Drawings on the course "machine part"

Contents

Introduction

Kinematic calculation of the drive

Calculation of chain transmission

Justification of selection of standard units and parts

Recommendations for selection of oil and lubrication of units

Brief description of drive assembly and maintenance

Design Design TB Requirements

List of literature

Specification

Introduction

Mechanical mixing of various foodstuffs is widespread in catering enterprises. Mixing is used when preparing dough, mince, salads, creams and the like.

The essence of mixing consists in formation of a new homogeneous product from individual particles of heterogeneous products. At the same time, heterogeneous particles of the product are carried away in motion by working tools of mixing machines, which mix these particles from one place to another in different directions, evenly distributing them throughout the entire volume.

With mechanical stirring, a wide variety of working tools are used: plates, curved rods, shaped, frame, propeller and other blades that move in different planes.

Working tools for dough preparation and whipped mixtures are most often of a more complex design and must move to provide mixing of the product in different directions. The resulting product should be uniform, ductile (for dough) and with uniform, stable air saturation of the mixture (for whipped mixtures).

Intensity of mechanical action of working elements on processed product is determined mainly by length of mixing, speed of their relative movement, as well as surface of working elements.

An increase in the speed of the working elements leads to an acceleration of the mixing process, but at the same time the power effect on the product increases, which can lead to an unacceptable change in the properties of the mixture.

For these reasons, for each type of mixture of food products, specific forms of working organs are used and regime parameters (speed of movement and duration of treatment) are empirically set for them.

Depending on the process, mixing equipment can be divided into three groups:

- for mixing loose products (machines for production of salads, vinaigrettes);

- for mixing plastic products (dough kneading machines, stuffing machines);

- for mixing liquid, viscous products (whipping machines).

According to the structure of the working cycle, periodic and continuous machines are distinguished.

According to arrangement of working elements and working chambers, machines can be with vertical, inclined and horizontal arrangement. Most often, machines with a vertical arrangement of working organs and a working chamber are manufactured (all whipping machines and a number of kneading machines). Sometimes there is an inclined arrangement of working elements with the vertical arrangement of the working chamber (TMM dough kneading machines - 1M, MBTM - 140). The inclined and horizontal arrangement of working organs and working chambers is less common (the mechanism for mixing salads and venegretts is an inclined arrangement, mince machines of the type MS8-150, machines for kneading steep dough MTM - 15 - horizontal arrangement ).

Recommendations for selection of oil and lubrication of units.

Reduction gear box lubrication.

The hooking of the conical ring gears is usually lubricated with liquid oil. The following lubrication methods are used in the reducers: crankcase, crankcase flow, centrolized or jet. In two or three step gears, a combined method of lubrication can also be used: for single-stage centrolized, and the other - crankcase.

The lubrication method is selected depending on the circumferential speed. At circumferential speeds not more than 10 m/s, crankcase is used by immersing the wheel or gear in the oil bath of the reduction gear box. If the axial distance in such transmissions is not more than 300 mm, then the value of the circumferential speed can be allowed up to 12 m/s. With a further increase in the circumferential speed, oil mixing losses increase sharply, as a result of which the reduction gear box is strongly heated. Oil temperature in the reduction gear bath is allowed up to 60650С and only in rare cases up to 850С.

All gearboxes, especially single-stage gearboxes of a wide type, should be checked for heating. The lower the temperature, the better the engagement lubrication conditions will be, as the viscosity decreases with increasing temperature and the physical and mechanical properties of the lubricant deteriorate.

At circumferential speed in engagement of 1012 m/s, the wheel must be immersed in the oil bath at no more than 2-3 tooth heights. At lower speeds, this amount of immersion can be increased (as in two and three step gears).

The crankcase flow method of lubrication consists in the fact that oil is supplied to the reduction gear bath on one side and on the other side. As a result, a constant level of oil in the bath is maintained and at the same time it is cooled.

Center-faced lubricant is used at circumferential transmission speeds of more than 10 m/s. If cooling is also required on a row with lubrication, then jet lubrication is used at lower speeds.

At high circumferential speeds and the need for forced cooling of the reduction gear box, oil is fed to the engagement and bearings under pressure from pumps or other devices. Individual lubrication stations serving only one reduction gear are equipped with gear pumps, and larger stations are equipped with piston pumps. Mesh plate filters are used to clean oil from dirt and other impurities.

To preserve the physical and chemical properties of oil for a longer service life, as well as for better settling of oil, tanks - settling tanks are included in the lubrication system, with a capacity of 820. Stations are equipped with technical and electrical contact pressure gauges, resistance thermometers. For monitoring of lubrication supply to bearings and for engagement, oil flow indicators are installed in the lines. If the specified ratio is not met, overflows of the reduction gear can occur, its leakage through the seals and heating of the reduction gear due to losses in oil mixing.

At circumferential speed up to 10 m/s. Oil is fed into engagement in direction of rotation. Oil is brought into engagement through nozzles or by splash.

In one - and two-stage reduction gears, at circumferential speed of the wheel of one of the stages, more than 2 m/s with bearings are lubricated with oil sprayed by the wheel. In tri- and multistage gears, low-speed shaft bearings are often lubricated with thick ointment.

Grease chain transmission.

Continuous crankcase lubrication of the following types should be used for critical power transmissions:

a) dipping the chain into the oil bath, the dipping of the chain into the oil at the deepest point not exceeding the width of the plate; is used up to the chain speed of 10 m/s to avoid unacceptable oil agitation.

b) spraying by means of special spraying protrusions or wheels from reflecting flaps, through which oil flows to the chain (ο= 612 m/s) in cases when the oil level in the bath cannot be raised to the chain location.

c) circular jet lubrication from the pump, the most advanced method (for powerful high-speed transmissions).

d) circulating greasing by dispersion of drops of oil in a current of air under pressure (υ> 12).

In medium-speed transmissions, plastic intramural or drip wetting is used.

At periodic operation and low chain speeds, periodic lubrication with the help of a manual oiler can be allowed.

To lubricate the chain transmission, we accept the plastic lubricant TSIATIM221, GOST9433-60, designed for friction assemblies and conjugated surfaces: "metal metal" and "metal rubber," operating in the temperature range from -60 to + 1500C in aggressive media. It is also possible to use plastic lubricants such as TSIATIM201 (GOST 626774), TSIATIM203 (GOST 877373).

Brief description of the assembly, operation and maintenance of the drive.

The assembly order of the actuator is described in the assembly drawings.

Electric motor and conical-cylindrical reduction gear are installed on frame. Between the electric motor and slow-moving shaft of the reduction gear box there is an elastic bushing-pin clutch. Electric motor and reduction gear are installed on slots of frame and fixed with bolts.

After installation of electric motor and reduction gear box, drive sprocket is put on high-speed shaft of reduction gear box, and drive sprocket is installed at axial distance. Sprockets are rigidly mounted on shafts using keys. Then drive roller chain is put on drive and driven sprockets and tension is performed by means of tensioner.

After installation of all drive elements, protective casings are installed; check of oil level in reduction gears and lubrication of chain transmission.