Gearbox calculation design - drawings, DBE

Contents

1. Introduction

2. Design Task

3. Preliminary calculation of the drive:

4. Calculation of closed conical transmission

5. Calculation of cylindrical gear for contact gear

endurance

6. Defining Component Support Reactions and Bending Reactions

moments

7. Shaft Design Diagrams

8. Selection of bearings

9. Selection of keyways and check calculation of keyway connection

10. Calculation of chain transmission

11. Chassis Design

11.1 Selection of valves. Gearbox Layout

11.2 Conical Housing Assembly Layout

11.3 Arrangement of intermediate and slow shaft assembly

11.4 Lubrication of engagement and bearings

11.5 Thermal calculation of reduction gear box

List of literature used

Introduction

A reduction gear is a mechanism consisting of gear or worm gears, made in the form of a separate unit and serving to transfer rotation from the shaft of the engine to the shaft of the working machine .

The purpose of the reduction gear is to reduce the angular speed and, accordingly, increase the torque of the driven shaft compared to the driving one.

The reduction gear consists of a body (cast iron or welded steel), in which the transmission elements are placed - gears, shafts, bearings, etc. In some cases, gear box housing also accommodates devices for lubricating engagement and bearings or cooling devices.

The reduction gear is designed either to drive a certain machine, or to a given load (torque on the output shaft) and gear ratio without specifying a specific purpose. The second case is typical for specialized plants in which serial production of gearboxes is organized.

Gearboxes are classified according to the following main features: type of transmission; number of steps; type of gears; relative location of reduction gear shafts in space.

Tapered gears are used to transmit motion between shafts whose axes intersect usually at an angle of 900. gears with angles other than 900 are rare. The most common type of conical reduction gear - with a horizontally located slow-moving shaft, also exists with a horizontally located slow-moving shaft. It is possible to make a reduction gear with a vertically located high-speed shaft; in this case, the drive is carried out from the flange motor.

Calculation of closed bevel gear train

4.1 Selection of gear materials. Define Allowable Stresses

We choose materials with high mechanical characteristics

[p. 34, Chernavsky]:

for gear - steel 50, heat treatment - improvement, hardness HB 300;

for the wheel - steel 45, heat treatment - improvement, hardness HB 280;

Defining Component Support Reactions and Bending Moments

To determine the directions of forces in gears and angular velocities at a given time, use the direction of the circumferential speed of the belt shown in Figure 2 (the wheels are conventionally extended in the kinematic diagram). The drive is reversible, in case of a change in the direction of rotation in the conical transmission, the circumferential forces Ft1 and Ft2 and in the cylindrical transmission, the circumferential forces Ft3 and Ft4 and the axial forces Fa3 and F a4 will change directions to opposite ones.

Chassis design.

11.2 Conical Wheel Assembly Layout

1. We define all structural dimensions of the gear rim and wheel hub and apply them to the drawing as recommended.

2. Draw the bearings of the wheel shaft.

3. We define the dimensions of bearing sockets, bearing covers, seals and apply these parts to the drawing.

4. We determine the thickness of the belts, the height of the bosses for studs and conduct the outer contour of the housing.

The shape and dimensions of the housing base are determined structurally depending on the position of the reduction gear box and the method of its attachment to the foundation.

11.3 Arrangement of intermediate and slow shaft assembly

1. We place the bearings according to the selected distance between them.

2. We define the dimensions of bearing sockets, bearing covers and seals and apply all these parts to the drawing.

3. We stroke the internal contour of the housing.

4. We conduct the outer contour of the housing on the projection.