The device of the lathe on metal - the scheme and the basic knots
Essentially, lathe device, regardless of the model and level of functionality, includes typical structural elements, which determine the technical capabilities of such equipment. Design of any machine, relating to the category of turning group equipment, consists of the following basic elements, as: front and rear headstock, carriage, apron device, gearbox, gearbox, spindle equipment and drive motor.
The main parts of a lathe on metal
How the frame and the front head of the machine are arranged
The frame is a load-bearing element, on which all other constructive elements of the unit are established and fixed. Structurally, the frame is two walls, interconnected by transverse elements, giving it the required level of rigidity. The individual parts of the machine must move on the frame, for this purpose special guides are provided on it, three of which have a prismatic cross section, and one is flat. The rear headstock of the machine is located in the right part of the frame, on which it moves due to internal guides.
The cast frame of the lathe is strengthened by stiffening ribs and has the polished and hardened guides
The front headstock performs two functions simultaneously: gives the workpiece rotation and supports it during processing. On the front of this part of the lathe (it is also called "spindle grandmother") gearbox control levers are located. By means of such handles of a spindle of the machine the necessary frequency of rotation is provided.
To simplify gearbox control, next to the switching handle is a plate with the scheme, on which it is indicated, how to position the handle, so that the spindle rotates at the required frequency.
BF20 Yario gear selector lever
In addition to the gearbox, the front headstock of the machine is placed and the spindle rotation unit, in which rolling or plain bearings can be used. Cartridge device (cam or leash type) is fixed to the end of the spindle by means of a threaded connection. This unit of the lathe is responsible for transfer of rotation of preparation in the course of its processing.
Guide frames, on which the carriage of the machine moves (the lower part of the caliper), have a prismatic dissection. They are subject to high requirements for parallelism and straightforwardness. If you ignore these requirements, then it will be impossible to ensure high quality processing.
The purpose of the rear head of turning equipment
Rear head of the lathe, the design of which may provide several options, necessary not only for fixing parts, having a considerable length, but also for mounting various tools: drill, taps, sweep, etc. Additional center of the machine, which is mounted on the rear headstock, can be rotating or stationary.
Rear headstock device: 1, 7 - handles; 2 - handwheel; 3 - Eccentric; 4, 6, 9 - screws; 5 - thrust; 8 - quill; A - counterbore
The scheme with the rotating back center is used in that case, if high-speed machining of parts is performed on the equipment, as well as when removing chips, having a significant cross section. When implementing this scheme, the rear headstock is made with this design: in the hole of the quill are installed two bearings - the front is persistent (with conical rollers) and rear radial, - and also the plug, the inner part of which is bored under the cone.
Axial loads, arising from the processing of parts, perceived as a persistent ball bearing. Installation and fixing of the back center of the equipment are provided at the expense of a conical opening of the plug. If it is necessary to install a drill or other axial tool in such a center, the sleeve can be rigidly fixed with a stopper, which will prevent it from rotating with the tool.
Rotating center KM-2 of the Turner-250 desktop lathe
Rear grandmother, the center of which does not rotate, fixed on the plate, moving along the guides of the machine. Quill, installed in such a grandmother, moves along the hole in it with a special nut. In front of the quill itself, in which set the center of the machine or the shank of the axial tool, perform a conical hole. Moving nuts and, in accordance, the quill is provided by the rotation of a special flywheel, connected to the screw. What is important, quill can move in the transverse direction, without such movement it is impossible to carry out processing of details with a flat cone.
Spindle as an element of a lathe
The most important structural unit of the lathe is its spindle, which is a hollow shaft of metal, the inner hole of which has a conical shape. What is remarkable, for the proper functioning of this site are responsible for several structural elements of the machine. It is in the inner conical hole of the spindle that various tools are fixed, mandrels and other devices.
Drawing of the spindle of the lathe 16K20
That on a spindle it was possible to establish a faceplate or the turning cartridge, in its design a carving is provided, and for centering of the last also a collar on a neck. in addition, to prevent the cartridge from unscrewing accidentally when the spindle is stopped quickly, on some models of lathes the special groove is provided.
The results of processing on the machine of details from metal and other materials largely depend on quality of manufacturing and assembly of all elements of a spindle knot.. In the elements of this node, in which it can be fixed as a workpiece, and the tool, there should not be even the slightest backlash, which causes vibration in the process of rotational motion. This must be carefully monitored as during the operation of the unit, and when purchasing it.
In spindle units, which can be immediately determined by their drawings, plain or roller bearings with roller or ball elements can be installed. Of course, high rigidity and accuracy are provided by rolling bearings, they are installed on devices, performing workpiece processing at high speeds and with significant loads.
Support structure
The lathe support is a node, thanks to which fixing of the cutting tool is provided, as well as its movement in the slope, longitudinal and transverse directions. It is on the caliper is the tool holder, moving with it due to manual or mechanical drive.
Support with the carriage of the Optimum D140x250 machine
The movement of this site is provided by its structure, characteristic of all lathes.
- Longitudinal movement, for which the lead screw is responsible, performs caliper carriages, while it moves along the longitudinal guides of the frame.
- Transverse movement is carried out by the upper - rotary - part of the caliper, on which the tool holder is installed (such a move, due to which you can adjust the depth of processing, carried out on the transverse guides of the caliper, having the shape of a swallow's tail).
The tool holder is a quick-change MULTIFIX cartridge type
Tool holder, which is also called a chisel head, is installed at the top of the caliper. The latter can be fixed at different angles with the help of special nuts. Depending on the need, single or multi-seat tool holders can be installed on lathes. The body of a typical cutter head has a cylindrical shape, and the tool is inserted into a special side slot in it and fixed with bolts. At the bottom of the cutter head there is a protrusion, which is inserted into the corresponding groove on the caliper. This is the most typical scheme of fastening the tool holder, used mainly on machines, designed to perform simple turning operations.
Electric part of a lathe
All modern lathes and screw-cutting lathes on metal, differ in rather high complexity of the design, are driven by a drive, as which electric motors of various power are used. Electric motors, installed on such units, can be asynchronous or run on direct current. Depending on the model, the engine may produce one or more speeds.
Electrical circuit of the lathe 1K62 (click to enlarge)
On most models of modern lathes on metal motors with a short-circuited rotor are established. To transmit torque from the engine elements of the gearbox of the machine can be used belt drive or direct connection to its shaft.
Models of lathes are presented on the modern market, on which the spindle speed is regulated by a stepless circuit, for which electric motors with independent excitation are used. Adjustment of speed of rotation of a shaft of such engine can be carried out in an interval 10 to 1. However, due to the large size and not very economical consumption of electricity, such electric motors are used very rarely.
Two-speed motor with flat belt pulley
As mentioned above, electric motors can also be used to drive lathes, operating on direct current. These are the electric motors, which are large, provide a stepless change in the speed of their rotation of the output shaft.
The electric motor is the main part of the electrical system of any lathe, but it also includes many additional elements. All of them, functioning in a complex, provide convenience of control of the machine, as well as the efficiency and quality of technological operations, which are performed on it.
