HEADING (DEVELOPMENT OF RGL-225-35 GEARBOX)

Contents

CONTENTS

Introduction

0. General description of assembly structure and operation

1. Calculation and selection of interference fits

2. Select fits for smooth cylindrical joints by similarity

3. Calculation and selection of rolling bearing fits

4. Selecting Degrees of Precision and Threaded Joint Fits

5. Selection of tolerances and fits of key joint

6. Select the degrees of accuracy and type of gear mating

7. Defining Tolerances and Limit Deviations of Dimensions in a Dimension Chain

8. Calculation and description of threaded gauge for inner surface (plug)

9. ESKD Purpose and Entity

List of used literature

Introduction

One of the main goals of the designer in the course of designing and designing new and improving obsolete products is the development of drawing documentation for drawings, ensuring the necessary processability and high quality of products. The purpose of the course work in the discipline "Accuracy rationing and technical measurements":

1) The student acquires the necessary knowledge and skills for calculation and selection of tolerances and fits of standard joints of machine parts:

- calculation and selection of interference fit;

- calculation and selection of rolling bearings fits;

- selection of fits for smooth cylindrical joints by similarity method;

- selection of tolerances and fits of splined joint;

- selection of degrees of accuracy and fits of threaded connection;

- selection and calculation of accuracy of gears and gears;

2) Definition of tolerances and limit deviations of dimensions included in the dimension chain.

3) Normalizing the accuracy of the shape and location, roughness of the surfaces of the assembly.

The advantages of coursework compared to other types of training are the almost complete independence of the student during its performance, the need to use knowledge from other parallel fields.

General description of assembly structure and operation

Globoid elevator gearbox (RGL) with flange attachment of the electric motor, designed for the assembly of elevator winches of both passenger and hospital elevators. Gearboxes are operated in areas with moderate climate, shall be installed in rooms with ambient temperature from "minus 15̊ to +40̊S" and operated in explosion-proof and non-aggressive external environment. The gearbox is installed and can be operated only when the worm is located under the wheel under constant or variable loads with periodic stops with one direction of rotation of the worm or reverse. Operation in continuous operation with reduced load by 40% is allowed. The gearboxes are mainly operated at a worm speed of 1000 rpm. Gearboxes can be operated at a worm speed of 1500 rpm with a reduced torque of 20%.

Outer rings of radial-thrust bearings are fixed in the sleeve by a cover, which together with the sleeve is screwed to the reducer housing with eight studs or bolts. The connector between the cover and the sleeve is sealed with a paranite gasket, the thickness of which is selected depending on the value of the gap between them in the absence of gaskets. RGL reduction gear ring is attached with tension to the hub and is additionally locked with six bolts. Hub is connected with output shaft by light-press fit. To prevent displacement of hub relative to shaft, key is installed in this connection. Output shaft rotates in conical roller bearings. The outer bearing ring on the side of the cable-carrying pulley rests against the cut-in cover. The correct position of the middle plane of the worm wheel relative to the axis of the worm shaft is achieved by installing a set of gaskets between the outer bearing ring and the cut-in cover. On the second side there is a special screw and insert in the cover, at that the outer ring of the bearing is supported not by the cover, but by the insert. By rotating the screw, it is possible to push the shaft to the opposite cover (simultaneously with the selection of the corresponding gaskets) and thereby set the specified play in the bearings and the correct displacement of the worm wheel (rim) relative to the worm within the permissible limits. After adjustment, screw position is fixed by special cotter pin and seal. Rotation from the electric motor to the reduction gear is transmitted by means of a clutch of the DVVP type (elastic clutch, bushing-flange clutch). The coupling design shall be selected to ensure smooth start-up and stop of the drive (acceleration during passenger elevators operation shall not exceed (2 m/s2). In cases when the coupling fails to achieve this, a flywheel (wheel) is installed at the second end of the worm shaft. Half-coupling installed on worm shaft of reduction gear is simultaneously brake pulley of winch. The forces between the brake pads and the pulley shall ensure the specified stop accuracy and retention of the cockpit during static tests. Lubrication in worm gears, especially with globoid engagement, plays a dual role. First, it reduces the coefficient of friction between the working surfaces of the worm shafts and the wheel, thereby eliminating the burrs on the wheel due to the setting (local welding) of the contact surfaces. Second, the lubricant acts as the contact zone cooler. During the operation of worm gears, a significant amount of heat is generated due to the low efficiency of the gears (cl. d of the order of 0.6-0 8). The lubricant is a kind of coolant that takes heat from the rubbing surfaces and transfers it to the walls of the reducer, and those, in turn, to the environment. Due to the fact that the dimensions of the worm cylindrical and globoid reducers are approximately the same, and the dimensions of the latter are smaller, the globoid reducers have a more stressed thermal mode compared to the worm cylindrical reducers. In this regard, they have larger oil baths than worm cylindrical ones. In addition, they are lubricated with oils of greater viscosity, since the viscosity of the oil drops sharply with increasing temperature

9. ESKD Purpose and Entity

Unified Design Documentation System (ESKD) - a set of standards that establish rules and regulations for the development, design and circulation of design documentation. The ESKD establishes for all organizations a single procedure for the organization of design, common rules for the design and execution of drawings, which simplifies design work, contributes to the improvement of quality and the level of interchangeability. The ESKD harmonizes the design and reading of drawings and diagrams with ISO and IEC recommendations. The introduction of ESKD standards allows you to exchange design documentation without re-issuing it.

The main purpose of the ESKD standards is to establish uniform optimal rules, requirements and standards for the execution, design and circulation of design documentation, which ensure the use of modern methods and tools at all stages of the product life cycle; possibility of interchange of design documentation without its re-registration; optimal completeness of design documentation; mechanization and automation of processing of design documents and information contained in them; high quality of products; availability of requirements in design documentation ensuring safety of products use for life and health of consumers, environment, as well as prevention of damage to property; possibility to expand unification and standardization in product design and development of design documentation; possibility of certification of products; reduction of time and labor intensity of production preparation; correct operation of products; rapid preparation of documentation for rapid re-installation of existing production; simplifying the forms of design documents and graphics; possibility of creating and maintaining a single information base; The possibility of harmonizing ESKD standards with international standards (ISO, IEC) in the field of design documentation; The ability to inform product lifecycle support.