RU2607008C2 - Hydraulic coupling - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to machine building, and specifically to hydraulic couplings. In hydraulic coupling energy is transferred by fluid, which passes through turbine, moving inside turbine wheel blades, made in form of rounded channel passage.

EFFECT: enabling higher efficiency at machine acceleration.

1 cl, 3 dwg

Description

The claimed invention relates to mechanical engineering and, in particular, to devices for transmitting rotation. The essence of the invention: in fluid coupling (hereinafter referred to as “GM”), energy is transmitted by a fluid that passes through a turbine, moving inside the turbine wheel blades made in the form of a rounded channel-channel and being in force with them, existing and scientifically proven, for example: a textbook "Hydraulics, hydraulic machines and hydraulic drives" edited by T.M. The towers. M., ed. "Mechanical Engineering", 1970, §1.47. "Forces of the action of the flow on the channel walls" - p. 167 and example 15 - p. 168.

From the scientific and technical literature, for example: [1 ... 3] there are known devices for transmitting rotation - hydrodynamic couplings (hereinafter referred to as hydraulic couplings), the main components of which are: a housing, pump and turbine wheels placed in it with hydrodynamic profiles mounted on them - flat shoulder blades.

The disadvantages when using the PM as a commercial product for the transmission of the machine are:

- the PM torque decreases depending on the i-ratio of the rotational speeds of the driven and drive shafts, which reduces the acceleration rate of the machine;

- The efficiency of the paper machine depends on i, which limits the range of its high values.

As a prototype, the selected model [4] of the GPP-500MA model (hereinafter referred to as PP) manufactured by NPK Gidrotransmash LLC, Ukraine, Donetsk. The objective of the invention is:

- eliminate the dependence of the torque of the GM from i;

- eliminate the dependence of the efficiency of the GM from i.

The technical result that can be obtained by the implementation and use of GM as a marketable product for the transmission of a machine is:

- independence of the GM torque from i, i.e. its constancy, which increases the intensity of acceleration of the car;

- independence of the efficiency of the GM from i, which expands the range of its high values in the acceleration mode of the machine.

The result is achieved by the fact that the fluid coupling contains a housing, the pump and turbine wheels placed in it with blades fixed on them, characterized in that the turbine wheel blades are made in the form of a rounded channel channel (hereinafter referred to as blades).

General information

A significant difference in the characteristics, respectively, and the operational properties of the oil and gas and lubricants is determined by the fundamental difference in the features of the working processes occurring in the oil and gas.

During the rotation of the pump impeller, a fluid flows through a turbine wheel in a continuous flow, flowing from a turbine wheel to a discharge line (entrance to the impeller) to a discharge line (exit from the impeller) through a turbine wheel blades and being in force interaction with them, and returns to the entrance of the impeller.

In a GM, when a turbine is fed into a pressure chamber, for example, by a centrifugal pump from a tank, a liquid (does not have to be one infinite and continuous ring link) passes from the supply line (entrance to the turbine wheel) to the discharge line (exit from the turbine wheel) in a continuous flow moving inside the blades of the turbine wheel and being in force interaction with them, it returns to the tank from the drain cavity of the turbine. At the same time, a torque M _{gm is} formed on the GM turbine, which is determined by the formula:

P is the force of action of the flow on the channel walls of the turbine blade of the GM turbine;

R is the distance between the axis of rotation of the GM and the vector P;

z is the number of blades.

The feature of the workflow determines the characteristic properties, parameters and characteristics of the GM:

- GM does not have self-regulation, i.e. M _gm does not depend on the i-ratio of the speed of rotation of the driven shaft n _gm to the speed of rotation of the drive shaft n _d ;

- the efficiency of the GM ϕ does not depend on i;

- M _gm = f (n _d ) and is proportional to n _d ² ;

- n _gm = f (n _d ) and is directly proportional to n _d ;

- ϕ is similar to the efficiency of a centrifugal pump GM ϕ _n and ϕ = f (ϕ _n );

- M _gm = f (n _gm ) and are inversely related.

Description of the device and operation

In FIG. 1 shows a structural diagram of a GM in which, in order to reduce energy losses, the pump and turbine are coaxially and extremely close to each other in the housing. The position of the circuit elements corresponds to the steady state operation.

GM consists of a pump, for example, a centrifugal pump (hereinafter referred to as the pump), the main elements of the flowing part of which are inlet 1, pump wheel 2 and outlet 3. The pump wheel 2 is rigidly connected to the drive shaft 4. The driven shaft 5 is rigidly connected to the housing 6 a turbine, which also includes a turbine wheel rigidly connected to the casing 6, the main elements of which are the disk 7 and the blades 8 with channels rigidly connected to it (see sections B-B and B-C).

GM works as follows.

After starting the engine, the pump, driven by the engine torque M _d with the number of revolutions n _d , delivers a fluid with capacity Q and pressure N from the inlet 1 through the outlet 3 through the channels of the blades 8 to the inlet 1. In this case, a P occurs at each blade the design of the blade in the form of a branch with an angle of rotation of 180 ° is determined by the formula:

ρ is the fluid density;

V is the average fluid velocity in the channel;

F is the cross-sectional area of the channel.

Characteristic features of GM parameters and characteristics

The characteristic features of the parameters and characteristics of the GM determines their relationship. The relationship between the parameters of the GM is carried out through the parameters of the flow of the working fluid (neglecting friction in the bearings).

In determining the relationship, the following assumptions are made:

- the movement of fluid in the GM has a turbulent mode;

- mechanical, volumetric losses, disk friction and friction against air are negligible;

- hydraulic losses in the channels do not depend on the speed of rotation of the blades relative to the axis of rotation of the GM.

We substitute expressions (2), (3) in (1) and, omitting the intermediate transformations, we obtain:

Since, according to the theory of similarity of vane pumps, Q is directly proportional to n _d , then from (4) it follows: M _gm = f (n _d ) and proportional to n _d ² .

In the steady state, energy is transferred per unit time - the transmitted power N _{gm is} equal to:

Define n _um using (5):

From the power balance:

N _n - energy transmitted to the liquid by the pump wheel 2 per unit time;

N _p - energy loss per unit time when the fluid moves along the channels of the blades;

γ is the volumetric weight of the liquid;

h _p - pressure loss in the channel of the scapula.

The balance of energy (pressure) of the fluid flow between the sections at the inlet and outlet of the channel in the blade according to the Bernoulli equation is equal to:

p _I - pressure at the entrance to the channel;

p _o - pressure at the outlet of the channel;

N _np - the required pressure;

N is the force with which the wall of the channel of the scapula acts on the liquid;

ξ is the resistance coefficient;

g is the acceleration of gravity;

ξ _in , ξ _out , ξ _from are the resistance coefficients of the channel input, output, and rotation, respectively;

λ is the coefficient of friction losses;

l is the channel length;

d is the diameter of the channel.

With steady fluid movement:

We substitute expressions (7), (8), (9), (10), (11), (12), (15), (16), (2), (3), (4) and (6) and Omitting the intermediate transformations, we obtain:

Since, according to the theory of similarity of vane pumps, Q is directly proportional to n _d , then from (17) it follows: n _gm = f (n _d ) and directly proportional to n _d .

Define ϕ:

N _d - engine power;

The relationship between bulk density and fluid density:

We substitute expressions (5), (4), (17), (19), (8), (15), (11), (10), (12), (16), (2) in (18), (3), (13), (3), (20) and, omitting the intermediate transformations, we obtain:

Since it is assumed that ξ = const, it follows from (21) that ϕ is similar to ϕ _n and ϕ = f (ϕ _n ).

We define R from (4) and (17), equate the right sides of the equations and, omitting the intermediate transformations, we obtain:

From (22) it follows: M _gm = f (n _gn ) and are connected inversely by a proportional relationship.

To determine H _nn = f (Q), we substitute expressions (10), (12), (16), (2), (3), (13), (3), (20) in (11) and, omitting the intermediate transformations, we get:

The ability to achieve the claimed technical result

GM ensures the achievement of the claimed technical result, which confirms the comparison, for example: the acceleration mode of two cars equipped with engines [5] of the model 740.74-420 (hereinafter referred to as DC): maximum net power N _d = 309 N * m (420 hp ), the maximum useful torque M _dm = 1864 N * m, the crankshaft rotation speed corresponding to the maximum torque n _dm = 1300 rpm, the nominal crankshaft speed n _day = 1900 rpm. In this case, the transmission of one car (machine No. 1) includes GM, and the transmission of the second (machine No. 2) includes software.

Accept the conditions of the acceleration mode:

- the acceleration of cars begins under the influence of moments:

M _PGM - starting torque of the GM;

M _pgdm - starting moment of the paperwork;

after unlocking their drive wheels upon reaching the established work of the recreation center with a crankshaft speed of n _dm ;

- acceleration is completed when the speed of rotation of the driven shafts of the couplings is equal to the speed n _ngm - the nominal speed of rotation of the driven shaft of the GM.

To perform the calculations, the characteristic of the pump GM Н = f (Q) and the dependence of the required pressure Н _нп = f (Q) are required.

Figuratively, the GM represents a centrifugal pump equipped with a bypass, the casing of which is simultaneously the casing of the GM turbine and is not connected with the foundation: the bypass function is performed by the GM turbine wheel combined with the pump casing, the disk of which separates the pump inlet and outlet cavities, and the blades connect them. Therefore, for H = f (Q), due to its absence, we take the characteristic of the analogue (see Fig. 2).

The centrifugal pump manufactured by OAO LMS Hydraulic Hydrometeorological and Hydromechanical Plant, grade 1D630-125, was selected as an analogue: feed Q _a = 630 m ³ / h, head N _a = 127 m, shaft power N _a = 291 kW, shaft rotation speed n _a = 1450 r / min, the highest efficiency ϕ _a = 75%, the diameter of the impeller D _a = 590 mm (according to the factory catalog).

In order to coordinate the work of the DC in the mode with M _dm and the work of the GM with the highest ϕ (ϕ _n -ϕ _a = 75%) and the condition: Q * γ * N / ϕ _a ≤M _dm * n _dm = 254 kW, rebuild H = f (Q) and N _a = f (Q) according to the formulas of the theory of similarity of vane pumps for rotation speed n _a = 1300 rpm and determine the characteristic point A with the parameters: Q _A = 628 m ³ / h and N _A = 98 m (see Fig. 2).

To perform subsequent calculations of FIG. 2 is supplemented by graphs ϕ _a = f (Q), ϕ = f (ϕ _a ) and a graph Н _нп = f (Q), constructed on the basis of coordinates A, i.e. H _np = (H _A / Q _A ² ) * Q ² .

Given that N _nn = N _And with n _a = n _d = n _dm from (23) we determine F:

When calculating F, we take: z = 10 pcs., Ξ = 0.72 (the value is provided constructively and technologically, including by performing the input and output sections of the channel in the form, respectively, of a confuser and a diffuser).

From (4), taking into account (24), we determine R:

R = M _dm * F * z / (2 * ρ * Q _A ² ) = 0.2635 m.

From (17) we determine n _NGM :

n _ngm = Q _A / (F * z * R) = 735 rpm.

To fulfill (24), we assume that the PP is slightly modified and the parameters of the modified PP (hereinafter _referred to as the test - PD) are: rated torque M _npd = 852 N * m, starting torque M _efficiency = M _pgdm = M _dm = 1864 N * m , nominal revolutions of the drive shaft n _npd = 1300 rpm, the ratio of stopping torque (when sliding 100%) to the nominal - 2.19 ... 2.4 and the nominal slip S _fr - not more than 3%.

In FIG. Figure 3 shows graphs of the characteristics of GM and PD: M _gm = f (n _gm ), ϕ = f (n _gm ), M _pd = f (n _pd ) and ϕ _pd = f (n _pd ), where M _pd and n _pd - accordingly, the torque on the driven shaft of the PD and its rotation speed, ϕ _pd - the efficiency of the PD.

The graph M _gm = f (n _gm ) is plotted at the point with coordinates: M _gm = M _pdm for n _gm = 0 and the second point with coordinates: M _gm = M _pdm for n _gm = n _ngm , because from (4) it follows that M _gm = const, since Q = const for n _d = const.

The graph ϕ = f (n _gm ) is obtained by rebuilding (see Fig. 2) the graph ϕ _a = f (Q) taking into account Q = f (n _d ), n _gm = f (n _d ) and (21).

It is known [1, p. 294] that the moment characteristics of a paper machine, as a rule, have the form of falling curves and, in operational calculations, the characteristics obtained empirically are used.

Due to the lack of experimental characteristics of the PD, the schedule M _pd = f (n _pd ) is constructed at a point with coordinates: M _pd = M _ppd at n _pd = 0 and a second point with coordinates: M _pd = M _npd at n _pd = n _npd * 0, 97 = 1261 rpm (taking into account S _pd = 3%).

The graph ϕ _pd = f (n _pd ) is constructed according to [1, p. 295].

From the graphs (see Fig. 3) it follows that when accelerating cars in the range of revolutions n _gm and n _pd from zero to n _ngm :

- PD torque decreases, and the GM torque is constant;

- The efficiency of the GM in the range of high values exceeds the efficiency of the PD.

Thus, the GM ensures the achievement of the claimed technical result:

- GM torque does not depend on i, i.e. constant, which increases the acceleration rate of the machine;

- The efficiency of the GM is independent of i, which expands the range of its high values in the acceleration mode of the machine.

Information sources

1. Hydraulics, hydraulic machines and hydraulic drives / edited by T.М. The towers. M., "Engineering", 1970 (p. 291 ... 323).

2. Torque converters / А.N. Narbut. M., "Engineering", 1966 (p. 6).

3. Stesin S.P., Yakovenko E.A. Hydromechanical gears. M .. "Engineering", 1973, (p. 28 ... 92).

4. Characteristics of the hydraulic clutch GPP-500MA.

5. Characteristics of the engine model 740.74-420.

Claims (1)

A fluid coupling comprising a housing, pump and turbine wheels located therein with blades fixed on them, characterized in that the turbine wheel blades are made in the form of a rounded channel channel.

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