Calculation of Longitudinal Milling Machine Speed Box

Contents

Contents

Introduction

Source Data:

1 Definition of cutting modes

1.1 Cutting modes during rough machining

1.2 Calculation of minimum spindle rotation speed:

1.3 Calculation of maximum cutting force

1.4 Torque on the spindle:

1.5 Cutting power:

2 Kinematic calculation

2.1 Structural Grid Construction

2.2 Graph of RPM numbers:

2.3 Determination of the number of gears

2.4 Build kinematic diagram:

3 Power calculation of speed box:

3.1 Determine the speed box efficiency:

3.2 Selection of electric motor:

3.2.1 Required electric motor power:

3.2.2 Motor Selection

3.3 Determine the actual speed of each shaft

3.4 Determine the power on each shaft

3.5 Determine the torque on each shaft:

3.6 Determine the gear module:

4 Calculation of speed box elements

4.1 Calculation of geometrical parameters of gears

4.2 Preliminary calculation of shaft diameters

5 Calculation of spindle for stiffness

6 Calculation of forces on controls

7 Description of speed box design

8 Feasibility Analysis

List of literature used

Application

Introduction

Longitudinal milling machines are designed for processing large-sized parts mainly with end cutters. The double-sided machine has 4 milling heads - 2 with vertical and 2 with a horizontal spindle arrangement. Each milling head has an independent drive: an electric motor and a speed box. The left horizontal head moves vertically along dovetail guides.

Description of speed box design

The speed box mechanism is located in the housing, casting from gray cast iron. Rotation to the first shaft of the box is transmitted through the bushing clutch. The box consists of 4 shafts and a spindle. On the 1st shaft, a cylindrical gear is cantilevered, which is in constant engagement with the wheel on the second shaft. Movable units are based on splined engagement of shafts. Gear wheels 2, 3 and 4 of shafts transmit torques through keys. On the shaft 4 there is a gear on radial bearings, which is in constant engagement with the wheel of the fifth shaft. Torque is transmitted by means of elastic coupling. The use of the coupling is due to the significant dimensions of the gear and, if it moves, significant forces arise on the control handle.

Gear wheels of the spindle (fifth) shaft are made in the form of a block of wheels, transmission of torque to the spindle - by means of splined engagement.

Spindle supports are mounted in pinoles, which are capable of axial block movement by means of worm and rack engagement with the help of a moss. After setting of required axial position of pinol, it is fixed with screw clamp by means of wedge bushings.

Feasibility Analysis

The speed box developed meets the following performance indicators:

1) A structural grid with a fan-shaped structure is used, which provides minimum dimensions.

2) The number of parts is minimized, which improves the reliability of the box.

3) Increases productivity by using a single-handed control mechanism compared to others (drum type, etc.).

4) The controls are located with the maximum possible convenience for the worker. Their design is simple and reliable.