Definition of the Reducer efficiency with cylindrical strait wheels. Moscow State Technical University. N. E. Bauman Concept of useful effect

Laboratory work number 5.

Research efficiency gearbox.

Goals and work tasks : Studying the method of experimental determination of the efficiency (efficiency) of the gearbox, obtaining the dependence of the Reducer efficiency from the size of the resistance applied to the output shaft of the gearbox, estimate the parameters of the mathematical model describing the dependence of the Reducer efficiency from the moment of resistance and determination of the torque of the resistance corresponding to the maximum efficiency of the efficiency .

5.1. Single information about the efficiency of the mechanisms.

Energy, summing up to the mechanism in the form of work A D of the driving forces and moments per cycle of the steady mode, is spent on the performance of useful work A PS i.e. work of forces and moments of useful resistance, as well as to perform work A T, related to overcoming friction forces in kinematic pairs and resistance forces of the medium: a d \u003d and PS + A T. Values \u200b\u200band PS and A T are substituted into it and subsequent equations on absolute value. The mechanical coefficient of useful is the relationship:

Thus, the efficiency shows how the proportion of mechanical energy supplied to the car is useful to be spent on the performance of the work for which the machine is created, i.e. It is an important characteristic of the machine mechanism. Since friction losses are inevitable, always<1. В уравнении (5.1) вместо работ А д и А пс, совершаемых за цикл, можно подставлять средние за цикл значения соответствующих мощностей:

(5.2)

Reducer - This is a toothed mechanism designed to reduce the angular velocity of the output shaft relative to the input. The ratio of the angular velocity at the inlet to the angular velocity at the exit is called the gear ratio of the gearbox:

For gearbox, equation (5.2) takes the form:

(5.4)

Here M. FROM them D. - The average values \u200b\u200bof the moments at the output and the input shafts of the gearbox. Experimental definition of efficiency is based on measuring the values \u200b\u200bof M FROM and M D. and the calculation of the formula (5.4).

5.2.Factors. Determining the field variation field.

Factors Called the system parameters that affect the measured value and can be purposefully changed during the experiment. In the study of the efficiency of the gearbox, the factors are the moment of resistance M C on the output shaft and the frequency of rotation of the input shaft of the gearbox N 2.

At the first stage of the experiment, it is necessary to determine the limit values \u200b\u200bof the factors that can be implemented and measured on this installation, and build a field of variation of factors. Approximately this field can be built in four points. For this, at a minimum resistance torque (the installation brake is turned off), the rotational speed regulator set its minimum and maximum values. The magazine register the testimony of the tachometer and, as well as the corresponding indicators of the brake indicator and. In this case, if the value exceeds the upper limit of the tachometer scale, then it takes it equal to the greatest value of this scale.

Then turn on the brake and the torque regulator set the maximum torque M C Max . The rotational speed regulator is set first the maximum frequency value for this load, and then the minimum stable (about 200 rpm). The log records the frequency values, and the corresponding indicators of the brake indicator and portraying the resulting four points on the coordinate plane and connecting them with straight lines, build the field of variation of factors (Fig. 5.1). Inside this field (with some deviations from borders), the study area is chosen - the limits of changing the factors in the experiment. With a single-factor experiment, only one of the factors change, all other are supported at a given constant level. In this case, the area of \u200b\u200bthe study is a straight line (see Fig. 5.1, straight n d. \u003d const).

5.3. Select the model and experiment planning.

As a mathematical model of the process under study, polynomials are most often used. In this case, for addiction with N. D.\u003d const

we accept polynomial species

The task of the experiment consists in obtaining empirical data to calculate the rating of the coefficients of this model. Since with m c \u003d 0 efficiency of the system is zero, then the polynom can be simplified, excluding a member from it B. 0 which is zero. The results of the experiment are processed on the computer on the KPD program, which allows to determine the coefficients of the model B K. And to print dependency graphics: experimental indicating confidence intervals and built according to the model, as well as the value of the moment of resistance m C0. corresponding to the maximum

5.4. Description of the experimental installation.

The study of the Reducer efficiency is carried out on the installation of the DP-4 type. Installation (Fig. 5.2) contains an object of study - gearbox 2 (planetary, worm, inline, wave), a mechanical energy source - electric motor 1, energy consumer - powder electromagnetic brake 3, two regulators: engine speed control potentiometer 5 and potentiometer 4 of the regulator The moment of the brake, as well as the device for measuring the frequency - engine rotation (tachometer 6) and torque motors on the motor shaft and brakes.

Devices for measuring engine moments and brakes are similar to design (Fig. 5.3). They consist of support with rolling bearings, which provides the possibility of rotation of the stator 1 and rotor 2 relative to the base, the measuring lever with the shoulder L and Based on a plate spring 4 and an arrow indicator 3. Spring deflection is measured using the indicator, the deflection value is proportional to the torque in the stator. The value of the moment on the rotor is approximately estimated at the time on the stator, neglecting the moments of friction and ventilation losses. For targeting indicators Installation is completed with removable levers 6, which shall be applied in increments L, and loads 5. On the engine tariff levers LD \u003d 0.03 m, the brakes L d. \u003d 0.04 m. Mass of goods are equal: m 5d \u003d 0.1 kg and m 5t \u003d 1 kg, respectively. Powder brake is a device consisting of a rotor and a stator, in the ring gap between which there is a ferromagnetic powder. By changing the potentiometer 5 voltage on the windings of the brake stator, it is possible to reduce or increase the strength of the resistance to the shift between the powder particles and the moment of resistance to the brake shaft.

5.5. Target indicators of moments meters.

Tarising - Experimental determination of dependence (analytical or graphic) between the testimony of the measuring device (indicator) and the measured value (torque). When tarized, the measuring device using a lever and cargo is loaded by the values \u200b\u200bof torque matches M T I, and the indicator readings are recorded.
To eliminate the influence of the initial moment M t O \u003d G 5 L. O., go from the coordinate system f "0" m "into the system F 0 M (Fig. 5.4), i.e. set the scale of the indicator on zero after the location of the cargo G 5 At the zero value of the scale on the lever.

At the targeting, the average values \u200b\u200bof the indicator of the brake indicator at all stages of the load m m c I. . Tariff dependence for the moment of the engine has the form . The area of \u200b\u200bresearch and levels of factor at tarization are determined by the length and step of marking of the levers 6 and the masses of cargo 5.

To obtain target dependence conduct n original experiments (at various levels m t i.) from M. repetitions at each level, where n\u003e \u003d k + 1; m\u003e \u003d 2; k is the number of model coefficients (they take n \u003d 5, m\u003e \u003d 2; k - the number of model coefficients (they take n \u003d 5, m \u003d 3). Calibration facilities B K. Calculate on the array of calibration results on the computer on the program "KPD".

1. The purpose of the work

Deepening the knowledge of theoretical material, obtaining practical skills of self-experimental definition of gearboxes.

2. Basic theoretical provisions

The mechanical efficiency coefficient of the gearbox is the ratio of power, useful (resistance power N C. to the power of driving forces N D. on the input shaft of the gearbox:

The power of the driving forces and forces of resistance can be determined according to the formulas

(2)

(3)

where M D. and M S. - moments of the driving forces and forces of resistance, respectively, NM; and - the angular velocities of the shafts of the gearbox, respectively, input and output, from -1 .

Substituting (2) and (3) in (1), we get

(4)

where - the gear ratio of the gearbox.

Any complex machine consists of a number of simple mechanisms. The efficiency of the machine can be easily defined if the efficiency of all simple mechanisms included in it are known. For most mechanisms, analytical methods for determining the efficiency have been developed, but deviations in the purity of the processing of the rubbing surfaces of parts, the accuracy of their manufacture, changes in the load on the elements of kinematic pairs, the lubrication conditions, the speed of relative movement, etc., lead to a change in the friction coefficient.

Therefore, it is important to be able to experimentally determine the efficiency of the mechanism under study under specific operating conditions.

Necessary to determine the efficiency of the gearbox parameters ( M d, m with and L R.) You can determine using DP-3K devices.

3. DP-3K device device

The device (Figure) is mounted on the resulting metal base 1 and consists of an electric motor 2 with a tachometer 3, a loader device 4 and the gearbox under study.

3 6 8 2 5 4 9 7 1

11 12 13 14 15 10

Fig. Kinematic diagram of the device DP-3K

The electric motor housing is hinged in two supports so that the axis of rotation of the engine shaft coincides with the axis of the corps of the case. The fixation of the engine housing against circular rotation is carried out by a flat spring 6. When the torque is transmitted from the electric motor of the spring gearbox, it creates a jet attached to the electric motor housing. The motor shaft is tested with the gearbox input shaft through the coupling. The opposite end is articulated with a tachometer shaft.

The gearbox in the DK-3K device consists of six identical pairs of gear wheels mounted on ball bearings in the housing.

The upper part of the gearboxes has an easy-graded cover made of organic glass, and serves to visually observe and measure gear wheels when determining the transfer ratio.

The load device is a magnetic powder brake, the principle of operation of which is based on the property of the magnetized medium to resist the ferromagnetic bodies in it. A liquid mixture of mineral oil and iron powder is applied as a magnetized medium in the design of the loading device. The body of the loader is installed balancing with respect to the base of the device on two bearings. The limitation of circular rotation of the housing is carried out by a flat spring 7, which creates a jet, which balance the moment of the resistance forces (braking torque) created by the loading device.

Measuring devices of the torque and braking moments consist of flat springs 6 and 7 and the indicators of the hourly type 8 and 9, measuring springs, proportional to the torque values. The springs are additionally pasted strain gauges, a signal from which through a strain gauge can also be fixed on an oscilloscope.

On the front part of the base, the control panel 10 is located on which:

Toggle switch 11 on and off the electric motor;

Rotation frequency control knob 12 of the electric motor;

Signal lamp 13 of the instrument on;

Toggle switch 14 on and off the chain of the loading of the load device;

Handle 15 adjustment of the excitation of the load device.

When performing this laboratory work:

Determine the gear ratio of the gearbox;

Cancel measuring devices;

Determine the efficiency of the gearbox, depending on the resistance forces and on the speed of the electric motor.

4. Procedure for performing work

4.1. Determination of gear ratio reducer

The transfer ratio of the gearbox of the DP-3K device is determined by the formula

(5)

where z. 2 , z. 1 is the number of teeth, respectively, larger and smaller wheels of one stage; to\u003d 6 - the number of steps of the gearbox with the same gear ratio.

For the gearbox of the device DP-3K, the transfer ratio of one step

Found Gate Record i P. Check the experienced way.

4.2. Target measuring devices

The targeting of the measuring devices is performed when the device is disconnected from the source using tarium fixtures consisting of levers and cargo.

To target the measuring device of the motion of the electric motor, it is necessary:

Install on the electric motor housing Calibration device DP3A Sat. 24;

Install the load on the lever of the tariff device to the zero mark;

Install the indicator arrow to zero;

By installing the cargo on the lever on subsequent divisions, fix the indicator readings and the corresponding division on the lever;

Determine average value m cf. Indicator Formula Prices

(6)

where TO - the number of measurements (equals the number of divisions on the lever); G. - cargo weight, N.; N I. - indication of the indicator - the distance between the divide on the lever ( m.).

Middle Definition m C.Sr.prices of fission indicator of the load device are made by installation on the body of the loading device of the Tarising device DP3A Sat. 25 by a similar method.

Note. The weight of goods in the tariff devices DP3K Sat. 24 and DP3K Sat. 25 is respectively 1 and 10 N..

4.3. Definition of the Reductor efficiency

Definition of the Reducer efficiency depending on the resistance forces, i.e. .

To determine dependence, it is necessary:

Turn on the device 11 of the electric motor and the speed adjustment knob 12 set the specified by the teacher N;

Install the loading knob 15 of the load of the loading device to zero, turn on the excitation supply chain 14;

Smooth turn of the excitation current control knob Set the first value (10 divisions) arrow of the indicator arrow M S. resistance;

Handle 12 speed adjustment set (adjust) Initial specified rotational speed n.;

Fix the readings H 1 and H 2 indicators 8 and 9;

Further adjustment of the excitation current to increase the moment of resistance (load) to the next predetermined value (20, 30, 40, 50, 60, 70, 80 divisions);

Maintaining the speed of rotation unchanged, fix the indicators readings;

Determine the values \u200b\u200bof moments of driving forces M D.and resistance forces M S. For all measurements by formulas

(7)

(8)

Determine for all measurements of the Reducer efficiency by formula (4);

Apply indicators h. 1 I. h. 2, the values \u200b\u200bof the moments M D. and M S. and the found values \u200b\u200bof the Reducer efficiency for all measurements in the table;

Build a graph.

4.4. Definition of the Reducer efficiency depending on the number of rotation of the electric motor

To determine graphical dependence, it is necessary:

Enable the toggle switch 14 of the power and excitation chain and the excitation current adjustment knob to set the status value specified by the teacher M S. on the output shaft of the gearbox;

Include an electric motor device (toggle switch 11);

By installing the speed adjustment handle 12, a number of values \u200b\u200b(from the minimum to the maximum) rotational speed of the motor shaft and maintaining the constant moment value M S. load fixing indicator readings h. 1 ;

Give a qualitative assessment of the effect of the rotation frequency N on the Reducer efficiency.

5. Drawing up a report

The report on the work must contain the name

the purpose of the work and the task of determining the mechanical efficiency, the main technical data of the installation (type of gearbox, the number of teeth on wheels, the type of electric motor, the loading device, measuring devices and instruments), calculations, description of the target of the measuring devices, the table of experimentally obtained data.

6. Control questions

1. What is called mechanical efficiency? Its dimension.

2. What is the mechanical efficiency depends on?

3. Why are the mechanical efficiency determined by an experimental way?

4. What is the sensor in the measuring devices of the torque and braking moments?

5. Describe the load device and its principle of operation.

6. How will the mechanical efficiency of the gearbox change, if the moment of resistance forces increases (decrease) twice?

7. How will the mechanical gearbox efficiency change if the moment of resistance forces increases (decrease) by 1.5 times?

Laboratory work 9.

1. The purpose of the work

Research of the Reducer efficiency at various loading modes.

2. Description of the installation

To study the operation of the gearbox, the DP3M brand is used. It consists of the following main nodes (Fig. 1): the test gearbox 5, the electric motor 3 with the electronic tachometer 1, the loader 6, the device for measuring moments 8, 9. All nodes are mounted on one base 7.

The electric motor housing is hinged in two supports 2 so that the axis of rotation of the motor shaft coincides with the axis of the rotation of the housing. The fixation of the housing of the electric motor from the circular rotation is carried out by a flat spring 4.

The gearbox consists of six of the same straight cylindrical gears with a gear ratio of 1.71 (Fig. 2). The gear wheel block 19 is installed on the stationary axis 20 on the ball bearings. The design of the blocks 16, 17, 18 is similar to block 19. The transmission of torque from the wheel 22 to the shaft 21 is carried out through the key.

The measuring devices of the torque and braking moments consist of flat springs that create reactive moments, respectively, for the electric motor and a loading device. Flat springs are pasted strain gauges connected to the amplifier.

On the front of the device, the control panel is located: the power supply button "Network" 11; Button power out the load circuit of the loading device "Load" 13; button on the motor "Engine" 10; Electrical speed control knob "Speed \u200b\u200bcontrol" 12; The control knob of the excitation current of the load device 14; Three ammeter 8, 9, 15 to measure respectively frequency N, Moment M 1 Moment M 2.

Fig. 1. Installation scheme

Fig. 2. Testing gear

Technical characteristics of the device DP3M:

3. Estimated dependencies

Definition of the Reducer efficiency is based on the simultaneous measurement of moments at the input and output shafts of the gearbox with the steady speed of the rotational speed. At the same time, the calculation of the Reducer efficiency is made by the formula:

= , (1)

where m 2 is the moment created by the load device, n × m; M 1 - moment developed by the electric motor, n × m; U is the gear ratio of the gearbox.

4. Procedure for performing work

At the first stage, at a given constant speed of rotation of the electric motor, a study of the Reducer efficiency is examined depending on the moment created by the load device.

First, the electric drive and the speed adjustment knob is set to a specified speed of rotation. The adjustment knob of the load of the load device is set to zero. The excitation power supply circuit is turned on. A smooth rotation of the excitation adjustment knob is set to the first of the specified values \u200b\u200bof the load torque on the gearbox shaft. The speed adjustment knob is supported by the specified speed of rotation. Micronmmeters 8, 9 (Fig. 1) Moments on the shaft of the engine and the loading device are recorded. Further adjustment of the excitation current increase the torque of the load until the next specified value. By supporting the frequency of rotation unchanged, the following values \u200b\u200bof M 1 and m 2 are determined.

The results of the experiment are recorded in Table 1, and a graph is built \u003d f (m 2) with n \u003d const (Fig. 4).

At the second stage, at a given constant moment of load m 2, the Reducer efficiency is investigated depending on the frequency of rotation of the electric motor.

The excitation power supply circuit and the excitation current adjustment knob is set to the specified torque value on the output shaft of the gearbox. The speed adjustment knob is set by a number of rotational frequencies (from minimal to maximum). For each speed mode, the unchanged moment of the load m 2 is maintained, micronmmeter 8 (Fig. 1) is recorded on the motor shaft M 1.

The results of the experiment are recorded in Table 2, and a graph is built \u003d f (n) with M 2 \u003d const (Fig. 4).

5. Conclusion

It is explained from which the power loss in the toothed gear and how the efficiency of the multistage gearbox is determined.

Conditions are listed to increase the Reducer efficiency. The theoretical substantiation of the obtained graphs is given \u003d f (m 2); \u003d F (n).

6. Registration of the report

- Prepare a title page (see sample on page 4).

- depict the kinematic scheme of the gearbox.

Prepare and fill in Table. one.

Table 1

from the moment of the loaded device

- Build a Dependency Schedule

Fig. 4. Chart of dependence \u003d f (m 2) with n \u003d const

Prepare and fill in Table. 2.

table 2

The results of the study of the Reducer efficiency depending on

from the frequency of rotation of the electric motor

- Build a chart of dependency.

n, min -1

Fig. 5. Chart of dependence \u003d F (n) at m 2 \u003d const

Come on (see paragraph 5).

Control questions

1. Describe the design of the DPSM device, from which major nodes it consists?

2. What power loss take place in the gear transmission and what is its efficiency?

3. How do such characteristics of a toothed transmission, as power, torque, rotational speed are changed from leading to the slave shaft?

4. How is the transfer ratio and the Multistage Reducer efficiency?

5. List the conditions to enhance the Reducer efficiency.

6. The procedure for performing work in the study of the Reducer efficiency, depending on the moment of the supplied load device.

7. The procedure for performing work in the study of the Reducer efficiency, depending on the frequency of rotation of the engine.

8. Give the theoretical explanation of the obtained graphs \u003d F (m 2); \u003d F (n).

Bibliographic list

1. Reshetov, D. N. Machine details: - Tutorial for students of machine-building and mechanical specialties of universities / D. N. Reshets. - M.: Mechanical Engineering, 1989. - 496 p.

2. Ivanov, M. N. Machine details: - Tutorial for students of higher technical educational institutions / M. N. Ivanov. - 5th ed., Pererab. - M.: Higher School, 1991.- 383 p.

Laboratory work number 8

In most mechanisms with an electric motor there is a cylindrical gearbox. It reduces the number of revolutions and increases the power of the unit. The gear mechanism of the torque transmission through the cylindrical wheels has the highest efficiency compared to other methods. Various types of cylindrical gearboxes are widely used in metallurgical and machine-building equipment, electric tools and cars.

Constructive features

The basis of any gearbox is the transmitting rotational moment and changing the number of rolver shaft. For cylindrical engagement, the ability to rotate in both directions is characteristic. If necessary, the slave shaft with the wheel is connected to the engine and becomes the lead. They are located in parallel in this design, horizontally and vertically. The device of cylindrical gearboxes may be the most, but it necessarily includes its design:

leading;
slave shaft;
gear;
wheel;
bearings;
housing;
covers;
lubrication system.

The housing and the lid are cast from cast iron or are made from a low-carbon sheet with a thickness of 4 - 10 mm depending on the dimensions and power of the node. Welded make small gearboxes. The rest have a strong cast case.

Characteristics of cylindrical gearboxes

The number of engagement, the type of tooth and the mutual location of the shafts for all types of equipment describes GOST gearboxes cylindrical. It contains sizes of all parts that can be used in cylindrical gearboxes at various quantities of steps. Maximum one pair 6.5. The total multistage gearbox can be up to 70.

More than the cylindrical gearbox may be a gear ratio at worm gear, it can reach 80. At the same time, they are compact, but are rarely used due to low efficiency. In cylindrical single-stage gearboxes of the efficiency of 99 - 98%, the highest of all types of gears. Curious and cylindrical gearboxes of the shafts. If they have cylindrical parallel, the worm is located to the wheel at an angle. Consequently, the trees lead and the slave exit from perpendicularly located side walls of the case.

The cylindrical gearboxes are the most noisy, when contacting the teeth, the surface of the surface is one of the other. This eliminates strong friction and overheating.

For lubrication, it is enough to pour oil into the pallet that the lower gears partially plunged into it. When rotating the teeth, the oil is captured and splash it to other details.

Design and calculation procedure

The calculation of the future gearbox begins with the determination of the transfer moment and the selection of its normalized pairs. After that, the diameters of the parts and the edge distance of the shaft are specified. A kinematic scheme is drawn up, the optimal shape of the body and the lid, the bearing numbers are determined. The assembly drawing includes the kinematic diagram of a two-stage gearbox, a lubrication system and methods for its control, types of bearings and places of their installation.

GOST 16531-83 describes all possible types and sizes of gear wheels, which can be used in cylindrical gearboxes with an indication of the module, the number of teeth and diameter. In the size of the gear, the shaft is selected. His strength is calculated taking into account the rotational moment on twisting and bending. The minimum size is determined, multiplied by the strength coefficient. Then the nearest larger normalized shaft is selected. The key is calculated only on the cut and selected similarly.

Download GOST 16531-83

Bearing is selected by the shaft diameter. Its type is determined by the direction of the tooth. In case of ososophy, they put stubborn, more expensive. The spanning gear does not load them in the axial direction, and one-row ball bearings work for several thousand hours.

The assembly scheme is indicated in the drawing at the bottom and describes in detail in the technological documentation, which is issued in production together with the drawings. On the main drawing with a common view, the table indicates the technical characteristics of the gearbox, which are then transferred to the passport:

number of steps;
ratio;
the number of revolutions of the leading shaft;
output power;
dimensions;

Additionally, the vertical arrangement of the engagement, the direction of rotation of the shaft and the installation method are: flange or paws.

Types of cylindrical gearboxes

Cylindrical gearboxes are diverse in design, sizes and power, they are divided into species in several characteristics:

fastening type;
the location of the shafts;
number of steps;
slicing tooth.

Specifications include types of bearings and type of shaft connections.

Cylindrical single-stage gearboxes can be attached to the engine and the body of the working knob flanges. The design is compact, with minimal costs of materials. In the main one, they are installed on the sole with protrusions around the perimeter or on the paws with holes under. Small-sized nodes can be installed on a welded frame. For overall units, a special foundation is made.

The location of the shafts

Input and output shafts can be placed horizontally, vertically, in parallel to each other, but in different planes for multistage nodes. If there are only one engagement, the shafts are in the same plane, strictly vertical or horizontal. They are rarely displayed in one direction, only with the ability to compact the location of the engine and the working unit. At the two-stage cylindrical gearbox, the mid-scene distance is larger and can be mounted engine from the actuator.

Cylindrical gearboxes can produce with vertical location of shafts. It is convenient to install them on the car, but the upper engagement and bearings are lubricated weakly. For long-term work with large loads, they are not suitable.

The cylindrical horizontal gearbox is overall, takes a lot of space. It is heated less, withstands the load and vibration, stable. In models from 3 or more steps, the shafts are located horizontally. Lubrication pulls out all bearings. In multi-row structures, an additional irrigation is made from above, with an oil belt installed in the lid.

Speed \u200b\u200bboxes

A variety of cylindrical gearbox with a movable intermediate shaft is a widely known box of speeds. When changing the position of the shaft, some couples come out of the engagement, others begin to interact. As a result, the gear ratio changes, the speed of rotation at the output.

Speed \u200b\u200bboxes are made with a straight tooth. The osostices are rarely found when large loads on the actuator.

The use of cylindrical gearboxes

- Lowering the number of engine speeds and an increase in power on the output shaft. The assembly of the cylindrical gearbox does not represent complexity. In the center of the holes pass the connector of the housing and cover. Bearings are planted on the shafts, installed in the harvested sockets and support outside the covers.

Wheels and gears are attached to shafts with a key.

To adjust the mid-scene distance, it is necessary to make a boring body with great accuracy.

Maintenance gearboxes simple. It is necessary to regularly attach the oil, periodically change it. Details located inside are designed for long-term operation for at least 10 years.

Reducer are used in various industries. Separate types of large equipment are able to withstand any weather conditions. They are installed in quarries and open areas, on gantry cranes.

Rolling and blacksmith-presses will not be able to work without gearboxes. In this industry, many varieties of gearboxes are in demand. Purpose stand on the cranes. Powerful chevron rotate crank presses, rollers, manipulators feeding metal.

Rolling T-regular mills work exclusively thanks to the tools transmitting the rotation of the engine to the rolls and work nodes.

Under each hood hide a box of speeds. Each machine has a gearbox or several. Small transmissions are installed in the power tools and adjust the speed of rotation of the spindle of a drill, a grinder and a mill.

Advantages and disadvantages

The cylindrical transmission mechanism has been widely used in various fields. It has indisputable advantages compared to worm:

high efficiency;
not heated;
works in both directions.

The advantages and disadvantages of the cylindrical gearbox depend on the characteristics of the gear and other structural elements.

Benefits

The main positive point is the high efficiency. It significantly exceeds the exit capacity with the same engines, all gears and other types of gears.

A node can work for a long time without interruptions, switching an infinite number of times from one mode to another and even change the direction of rotation.

Heat release is minimal. There is no need to set the cooling system. The lubricant is sprayed with lower wheels, lubricates the upper gears, bearings and collects down, in the pallet, all the dirt, squeezed particles of the metal. It is time to periodically precise the oil and once every 3 to 6 months to change it. The work of preventive measures depends on the operation mode.

The output shaft is installed in rolling bearings and practically does not have a backlash. Moving it is fairly accurate to use a gear mechanism as the actuator of accurate devices and devices. The axial and radial beating of mating parts do not affect the operation of the mechanism.

The efficiency of work does not depend on voltage drops. The gear ratio is stable. If the engine rotation speed falls, the rotation of the slave wheel is slowed proportionally. Power remains unchanged.

disadvantages

Positive quality - no friction and braking, under certain conditions creates problems. In the load-lifting mechanisms when installing a cylindrical gearbox, it is necessary to put a strong brake in order to keep weight items on weight and prevent their independent lowering. In worm gears, only the worm can be the leading and due to the large friction there is an effect of self-motion.

The problem of all gears in the absence of a safety mechanism.

When overloading or sharp turn on the belt slips on the pulley. The tooth can only break, and the item will have to be changed. As additional fuses are used by the swords. They are calculated on the cut without the stock of strength. Replace the cut-off clutch simple item is much easier.

The cost of working parts is large. Production technology is long and complex. In this, this tooth is gradually erased, the gap increases between the working surfaces. To change the intercentrose distance, as in the rush and worm gears in the gearbox, it is impossible to periodically replace the gears, wheels, bearings.

The more Evolvent is erased, the stronger the teeth are knocking on each other, and the gearbox is noise.

The worm reducer is one of the classes of mechanical gearboxes. Reducers are classified by the type of mechanical transmission. The screw, which underlies the worm gear, looks like a worm, hence the name.

Motor gear - This is an aggregate consisting of a gearbox and an electric motor that consist in one block. Worm gearbox Created In order to work as an electromechanical engine in various general-purpose machines. It is noteworthy that this type of equipment works perfectly both at constant and variable loads.

In a worm gearbox, an increase in torque and a decrease in the angular velocity of the output shaft occurs due to the energy conversion concluded in high angular velocity and low torque on the input shaft.

Errors when calculating and choosing a gearbox can lead to premature failure of it and, as a result, at best to financial losses.

Therefore, the work on calculating and selecting the gearbox must be trusted with experienced designers specialists who will take into account all the factors from the location of the gearbox in space and working conditions to the heating temperature during operation. Confirming this by the corresponding calculations, the specialist will ensure the selection of the optimal gearbox under your specific drive.

Practice shows that the properly selected gearbox provides for no less than 7 years - for worm and 10-15 years old for cylindrical gearboxes.

The choice of any gearbox is carried out in three stages:

1. Choosing a gearbox type

2. Select the size of the gap (sizes) of the gearbox and its characteristics.

3. Check payments

1. Choosing a gearbox type

1.1 Original data:

The kinematic drive diagram indicating all the mechanisms connected to the gearbox, their spatial location relative to each other with the place of attachment and installation methods of the gearbox.

1.2 Determination of the location of the axes of the shafts of the gearbox in space.

Cylindrical gearboxes:

The axis of the input and output shaft of the gearbox is parallel to each other and lie only in one horizontal plane - a horizontal cylindrical gearbox.

The axis of the input and output shaft of the gearbox is parallel to each other and lie only in one vertical plane - a vertical cylindrical gearbox.

The axis of the input and output shaft of the gearbox may be in any spatial position. At the same time, these axes lie on one straight line (coincide) - a coaxial cylindrical or planetary gearbox.

Conid-cylindrical gearboxes:

The axis of the input and output shaft of the gearbox is perpendicular to each other and lie only in one horizontal plane.

Worm gearboxes:

The axis of the input and output shaft of the gearbox can be in any spatial position, while they cross at an angle of 90 degrees to each other and do not lie in the same plane - a single-stage worm gearbox.

The axis of the input and output shaft of the gearbox can be in any spatial position, while they are parallel to each other and do not lie in the same plane, or they are crossped at an angle of 90 degrees to each other and are not lying in the same plane - two-stage gearbox.

1.3 Determination of the method of fastening, assembling position and optional of the gearbox.

The method of fastening the gearbox and the mounting position (fastening on the foundation or the driven shaft of the drive mechanism) is determined by the specifications given in the catalog for each gearbox individually.

The assembly option is determined by the schemes in the catalog. The schemes of "assembly options" are given in the "Designation of Reducers" section.

1.4 In addition, when choosing a type of gearbox, the following factors can be taken into account

1) noise level

the lowest - worm gearboxes
the highest - in cylindrical and conical gearboxes

2) Efficiency coefficient

the highest - in planetary and single-stage cylindrical gearboxes
the lowest - worm, especially two-stage

Worm gearboxes are preferably used in re-short-term operating modes

3) Material intensity for the same torque values \u200b\u200bon a low-speed shaft

the lowest is the planetary single-stage

4) Dimensions with identical gear ratios and torque:

the largest axial - in coaxial and planetary
the greatest in the direction of perpendicular axes - at cylindrical
the smallest radials to the planetary.

5) Relative value of rub / (nm) for the same interlineal distances:

the highest - conical
the lowest is the planetary

2. Selection of dimensions (sizes) of the gearbox and its characteristics

2.1. Initial data

The kinematic drive diagram containing the following data:

view of the drive machine (engine);
required torque on the output shaft T Rem, NHM, or the power of the motor installation r, kW;
rotation frequency of the input shaft of the gearbox N Bh, rpm;
frequency of rotation of the output shaft of the gearbox n out, rpm;
the nature of the load (uniform or uneven, reversible or non-observative, the presence and magnitude of overloads, the presence of jolts, shocks, vibrations);
required duration of operation of the gearbox in the clock;
average daily work in the clock;
the number of inclusions per hour;
duration of inclusions with a load, PV%;
environmental conditions (temperature, heat removal conditions);
duration of inclusions under load;
radial console load applied in the middle of the landing part of the ends of the output shaft F out and the input shaft F BX;

2.2. When choosing a gabarit of the gearbox, the following parameters calculate:

1) gear ratio

U \u003d n q / n out (1)

The most economical is the operation of the gearbox at a speed of rotation at the entrance of less than 1500 rpm, and in order to more prolonged the reduction of the gearbox, it is recommended to apply the frequency of rotation of the input shaft less than 900 rpm.

The gear ratio is rounded to the desired side to the nearest number according to the table 1.

The table selects the types of gearboxes of satisfying the specified gear ratio.

2) Calculated torque on the output shaft of the gearbox

T q \u003d T Cre x to dignity, (2)

T Rem - the required torque on the output shaft, NHM (source data, or formula 3)

To the dir - the coefficient of operation

With a well-known motor installation power:

T Ref \u003d (p require x U x 9550 x efficiency) / n Vx, (3)

R Reb - Motor Installation Power, kW

n VK - the frequency of rotation of the gearbox input shaft (provided that the motor installation shaft is directly without additional transmission transmits rotation to the input shaft of the gearbox), rpm

U is the gear ratio of the gearbox, formula 1

Efficiency - the efficiency of the reducer

The operating factor is defined as a product of coefficients:

For gear gearboxes:

By dir \u003d to 1 x to 2 x to 3 x to PV X to the roar (4)

For worm gearboxes:

By dir \u003d k 1 x to 2 x to 3 x to PV X to the roar to h (5)

K 1 - Type factor and motor installation characteristics, Table 2

K 2 - Duration Coefficient Table 3

K 3 - ratio of the number of starts Table 4

To PV - Duration Coefficient Table 5

To the roar - the coefficient of reversibility, with non-observe work to the roar \u003d 1.0 with a reversing work to the roar \u003d 0.75

To h - coefficient, taking into account the location of a worm pair in space. When the worm is located under the wheel to h \u003d 1.0, when arranged above the wheel to h \u003d 1.2. When the worm is located on the side of the wheel to h \u003d 1.1.

3) Calculated Radial Cantilever Load on the Output Shaft Gearbox

F out .Rech \u003d F out to dir, (6)

F out - radial console load applied in the middle of the landing part of the end of the output shaft (source data), n

By dir - the coefficient of operation mode (formula 4.5)

3. The parameters of the selected gearbox must satisfy the following conditions:

1) T nom\u003e t calc, (7)

Nom - nominal torque on the output shaft of the gearbox, cited in this catalog in the specifications for each gearbox, NHM

T Settletry torque at the output shaft of the gearbox (Formula 2), NHM

2) F Nome\u003e F out. (8)

F Nom - nominal console load in the middle of the landing part of the ends of the output shaft of the gearbox, driven in the technical characteristics for each gearbox, N.

F out. Honor - calculated radial console load on the output shaft of the gearbox (formula 6), N.

3) R wh.< Р терм х К т, (9)

P ВХ.Sch - estimated power of the electric motor (Formula 10), kW

P TERM - thermal power, the value of which is given in the technical characteristics of the gearbox, kW

K T - temperature coefficient, the meanings of which are shown in Table 6

The calculated power of the electric motor is determined by:

P ВХ.Schch \u003d (t no x n) / (9550 x KPD), (10)

T Ot - the estimated torque on the output shaft of the gearbox (Formula 2), NHM

n out - the frequency of rotation of the output shaft of the gearbox, rpm

Efficiency - efficiency ratio of the gearbox,

A) for cylindrical gearboxes:

single-stage - 0.99
two-stage - 0.98
three-speed - 0.97
four-stage - 0.95

B) for conical gearboxes:

single-stage - 0.98
two-stage - 0.97

C) for conedic-cylindrical gearboxes - as a product of the values \u200b\u200bof the conical and cylindrical parts of the gearbox.

D) For worm gearboxes of efficiency, driven in specifications for each gearbox for each gear ratio.

Buy the worm gearbox, find out the cost of the gearbox, correctly select the necessary components and help with questions arising during operation, the managers of our company will help you.

Table 1

table 2

Leading machine	Generators, elevators, centrifugal compressors, uniformly loaded conveyors, liquid mixers, centrifugal pumps, gear, screw, booms, blowers, fans, filtering devices.	Water treatment facilities, unevenly downloadable conveyors, winches, cable drums, running, swivel, lifting cranes, concrete mixers, furnaces, transmission shafts, cutters, crushers, mills, equipment for the oil industry.	Punching presses, vibration devices, sawmills, rumble, single-cylinder compressors.	Equipment for the production of rubber products and plastics, mixing machines and equipment for shaped rolled products.
Electric motor steam turbine
4, 6-cylinder internal combustion engines, hydraulic and pneumatic engines
1st, 2, 3-cylinder internal combustion engines

Table 3.

Table 4.

Table 5.

Table 6.

cooling	Ambient temperature, with about	Duration of inclusion, PV%.
cooling	Ambient temperature, with about
Reducer without strange cooling.




Reducer with water cooling spiral.