1. design theme: two-stage spur gear reducer

1. Requirements: proposed transmission relationship: composed of motor, V-belt, reducer, coupling and working mechanism.

2. Working conditions: two shifts, slight vibration, small batch production, one-way transmission, used for 5 years, the allowable error of conveyor belt is 5%.

3. Know the situation: the rotating speed of the conveyor belt drum,

The gearbox output shaft power horsepower,

Second, the overall design of transmission device:

1. Composition: The transmission device consists of motor, reducer and working machine.

2. Features: The gears are asymmetrically distributed relative to the bearings, so the axial load distribution is uneven, which requires the shaft to have greater rigidity.

3. Determine the transmission scheme: Considering the high motor speed and high transmission power, set the V-belt in the high-speed stage. The transmission scheme is as follows:

Third, choose the motor.

1. Calculate the power required by the motor; See table1-7 on page 3 of the manual;

-Belt transmission efficiency: 0.96

-Transmission efficiency of each pair of bearings: 0.99

-Transmission efficiency of cylindrical gear: 0.96

—— Transmission efficiency of coupling: 0.993

—Transmission efficiency of drum: 0.96

Description:

-Overall efficiency of the transmission between the motor and the working machine:

2. Determine the motor speed: refer to table 1 on page 7 of the instruction manual: take V-belt transmission ratio i=2 4.

The transmission ratio of two-stage cylindrical gear reducer i=8 40, so the optional range of motor speed is:

The rotating speeds in this range are: 750, 1000, 1500, 3000 respectively.

According to the required power and speed of the motor, please refer to the table 12- 1 on page 155 of the manual for four suitable motor models, so there are four transmission ratio schemes as follows:

Scheme motor model rated power synchronous speed

R/min rated speed

R/min weight total transmission ratio

1y 1 12M-2 4KW 3000 2890 45kg 152. 1 1

2y 1 12M-4 4KW 1500 1440 43kg 75.79

3y 132m 1-6 4KW 1000 960 73kg 50.53

4y 160m 1-8 4KW 750 720 1 18kg 37.89

Considering the size and weight of the motor and transmission device, as well as the transmission ratio of belt drive and reducer, it can be seen that the second scheme is more suitable, so the motor model is Y 132M 1-6, and its main parameters are as follows:

Rated power kW full load speed synchronous speed quality A D E F G H L AB

4 960 1000 73 2 16 38 80 10 33 132 5 15 280

4. Determine the total transmission ratio and distribution transmission ratio of the transmission device:

Total transmission ratio:

Distribution transmission ratio: take

Calculation of classics

Note: Refers to pulley transmission ratio, high-speed transmission ratio and low-speed transmission ratio.

5. Calculate the motion and dynamic parameters of the transmission device:

Set the shafts of the transmission device as 1 shaft, 2-shaft, 3-shaft and 4-shaft in turn from high speed to low speed.

—— Transmission efficiency between motor and shaft 1, shaft 1 and shaft 2, shaft 2 and shaft 3, and shaft 3 and shaft 4 in turn.

1. Speed of each axis:

2 Input power of each shaft:

3 Input torque of each shaft:

The results of motion and dynamic parameters are as follows:

Name of shaft power P KW torque T Nm speed r/min

Input output input output

Motor shaft 3.67 36.5 960

1 axis 3.52 3.48106.9105.8314.86

2 Axis 3.213.18 470.3 465.668

3-axis 3.05 3.021591.51559.619.

4 Axis 3 2.971575.61512.619.1

V-belts and pulleys of six designs:

1. Design V-belt

① Determine the V-belt model.

Look up the textbook table 13-6: then

According to =4.4, =960r/min, from the textbook diagram 13-5, choose the A-type V-belt and take it.

Look up the table on page 206 of the textbook 13-7.

Is the slip rate of belt drive.

② Check the belt speed: the belt speed is within the range and appropriate.

③ Take the reference length and center distance of V-belt a:

Initially select the center distance a: and take.

From the textbook page 195 (13-2): refer to the table on page 202 of the textbook 13-2. Calculate the actual center distance from the formula 13-6 on page 206 of the textbook.

④ Check the wrap angle of the small pulley: it is obtained from the formula 195 on page 13- 1 in the textbook.

⑤ Find the z number of V-band; From the formula 13- 15 on page 204 of the textbook;

Look up the table 13-3 on page 203 of the textbook and get it by interpolation.

EF=0. 1

= 1.37+0. 1= 1.38

EF=0.08

Look up the table on page 202 of the textbook 13-2.

Look up the table 13-5 on page 204 of the textbook and get it by interpolation. = 163.0 EF=0.009

=0.95+0.009=0.959

rule

Take root.

⑥ To find the pressure acting on the pulley shaft: Look up the table in the textbook 13- 1 page 20 and get q=0. 10kg/m, so the initial tension of a single V-belt is determined by the formula on page 97 of the textbook1kloc-.

Pressure act on that shaft:

.

Seven-gear design;

1 design of high-speed gear;

① Material: the high-speed pinion is quenched and tempered steel with a tooth surface hardness of 250HBS. The steel for high-speed gears is normalized, and the tooth surface hardness is 220HBS.

② Check the table on page 166 of the textbook: 1 1-7.

Check the textbook page 165, table 1 1-4.

Therefore.

Check the textbook page 168, table 1 1- 10C.

Therefore.

③ Design according to the contact strength of tooth surface: 9-grade precision manufacturing. Look up the load coefficient in the table 1 1-3 on page 164 of the textbook, and calculate the center distance by taking the tooth width coefficient: according to the formula on page 1 1-5 of the textbook:

Considering that there is little difference between high gear and low gear.

Then take it.

Actual transmission ratio:

Transmission ratio error:.

Tooth width: take

High-speed gear: high-speed pinion;

(4) Check the bending strength of gear teeth:

Check the textbook page 167, table 1 1-9:

According to the minimum tooth width:

So it is safe.

⑤ peripheral speed of gear:

Look up the textbook +0 1-2, page 65438, table 162, and you will know that the accuracy of Grade 9 is appropriate.

2. Design of low-speed gear;

① Material: the low-speed pinion is tempered with steel, and the tooth surface hardness is 250HBS.

The low-speed gear steel is normalized, and the tooth surface hardness is 220HBS.

② Check the table on page 166 of the textbook: 1 1-7.

Check the textbook page 165, table 1 1-4.

Therefore.

Check the textbook page 168, table 1 1- 10C.

Therefore.

③ Design according to the contact strength of tooth surface: 9-grade precision manufacturing; Refer to table 16438+0-3 on page 65438 of the textbook for the load coefficient, and take the tooth width coefficient.

Calculate the center distance: get +0 1-5 from the formula 165 on page 65438 of the textbook:

Take what you took.

Calculation of transmission ratio error: appropriate

Tooth width: then take

Low speed gear:

Low speed pinion:

④ Check the bending strength of gear teeth: refer to Table 167 in the textbook:

According to the minimum tooth width:

Safe.

⑤ peripheral speed of gear:

Look up the textbook +0 1-2, page 65438, table 162, and you will know that the accuracy of Grade 9 is appropriate.

The structural dimensions of the eighth reducer body are as follows:

Name symbol calculation formula result

Box bottom thickness

10

Box cover thickness

nine

Box cover flange thickness

12

Box seat flange thickness

15

Thickness of bottom flange of box bottom

25

Anchor screw diameter

M24

Number of anchor screws

Refer to manual 6

Diameter of connecting bolt beside bearing

M 12

Diameter of connecting bolt between cover and seat

=(0.5 0.6)

M 10

Bearing end cover screw diameter

=(0.4 0.5)

10

Diameter of manhole cover screw

=(0.3 0.4)

eight

Diameter of locating pin

=(0.7 0.8)

eight

Distance to the outer box wall

Consult the manual table 1 1-2 34

22

18

Distance to flange edge

Consult the manual form 1 1-2 28

16

Distance from outer box wall to bearing end face

= + +(5 10)

50

Distance between top circle of big gear and inner box wall

& gt 1.2

15

Distance between gear end face and inner wall of box body

& gt

10

Thickness of box cover and box seat rib

nine

8.5

Outer diameter of bearing end cover

+(5 5.5)

120 (axis 1)

125(2 axes)

150 (triaxial)

Distance of connecting bolt beside bearing

120 (axis 1)

125(2 axes)

150 (triaxial)

Nine-axis design:

1 design of high-speed shaft;

① Material: 45 # steel is selected for quenching and tempering treatment. Look up the table 14-2 on page 230 of the textbook and take C= 100.

② Determination of shaft diameter: According to the formula 14-2 on page 230 of the textbook, since the motor shaft diameter with a small pulley is installed, the shaft diameter of the first section of the high-speed shaft is equipped with a large pulley. Please refer to the table 1- 16 on page 9 of the manual. l 1 = 1.75d 1-3 = 60 .

Because the big pulley should be positioned by the shoulder and should be equipped with a sealing ring, please refer to Table 7- 12 on page 85 of the manual, and L2=m+e+l+5=28+9+ 16+5=58.

Section, so check table 6- 1 on page 62 of the manual. Select 6009 bearing.

L3=B+ +2= 16+ 10+2=28 .

The section is mainly for locating bearings. L4 is determined according to the inner wall line of the box.

Diameter of assembled sector gear: judge whether the gear shaft is manufactured;

See table 4- 1 on page 5 of the manual:

Get: e = 5.9 < 6.25.

Assemble the bearing in sections, so L6= L3=28.

2 check the shaft and bearing: l1= 73l2 = 211l 3 = 96.

The circumferential force acting on the gear is:

The radial force is

External force acting on 1 shaft pulley:

Find out the reaction force of vertical support:

Find the vertical bending moment and draw the vertical bending moment diagram:

Find the supporting force of the horizontal plane:

allow

ordinary

ordinary

Find and draw the horizontal bending moment diagram:

Find the reaction force generated by f at the fulcrum:

Find and draw the bending moment diagram generated by F force;

Bending moment at f a:

Find the resultant bending moment diagram:

Consider the worst case and add it directly.

Find the equivalent bending moment of dangerous section:

As can be seen from the figure, the section at m-m is the most dangerous, and its equivalent bending moment is: (take the conversion factor).

Calculate the shaft diameter at the dangerous section:

Because the material is quenched and tempered, check the allowable bending stress in table 14- 1 on page 225 of the textbook and page 23 1 of the textbook, and then:

Because the shaft is safe.

3 bearing life inspection:

Bearing life can be checked by formula, because bearings mainly bear radial load, so please refer to tables 16-9 and 10 on page 259 of the textbook.

According to the most unfavorable consideration, there are:

The bearing meets the requirements.

4 The stress analysis diagram of bending moment and shaft is as follows:

5 key design and inspection;

According to, cast iron HT200 was selected as the V-belt pulley. Refer to the textbook table 10-9. Because it is in the range, the key:,

Use type a public key:

Key check. For l1=1.75d1-3 = 60, the selected keys are:

Design of intermediate shaft:

① Material: 45 # steel is selected for quenching and tempering treatment. Look up the table 14-2 on page 230 of the textbook and take C= 100.

② According to the formula 14-2 on page 230 of the textbook:

Bearings need to be assembled. Please refer to table 1- 16 on page 9 of the manual and table 6- 1 on page 62 of the manual, and select 6208 bearing, L1= B+=18+10.

When assembling the low-speed pinion, take L2= 128, because it is shorter than the length of the gear hole.

The section is mainly for positioning high-speed gears, so L3= = 10.

Assemble high gear, take L4=84-2=82.

Bearings need to be assembled. Please refer to table 1- 16 on page 9 of the manual and table 6- 1 on page 62 of the manual. Select 6208 bearing, L1= B++3+=18+65438.

③ Check the shaft and bearing: l1= 74l2 =117l3 = 94.

Circumferential force acting on gears 2 and 3:

ordinary

Radial force:

Find the supporting reaction of vertical plane

Calculate the vertical bending moment:

Find the supporting force of the horizontal plane:

Calculate and draw the horizontal bending moment diagram:

Find the synthetic bending moment diagram, and consider it according to the most unfavorable situation:

Find the equivalent bending moment of dangerous section:

As can be seen from the figure, the sections at M-M and N-N are the most dangerous, and the equivalent bending moment is: (take the conversion factor).

Calculate the shaft diameter at the dangerous section:

N-n section:

M-m section:

Because the shaft is safe.

Bearing life inspection:

Bearing life can be checked by formula, because bearings mainly bear radial load, so please refer to tables 16-9 and 10 on page 259 of the textbook.

Then, the service life of the bearing is within years, so the bearing meets the requirements.

(4) The analysis diagram of bending moment and axial stress is as follows:

⑤ Key design and inspection:

The reference textbook table 10- 1 1 is known, so it is taken.

Because the gear material is 45 steel. Check the textbook 155, table 10- 10

L =128-18 = 1 10 Take the key length as110. L = 82- 12 = 70, and the key length is 70.

According to the extrusion strength condition, check the key as follows:

So the selected key is:

Design of driven shaft;

(1) Determine the diameter of each shaft segment.

① Calculate the minimum shaft section diameter.

Because the shaft mainly bears torque, according to the calculation of torsional strength, it is obtained by formula 14-2:

Considering that the shaft section has a keyway, choose the shaft section.

Refer to table 1- 16 on page 9 of the manual and round it to the standard value. take

(2) In order to locate the coupling axially, a shaft shoulder is arranged at the overhanging end, so the shaft diameter of the second section is. Look up table 7-2 on page 85 of the manual, and it is found that this dimension conforms to the standard values of bearing cover and sealing ring, so it is selected.

(3) Design the shaft section. In order to make the bearing easy to assemble and disassemble, refer to Table 6- 1 on page 62 of the instruction manual, and locate the bearing with an oil baffle ring. Select bearing 62 15:.

(4) when designing the shaft section, considering the axial positioning of the oil baffle ring, so take

⑤ The other end is designed with a journal. The power take-off and bearing are positioned by the oil baffle ring, and the other end of the oil baffle ring is positioned by the gear tooth root.

⑥ The wheel is easy to assemble and disassemble, and the axle head is designed. Please refer to table 1- 16 on page 9 of the manual.

⑦ Design collar and width b

The gear is axially positioned, so take

,

⑵ Determine the length of each shaft section.

The size of the coupling is determined (which will be discussed later).

Because, so ... ...

The length of the shaft head is shorter than that of the wheel hole.

The length of other shaft segments is determined by the structure.

(4) Check the shaft and bearing: l1= 97.5l2 = 204.5l3 =116.

Find the equivalent bending moment, bending moment, bending moment and dangerous section of the acting force.

Circumferential force acting on the gear:

Radial force:

Find out the reaction force of vertical support:

Calculate the vertical bending moment:

. m

Find the supporting force of the horizontal plane.

Calculate and draw the horizontal bending moment diagram.

Find the reaction force generated by F at the fulcrum.

Find the bending moment diagram generated by F force.

Bending moment at f a:

Find the composite bending moment diagram.

Consider the worst case and add it directly.

Find the equivalent bending moment of dangerous section.

As can be seen from the figure, the section at m-m is the most dangerous, and its equivalent bending moment is: (take the conversion factor).

Calculate the shaft diameter of the dangerous part.

Because the material is quenched and tempered, check the allowable bending stress in table 14- 1 on page 225 of the textbook and page 23 1 of the textbook, and then:

Considering the influence of keyway, take

Because the shaft is safe.

(5). Bearing life inspection.

Bearing life can be checked by formula, because bearings mainly bear radial load, so please refer to tables 16-9 and 10 on page 259 of the textbook.

According to the most unfavorable consideration, there are:

Then,

The service life of the bearing is 64.8 years, so the bearing on the shaft meets the requirements.

(6) The force analysis diagram of bending moment and shaft is as follows:

(7) Key design and inspection:

Because d 1=63, look up the textbook 153, table 10-9, and select the key to look up the textbook 155, table 10.

Because the primary key length of L 1= 107 is 100, the selected key is:

Check the textbook 153 page table 10-9 with files. Select the key to view the textbook 155 page table 10- 10.

Because L6= 122 primary key length is 100, check.

So the key chosen is:.

Design of ten-axis high-speed big gear

Due to the adoption of the web structure

Code structure dimensions and calculation formula results

Hub diameter

Seventy two

Axial length of hub

84

Chamfering size

1

Root circle thickness

10

Maximum diameter of web

32 1.25

Plate hole diameter

62.5

Web thickness

25.2

Design of motor pulley

Code structure dimensions and calculation formula results

Manual 157 Page 38

68.4 mm

Take 60 mm

8 1 mm

74.7 mm

10mm

15mm

5 mm

XI。 Selection of coupling:

To calculate the torque required by the coupling: refer to table 17- 1 in textbook 269 and table 8-7 on page 94 of the manual to select HL6 elastic pin coupling.

Determination of lubrication mode:

Because the transmission device is light in weight and low in transmission speed, its speed is far less than that, so grease lubrication is adopted, and the box body is lubricated by No.50 in SH0357-92, and installed to the specified height.

Thirteen. For other related data, please refer to the assembly drawing and related data list in the manual.

Fourteen References:

Course Design Manual of Mechanical Design (2nd Edition) —— edited by Tsinghua University Wu and Luo, University of Science and Technology Beijing.

Course Design Guide for Mechanical Design (2nd Edition) —— edited by Luo and Li.

Mechanical Curriculum Design (Chongqing University Press)-edited by Zhou Yuankang, etc.

Textbook Fundamentals of Mechanical Design (4th Edition) —— edited by Yang Kezhen and Cheng Guangyun.