A paper on gear transmission design

Code for design of single-stage spiral cylindrical reducer

School of mechanical and automotive engineering

Specialized industry

Class level

Student number

surname

Head of professional teaching and research section and research institute

teacher

date month year

XXXXXXX University

Curriculum design (thesis) appointment letter

"Course Design (Paper) Task Book" is distributed to students of vehicle engineering class, and the contents are as follows:

1. Design theme: V-belt-single-stage spiral cylindrical reducer

2. Projects to be completed:

(1) A general assembly drawing of the reducer (A 1)

(2) Gear Parts Drawing (A3)

(3) Shaft Parts Drawing (A3)

(4) Design specification.

3. The design (thesis) assignment was issued on, 2008, and should be completed before, 2008, and then be defended.

The person in charge of the professional teaching and research office and research institute shall conduct a review on the year, month and day.

The lecturer released the year, month and day.

Comments on course design (thesis): Overall evaluation results of course design (thesis);

Signature of the person in charge of course design (thesis) defense:

date month year

catalogue

I. Determination of transmission scheme -5

Two. Raw data -5

Three. Determine the motor model -5

Four. Determine the total transmission ratio and distribution of the transmission -6

Verb (abbreviation of verb) Design and calculation of transmission parts -7

Design of main structural dimensions of casting box of intransitive verb reducer-13

Seven. Axis design-14

Eight. Selection and calculation of rolling bearing-19

Nine. Selection and strength check of key connection -22

X. Selection and calculation of coupling -22

XI。 Lubrication of reducer -22

Twelve. Reference -2 Calculation Process and Description

I. Drafting of transmission scheme II. Raw data:

Belt tension: F=5700N, belt speed: v=2.28m/s, drum diameter: d = 455 mm.

Conveyor efficiency: the load has a slight impact when working; When working indoors, the moisture and ash are in a normal state, and the mass production of products is batch production, allowing the total speed ratio error of 4%, requiring the service life of gears to be 10 years, and working in two shifts; The service life of the bearing shall not be less than 15000 hours.

Third, the motor selection

(1) motor type selection: Y series three-phase asynchronous motor is selected.

(2) Select the motor power:

Power required for conveyor spindle:

Total transmission efficiency:

,,,, respectively: V-belt drive, gear drive (closed, accuracy grade 8), tapered roller bearing (a pair of roller bearings), coupling (rigid coupling) and conveyor belt efficiency. Check the course design table 2-3.

Take away:

So:

Power required by motor:

Look-up table 16- 1 Of course, the rated motor power Y200L 1-6 is designed.

(3) Select the speed of the motor

Take V-belt transmission ratio range (Table 2-2) ≤ 2 ~ 4; Transmission ratio of single-stage gear reducer = 3 ~ 6

Drum speed:

Reasonable synchronous speed of motor;

Look up the motor model and main data 16- 1 as follows (synchronous speed is consistent).

Motor model rated power (kW) synchronous speed (r/min) full load speed nm

(rpm) load locking torque

Rated torque maximum torque

Rated torque

y200l 1-6 18.5 1000 970 1.8 2.0

Refer to table 16-2 for motor installation and related dimensions.

Center height

H contour size

Installation dimensions of support legs

Diameter of anchor bolt hole

Axial extension dimension

Nominal dimensions of keys

200 775×(0.5×400+3 10) ×3 10 3 18×305 19 55× 1 10 16×

5. Calculate the total transmission ratio and allocate the transmission ratios at all levels.

Total transmission ratio of transmission:

V-belt transmission ratio: Transmission ratio of single-stage cylindrical gear reducer;

(1) Calculate the input power of each axis.

Motor shaft:

Shaft Ⅰ (high speed shaft of reducer):

Shaft Ⅱ (low speed shaft of reducer):

(2) Calculate the rotating speed of each shaft.

Motor shaft:

Axis 1:

Axis 2:

(3) Calculate the torque of each shaft.

Electric reel

Axis 1:

Axis 2:

The above data list is as follows:

parameter

Shaft name input power

( )

Lift front wheel speed

( )

Input torque

( )

drive ratio

efficiency

Motor shaft15.136 970182.141.6893 0.95

First shaft (reducer high-speed shaft) 14.79 574.20 3938+0560.97

Ⅱ shaft (low speed shaft of reducer)13.669 95.701364.07

V. Design and calculation of transmission parts

1. Design and calculation of common V-belt drive

(1) Determine the calculated power.

In the formula, the working condition coefficient = 1.3.

(2) According to the calculated power and the rotation speed of the small pulley, check the mechanical design basic drawing 10- 10, and select the SPA narrow V belt.

③ Determine the reference diameter of the pulley.

Take the small pulley diameter:,

Diameter of large pulley:

According to the national standard: GB/T13575.1-1992, take the large pulley diameter.

④ Verify the belt speed:

Between. Therefore, the speed of the belt is appropriate.

⑤ Determine the reference diameter and transmission center distance of V-belt.

The distance between transmission centers in the primary election is:, which was originally determined.

Reference length of v-belt:

Check the mechanical design table 2.3 and select the reference diameter length of the belt.

Actual center distance:

⑥ Check the minimum wrap angle of the driving wheel.

Therefore, the wrap angle on the driving wheel is appropriate.

⑦ Calculate the root number z of the V-belt.

, by,,

Look up the mechanical design table 2.5a, from table 2.5c, get the increment of rated power:, look up table 2.8, get, look up table 2.9, get.

, take the root.

⑧ Calculate the appropriate initial tension of V-belt.

Check mechanical design table 2.2, take

get

Pet-name ruby calculate the load acting on the shaft:

Attending the structural design of pulley (unit) mm

band wheel

measure

Small pulley

Groove c

Reference width

1 1

Depth of groove on datum line

2.75

Depth of groove under datum line

1 1.0

Slot spacing

15.0 0.3

Slot allowance

nine

Rim thickness

outside diameter

inner diameter

Belt pulley width

Belt pulley structure net type

The V-belt pulley is made of cast iron HT 150 or HT200, and its maximum allowable circumferential speed is 25m/s. 。

2. Gear transmission design calculation

(1) Select the gear type, material, accuracy and parameters.

① helical cylindrical gear transmission (external meshing) is selected;

② Selection of gear material: 45 steel is selected from the textbook schedule 1. 1, the surface is quenched after quenching and tempering, and the tooth surface hardness HRC1= hrc2 = 45;

(3) Select the gear with an accuracy of 7 (GB10095-88);

④ Primary helix angle

⑤ Select the number of teeth of the pinion; Number of teeth of big gear

(2) Design according to contact fatigue strength of tooth surface.

By the design calculation formula for trial calculation, namely

A, determining each calculated value in the formula

① Test load coefficient Kt= 1.5

② Torque transmitted by pinion:

③ The tooth width coefficient is obtained from the mechanical design table 12.5 (hard tooth surface gear, the value is lower than the limit).

(4) The elastic influence coefficient is obtained from the mechanical design table 12.4.

⑤ Node area coefficient

So, we get =2.4758.

⑥ coincidence degree of end face

Substitute the above formula to get:

⑦ contact fatigue strength limit σ hlim1= σ hlim2 =1000 MPa (figure 12.6).

8 pressure cycle

n 1 = 60nⅰjLh = 60x 574.20 x 1x(2x8x 300 x 10)= 16.5 x 108

N2 = n 1/I2 = 16.5 x 108/6 = 2.75 x 108

Pet-name ruby contact fatigue life coefficient according to figure 12.4 calculation.

Attending contact fatigue allowable stress

= 0.91.1000/1.2 MPa =758.33 MPa.

= 0.96 1000/ 1.2 MPa =800 MPa

Because = = 779. 165 Mpa <1.23 = 984 MPa, it = = 779.165 MPa.

B. Calculation

① Trial calculation of pinion indexing circle

② Calculate the circumferential speed: =

③ Calculated tooth width: =157.24 = 57.24 mm.

④ Ratio of tooth width to tooth height:

/(2.25 )

⑤ Calculate the load factor k.

According to v=2.28m/s, 7-level accuracy and dynamic load coefficient = 12. 1.

Check according to schedule 12.2; According to the attached table 12. 1 .25.

Refer to the 6-level precision formula in the textbook appendix 12.3, and estimate < 1.34, symmetry.

1.3 13 = 1.5438+03.

According to the attached figure 12.2, the radial load distribution coefficient = 1.26.

load coefficient

⑥ Correct the diameter of dividing circle according to the actual load coefficient.

⑦ Calculation modulus

3, according to the tooth root bending fatigue strength design.

A, determining various parameters in a formula

① load factor k:

rule

② Tooth profile coefficient and stress correction coefficient

Equivalent number of teeth = = 2 1.6252,

= = 1 12.2453

③ Influence coefficient of helix angle

Axial plane coincidence = = 0.9385

Take = 1 =0.9374.

④ Allowable bending stress

If you look up Figure 6.5 of the textbook and take = 1.4, then

= 0.86 500/ 1.4 MPa =307 MPa

= 0.88 500/ 1.4 MPa =3 14 MPa

⑤ Determine

=2.73 1.57/307=0.0 1396

=2. 17 1.80/3 14=0.0 1244

Calculate by replacement formula

B. calculating the modulus mn

Comparing the results of two strength calculations, determine

4. Calculation of geometric dimensions

① Center distance = 3 (21+126)/(2cos80) = 223mm.

Take the center distance

② Correction of spiral angle:

③ Diameter of dividing circle:

④ tooth width, B2=65 mm, B 1=70 mm.

⑤ The geometric dimensions of gear transmission are shown in the following table (see the part drawing for details).

Name code calculation formula result

Pinion and bull gear

center distance

223 mm

drive ratio

six

normal module

Design and check 3.

Terminal modulus

3.034

Normal pressure angle

angle of helix

Generally speaking,

appendix

3 mm

height of tooth

3.75 mm

Full tooth height

6.75 mm

Top clearance c

0.75 mm

Tooth number z

2 1 126

Standard middle diameter

64.188mm 382.262mm

Diameter of tooth tip circle

70.188mm 388.262mm

Diameter of root circle

57.188mm 375.262mm

Gear width b

70 mm 65 mm

Spiral angle direction

Left-handed and right-handed

Design of main structural dimensions of casting box of intransitive verb reducer.

Check the empirical formula in Table 3- 1 for design basis, and the results are shown in the following table.

Name code size calculation result (mm)

Base wall thickness

eight

Box cover wall thickness

eight

Thickness of convex circle on the upper part of the base

Thickness of convex circle of box cover

Thickness of convex circle at lower part of base.

Bottom rib thickness e

eight

Thickness of bottom cover rib

seven

Diameter d of anchor bolt or Table 3.4

Number of anchor bolts in Table 3-4 6

Diameter of connecting bolt of bearing seat

0.75d 12

Diameter of bolt connecting box seat and box cover

(0.5—0.6)d 8

Bearing cover fixing screw diameter

(0.4—0.5)d 8

Diameter of manhole cover fixing screw

(0.3—0.4)d 5

Diameter of distribution circle of bearing cap screws

155/ 140

End face diameter of bearing seat flange

185/ 170

Overall dimensions of bolt hole flange

Table 3-2218,30

Overall dimensions of flange of anchor bolt hole

Table 3-3 25, 23, 45

The distance between the inner wall of the box and the gear.

The distance between the inner wall of the box and the end face of the gear.

Basement depth h

244

Distance from outer box wall to bearing end face

Seven. Design and calculation of shaft

1. Design of high-speed shaft

① Selection of shaft material: choose 45 steel, tempered, HBS=230.

② Preliminary estimate the minimum diameter of the shaft.

According to the textbook formula, take = 1 10, then = 32. 182 mm.

Because there is a keyway at the connection with the V-belt, the diameter should be increased by 5%.

③ Structural design of shaft:

Considering the mechanism requirements of pulley and the rigidity of shaft, the shaft diameter of pulley is selected, and the shaft diameter of bearing is selected according to the size of seal:

Distance between two bearing fulcrums:,

In which:-pinion tooth width,

-clearance between the inner wall of the box and the end face of the pinion,

-the distance between the inner wall of the box and the bearing end face,

-bearing width, select 303 10 tapered roller bearing, look up the table 13- 1, and get the following results.

Get:

Distance from pulley symmetry line to bearing fulcrum

In which:-the height of the bearing cover,

T- flange thickness of bearing cover, therefore,

-Distance from the end face of the bolt head to the end face of the pulley,

-Height of M8 bolt head of bearing cover, and look up the table to get mm.

-the width of the pulley,

Get:

2. Check the strength of the shaft according to the comprehensive stress of bending and torsion.

① Calculate the force acting on the shaft.

Force analysis of pinion

Circumferential force:

Radial force:

Axial force:

(2) Calculate the reaction force.

Horizontal plane:

Vertical plane:

So:

③ Make a bending moment diagram.

Horizontal bending moment:

Vertical bending moment:

Composite bending moment:

④ Make a torque diagram (see page 22) T 1=239. 15Nm.

When the torsional shear force is a pulsating cyclic strain force, take this coefficient,

Then:

⑤ Check the strength of the shaft according to the combined stress of bending and torsion.

The material of the shaft is 45 steel, which is quenched and tempered, its tensile strength limit and allowable stress when the stress changes symmetrically.

As can be seen from the bending moment diagram, the calculated bending moment of section A is the largest, and the calculated stress here is:

The axis diameter of section D is the smallest, and the calculated stress here is:

(safety)

6. The structural diagram of the shaft is shown in the part drawing.

2. Design of low speed shaft

(1). Selection of shaft material: 45 steel, quenched and tempered, HBS=230.

(2) Preliminary estimation of the minimum diameter of the shaft: A= 1 10,

Two keys, so

Considering the mechanism requirements of the coupling and the rigidity of the shaft, the shaft diameter at the coupling is selected. According to the size of the seal, the shaft diameter at the bearing is selected as 302 14 bearing T=26.25.

(3) The structural design of the shaft and the preliminary determination of the shaft diameter and axial dimension: Consider

-Distance from the end face of the bolt head to the end face of the pulley,

K-height of bearing cover M 12 bolt head. Look-up table can give k=7.5mm and select 6 bolts.

L-length of coupling, L= 125mm.

Get:

(4) Check the strength of the shaft according to the bending synthetic stress.

① Calculate the force acting on the action axis.

Force analysis of gear: circumferential force: n

Radial force:

Axial force:

(3) Calculate the reaction force:

Horizontal plane:

Vertical plane,

③ Make a bending moment diagram.

Horizontal bending moment:

Vertical bending moment:

Composite bending moment:

④ Make a torque diagram T2 = 1364.07 Nm.

When the torsional shear force is pulsating cyclic strain force, take this coefficient, then:

⑤ Check the strength of the shaft according to the combined stress of bending and torsion.

The material of the shaft is 45 steel, which is quenched and tempered, its tensile strength limit and allowable stress when the stress changes symmetrically.

As can be seen from the bending moment diagram, the calculated bending moment of section C is the largest, and the calculated stress here is:

The axis diameter of section D is the smallest, and the calculated stress here is:

(safety)

(5) The structural diagram of the shaft is shown in the part drawing:

Eight, the selection and calculation of rolling bearing

1. Selection and life calculation of high-speed shaft rolling bearing

① selected bearing: tapered roller bearing with model 303 10 (one pair is installed on each shaft).

② radial load of bearing a.

Radial load of bearing b:

For 303 10 tapered roller bearing, the axial force is obtained from it.

So bearing A is "loose" and bearing B is "compressed", then

Calculate equivalent dynamic load