Lathe-screw cutter. 16K20 - backstroke

Contents

Introduction

Engineering Specification

Overview of existing lathe types

Construction and operation of the main units of the 16K turning-screw machine

Description of machine kinematic diagram

Kinematic calculation of feed box

Create a structural grid and feed schedule

Calculation of cutting modes

Calculation of spindle for stiffness

Calculation of belt transmission

List of literature used

Specification for one of the machine units (tailstock)

Introduction

The high growth rate of production of engineering and other industries requires the development and implementation of the latest high-performance equipment, various types of machine tools and automatic lines.

The problem of improving the use of existing metal-cutting equipment due to its improvement (increased processing speeds, increased accuracy and reliability of operation, increased drive power, use of automation and process control means, use of devices and devices, which extends the technological capabilities of machine tools, occupies an important place. This project proposes the modernization of the 16K20 turning-screw machine in order to ensure a more complete use of the cutting properties of the hard alloy tool in the processing of parts from alloyed steels.

Overview of existing lathe types

Lathes are divided into universal and specialized. Universal machines are designed to perform a wide variety of operations. Specialized machines perform a narrower range of operations. Universal machines, in turn, are divided into turning-screw and turning. Turning machines are designed to perform all turning operations, except for cutting threads with cutters.

Our industry produces various models of turning and turning-screw machines - from desktop to heavy. The largest diameter of the surface to be treated ranges from 95 to 5,000 mm with a billet length of 125 to 24,000 mm. Some screw-turning machines are equipped with a copying device that allows you to process complex contours without the need for shaped cutters and a combined boring tool, and also greatly simplifies the adjustment and lifting of the machine.

In our country and abroad, a turning and screw-cutting machine is widely used. 16K20 production of the Moscow machine tool plant "Red Proletarian" named after A.I. Efremov.

Turning-screw machine modules 16K20 are designed for various turning operations:

external treatment of cylindrical and conical surfaces;

bores;

trimming of ends;

cutting of metric, inch, modular, pitch and end threads.

Part holes can be drilled and countersunk on the machine.

The machine consists of the following main units: a front head with a spindle, a bed, a caliper with a cutter holder, an apron, a rear head.

Description of machine kinematic diagram

The workpiece to be processed is fixed in a cam cartridge installed on the front end of the spindle. If the blank is long, then it is installed in the centers of the front and rear heads. When the machine is in operation, the workpiece being machined together with the spindle makes a continuous rotational movement. This movement is the main labor movement. The cutter is fixed in the cutter holder of the caliper and has a longitudinal and transverse movement during operation, which is a feed movement.

The main movement. The main movement in the machine is the rotation of the spindle, which it receives from the motor 1 through a V-belt transmission with pulleys 2-3 and a speed box. double-sided friction clutch is installed on receiving shaft. To obtain direct rotation of the spindle, the clutch is shifted to the left, and the rotation is driven by the following chain of wheels: 4-8 or 59, 10-13 or 1114, or 1215, shaft IV, wheels 1821 or 1922, spindle V. From shaft IV, the rotation can be transmitted through the overrun 1623 or 1724 25-27 and 2622 while moving to the right of block 2122 on the spindle. By switching the wheel blocks, it is possible to obtain 12 wheel engagement options when transmitting the rotation from shaft IV directly to the spindle and 12 options when transmitting the rotation through the overrun.

Reversing the spindle is performed by moving the coupling 6 to the right. Then, rotation from shaft II to shaft III is transmitted through gears 728, 29-12, and the latter receives reverse rotation. Practically, the spindle has only 22 speeds, since the values ​ ​ of 500 and 630 revolutions per minute are repeated twice.

Feed motion. The feed mechanism transmits movement to the caliper along four kinematic chains: screw-cutting, longitudinal and transverse feed, fast movement. Rotation of shaft VIII from spindle V is transmitted through gears 2032, and when cutting threads with an increased pitch from spindle V through a pitch increase link: wheels 2226, 27-25, 2316 or 2417 and through wheels 1633.

From shaft VIII, motion is transmitted through a reversing mechanism with wheels 3035 or 313435 to shaft IX, then through replaceable wheels a-b-d or a-b-c-d to the input shaft X of the feed box. Switching the couplings 116. 60. 43 and 50, as well as rearranging the block gears 5758. 45-46. 4748. 52-53 various combinations of connecting the wheels 36... 64 feed box are carried out. Either the lead screw 61 or the lead screw XVI can be connected from the input shaft XV of the rotary feed box. In the first case, through the clutch 60, in the second - through the wheels 5962, 63-66, the overtaking clutch 67 and the wheels 6864.

Screw-cutting chain. When threading, the caliper is fed from the lead screw 61 through a mother nut fixed in the apron. The required thread pitch can be obtained by switching gears and couplings in the feed box or by installing replaceable wheels a, b, c, d on the guitar. In the latter case, the feed box mechanism is turned off by the sleeves 116 and 60. Clutch 117 is used to prevent breakdowns during accidental overloads.

Longitudinal and transverse feed of caliper. A running shaft XVI is used to transmit movement to the apron mechanism. A gear 65 slides along it along the key vase, transmitting rotation through the wheels 69, 70, 71, with the clutch 72 and the worm pair 7374 on the shaft XVII.

One of the cam sleeves 77 or 84 is included to obtain the feed of the caliper and reverse it. Then, rotation from the shaft XVII is transmitted by the gears 758376 and 7892 or 8592 to the shaft XVIII and further to the rack wheel 94, which, rolling along the rack 95 fixed to the machine bed, performs longitudinal movement of the caliper.

Transverse feed and reversal are performed by actuation of couplings 87 or 90. In this case, rotation is transmitted from shaft XVII through gears 7586 and 88939896 or 758689 and 91939896 to screw 97, which imparts movement to the transverse carriage of the caliper.