-slacking of a construction by a longitudinal joint is to be compensated by increase of cross-sections of body walls; that is why revived construction is heavy; body spaces are to be carefully sealed along figured plane but without breaking cylindrically of internal machined surfaces, which is usually obtained by lapping of butt surfaces and their installation on sealing. Mixed assembly is applied in order to use advantages and eliminate disadvantages of axial and radial kinds of assembly. Construction of one-step reduction gear-box with such kind of assembly is shown at fig. 2,19. The body is provided with cover with plane of joint, positioned above the place for bearings. That's why resulting construction is rigid, as gear wheel shafts are carried by body walls. Assembly is carried out in the following orders: gear wheels (which here must be fitted on) are brought into the body; shafts are pushed through bearings and hoops of wheels (shafts are to be stepped ones) and wheels are fixed on shafts. The resulting construction is relatively simple, but assembly of reduction gear-box is difficult.
Comparing advantages and drawbacks of axial and radial kinds of assembly, we see, that axial assembly is expedient to be used in the cases, when in order to create strong and light construction we can agree to some operational inconveniences.
If construction mass is of small importance and if raised production cost is permitted for the sake of convenience of assembly and operation, then radial assembly is applied.
Sometimes assembly system i? unambiguously preset by unit design. So, for stationary rotor machine, mounted on foundation, axial assembly system can't be applied due to operational considerations: in order to inspect internal mechanisms a machine is required to be removed from foundation. Here only radial or mixed assembly is available, if a construction, similar to the one, shown at fig. 2. 19., can be created.
In assembly of multicylinder crankshafts it is practically impossible to apply axial assembly due to shaft configuration and assembly conditions of split connecting rod ends.
There are limitations for this kind of assembly in the other classes of machines too (turbines, propeller shafts, etc.).
Memorize the following words and give their Russian equivalents',
A"ial assembly, radial, mixed one, butt planes, perpendicular, to be solid, shaft, aligned, advantages of, moulded, feeding of cutting tools, rigidity, sealed, disadvantages, assembly of unit is complex, axial, clearances, difficult, due to, shaft, special devices, raising of accuracy, to disassemble, in radial assembly, transversal, longitudinal axes, joint, transversal bolts, register pins, radial assembly, taking off, expose, mounted, inconvenient, control pins, geared transmission, gear-shaft, plain bearing, rigidity, slacking, sealed, figured plane, cylindrically of internal machined surfaces, lap, sealing, mixed assembly, in order, resulting construction is rigid, gear wheel shaft, gear wheels, fit on, hoops of wheels, gear-box, one-step reduction gear-box, gear wheel shafts, advantages and drawbacks, axial and radial kinds, expedient, agree, operational inconveniences, construction mass, for the sake of, assembly system, unambiguously, precept, unit design, stationary rotor machine, in order to inspect, internal mechanisms, crankshafts, split connecting rod ends, turbines, propeller shafts.
Find English counterparts for the following words:
Сельскохозяйственное машиностроение, осевая, радиальная, смешанная, осевое направление, сборка плоскости, продольная ось, конструкция, корпус, крышка, преимущество, вводить, фиксация, литая деталь, обрабатываемая поверхность, подвод, обработка, производится,
непрерывный, цилиндрическая поверхность, скоростная обработка, высокая жесткость, стадия, регулировка, полости, уплотняются, подшипник, элемент, ступень, демонстрация, предыдущие, поперечный, плоскость, втулка, укладывают, корпус, штифт, регулирование, обнажается, внутренность, открытый способ, относительный, редуктор, сложный, недостатки, преимущества, прочный, эксплуатация, агрегат, стационарная, коленчатый вал, многоцилиндровый поршневой цилиндр.
Questions, to the text and subjects for discussion
1.What kinds of assembly in agricultural machine-building do you
know?
2.Study fig.2.17 and speak about Construction All with geared
transmission with axial assembly?
3.In what kind of assembly:
1)ai j machined surfaces opened for view?
2)is assembly of a unit complex?
3)is inspection of internal parts difficult?
4)is the inspection of internal surfaces convenient?
5)is it difficult to make a body, consisting of two massive castings?
6)is machining inconvenient?
7)is there difficulty of resaving required rigidity?
4.What kind of assembly is applied in order to use advantages and
eliminate disadvantages of axial and radial kinds of assembly? Analyze
fig.2.19.
5.Compare advantages and drawbacks of axial and radial assembly.
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