 and 4 transmissions, 16 is a transmission synchronizer 5, 17 is a rear gear.

1.6 Check of transmission ratios:

i1 = Z2/ Z1 = 3.636

i2 = Z2/ Z1 = 1.95

i3 = Z2/ Z1 = 1.357

i4 = Z2/ Z1 = 0.941

i5 = Z2/ Z1 = 0.789

Transmission ratios are checked as per GOST 2185-89

1.7 Condition of teeth engagement:

1 transmission 2 (Z1 + Z2 )/2 = 2 (12 + 43 )/2 = 55 - integer

2 transmission 2 (Z1 + Z2 )/2 = 2 (20 + 40 )/2 = 60 - integer

3 transmission 2 (Z1 + Z2 )/2 = 2 (25 + 35 )/2 = 60 - integer

4 transmission 2 (Z1 + Z2 )/2 = 2 (35 + 33 )/2 = 68 - integer

5 transmission 2 (Z1 + Z2 )/2 = 2 (40 + 32 )/2 = 72 - integer

Integer - Condition Met

1.8 We accept coefficient of mixture of X1 and X2 equal 0.

1.9 Angle of teeth inclination = 0.

1.10 The degree of transmission accuracy as per GOST 164391 is 7

1.11 Surface roughness as per GOST 278983 Ra = 2

1.12 Loading cyclogram:

T1 = Mdt. dv = 103.9 N • m

Materials

2.1 Steel grade and gearbox gear improvement modes:

Drive gear - Z1

Driven gear (wheel) - Z2

Table 2 Steel brand and gear improvement modes

Defining Geometric and Kinematic

parameters

3.1 Dividing angle of profile in end section:

Contact endurance calculation

4.1 Coefficient taking into account mechanical properties of mating gears:

For steel gears ZE = 190

4.2 Coefficient taking into account shape of conjugated surfaces of teeth in the engagement pole:

This indicates that the resonance zone is far away and the calculation can be carried out according to the main formula:

4.7 Coefficient taking into account the influence of manifestations of engagement error on dynamic load:

According to GOST 2135487, at hardness and for helical gears, δh = 0.004 is selected

4.8 Factor taking into account the influence of the difference in the engagement steps of the gear teeth and the wheel:

For degree of accuracy according to smoothness standards at module m = 2.5

Go = 47

4.12 Tolerance for tooth direction error:

According to GOST 164391 for the 7th degree of accuracy according to the contact standards with the width of the gear rim b = 16 mm

4.13 Deviation of contact lines position as a result of manufacturer's error:

4.14 Actual deviation of contact lines position in the initial period of transmission operation:

4.20 Limit deviation of engagement pitch according to GOST 164381 for the 7th degree of accuracy according to smoothness standards at m = 2.5 mm. and respectively dividing diameters d1 = 30 mm. and d2 = 107.5 mm:

fpb1=18

fpb2=18

4.21 Contact endurance limit:

nlim2 = 17HHRCe + 20 = 17 • 50 + 200 = 1050 mPa.

4.26 Design contact voltage:

n = but mPa.

4.27 Contact endurance limit:

For cement gear

nlim1 = 23 NNRCe = 23 • 59 = 1360

For wheel hardened with HF heating

нlim2 = 17 HHRCэ+200 = 17•50+200 = 1050

4.28 Safety factor:

For gear and wheel with surface strengthening of teeth we accept

and

4.29 Basic numbers of stress cycles corresponding to the endurance limit:

since

then

4.30 Total number of voltage cycles:

4.32 Coefficient taking into account roughness of conjugated surfaces of teeth:

At surface roughness with Ra = 2 μm

ZR = 0,95

4.33 Coefficient taking into account the circumferential speed at H > 350 HV:

4.34 Coefficient taking into account the effect of lubrication:

4.35 Gear size factor

Since and, then

4.36 Allowable contact stresses of gears:

Less of these two values are taken as

i.e. mPa.

4.38 Comparison of design and allowable stresses:

,

therefore, fatigue endurance by contact is ensured.

Bending endurance calculation

5.1 District force:

5.2 Factor taking into account external dynamic load:

Since external loads are taken into account in the cyclogram, they are accepted

AC = 1

5.3 Coefficient taking into account influence of occurrence of engagement errors on dynamic load:

For oblique transmission

5.4 Coefficient taking into account the influence of the difference in the engagement steps of the gear teeth and the wheel:

For the 7th degree of accuracy according to smoothness standards, with module m = 2.5 mm.

5.5 Specific circumferential dynamic force:

5.9 Factor considering load distribution between teeth:

5.10 Factor taking into account tooth shape and stress concentration:

For gear wheels uncut with a cutter without a protuberant.

5.15 Teeth endurance limits corresponding to the base number of stress cycles:

For the nitrocemented gear wheel from steel of the HGN brand 25

For a 40XN steel wheel, tempered during heating of the HPV with a tempered layer repeating the outline of the depression

5.16 Coefficient taking into account the effect of grinding of the transition surface of the tooth:

For gears with non-ground teeth

5.17 Factor taking into account the influence of deformation hardening:

5.18 Factor taking into account the effects of two-way load application:

At one-way application of load YA = 1

5.19 Manufacturing technology factor:

Since in the gear and wheel manufacturing technology there are no deviations from the notes

and

5.20 Bending endurance limit of teeth:

5.24 Coefficient taking into account stress gradient and sensitivity of material and stress concentrations (reference coefficient):

5.25 Coefficient taking into account the roughness of the transition surface.

For nitro-cement gear:

For the wheel during hardening of HPV, when the hardened layer repeats the outline of the depression.

5.26 Gear size factor:

Therefore, the bending endurance of the teeth is guaranteed with a probability of not breaking more than 99%.

Calculation of screw connection

6.1 Calculation of screw pair thread for strength:

The condition of strength of the thread by shear stresses is determined by the formula:

where H-nut height, H = 10 mm.

K - thread completeness factor, K = 0.87.

Km - load unevenness factor for threads, Km = 0.7.

d1 is the internal diameter of the thread. For M6 d1 = 5.67 mm.

Since the screw and nut materials are not the same, only screw threads are calculated from the shear stresses, since d1 < d

Conditions of wear resistance of running thread by crushing stresses are determined by formula:

cm = F/( Pd2hz) [ cm]

where Z = H/P - number of nut operating turns, Z = 7

d2 = 5.402 mm

h - profile height, h = 1.165mm

cm = 1000/( 3.14 • 5,402 • 1,165 • • 7) = 0.7 mPa.

Compression stresses are not more than shear stresses, and permissible stresses [cm] are several times more than [].

Consequently, the strength calculation of the thread passes.

6.2 Determination of tightening force and screwing moment:

Thus, the tightening force and the screwing moment when installing the locking screws on the rim of the gears fully suits us. At the same time, the win is valid: Fzat/Fk = 21130/67.3 = 313.9 times.

Conclusion

In this course project, it was proposed to replace the non-detachable primary shaft with an assembly unit. In particular, install (press) removable rims on gear gears 2, 3 and 4, replace the material of the primary shaft.

This innovation allowed us to increase the gearbox resource as a whole by 35%, reduce the cost of repair in the event of a failure of any of the gears 2, 3 or 4 gears.

The calculation was made on the basis of GOST 164391 in particular, the calculation for contact endurance was carried out.

Calculations showed that during the operation of the gearbox with this innovation, fatigue endurance in contact is provided.

And also a calculation was made for the bending endurance of the gear that showed that the endurance of the teeth during bending is guaranteed with a probability of non-destruction of more than 99%

Thus, this innovation completely suits us.

List of sources used

1.Anuryev V.I. Reference Book of the Designer - Mechanical Engineer: Mechanical Engineering, 1979

2.AfanasyevL.L., Maslov A.A. Garages and car maintenance stations. (Album of drawings) M.: Transport, 1980216 p.

3. Napolsky G.M. Technical design of motor transport enterprises and maintenance stations - M.: Transport 1985231 s.

4. Technical operation of cars/Textbook for universities/Kuznetsov E.S. Voronov V.P. - M.: Transport 1991413 p.

5. Panin A.V. Technological Design of Motor Transport Enterprises/Training Manual/- Barnaul.: B AND, 198899 p.

6. Type projects of workplaces at the motor transport enterprise M.: Transport 1977197 s.